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3 Sources of Knowledge: Rationalism, Empiricism, and the Kantian Synthesis

K. S. Sangeetha

Chapter Learning Outcomes

Upon completion of this chapter, readers will be able to:


We all have many things going on in our minds, such as beliefs, desires, hopes, dreams, imaginary figures, knowledge, love, and hatred—to name a handful. Have you ever considered their source? How do they come to be part of the thinking process? How do they become ideas in our minds? Some philosophers attribute the source of our ideas to the senses, including the inward senses (such as emotions) and the five outward senses (sight, smell, hearing, taste, and touch). We might sense the world directly or indirectly through the thoughts of others. Some philosophers even claim that all our ideas must come from our senses. This claim holds that each of us is born with a mind that is like a tabula rasa (Latin for a “blank slate” or “blank tablet”) on which nothing is written and to which we add contents through experience as we become exposed to the world. Knowledge that is dependent on experience, or which arises after experience, is called a posteriori (Latin for “from the latter”). Since a posteriori knowledge is empirical (based on observation or experience), this view is called empiricism .

Opposed to empiricism is rationalism , the view that reason is the primary source of knowledge. Rationalists promote mathematical or logical knowledge as paradigm examples. Such knowledge can be grasped, they claim, through reason alone, without involving the senses directly. They argue that knowledge accessed through reasoning is eternal (i.e., it exists unchanged throughout the past, present, and future). For instance, two plus three remains five. Rationalists are impressed by the certainty and clarity of knowledge that reasoning provides, and they argue that this method should be applied to gaining knowledge of the world also. The evidence of the senses should be in conformity with the truths of reason, but it is not a prerequisite for the acquisition of these truths.

Knowledge that is independent of (or prior to) observation and experience is called a priori (Latin for “from the former”). Rationalists maintain that reason is the basis of a priori knowledge . But where do we ultimately get the ideas on which reason is based, if not from observation or experience? Rationalists tend to favor innatism , the belief that we are born with certain ideas already in our minds. That is, they are “innate” in us. Potential examples include mathematical or logical principles, moral sense, and the concept of God. While innatists claim that such ideas are present in us from birth, this does not guarantee our immediate awareness of their presence. Reason is the faculty that enables us to realize or access them. In what follows, innate ideas thus serve as the foundation of a model for rationalism. [1]

Rationalism’s Emphasis on A Priori Knowledge

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French philosopher René Descartes (1596–1650) and German philosopher Gottfried Wilhelm Leibniz (1646–1716), two important rationalist thinkers, support the existence of innate ideas and their realization through reason. They argue that the truths revealed by such ideas are eternal, necessary, and universal.

For Descartes, there are different modes through which we acquire knowledge: some ideas are innate, some are externally sourced, and others are constructed by us. Descartes gives the example of the idea of God as innate in us, as well as the idea of one’s own existence ([1641] 1985, Third Meditation). According to Descartes, innate ideas like truths of geometry and laws of logic are known through reason independently of experience, because experience gives us only particular instances from which the mind discovers the universal ideas contained in them. Therefore, they are a priori . Descartes’s innate ideas have been compared to the stored information in a book. The ideas are in us, though not always present to the mind. Once we start reading the book, the contents reveal themselves to us, just as reasoning reveals our innate ideas to us. In other words, it is only through careful “reading” (thinking) that we come to understand which ideas are innate and which come to us from elsewhere.

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Leibniz  calls innate ideas “principles.” Like Descartes, Leibniz maintains that principles are accessed by reason. The universal nature of mathematical truths, for example, is not revealed by the senses. It is the faculty of reason that acquires universal truths from individual instances. Leibniz argues that a collection of instances based on the senses cannot lead us to necessary truths. At the same time, it is also clear that we can grasp many necessary truths, such as mathematics. Therefore, the mind is the source, which means these truths are there innately. However, innate ideas are not full-fledged thoughts for Leibniz: he holds that our minds are structured so that certain ideas or principles will occur to us once prompted by the senses, although they are not derived from the senses. Ideas and truths are innate in us initially as dispositions or tendencies rather than as actual conscious thoughts ([1705] 2017, Preface).

Opposing A Priori Knowledge by Rejecting Innate Ideas

The empiricist claim that all our knowledge comes from experience is in stark contrast to the concept of innate ideas. For empiricists, all knowledge is a posteriori , meaning acquired through or after experience. John Locke (1632–1704), a British empiricist philosopher, adopts two approaches to question innate ideas as the basis of a priori knowledge. Firstly, he shows that innate ideas are based on dubious claims; secondly, along with Scottish empiricist David Hume (1711–1776), Locke shows how empiricism is able to offer a better theory of knowledge through the a posteriori .

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Locke starts by questioning the “universal nature” of innate ideas. He opposes the claim that innate ideas are present in all of us by noting that sufficiently young children, and adults without the requisite education, lack a concept of God or knowledge of logical or mathematical principles. Therefore, it is baseless to say that innate ideas are universal. It is through experience and observation that we acquire such ideas. That is, they are a posteriori ([1690] 2017, Book I).

Here Leibniz defends the innatist view from Locke’s objection by showing how children and those without the requisite education are capable of employing logical and mathematical principles in their everyday lives without understanding what they are or being able to articulate them in words ([1705] 2017, Book I). A child, to use an example of my own, knows without any confusion that she cannot be sitting in both parents’ laps at the same time. Similarly, those without formal mathematical training could still know that two adjacent triangular cornfields separated by a fence on their longest side can make a square cornfield by removing the fence that divides them. Evidently, as Leibniz argues, general principles of logic and mathematics are innate. But this does not mean that all innate ideas are universally held. It is possible that we all have innate ideas yet some of us are unaware of them.

Locke further argues, however, that there can be nothing in the mind of which it is unaware ([1690] 2017, Book II). Having innate ideas without being aware of them is not a viable position for Locke. An idea first has to be experienced or thought. How else could it be “in” the mind? On this point Leibniz disagrees with Locke: it is possible to have a plethora of ideas in our minds without being aware of them ([1705] 2017, Preface). For instance, suppose you absorb a “tune” playing in the marketplace without being consciously aware of it. The tune is not readily accessible or transparent to your mind, in that you cannot recall it; however, it may be recognizable upon hearing it again. So, it must have been “in” you somewhere in some sense. Similarly, an innate idea could be in your mind, without you yet being aware of it. We are born with the facility to realize innate ideas when favorable conditions obtain later in life, such as the ideas of beauty, justice, and mathematical truths.

Locke’s reply is that the realization of ideas or capacities in the right circumstances is applicable to all ideas—not just those which are purportedly innate ([1690] 2017, Book I). He challenges innatists to produce a criterion to distinguish innate from non-innate ideas. Leibniz responds with such a criterion: innate ideas are necessary (they must be true, cannot be false), whereas non-innate ideas are merely contingent (possibly true, possibly false). We can distinguish truths that are necessary (and therefore eternal on Leibniz’s view) from contingent truths dependent on varying matters of fact ([1705] 2017, Preface).

Empiricism’s Emphasis on A Posteriori Knowledge

Locke claims to show how the mind, which is like a tabula rasa at birth, acquires knowledge. For empiricists, experience alone furnishes our mind with simple ideas , which are the basic elements of knowledge. Once shown that all ideas can come from experience, it would be redundant to additionally posit innate ideas. So, does a posteriori knowledge lead us to reject a priori knowledge? Let us find out.

For Locke, knowledge based on experience is easy to understand. He asks us to suppose that we have innate ideas of colors and that we can also see colors with our eyes. In this case, since we don’t need to rely upon both, we go with our senses, because it is easier and simpler to understand knowledge derived from sense experience than from knowledge derived from some source of which we are unaware ([1690] 2017, Book I, Chapter ii, Para. 1). Here Locke applies the principle of Ockham’s razor , which suggests that as far as possible we should adopt simple explanations rather than complicated ones. [2] Simple explanations have the advantage of being less prone to error and more friendly to testing than complicated ones that do not add explanatory value.

The next question is whether a posteriori knowledge alone gives us adequate knowledge of the world. Let us take an instance of experiencing and thereby knowing a flower, such as a rose. As we experience the rose, its particular color, texture, and fragrance are the ideas through which we become aware of the object. But when we are not experiencing or sensing the rose, we can still think about it. We can also recognize it the next time we see the flower and retain the belief that it is sweet smelling, beautiful to look at, and soft to the touch. This shows that, in addition to sensing, the ability to form concepts about the objects we encounter is crucial for knowing the world. Experience also makes it possible for us to imagine what we have not directly experienced, such as a mermaid ([1690] 2017, Book III, Chapter iii, Para. 19). Such imaginings are made possible because we have directly experienced different parts of this imagined object separately. Conjoining these experiences in the mind in an ordered manner yields the imagined object ([1690] 2017, Book II, Chapter iii, Para. 5). Had we not experienced and thereby formed the concepts of a fish and a woman separately before, we would not be able to imagine a mermaid at present.

These considerations lead Locke to categorize all our sense experiences into simple and complex ideas. Simple ideas are basic and indivisible, such as the idea of red. Complex ideas are formed by the mind, either from more than one simple idea or from complex impressions ([1690] 2017, Book II, Chapters ii & xii). Complex ideas are divisible because they have parts. Examples include golden streets, an army, and the universe. My idea or concept of an object, whether simple or complex, can be ultimately traced back to its corresponding sense impressions.

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Hume, another important empiricist philosopher, writes of ideas as the “copies” of “impressions.” Impressions are “vivid” and “lively” as received directly from sense experience. Hume also allows inward impressions, including jealousy, indignation, and so on. Ideas are mental copies of inward or outward impressions, rendering them “faint” or “feeble” (try comparing a perceptual experience with recalling it from memory) ([1748] 2017, Sections 1 & 2). Hume argues that where there are no impressions, there can be no ideas. A blind man can have no notion of color, according to Hume. One cannot be born with ideas that are not derived from any impressions. So, there are no innate ideas for Hume. However, he agrees that our tendencies to avoid pain, or to seek many of our passions and desires, are innate. Here I would argue that even these tendencies are based on our sense impressions and the corresponding ideas we form from those impressions. The mental inclination to repeatedly seek pleasure or avoid pain comes to us only after the first incident of exposure to either sensation.

In contrast to Descartes, even the idea of God falls under the a posteriori for Hume. Since none of us has experienced God directly, Hume argues, there is no impression of God available to us from which to form the corresponding idea. In Hume’s view, our imagination forms this idea by lavishly extending our experience of the good qualities possessed by people around us ([1748] 2017, Sections 1 & 11). Given that even the idea of God can be derived from sense impressions, this lends further support to the empiricist claim that all our ideas are a posteriori . Therefore, according to Hume, the rationalist claims for the existence of innate ideas and a priori knowledge are mistaken.

The Inadequacy of the Tabula Rasa Theory

A weakness of the empiricist’s tabula rasa theory can be exposed if we can show that not all our ideas are derived from corresponding impressions. However, this would not mean we must return to the rationalist’s theory of innate ideas, as we shall see. The plan is to explore a third alternative.

The presence of general concepts in our minds shows there is not always a one-to-one relation between ideas and corresponding sense impressions. For example, we see different instances of the color blue around us, and from these instances we form a general concept of blue. This general concept is not copied from one particular impression of blue, nor even from a particular shade of blue. We also have abstract concepts (such as justice, kindness, and courage), which are not traceable to corresponding sense impressions. In such cases, we experience different acts or instances of justice, kindness, and courage. But if these abstract concepts are copied from their particular impressions, then only these instances—and not the concepts themselves—would be in our minds. It follows that concepts are formed or understood rather than copied . Similarly, relational concepts (such as “on”-ness, betweenness, sameness, and the like) are realized not by copying the impressions involved. In fact, there are no impressions at all corresponding to these relational concepts. We instead receive impressions of particulars standing in such relations—the cat sitting on the mat, the English Channel flowing between the United Kingdom and Europe, one minus one equaling zero, and so forth.

In sum, the formation of general, abstract, and relational concepts in our minds shows that an uninterrupted flow of impressions would not constitute all the ideas we have. Instead, it requires that from birth the mind is at least partially equipped with a structure or architecture that enables it to make sense of the raw impressions it receives and to form concepts where there is no one-to-one correspondence between impressions and ideas. It challenges the authenticity of a tabula rasa . This takes us to a stage where we need to figure out the indispensable third alternative, which can facilitate a more complete knowledge of the world. This necessitates a crossover between the a priori and the a posteriori , or a reconciliation of the two.

Percepts-Concepts Combination

The immediacy and direct nature of sensations, impressions, and perceptions make them certain. [3] Let us briefly unpack this idea. Consider whether we can ever be wrong about our sensations. It is commonly thought that while we can be wrong about what the world is like, we cannot be wrong about the fact that we are having particular sensations. Even if you are dreaming this very second, and there is no actual book before your eyes, you cannot deny that you are having certain sensations resembling a white page and black font in the shape of words. Therefore, our sensations are certain and we cannot doubt that they exist. However, it is possible that sometimes we are unsure how to characterize a particular sensation. For instance, you may see a flashy car and be unsure whether the color is metallic green or gray. So, you might get into confusion in describing your sensation, but that does not affect the certainty and indubitability of the sensation itself, of what is here and now for you.

German philosopher Immanuel Kant (1724–1804) argues that for our perceptions to make sense to us, they should be received into concepts that exist within our minds.These structures of understanding allow our minds to process the impressions that we experience. Unless the manifold raw sensations we receive from experience are classified into different categories of understanding, we cannot make sense of them.

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For instance, the mind should have the ability to recognize whether two sensations are similar or different, to say the least. Without this ability, we cannot make sense of experience. Or consider that we also perceive that objects are in space and time, stand in cause-effect relations, and belong to the categories of unity-plurality, assertion-negation, particular-universal, and the like. Here again, we are incapable of understanding any experience that is not processed through these categories. Kant argues, therefore, that space, time, causation, quantity, quality, and the like are represented to us in innate structures or concepts that our minds are fitted with prior to experience.

According to Kant, these categories are transcendental in the sense that they bridge the gap between mind and world. They are hidden structures, bridges, or concepts that occupy the otherwise blank slate and mold our way of thinking and experiencing the world. Of course, these concepts also require inputs, or percepts (the immediate objects of awareness delivered directly to us in perceptual experience through the senses). As Kant’s view is famously expressed, “Percepts without concepts are blind and concepts without percepts are empty” ([1781] 1998, 209).

So far, we have seen through various stages that rationalism and empiricism are incomplete. Kant’s transcendental idealism (as his view is called) strikes a balance, reconciling the two accounts. He combines sensory input and inborn concepts into a unified account of how we understand the world. Before we conclude the chapter with the final step in Kant’s approach, let us return to Descartes and Hume once again, the two philosophers who most influenced Kant.

Synthetic A Priori Knowledge

Descartes thinks that reason alone can provide certainty to all human knowledge. Intuition and deduction are tools through which the faculty of reason operates. Intuition is the capacity to look inward and comprehend intellectual objects and basic truths. Being a geometrician, Descartes thinks that deduction (the type of reasoning whereby the truth of the conclusion is guaranteed by the truth of the premises) should be used for gaining knowledge of the world, starting with the input of “clear and distinct” ideas. [4] Since intuition is dissociated from the evidence of the senses, the truths it unfurls can be known a priori . The result is that substantial knowledge of the world can be acquired a priori ([1701] 1985).

According to Hume, there are two ways in which reasoning aims to gain knowledge of the world: through “relations of ideas” and through “matters of fact” ([1748] 2017, Section 4). Hume thinks that the method of deduction establishes relations between the ideas we have already acquired through experience (e.g., that a mother is a woman parent). These relations of ideas are the kind of truths that we find in logic and mathematics (for instance, the proposition that a circle is round). They are true by definition. Such truths are necessary or certain (their denials lead to contradiction). They are also known a priori , since they do not rely on how the world is. For this reason, relations of ideas and deduction do not yield substantive new knowledge of the world; the knowledge they impart is already understood by us (as the above examples show), even if our understanding is merely implicit within the premises of a deductive argument whose conclusion makes it explicit.

Matters of fact , for Hume, are based on observation and experience. Some of them are generalizations arrived at by induction from particular instances. Inductive truths are uncertain. They are at best probable , since they are dependent on how the world is. For instance, we have the experience of heat from fire so far; but we cannot be certain that this will be the case tomorrow also (maybe we will unexpectedly feel some other sensation like cold from fire). We expect that the future will resemble the past, but we cannot be certain about it. [5] Matters of fact provide us with a posteriori truths, which are contingently true (their denials can be conceived without contradiction). Since matters of fact are not true by definition, they add substantive new information to our existing knowledge, unlike relations of ideas ([1748] 2017, Section 4).

A rationalist initially, Kant was influenced by the division in knowledge made by Hume. Only a combination of reason and experience can give us adequate knowledge, according to Kant. He begins by providing an account of relations of ideas, which he terms analytic truths . In sentences that express analytic truths, the predicate term is already “contained” in, or is the meaning of, the subject term. For example, in the sentence, “a circle is round,” the predicate “round” is contained in the subject, “circle.” To take another standard example, in “a bachelor is an unmarried man,” the predicate “unmarried man” is the meaning of the subject term, “bachelor.” We cannot deny such truths without contradiction. They are necessarily true, which means that they’re true regardless of how the world is. Since we do no need to examine the world to tell whether they’re true, analytic truths are knowable a priori ([1781] 1998, 146, 157). [6]

Kant terms matters of fact synthetic truths : the predicate term is neither contained within nor is the meaning of the subject term. Synthetic truths are not true by definition. As such, it stands to reason that they are based on observation, and therefore must be a posteriori (although, as we will soon see, Kant argues that this is not the case for all synthetic truths). For instance, consider the proposition, “George the bachelor is a writer.” We have new information here about a particular person named “George” being a bachelor and writer, and experience is required to find this out. Since the opposites of synthetic truths are not contradictory, they are contingent ([1781] 1998, 147, 157). [7]

Kant maintains that only synthetic truths are capable of providing substantive new information about the world. That said, our sense experiences do not passively enter our minds, but do conform to our innate mental structures to facilitate knowledge. Since these structures work independently of experience, they are a priori . These innate a priori structures of our minds—our concepts—are actively engaged in making sense of our experiences ([1781] 1998). They do so by discriminating and organizing the information received in experience. But again, the ability to perform this activity presupposes that the world which furnishes both the information and our concepts is itself structured in a way that enables intelligibility. The particular ways in which the world must be structured—its space-time and cause-effect relations, for example—yield substantive truths about reality. These truths hold not merely because of the meanings of words or the logical forms of sentences. They are synthetic. And since we arrived at this result by way of a priori reflection, Kant argues that we possess “synthetic a priori ” knowledge of the world—a previously unrecognized category of knowledge, now to be added to the standard categories of synthetic a posteriori and analytic a priori knowledge. (See Table 1 below for a summary of these categories.)

Table 1 – Categories of Knowledge
Combining the epistemological distinction ( vs. ) with the semantic/modal distinction (analytic/necessary vs. synthetic/contingent) yields four possible categories.
Epistemological Distinction: vs. Analytic/Necessary (Relations of Ideas) Synthetic/Contingent (Matters of Fact)
(Empirical) Category of knowledge: analytic
Significance: Receives minimal attention (because it is not a primary source of contention in philosophical debates).
Examples: Mathematical truths (e.g., that the ratio of a circle’s circumference to its diameter is > 3) learned by physical measurement, a calculator, or testimony from a reliable source. (Although such truths are commonly considered analytic, Kant disagreed, classifying them as synthetic instead.)
Category of knowledge: synthetic
Significance: Emphasized by empiricists.
Examples: Truths about the external world known immediately via the senses or scientific investigation.
(Rational) Category of knowledge: analytic
Significance: Emphasized by rationalists.
Examples: The deliverance of pure logic; statements that are true by definition (known by grasping their meanings).
Category of knowledge: synthetic
Significance: Controversial category posited by the Kantian synthesis. While truths in this category are contingent in the strict logical sense (their denial is not logically contradictory), Kant claimed for them a kind of metaphysical necessity (in that they hold universally and are eternal).
Kant’s candidates: Euclid’s axioms of geometry, basic features of space/time, metaphysical truths, and moral truths.

There remains the question of how our concepts discriminate and organize the information received from the senses. These goals are achieved through acts of synthesis. By “synthesis,” Kant means “the act of putting different representations [elements of cognition] together, and grasping what is manifold in them in one cognition” ([1781] 1998, 77).

Kant explains three types of synthesis: the process starts with “synthesis of apprehension in perception,” passes through “synthesis of reproduction in imagination,” and ends with “synthesis of recognition in a concept” ([1781] 1998, 228–34). For Kant, apprehension in perception involves locating an object in space and time. The synthesis of reproduction in imagination consists in connecting different elements in our minds to form an image. And synthesis of recognition in a concept requires memory of a past experience as well as recognizing its relation to present experience. By recognizing that the past and present experience both refer to the same object, we form a concept of it. To recognize something as a unified object under a concept is to attach meaning to percepts. This attachment of meaning is what Kant calls apperception (Guyer 1987).

Apperception is the point where the self and the world come together. For Kant, the possibility of apperception requires two kinds of unity. First, the various data received in experience must themselves represent a common subject, allowing the data to be combined and held together. Second, the data must be combined and held together by a unified self or what Kant calls a “unity of consciousness” or “unity of apperception.” Kant concludes that because of such unity, all of us are equally capable of making sense of the same public object in a uniform manner based on our individual, private experiences. That is, we are in an unspoken agreement regarding the mind-independent world in which we live, facilitated by our subjective experiences but regulated by the innate mental structures given to us by the world. In sum, Kant’s theory makes possible shared synthetic knowledge of objective reality. [8] In conclusion, by considering the debate between rationalists and empiricists culminating in Kant’s synthesis, this chapter has shed light on the issue of how we achieve substantive knowledge.

Box 1 – Kant’s Copernican Revolution in Epistemology

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In his Critique of Pure Reason , Kant sums up his epistemology by drawing an analogy to the Copernican Revolution (the shift in astronomy from a geocentric to a heliocentric model of the universe, named after Nicolaus Copernicus (1473–1543), the sixteenth-century Polish mathematician and astronomer):

Up to now it has been assumed that all our cognition must conform to the objects; but all attempts to find out something about them a priori through concepts that would extend our cognition have, on this presupposition, come to nothing. Hence let us once try whether we do not get farther with the problems of metaphysics by assuming that the objects must conform to our cognition, which would agree better with the requested possibility of an a priori cognition of them, which is to establish something about objects before they are given to us. This would be just like the first thoughts of Copernicus, who, when he did not make good progress in the explanation of the celestial motions if he assumed that the entire celestial host revolves around the observer, tried to see if he might not have greater success if he made the observer revolve and left the stars at rest. Now in metaphysics we can try in a similar way regarding the intuition of objects. If intuition has to conform to the constitution of the objects, then I do not see how we can know anything of them a priori; but if the object (as an object of the senses) conforms to the constitution of our faculty of intuition, then I can very well represent this possibility to myself. Yet because I cannot stop with these intuitions, if they are to become cognitions, but must refer them as representations to something as their object and determine this object through them, I can assume either that the concepts through which I bring about this determination also conform to the objects, and then I am once again in the same difficulty about how I could know anything about them a priori, or else I assume that the objects, or what is the same thing, the experience in which alone they can be cognized (as given objects) conforms to those concepts, in which case I immediately see an easier way out of the difficulty, since experience itself is a kind of cognition requiring the understanding, whose rule I have to presuppose in myself before any object is given to me, hence a priori, which rule is expressed in concepts a priori, to which all objects of experience must therefore necessarily conform, and with which they must agree. ([1781] 1998, B xvi–B xviii)

Questions for Reflection

Impression Simple/complex idea Percept Concept
Relations of ideas Matters of fact Innate
Deduction Induction

Further Reading

Blackburn, Simon. 1999. Truth : A Compelling Introduction to Philosophy . Cambridge: Cambridge University Press.

Critchley, Simon. 2001. Continental Philosophy: A Very Short Introduction . Oxford: Oxford University Press.

Ellis, Addison. 2014a. “Idealism Pt. 1: Berkeley’s Subjective Idealism.” In 1000-Word Philosophy: An Introductory Anthology . https://1000wordphilosophy.com/2014/07/07/berkeley/ .

———. 2014b. “Idealism Pt. 2: Kant’s Transcendental Idealism.” In 1000-Word Philosophy: An Introductory Anthology . https://1000wordphilosophy.com/2014/08/11/idealism-pt-2-kants-transcendental-idealism .

Plato. (ca. 380 BCE) 2009. Meno . Translated by Benjamin Jowett. The Internet Classics Archive. http://classics.mit.edu/Plato/meno.html .

Russell, Bertrand. (1912) 2013. The Problems of Philosophy . Project Gutenberg. https://www.gutenberg.org/files/5827/5827-h/5827-h.htm .

Vernon, Kenneth Blake. 2014. “The Problem of Induction.” 1000-Word Philosophy: An Introductory Anthology . https://1000wordphilosophy.com/2014/05/26/the-problem-of-induction/ .

Chomsky, Noam. 1975. Reflections on Language . New York: Random House.

Descartes, René. (1641) 1985. “Meditations on First Philosophy.” In The Philosophical Writings of Descartes , translated by John Cottingham, Robert Stoothoff, and Dugald Murdoch, 1–62. Volume 2. Cambridge: Cambridge University Press.

———. (1701) 1985. “Rules for the Direction of the Mind.” In The Philosophical Writings of Descartes , translated by John Cottingham, Robert Stoothoff, and Dugald Murdoch, 7–77. Volume 1. Cambridge: Cambridge University Press.

Guyer, Paul. 1987. Kant and the Claims of Knowledge . Cambridge: Cambridge University Press.

Hume, David. (1748) 2017. Enquiry Concerning Human Understanding. Edited by Jonathan Bennett. https://www.earlymoderntexts.com/assets/pdfs/hume1748.pdf .

Kant, Immanuel. (1781) 1998. Critique of Pure Reason . Translated by Paul Guyer and Allen Wood. New York: Cambridge University Press.

Leibniz, G. W. (1705) 2017. New Essays on Human Understanding. Edited by Jonathan Bennett. http://earlymoderntexts.com/authors/leibniz .

Locke, John. (1690) 2017. An Essay Concerning Human Understanding . Edited by Jonathan Bennett. https://www.earlymoderntexts.com/authors/locke .

Quine, W. V. 1951. “Main Trends in Recent Philosophy: Two Dogmas of Empiricism.” Philosophical Review 60 (1): 20–43.

Vernon, Kenneth Blake. 2014. “The Problem of Induction.” In 1000-Word Philosophy: An Introductory Anthology . https://1000wordphilosophy.com/2014/05/26/the-problem-of-induction/ .

A mental representation, including individual concepts (such as the concepts “fire” and “hot”) and the thoughts constructed therefrom (such as “the fire is hot”).

A Latin term meaning “blank tablet” or “blank slate.” Empiricists like John Locke argue that the human mind is like a tabula rasa at the time of birth, and that the mind acquires knowledge through sense experience and from its ability to reflect upon its own internal operations.

Knowledge that is dependent on, or gained through, sense experience. A posteriori truths are truths known after experience.

Based on observation or experience.

The philosophical position according to which all our beliefs and knowledge are based on experience. Empiricism is opposed to rationalism.

The philosophical position that regards reason, as opposed to sense experience, as the primary source of knowledge. Rationalism is opposed to empiricism.

Knowledge gained without sense experience. A priori truths are truths known prior to experience.

The philosophical position, held by many rationalists, according to which we have certain ideas in our minds from birth, ideas which can be realized through reason.

When applied to claims, statements, or propositions, the term “necessary” refers to that which must be true. In other words, it is impossible for a necessary truth to be false. For example, it is a necessary truth that a triangle has three sides, which means that it is impossible for a triangle to have any other number of sides. The opposite of necessity is contingency.

When applied to claims, statements, or propositions, the term “contingent” refers to that which is possibly true and possibly false, not necessary. For example, it is a contingent truth that crows are black, since they are black but could have been white. The claim that crows are white is a contingent falsehood, since it happens to be false but could have been true.

Ideas that contain a single element, such as a patch of brown or the idea of red. Simple ideas are basic and indivisible as opposed to complex ideas.

The methodological principle which maintains that given two competing hypotheses, the simpler hypothesis is the more probable (all else being equal). As the “razor” suggests, we should “shave off” any unnecessary elements in an explanation (“Entities should not be multiplied beyond necessity”). The principle is named after the medieval Christian philosopher/theologian William of Ockham (ca. 1285–1347). Other names for the principle include “the principle of simplicity,” “the principle of parsimony,” and “the principle of lightness” (as it is known in Indian philosophy).

An idea formed by combining multiple simple ideas or impressions. For example, the complex idea “diamond street” is formed by putting simpler ideas into relation: a street made of diamonds.

A general idea of something which allows us to recognize it as belonging to a category, distinguish it from other things, and think about it. For example, to have the concept “table” is to be able to think about tables, distinguish them from other types of furniture, and recognize tables upon encountering them.

Kant’s term for that which is presupposed in, and is necessary for, experience; something a priori that makes experience possible.

That which is immediately or directly presented to one’s awareness in perceptual experience (prior to attaching meaning or applying a concept in apperception).

Kant’s synthesis of rationalism and empiricism utilizing a transcendental bridge between the mind and the world, making possible synthetic a priori knowledge. The term “idealism,” when not preceded by “transcendental,” may refer to the theories of Berkeley or Hegel, both of which should be distinguished from Kant’s view.

The capacity to look inward to directly comprehend intellectual objects and recognize certain truths.

A form of reasoning in which the truth of the premises logically guarantees the truth of the conclusion.

One of the two divisions of human understanding made by David Hume. Relations of ideas concern matters like logic and mathematics. Relations of ideas do not depend on how the world actually is. They are known a priori . Truths generated by relations of ideas are certain (not merely probable), true by definition, and therefore impossible to contradict.

One of the two divisions of human understanding made by David Hume. Our knowledge of matters of fact comes from observation or generalization from experiences. In other words, it is a posteriori . Because such truths are contingent, they are merely probable rather than certain.

A form of reasoning in which the truth of the premises makes probable the truth of the conclusion.

A truth that holds in virtue of the meanings of the words in a sentence (and the sentence’s logical form). In an analytic sentence, the predicate term is contained in, or is the meaning of, the subject term. Therefore, analytic truths are true by definition.

A truth expressed by a sentence in which the predicate term is neither contained in, nor is the meaning of, the subject term; the predicate adds some new information about the subject. That is, synthetic truths are not true by definition; therefore, they can be denied without contradiction.

The attachment of meaning to a perceptual input based on our past and present experiences and concepts.

Sources of Knowledge: Rationalism, Empiricism, and the Kantian Synthesis by K. S. Sangeetha is licensed under a Creative Commons Attribution 4.0 International License , except where otherwise noted.

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The Oxford Handbook of Epistemology

The Oxford Handbook of Epistemology

2 The Sources of Knowledge

Robert Audi is Professor of Philosophy and David E. Gallo Chair in Ethics at the University of Notre Dame. He works in ethics and in related philosophical fields, especially epistemology. His books include Action, Intention, and Reason (1993), The Structure of Justification (1993), Moral Knowledge and Ethical Character (1997), Religious Commitment and Secular Reason (2000), The Architecture of Reason (2001), The Good in the Right: A Theory of Intuition and Intrinsic Value (2004), and Moral Value and Human Diversity (2007).

This article identifies the sources from which one acquires knowledge or justified belief. It distinguishes the “four standard basic sources”: perception, memory, consciousness, and reason. A basic source yields knowledge or justified belief without positive dependence on another source. This article distinguishes each of the above as a basic source of knowledge, with the exception of memory. Memory, while a basic source of justification, plays a preservative rather than a generative role in knowledge. This article contrasts basic sources with nonbasic sources, concentrating on testimony. After clarifying the relationship between a source and a ground, or “what it is in virtue of which one knows or justifiedly believes,” this article evaluates the basic sources' individual and collective autonomy as well as their vulnerability to defeasibility. It examines the relationship of coherence to knowledge and justification, noting the distinction between a negative dependence on incoherence and a positive dependence on coherence.

Knowledge can be adequately explicated only in relation to its sources. This is in part why perception, intuition, and other generally recognized sources of knowledge have been so extensively discussed in epistemology. These and other apparent sources of knowledge are also widely considered sources of justification, and they can serve as such even if justification is not entailed by knowledge. My concern here will be primarily with sources of knowledge; but in order to bring out their epistemological importance, I will connect these sources with justification as well. I am speaking, of course, as if we may suppose that there is knowledge. Anyone who accepts some version of skepticism may simply take what is said to apply to what would be sources of knowledge or justification if there should be any knowledge or justification of the kind in question. I begin with what might be called the standard basic sources of knowledge, proceed to distinguish them from nonbasic sources and from grounds of knowledge, and, with the account of epistemic sources then before us, turn to questions of defeasibility and completeness.

I. Basic Sources of Knowledge and Justification

If, in the history of epistemology, any sources of knowledge deserve to be called the classical basic sources, the best candidates are perception, memory, consciousness (sometimes called introspection ), and reason (sometimes called intuition ). Some writers have shortened the list under the heading, “experience and reason.” This heading is apt insofar as it suggests that there might be some unity among the first three sources and indeed some possibility of other experiential sources; it is misleading insofar as it suggests that experience plays no role in the operation of reason as a source of knowledge. Any operation of reason that is an element in consciousness may be considered a kind of intellectual experience. The reflection or other exercise of understanding required for “reason” to serve as a source of knowledge is certainly one kind of experience.

Let us first explore what it is for a source to be basic and some of the conditions under which beliefs it yields constitute knowledge (these might be called success conditions ). We can then consider what kind of source might be nonbasic and whether the four standard basic sources are the only basic ones.

I take it that a source of knowledge (or justification) is roughly something in the life of the knower—such as perception or reflection—that yields beliefs constituting knowledge. To call a source of knowledge (or of justification) basic is to say that it yields knowledge without positive dependence on the operation of some other source of knowledge (or of justification). Thus, I might perceptually know that the clock says ten by virtue of seeing its face displaying that time; and I might know by brief reflection that if two people are first cousins, they share a pair of grandparents.

It may seem that the perceptual knowledge is possible only if I remember how to read a clock and that therefore perception cannot yield knowledge independently of memory. It is true that perceptual knowledge of the kind in question depends on memory in a certain way. But consider this. A being could acquire the concepts needed for reading a clock at the very time of seeing one, and hence would not need to remember anything in order to form the belief that the clock says ten. One possibility here is the creation of a duplicate of someone like me: reading a clock would be possible at his first moment of creation. It appears, then, that although perceptual knowledge ordinarily depends in a certain way on memory, neither the concept of perception nor that of perceptual knowledge is historical . That of memory, however, is historical, at least in this sense: one cannot remember something unless one has retained it in memory over some period of time.

The concept of a basic source can be better understood through a different kind of example, one that brings out how even a basic source can yield beliefs that fail to constitute knowledge and how its success in producing knowledge may depend on what we believe through other basic sources. Suppose that I see the clock on the wall only at dusk, but still make out the hands and come to believe (correctly) that it says ten. I now turn on a bright light that shows me a system of mirrors which I remember my son has installed to deceive me in ways that amuse him. I realize that it can display a different clock with the same appearance. I now may have good reason to doubt that the clock on the wall says ten; for I realize that I would believe it did, even if I did not actually see it, but saw only the mirror image of a similar clock that does say ten. Here my would‐be perceptual knowledge that the clock says ten is defeated by my realization that I might well be deceived. That realization, in turn, depends in part on my memory of my son's antics. We have, then, a case illustrating that, even ordinarily, I would not know the clock says ten unless there were no suitably strong “opposition” from a source different from perception. This dependence of perception on factors beyond perceptual experience, however, is what I call negative dependence ; it does not show that perception is not a source of knowledge, but only that (at least) on occasion the source can be in some way blocked. 1

One may now suggest that perception is not even a positively independent source because it depends on consciousness. The idea would be that one cannot perceive without being conscious; hence, perception cannot yield knowledge apart from the operation of another source of knowledge. Let us grant for the sake of argument that perception requires consciousness. 2 If it does, that is because it is a kind of consciousness: consciousness of an external object. We might then simply grant that perception is perceptual consciousness and treat only “internal consciousness” (consciousness of what is internal to the mind) as a source of knowledge distinct from perception. Internal consciousness, understood strictly, occurs only where the object is either internal in the way images and thoughts are (roughly phenomenal) or abstract, as in the case of concepts and (presumably) numbers. On a wider interpretation, we might have internal consciousness of dispositional mental states, such as beliefs, desires, and emotions. But even when we do, it seems to be through consciousness of their manifestations that we are conscious of them, as when we are conscious of anxiety through being aware of a sense of foreboding or of felt discomfort, or of unpleasant thoughts of failure, or the like.

To be sure, one might also treat consciousness as a kind of perception: external perception where the perceived object is outside the mind, internal where that is inside. But abstract objects are not “in” the mind, at least in the way thoughts and sensations are. In any case, it is preferable not to consider consciousness of these a kind of perception. One reason for this is that there is apparently a causal relation between the object of perception and whatever sensation or other mental element constitutes a perceptual response to it, and it is at least not clear that abstract entities have causal power, or at any rate the requisite kind. 3 This issue is too large to pursue here, but it may be enough to note that not all mental phenomena seem to be either perceptual in any sense or to be directed toward abstract objects. Consider daydreaming or planning. Neither need concern the abstract, nor must we suppose that there are objects in the mind having properties in their own right. 4 It would be unwise to assume that perception exhausts the activity of consciousness.

It does appear, however, that we may take perception to be a partly causal notion. If you see, hear, touch, taste, or smell something, then it affects you in some way. And if you may be said to perceive your own heartbeat or even your own anxiety, this is owing to their causing you to have some experiential impression analogous to a sense impression you might have through the five senses. Conceived in this way, perception is not a closed concept : it leaves room for hitherto unfamiliar kinds of experiential response to count as the mental side of perceiving an object and indeed for new or unusual kinds of objects to be perceptible. 5 This is not the place, however, to give an account of exactly what perception is. Any of the basic sources could be the subject of a deservedly long study. Let us proceed to memory as an epistemic or justificational source.

If, in speaking of perception, we are talking about a capacity to perceive, in speaking of memory we are talking about a capacity to remember. But remembering does not exhaust the operation of our memorial capacity to the extent that perceiving exhausts the operation of the perceptual capacity. There is also recalling , which entails but is not entailed by remembering; there is recollecting , which is similar to recalling but tends to imply an episode of (sometimes effortful) recall, usually of a sequence or a set of details; and there are memory beliefs , which may be mistaken and do not entail either remembering or even recalling. It is plausible to maintain, however, that remembering that p (where p is some arbitrarily chosen proposition) entails knowing it; and we also speak of knowing things from memory. When we do know things (wholly) in this way, it is not on the basis of other things we know. One may know a theorem from memory and on the basis of a simple proof from an axiom, but where one knows p wholly from memory—simply by virtue of remembering it—one does not at the time know it on the basis of knowing or believing anything else.

These points make it natural to think of memory as a basic source of knowledge. But I think it would be a mistake to claim that it is one. It is an epistemically essential source ; that is, what we think of as “our knowledge,” in an overall sense, would collapse if memory did not sustain it: we could know only what we could hold in consciousness at the time (at least this is so if what we know dispositionally at a time must be conceived as held in memory at that time, even though it is true then that if we were to try to bring any one of the propositions to consciousness then, we would normally have it there then 6 ). By virtue of playing this role, memory is an epistemic source in an important sense. But surely one cannot know anything from memory without coming to know it through some other source. If we remember it and thereby know it, we knew it, and we must have come to know it through, say, perception or reasoning. 7

If memory is not a basic source of knowledge, it surely is a basic source of justification. It is not easy to capture just how it plays this role. But consider believing that one sent a certain friend a holiday card. There is a way this belief—or at least its propositional object—can present itself to one that confers some degree of justification on the belief (I think it can confer enough to allow the belief to constitute knowledge if one is correct and there is no defeater of one's would‐be knowledge, but there is no need to try to show that here). Someone might object that it is only by virtue of knowledge, though consciousness, of one's memorial images that we can be justified in such beliefs, but I very much doubt this. 8 A remembered proposition can surface in consciousness without the help of images and, often, can spontaneously surface upon the need for the proposition as an answer to a question or as a premise for an inference one sets out to make or sees to be needed.

Given the points made about memory so far, I suggest that it is an essential source of knowledge and a basic source of justification. In the former case it is preservative , retaining knowledge already gained; in the latter it may be generative , producing justification not otherwise acquired.

It is worth noting here that we may not say ‘not otherwise acquirable ’. Whatever can be known or justifiedly believed by a given person on the basis of memory can also be known or justifiedly believed in some other way, say through the testimony of someone else. This indicates another notion we need in understanding sources of justification and knowledge. A basic source of justification need not be a unique source , even relative to a single kind of justification (or knowledge).

If, however, memory is not a unique source, it remains true that the non‐memorial source that is in principle available to one may depend, for its production of genuine knowledge, on memory or on knowledge of, or justification about, the past. If testimony is the source, for instance, the person attesting to a past event depends either on his own memory or on someone else's. If so, we might think that although memory is not a unique source for primary knowledge or primary justification regarding the past—where primary knowledge and justification are the kinds that do not (evidentially) depend on the knowledge or justification of anyone else—it is a unique source for secondary knowledge or justification regarding the past , as in the case in which I rely on someone's testimony about it. Perhaps, however, at the moment of his creation my duplicate could see smoke and know, by the visible facts, that there has been a fire. If so, then simultaneous testimony from him could give others such historical knowledge without dependence, for any of them, on (the operation of) their own memory. My duplicate would, arguably, “inherit” a capacity for induction from me, and I could not have acquired that capacity without relying on my memory; but he would still not actually have to rely on his own memory to know that there has been a fire. Here, then, we could have knowledge of the past that does not require the exercise of memory by the primary knower. Even if memory is not a unique source of any kind of knowledge or justification, the concept of such a source is significant, and it will surface again shortly.

Consciousness has already been mentioned as a basic source of knowledge. It seems clear that if any kind of experience of what is going on in the world can yield knowledge, it is introspective consciousness. Even philosophers who take pains to give skepticism its due, such as David Hume, do not deny that we have knowledge—presumably noninferential knowledge—of our own current mental life. 9 Granted, it is only consciousness of the inner world—or at least of whatever can exist “in” consciousness—that is a basic source if outer perception—consciousness of the external world—is not a basic source. But the inner world is a very important realm. It might include abstract objects, such as numbers and concepts, as well as sensations, thoughts, and other mental entities.

When we come to reason, there is, as with memory, a need to clarify what aspects of this general capacity are intended. Like ‘memory’, the term ‘reason’ can designate quite different things. One is reflection, another reasoning, another understanding, and still another, intuition. We reflect on a subject, reason from a premise, understand a concept or proposition, and intuit certain truths. These are only examples, and there is overlap: any of the objects in question must be understood (adequately, though not perfectly) if it is to be an object of reason, and one may need to reflect on a truth that one intuits in order to grasp its truth.

It will help to focus on a simple example, such as the logical truth that if all human beings are vulnerable and all vulnerable beings need protection, then all human beings need protection. We can reason from the “premises” (in the if‐clause) to the “conclusion” (in the then‐clause); but an assertive use of the if‐then sentence in question need not represent giving an argument. Moreover, the proposition it expresses is not the kind that would (normally) be known by reasoning. It would normally be known by “intuition” or, in the case in which such direct apprehension of the truth does not come to a person, by reflection that indirectly yields understanding. (The conclusion —that all human beings need protection—may of course be known wholly by reasoning from the premises. One's knowledge of it then depends on one's knowledge of them, which will surely require reliance on a different basic source. But the proposition in question is the conditional one connecting the premises with the conclusion, and knowledge of it does not require knowledge of either the former or the latter.)

I suggest, then, that “reasoning” is not a good heading under which to capture the ratiocinative basic source we are considering, and that indeed if we distinguish reasoning from reflection of a kind that yields knowledge that p apart from reliance on independent premises, it is best not to use the term ‘reasoning’ in explicating this source. What seems fundamental about the source is that when knowledge of, or justification for believing, a proposition comes from it, it derives from an exercise of reason regarding the proposition. This may take no time beyond that required to understand a sentence expressing the proposition (which may be virtually none; nor need we assume that all consideration of propositions is linguistically mediated, as opposed to conceptual in some sense). Here it is natural to speak of intuiting. But the proposition may not be so easily understood, as (for some people) in the case of the proposition that if p entails q and q entails r , and either not‐ q or not‐ r is the case, then it is false that p . Here it is more natural to speak of reflection. In either case the source seems to operate by yielding an adequate degree of understanding of the proposition in question and thereby knowledge. It does not appear to depend (positively) on any other source and is plausibly considered basic. 10

It also seems clear that reason is a basic source of justification. Such simple logical truths as those with the form of, ‘If all As are Bs and all Bs are Cs , then all As are Cs ’ can be justifiedly believed, as well as known, simply on the basis of (adequately) understanding them. In at least the vast majority of the kinds of cases in which reason yields knowledge it apparently also yields justification. It can, however, yield justification without knowledge. Careful reflection can make a proposition seem highly plausible even though it later turns out to be false. If we are talking only of prima facie (hence defeasible) justification, there are many examples in logic and mathematics. Consider Russell's paradox. There seems to be a class of nonteaspoons in addition to a class of teaspoons. The latter, however, is plainly not a teaspoon, since it is a class. So, it is a nonteaspoon and hence a member of itself. The same holds for the class of nonphilosophers: being a non‐philosopher, it is a member of itself. There must then be a class of such classes—a class of all and only those classes that are not members of themselves. But there cannot be one: this class would be a member of itself if and only if it is not a member of itself. Thus, what appears, on the basis of an exercise of reason, to be true may be false.

It may be objected that it is only inferentially that one could here believe there is a class of all and only classes that are not members of themselves and that therefore it is not only on the basis of the operation of reason that one would believe this. But surely we may take reasoning to be one kind of such operation, particularly deductive reasoning. It is true that the basic kind of knowledge or justification yielded by a source of either is noninferential; there is no good reason, however, to rule that inferential cases may not be included.

To be sure, there is still the question whether inference depends on the operation of memory, in the sense that one may draw an inference from a proposition only if one remembers it. But surely one can hold some simple premises before one's mind and at that very time draw an inference from them. If we allow that knowledge or justification deriving from simple inferences such as those in question here need not depend on memory, we may conclude that it can be on the basis of inferential reason that the proposition in question is believed. It is a contingent matter whether such an inference does depend on the operation of memory. If one must write down the premises to keep track of them, it would. If, however, one can entertain the premises and conclusion together and at that time see their logical relation, it does not. The distinction between these two cases is not sharp but is often quite clear. 11

Even regarding reason, then, we cannot say that we have an infallible source of knowledge: one whose every cognitive deliverance is a case of knowledge. To call a source basic is to affirm a measure of epistemic autonomy; it is not to affirm any wholesale epistemic guarantee. It is not even clear that every “deliverance” of a basic source has prima facie justification. But this is a plausible view, if (1) we take a deliverance of a source to be a belief based on it and not merely caused by it, and (2) we allow that a belief can be prima facie justified even when its justification is massively overridden. Let us suppose (1) and (2) hold. Plainly this would not entail indefeasible justification. If we suppose, then, that there would be no knowledge or justification without basic sources of them, we still cannot reasonably conclude that every belief those sources deliver is justified on balance or, if true, constitutes knowledge.

If we now return to the question of uniqueness, we find that, for reason, a plausible case for uniqueness is available, since some propositions, such as simple logical truths, seem (ultimately) knowable and justifiedly believable only on the basis of reason. To be sure, even simple logical truths can be known on the basis of testimony, as where someone who is logically slow first comes to know one through the testimony of a teacher. But can such truths be known or justifiedly believed without dependence on reason somewhere along the line? It would seem that the teacher must depend on it, or on testimony from someone who does, or who at least must rely on testimony from someone else who depends on reason, and so forth. 12 If this is right, then at least for primary knowledge and justification regarding simple logical truths, uniqueness holds.

Might we, however, make the parallel claim for perceptual and introspective cases? Could anyone (say) know the colors and feel of things if no one had perceptual knowledge? If we assume the possibility of an omnipotent and omniscient God, we might have to grant that God could know this sort of thing by virtue of (fully) knowing God's creation of things with these colors and textures. Still, wouldn't even God have to know what these properties are like in order to create the things in question with full knowledge of the nature of the things thus created? Suppose so. That knowledge is arguably of a phenomenal kind; if it is, the point would only show that consciousness is a unique source. Perhaps it is. If reason and consciousness are not only basic, but also the only unique sources, one can understand why both figure so crucially in the epistemology of Descartes or indeed any philosopher for whom what is accessible to conscious experience and to thought is epistemically fundamental in the far‐reaching way that is implied by the combination of basicality and uniqueness.

II. Testimony as an Essential Source

The four standard basic sources do not include testimony. At least since Thomas Reid, 13 however, there has been controversy over whether testimony belongs with these other sources or is nonbasic. There is no question of the importance of testimony. The issue is whether gaining knowledge or justification from it depends on the operation of another source.

It might seem that since to know that p on the basis of your testimony, I must perceptually know that you have attested to p , testimony‐based knowledge cannot be basic. I suggest that this admittedly natural assumption is a mistake: I do not even have to believe that you have attested to p , though to be sure I must be disposed to believe something to this effect and may not dis believe it. 14 But quite apart from whether I did have to believe this, perception would have to operate for me to receive your testimony. Granted, your attesting to p could cause a machine to produce the belief that p (perhaps even knowledge that p ) directly in me; but this would at best be a case of knowledge due to , not on the basis of , testimony. A mere cause of my knowing something is not a source of knowledge. A sudden curiosity can cause me to look up a phone number and thereby come to know it; the curiosity is not the source of my knowledge. If, by contrast, your attestation causes me to receive your testimony directly in my mind, like a message appearing in my interior monologue, I could acquire knowledge on the basis of the testimony; but this would show only that perception can be telepathic—or perhaps that there is a basic nonperceptual source of knowledge of other minds. There would still be no need for me to have my knowledge that p based (partly) on knowledge that you attested to it. 15

With justification, it seems equally clear that apart from perceptual justification for believing something to the effect that you attested to p , I cannot acquire justification for believing it on the basis of your testimony. If, however, I am right in thinking that one need not believe, as opposed to having grounds adequate for knowing or justifiedly believing, that the attester gave testimony that p , then something important about testimony emerges: it is a source of basic knowledge , that is, knowledge not grounded in other knowledge (or in justified belief of some other proposition). My knowledge that p need not be inferred from any premises nor based on a belief that p was attested to. The point that testimony is a source of basic knowledge distinguishes it from other nonbasic sources of knowledge, such as inference. (Even in the case of knowledge by virtue of an inferential operation of reason, the conclusion is known or believed on the basis of a premise, hence is not basic knowledge or basically justified.) The point also helps to explain why it is natural to consider testimony a basic source of knowledge; for it is typical of such sources that they yield noninferential knowledge.

There are four further points that distinguish testimony from the basic sources. First, one cannot test the reliability of a basic source or confirm a deliverance of it without relying on that very source. With perception one must, for instance, look again; with memory one must try harder to recall or must consult other memories—and one must remember the original belief being examined, lest the target of confirmation be lost from view. With testimony, one can check reliability using any of the basic sources.

The second point has already been suggested in connection with memory. Memory is central for our knowledge at any given moment in a way testimony is not. Even if knowledge could not be acquired without the benefit of testimony given to one at least to the extent one needs in order to learn a language (a process in which what parents or others attest to is crucial to acquiring a vocabulary), once we climb that linguistic ladder we can discard it and, given normal memory, retain what we know. With the other basic sources, reason in some minimal form is indispensable to possessing any knowledge (at least in protecting us from pervasive inconsistency), and to inferential development of knowledge, which depends on deductive and inductive logic. Consciousness and perception are essential for the development of new knowledge in their domains. There is, however, no domain (except possibly that of other minds) for which continued testimony is in principle needed for increase of knowledge. Similar (but not entirely parallel) points hold for justification.

The third point is perhaps even subtler. There is a sense in which testimonially based belief passes through the will—or at least through agency: the attester must select what to attest to and in the process can also lie, in which case the belief does not constitute knowledge (and the justification the recipient may get is, in a certain way we need not pursue here, objectively defective). For the basic sources, there is no analogue of such voluntary representation of information. Indeed, testimonially based beliefs normally pass through agency twice over, since one can normally withhold belief from the proposition in a way one cannot when it is fully supported directly by experience or reason (to be sure, even in those cases there is such a thing as double support, as where someone attests to a plainly self‐evident proposition one had not thought of but intuitively sees to be true on hearing it asserted).

Granted, it is a contingent matter when a person can withhold belief: some of us may be able to learn to withhold even beliefs that those speaking to us are people as opposed to robots. 16 But the normal level of control here is different from that applicable to testimony, where appraisal of credibility may always involve both the kinds of doubts we may have about basic sources and any we may have about the attester's response to them. To be sure, we sometimes speak of the “testimony of the senses.” But this is metaphor, at least insofar as it suggests that the senses derive knowledge from another source, as attesters must eventually do, since knowledge that p cannot derive from an infinite or circular chain in which no person giving testimony that p knows it even in part on a nontestimonial basis. 17

A fourth point of contrast between testimony and the standard basic sources has already been suggested. It concerns the need for grounds for the semantic interpretation of what is said on the basis of which it is taken to be that p . This is not a justificatory or epistemic burden intrinsic to the standard basic sources. Granted, much a priori knowledge and justification is acquired through consideration of linguistic expression of propositions. Still, on the most plausible account of the basis of such knowledge and justification, its object is nonlinguistic; the ground is apparently a kind of understanding of the proposition in question or, perhaps more directly, of the concepts figuring in or essential to it.

It must also be granted that a lack of semantic understanding will normally restrict the range propositions that are even candidates for one's a priori knowledge or justification, since one's comprehension of language will (for most of us, at least) limit the range of propositions we can get before our minds. Moreover, semantic misunderstanding —which is of course possible even in people of wide and deep semantic comprehension—may give us the wrong proposition or range of propositions. Nonetheless, neither of these defects need affect how good our grounds are once the right object is before us. To be sure, defeaters of knowledge or justification can come from semantically interpreted items and can afflict beliefs deriving from any of the standard sources; but none of those sources seems dependent on semantic grounds in the way that testimony is.

These contrasts between testimony and the basic sources are not meant to impugn the importance of testimony. In addition to being a source of basic knowledge, testimony is, like memory, an essential source of our overall knowledge. Our overall knowledge depends on it in far‐reaching ways, though not perhaps as much as, and certainly not in quite the same ways as, it depends on memory. The most important thing memory and testimony have in common may be that they transmit , rather than generate , knowledge (the case with justification is different, since memory is a basic source of that).

As to how testimony differs from both perception and memory, there is more to say than can be said here. It is not a question of reliability; it is only a contingent matter just how reliable each is. It is not even the semantic character of the deliverances of the source; one can see a sentence (as such), as one can hear testimony—indeed, the uttered sentence may constitute someone's testimony. A crucial point made earlier bears repeating: the acquisition of knowledge or even justified belief on the basis of testimony depends on the agency of another person. Normally, the attester must not lie, or seek to deceive, in attesting to p if we are to come to know that p on the basis of the testimony. By contrast, our responses to the deliverances of the basic sources is not normally mediated by anyone else's action. Testimony may be unreliable—or otherwise unworthy of one's acceptance—both because of natural connections between the state(s) of affairs the testimony concerns and because of the person's exercise of agency. This is not normally so for the testimony of the senses or of memory or of reason. The point is not that the exercise of agency cannot be a “natural” phenomenon—though philosophers who think that freedom is incompatible with determinism are likely to insist that it cannot—but that the concepts of knowledge and justification apparently presuppose that if it is a natural phenomenon, it is nonetheless special. 18

III. Sources and Grounds

To specify a source of knowledge is to indicate where it comes from, but it is also to do something more. I have already noted that to specify a mere cause of someone's knowing something is not to specify a source of the knowledge. In part this is because a source of something need not be a ground of it. As I am understanding sources of knowledge , and as they are generally conceived in philosophical literature, they are not just where knowledge comes from; they also provide the knower with grounds of knowledge. Grounds are what it is in virtue of which (roughly, on the basis of which) one knows or justifiedly believes. If you know that my knowledge that it is raining is perceptual, as opposed, say, to testimonial, you know not only that it comes from my perceiving something, but also that I have a perceptual ground, say a visual or auditory experience, for believing the proposition.

As this example makes clear, sources indicate the kinds of grounds to expect a person to have when the person has knowledge through that source. But the source is not itself the ground. We may of course call perception a ground of knowledge so long as we understand that so speaking of a ground does not specify just what it is. What about the converse question: Does specifying a ground of knowledge that p indicate the source of the knowledge? If the ground is experiential as opposed to propositional, then ordinarily it does. But we can speak of knowledge based on an impression that (say) a car is moving, while leaving open whether it is based on visual sensations or on inference from what one can see. It also seems possible for there to be grounds of knowledge that we cannot refer to any familiar source, as might be the case with certain religious experiences. Is this a kind of perception, or might there be a new nonperceptual source? There is probably no way to answer this in the abstract.

Suppose, however, one thought that a person could have knowledge simply implanted by virtue of a true belief 's being reliably caused, where the person's brain is directly affected by a calculator and one comes to believe a truth of arithmetic that would ordinarily require calculation. If we think knowledge is possible for the idiot savant (the “lightning calculator”), we may count this as knowledge. If the person has no sense of any basis of the belief, such as a sense of “things adding up that way,” it seems more accurate to speak of a basis for knowledge rather than a ground and of a cause rather than a source. But in a generic sense there is a source; and a basis is a ground in the widest sense of that term.

This is another of the many cases in which epistemologists may diverge, depending on whether they are internalists or externalists. For an internalist, if there is nothing that is in consciousness or accessible to it by reflective or introspective efforts and that can serve as justification or some kind of evidence for p , thenwe have at best a cause, not a ground, of knowledge. For an externalist, if the process by which the belief is produced is reliable and p is indeed true, that process itself may be said to be a ground of knowledge—or at least to ground it. Perhaps the externalist would agree with the internalist, however, that there is an important sense in which it is not the subject's ground . In any event, it seems fair to say that the dominant notions of source and ground in the philosophical literature are those in which sources supply accessible grounds (grounds accessible, by reflection or introspection, to the person for whom they are grounds). The four standard sources of knowledge and justification, moreover, are commonly taken to be the only basic ones.

IV. The Epistemic Autonomy of the Basic Sources

A basic source of knowledge does not have a positive epistemic dependency on some other source; but it does not in general yield indefeasibly justified beliefs (if it ever does), and it can produce true beliefs whose status as would‐be knowledge is undermined by some defeating factor. Each source, then, is to a significant degree subject to defeasibility. Defeat can come from a different source; hence we cannot adequately account for knowledge or justification apart from an understanding of the interconnections among the basic sources.

To what extent, then, is each basic source autonomous? To answer this we need to distinguish different kinds of autonomy. One way to focus the issue and to see the role of defeasibility in understanding the basic sources is to ask whether all the epistemic defeaters of beliefs that are well grounded in the standard basic sources (i.e., all the elements that defeat their justification or prevent their constituting knowledge) derive their defeating power from those same sources. The more general question here is whether, collectively, the standard basic sources are epistemically and justificationally self‐sufficient , roughly self‐sustaining in providing for all the knowledge‐conferring and justification‐conferring grounds of belief, and self‐correcting, in potentially accounting for all the grounds of defeat of (would‐be) knowledge and of justification. A quite similar question is whether, taken together, they are necessarily such that if a true belief enjoys adequate support from at least one of them, hence is properly evidenced, and that support is not defeated by at least one other, then the belief constitutes knowledge (or is justified on balance).

This self‐sufficiency thesis has some plausibility, particularly for justification. To show whether or not it holds would take far more space than I have, but we can go some distance toward an answer by exploring the two main aspects of the question whether the standard basic sources are autonomous. First, does each source yield the knowledge or justification it does independently of confirmation of the belief in question from any other source? Call this the question of individual autonomy . Second, if not, then does only the entire set of basic sources meet this independence condition? This would be collective autonomy , a freedom from the need for confirmation by any fifth source.

There is also a kind of negative autonomy : invulnerability to defeat by beliefs from another source. Such defeat may occur where “seeing is believing.” For instance, suppose I see a stone wall. My visual experience may yield a belief that there is one at the edge of the field, and that belief may constitute knowledge and retain justification despite a memory belief that, as of a few minutes ago, there was only a line of trees in that place. The justification that my memory belief had is thus defeated. As this example can also indicate, invulnerability to defeat from one source may be combined with vulnerability to another. If seeing a wall can yield knowledge or justification that overrides, and presumably cannot be overridden by, any provided by a memory belief of the kind in question, justification of a visual belief may be overridden by that of a tactual one. If, on a walk in the hot summer, I am justified by vision in believing that there is a water fountain before me, yet I cannot feel anything as I sweep my hands where its cool surface should be resisting them, I will neither know, nor any longer be justified in believing, that there is one there and am likely to conclude I am hallucinating. 19 Here, at least, with respect to both justification and knowledge, touch apparently takes priority over sight.

Positively, there apparently is a measure of individual autonomy. Each source can by itself yield some justification (as well as knowledge). If, for instance, I have a perceptual impression of a piano being played, I am prima facie justified in believing that one is being played. By contrast, if I have a sufficiently vivid and steadfast memory impression of a grassy meadow where I now see a stone wall, I may have some small degree of justification for believing the spot was covered with grass (and the wall has appeared quickly), even if the justification of my visual belief that there is a stone wall before me cannot be overridden by that of the memory belief alone. Certainly in the normal case, justification—of some degree—from one of the four standard sources does not wait upon corroboration from other sources. The same holds for knowledge.

To be sure, one cannot be justified in believing (or know) that a lot was vacant unless one has the required concepts, such as that of vacancy; and it may be that one does not acquire concepts adequate to make justified belief possible until one has a complex group of interrelated concepts. This may imply that one gets no justification at all in isolation from justification for many related propositions. That possibility is, however, quite compatible with some grounds of one's justification being single experiences. Epistemic autonomy is consistent with conceptual dependence. We cannot believe, and hence cannot know, a proposition essentially involving concepts we do not have. But a belief might have an isolated ground without in the least being isolated conceptually or in content from other beliefs.

Regarding negative individual autonomy on the part of a source—that is, its providing justification or knowledge that is overridable only by counterevidence from the same source—plainly the four standard sources do not have it. To take a different example, the justification of a memorially justified belief that there is a wall in the field can be overridden by a perception of smooth ground there. The same perception can prevent the belief 's constituting knowledge even if it is true. It may seem that reason—our rational capacity—is privileged as a source of justification. Strong rationalists might take it to possess negative individual autonomy. But surely there are some propositions, such as some in logic or mathematics, that I might justifiedly believe on the basis of reflection but, in part on the basis of sufficiently plausible testimony, can cease to be justified in believing or cease to know. Here the authority of that testimony would depend partly on perceptual and memorial factors crucial for my justifiedly accepting the credibility of the person who is its source. Thus, the overriding power of that authority does not derive from reason alone. 20

The case for collective negative autonomy is more plausible: there is some reason to think that where a belief constitutes knowledge or is justified in virtue of support from all four sources working together, its epistemic grounding (its grounding qua knowledge) and its justification are defeasible only through considerations arising from at least one of those very sources. If we assume that such defeat can come only from what confers or at least admits of justification, and if we add the highly controversial assumption that all epistemic grounding and justification of belief derive wholly from the four standard sources, we may conclude that those sources are epistemically and justificationally self‐sufficient. I make neither assumption, but I would suggest that in fact these sources may well be self‐sufficient. For there may in fact be no other basic sources (as opposed to causes) of knowledge or justification or of defeat. 21

There are at least two reasons for the caution just expressed. One concerns collective negative autonomy. The other concerns the self‐sufficiency thesis, in particular the idea that the standard basic sources are self‐corrective in providing (in principle) for all the kinds of correction needed to rectify erroneous beliefs. Let us take these points in turn.

First, it is widely recognized that sources of unreliability in our belief‐formation processes can prevent our beliefs from constituting knowledge even if we have no way, through the standard basic sources, of detecting the error. This is a lesson of the Cartesian demon scenario, in which our belief‐forming experiences, and even our efforts to check on the truth of our beliefs, are manipulated so that we cannot detect certain false beliefs. But, in principle, inanimate factors could conspire to produce the same unfortunate results. It would be a mistake, then, to say that the basic sources are necessarily self‐correcting.

Second, there is reason to think that the concept of knowledge, as opposed to that of justification, is external in roughly this sense: knowledge is possible without the knower's having internally accessible grounds for the belief constituting it. 22 Thus, suppose that, through the operation of a special mechanism in one's brain, one could know what a person very near one was thinking. Such a mechanism might deliver the beliefs constituting the knowledge whenever one concentrates attention on the person in question in a certain way but might yield no sense of any grounds for them; nor would there have to be any access to such grounds. Granted, one might gain inductive evidence of one's success, but if such knowledge is possible at all, one could presumably have it without dependence on inductive evidence of that success. There is much controversy over whether such externally grounded knowledge is possible; but, if it is, then the standard basic sources are not necessarily collectively self‐sufficient regarding knowledge even if they are for justification. There can be other sources of knowledge.

For justification as opposed to knowledge, however, there is reason to think that the four standard sources are indeed individually autonomous and, collectively, both self‐sufficient and self‐corrective. Each can provide grounds that can by themselves confer justification (as well as knowledge where the belief in question is true), though defeat by counterevidence can arise from the same or a different source and hence each lacks autonomy in the negative sense; and the entire set of sources seems, as regards justification, to be autonomous: self‐sufficient in accounting for justification (as well as for normally grounded knowledge) and, independently of any other sources, capable of accounting for defeaters of justification and, in part in that way, for correction of our beliefs. In addition, it is arguable that, at least in the case of reason and perception, there is also uniqueness, in the sense that there are kinds of knowledge and justification not possible apart from dependence on these sources. None of these properties holds for testimony, though it is like the basic sources in being both a source of direct knowledge and also epistemically essential in the ways I have described.

It has been plausibly argued, however, that one source, and perhaps the basic source, of justification is coherence among one's beliefs. Isn't my belief that the car was moving perhaps justified by its coherence with the beliefs that its orientation to the adjacent building seemed to be changing, that I recall tire sounds, and that cars are built to move? And isn't the justification of my belief that the ground where the wall stands was smooth later undermined mainly by its in coherence with the belief that I now see one there (one that looks quite old)? Let us explore the role of coherence in justification.

V. Coherence

Unfortunately, there is no account of coherence which we may simply presuppose. The notion is elusive, and there are highly varying accounts. 23 But this much is clear: we cannot assess the role of coherence in justification unless we distinguish the thesis that coherence is a basic source of justification from the thesis that in coherence can defeat justification. The power to defeat is destructive; the power to provide grounds is constructive. To see that the destructive power of incoherence does not imply that coherence has any basic constructive power, we should first note that incoherence is not the contradictory of coherence, its mere absence. It is something with a definite negative character: two beliefs that are logically and semantically irrelevant to each other, such as my beliefs that the sun is shining and that I am thinking about sources of knowledge, are neither mutually coherent nor mutually incoherent. The paradigm of incoherence is blatant logical inconsistency; positive coherence is widely taken to be far more than mutual consistency, yet far less than mutual entailment.

Clearly, that incoherence can defeat justification does not imply that coherence can create it. If it does create it (which is far from obvious), seeing this point is complicated because wherever coherence is plausibly invoked as a source of justification, there one or more of the four standard sources apparently operates in a way that provides for an explanation according to which both the coherence and the justification arise from the same elements responsible for well‐groundedness. 24 This is best seen through cases.

Consider my belief that a leaf blower is running, grounded in hearing the usual sharp blaring sounds. This appears to be justified by the relevant auditory impressions, together with background information about what the corresponding sounds indicate. If, however, I acquired a justified belief that someone is imitatively creating the blare, my justification for believing that a leaf blower is running would be undermined by the incoherence in my belief system. Does the defeating power of incoherence imply that my original justification requires coherence among my beliefs, including the belief that no one is doing that? Does one even have that belief in such a case? It would surely not be normal to have it when there is no occasion to suspect such a thing. But suppose the belief were required. Notice how many beliefs one would need in order to achieve coherence that is of sufficient magnitude to be even a plausible candidate to generate the justification in question, for example that my hearing is normal, that there is no other machine nearby that makes the same sounds, and so on. It is not quite clear how far this must go. Do we even form that many beliefs in the normal cases in which we acquire justified beliefs of the ordinary kind in question? To think so is to fall victim to a kind of intellectualism about the mind that has afflicted coherentist theories and opposing accounts of justification alike.

A further analogy may help to show how incoherence can be a defeater of justification without its absence, or beliefs that it is absent, or justification for believing something to this effect, being a source of justification. One's job may be the source of one's income, yet a severe depression might eliminate the job. It does not follow that the absence of a depression is a source of one's income. Surely it is not. Even positive economic conditions are not a source, though one's source depends on them. The idea of (positive) dependence is central in understanding that of a source. It must be granted that there is a negative sense in which one's job does depend on the absence of a depression; but that dependence—a kind of vulnerability—is too negative a condition to count as a source (much less a ground) of income. For one thing, it provides no explanation of why one has the income. Similarly, we might say that one's justification negatively depends on the absence of defeaters and positively depends on one's sources. But negative dependence on incoherence does not imply positive dependence on anything in particular, including coherence, as a source, any more than an income's negative dependence on the absence of a depression implies any particular source of that income.

To be sure, nothing can serve as a source of anything without the existence of indefinitely many enabling conditions . Some of these are conceptual. One may, for instance, be unable to believe a proposition even when evidence for it is before one; if a child has no concept of an insurance adjuster, then seeing one examining a damaged car and talk to its owner about deductibles will not function as a source of justification for the proposition that this is an insurance adjuster. Other enabling conditions are psychological, concerning our capacities or dispositions relevant to forming beliefs. If my sensory receptors are malfunctioning, or if I do not respond to their deliverances by forming beliefs in the normal way, then I may fail to be justified in certain perceptual beliefs.

Specifying a source provides both a genetic explanation of where a thing comes from and, through supplying a ground, a contemporaneous explanation of why it is as it is; enabling conditions, by contrast, provide neither. Taken together, they explain its possibility, but not its genesis or its character. It is neither correct nor theoretically illuminating to construe the absence of the enabling conditions as part of the source or as a ground. They are indispensable, but their role should be understood in terms of the theory of defeasibility rather than the theory of sources or of positive grounds.

The importance of incoherence as a defeater of justification, then, is not a good reason to take coherence to be a source of justification. This by no means implies that justification has no relation to coherence. Indeed, at least normally, justified beliefs will cohere, in one or another intuitive sense, with other beliefs one has, typically other justified beliefs. Certainly, wherever there is justification for believing something, there at least tends to be justification for believing a number of related propositions and presumably for believing a coherent set of them. This is easily seen by reflecting on the point that a single perceptual experience provides information sufficient to justify many beliefs: that someone is blowing leaves, that there is a lawn before me, that these blaring motors should be muted, and far more.

The conception of sources of knowledge and justification that I have sketched provides a way to explain why coherence apparently accompanies justified beliefs—actual and hypothetical—namely, that both are ultimately grounded in the same basic sources. In sufficiently rich forms, coherence may, for all I have said, commonly be a mark of justification: an indication of its presence. The coherence conception of knowledge and justification, however, does not well explain why justification of beliefs is apparently dependent on the standard sources. Indeed, as an internal relation among beliefs, coherence may be at least as easily imagined in artificial situations where the coherence of beliefs is unconstrained by our natural tendencies. In principle, wishful thinking could yield as coherent a network of beliefs as the most studious appraisal of evidence. 25

There is one kind of coherence that is entirely consistent with the well‐groundedness conception of justification that goes with taking it to derive from basic sources in the ways I have suggested. To see this, note first that one cannot believe a proposition without having the concepts that figure essentially in it. Whereof one cannot understand, thereof one cannot believe. Moreover, concepts come, and work, in families. This point is the core of a coherence theory of conceptual function: of the acquisition of concepts and their operation, most notably in discourse, judgment, and inference. That theory—call it conceptual coherentism , for short—is both plausible and readily combined with the kind of view I am developing. For instance, I am not justified in believing that there is a piano before me unless I have a concept of a piano. I cannot have that unless I have many other concepts, such as the concept of an instrument, of a keyboard, of playing, of sound, of music—no one highly specific concept need be necessary, and various alternative sets will do. In part, to have a concept (of something perceptible) is (at least for remotely normal persons) to be disposed to form beliefs under appropriate sensory stimulations, say to believe a specimen of the thing to be present when one can see it and is asked if there is such a thing nearby; thus, again it is to be expected that from a single perceptual experience, many connected propositions will be justified for the perceiver.

The coherence theory of conceptual function belongs more to semantics and philosophy of mind than to epistemology. But it has profound epistemological implications. That concepts are acquired in mutual relationships may imply that justification does not arise atomistically, in one isolated belief (or desire or intention) at a time. This does not imply, however, that, once a person acquires the conceptual capacity needed to achieve justification, justification cannot derive from one source at a time. This theory of conceptual acquisition and competence is also quite consistent with the view that, far from deriving from coherence, justification, by virtue of the way it is grounded in its sources, brings coherence with it.

VI. Conclusion

We have seen reason to consider perception, memory, consciousness, and reason to be basic sources of justification and, except in the case of memory, of knowledge. All can yield beliefs that are both noninferential in not being based on other beliefs and noninferentially justified in not deriving their justification from being based on any other beliefs. Testimony can also yield noninferential beliefs and even what might be called basic knowledge, but it is not a basic source or knowledge or justification. Like inference, it yields knowledge and justification only given the positive cooperation of at least one of the basic sources, but because it (commonly) yields noninferential beliefs, it is closer than inference to constituting a basic source.

The basic sources yield not only knowledge and justified belief, but also coherence. For instance, it is common for a single observation to produce a goodly number of cohering beliefs. The operation of reason—our rational capacity—tends to employ an interconnected group of concepts, such as those involving perceptible objects, psychological concepts, and logical relations, which dispose us to discover certain apparently a priori truths and to reason with and from them in ways that produce an integrated view; and memory preserves not only individual beliefs, but also our sense of some of their interconnections.

The operation of basic sources allows for defeasibility even when it yields amply justified beliefs or knowledge. Among the defeaters that can undermine would‐be justification or would‐be knowledge is incoherence. But it is essential to see that the pervasive possibility of defeat does not entail that each basic source has a positive dependence on any of the others, in the sense that in order to yield knowledge or justification, one source must rely on the operation of another one, or that any basic source positively depends on coherence.

At several points, I have indicated something about perception that may not apply to the other basic sources. Within very wide limits, the notion of perception is open‐ended. There is no fixed a priori list of perceptual modalities. In a way the notion is schematic: definite by virtue of paradigms like sight and touch that anchor it, yet capable of being filled out by changes in our relation to the world.

Might the same be said of the notion of a basic source of knowledge or of justification? Perhaps it might. The distinction between a schematic concept being filled out over time and a change of concepts by replacement is, to be sure, not sharp. I certainly want to make room for the possibility that there are or can be basic sources of knowledge or justification not considered here. Whether we call them new basic sources or instead should say that our concepts of knowledge or justification have changed would depend in large part on how they are related to the clearly basic sources that are now essential for understanding the notions of knowledge and justification. My concern has been to clarify those in relation to their sources, especially their basic sources but also testimony and inference, which are essential though not basic sources. How those two sources extend knowledge and justification gained through the basic ones is a large problem that cannot be even be approached here. 26

For each source of knowledge or justification, I have left room for cooperation between sources: two or more basic sources can together produce knowledge or justification, as can two or more nonbasic sources. Two or more sources from the different categories can also cooperate, as where testimony, a nonbasic source of justification, supports memory, which is a basic source of it, or where reason, by producing an inference to a proposition confirmed by memory, supports that faculty. The possibility of cooperation is matched by that of conflict. Skeptics find the latter possibility highly damaging to common‐sense views of the extent of our knowledge and justification. If I have been right, it may well be that the basic sources are collectively autonomous in a way that permits adjudication of this matter. I should like to think this is so; but even if it is, on some aspects of the question the jury is still out. 27

For detailed discussion of the distinction between positive and negative epistemic dependence, see my Epistemology (London: Routledge, 1998 ), esp. chap. 7.

If “blind sight” is a case of perception, this may not be so (though it is arguable that the subject simply does not believe there are visual sensations or other experiential elements corresponding to perception).

The apparent noncausal character of abstract entities is a main reason that knowledge of them—indeed their very existence—is often considered problematic. For one kind of challenge to the causal inertness claim see Alvin Plantinga, Warrant and Proper Function (Oxford: Oxford University Press, 1993 ).

For introspection and consciousness, as for external perception, one can devise a plausible adverbial view, as described in chap. 1 of Epistemology .

See Fred I. Dretske, Knowledge and the Flow of Information (Cambridge, Mass.: MIT Press, 1981 ), and William Alston, Perceiving God (Ithaca, N.Y.: Cornell University Press, 1991), for indications of how broad the notion of perception is.

The need for ‘if’ here has been suggested already: a duplicate of me would, at the moment of creation, know dispositionally a great deal I now know from memory (not all of it, of course, because some depends on my actual history and it would have no history yet); but it is unclear how this depends on memory. Perhaps we should say that it does not depend on remembering —hence does not require the operation of memory—but does depend on memorial capacity , since it would not be true of me that if I needed to bring a certain item of knowledge to mind I could, unless I had sufficient memorial capacity to retain it from the moment I needed it (e.g., a phone number) to the “next” moment, at which I bring it to mind.

Granted, I could memorially believe p but not know it (having too little evidence, say) and then be told by you that p . But if I now know it, this is on the basis of your testimony; I don't know it from memory until I retain the knowledge and not just the belief. Believing from memory can instantaneously become knowing, but does not instantaneously become knowledge from memory.

For a detailed discussion of the epistemology of memory, with many references to relevant literature, see my “Memorial Justification,” Philosophical Topics 23 (1995): 31–45.

See, for example, Hume's extraordinary affirmation of privileged access in the Treatise , cited and discussed in my Epistemology , chap. 3.

The relevant kind of understanding and the notions of a priori knowledge and justification in general are discussed in detail in chap. 4 of Epistemology and in my “Self‐Evidence,” in Philosophical Perspectives 13 ( 1999 ): 205–228.

Thus, for God or any being with infinite memorial capacity, no use of reason essentially depends on the exercise of memory. I might add even if the points made here about inference and memory are mistaken, the overall point that reason may ground justification for p without yielding knowledge of it can be illustrated by many other cases, presumably including the proposition that some classes are members of themselves (since this embodies a type‐error).

This point must be qualified if W. V. Quine is right in denying that there is a viable distinction between the empirical and the a priori—at least one would have to speak in terms of, say, differences in degree. For extensive criticism of Quine, see BonJour, “Against Naturalized Epistemology,” Midwest Studies in Philosophy 19 (1994): 283–300, and for the notion of a priori justification see also my “Self‐Evidence.”

See Thomas Reid, Essays on the Intellectual Powers of Man (Cambridge, Mass.: MIT, 1969). For a defense of a Reidian view see C. A. J. Coady, Testimony (Oxford: Oxford University Press, 1992 ). For a contrasting account of testimony more sympathetic to a Humean perspective see Elizabeth Fricker's chapter on testimony in Handbook of Epistemology , ed. Ilkka Niiniluoto and Matti Sintonen (Dordrecht: Kluwer, 2002).

For a developed distinction between these and a case for positing fewer beliefs than most philosophers apparently do, see my “Dispositional Beliefs and Dispositions to Believe,” Nous 28 (1994): 419–434.

This point may be more controversial for internalist than for externalist views, since an externalist can hold that my belief can constitute knowledge so long as it is reliably produced, even if I do not have accessible grounds for p , as I would if I had good inferential grounds for it. I cannot discuss the contrast between internalism and externalism in this paper. For discussion see, for example William P. Alston, Epistemic Justification (Ithaca, N.Y.: Cornell University Press, 1989 ), Paul K. Moser, Knowledge and Evidence (New York: Cambridge University Press, 1989 ), and my Epistemology , chap. 8.

I discuss the issue of voluntary control of belief and cite much relevant literature in “Doxastic Voluntarism and the Ethics of Belief,” Facta Philosophica 1, no. 1 (1999): 87–109.

This point is explained and defended in my “The Place of Testimony in the Fabric of Knowledge and Justification,” American Philosophical Quarterly 34 (1997): 404–422.

This point may support my view, defended in “The Place of Testimony,” that to acquire justification for p from testimony, one needs some degree of justification for taking the attester to be credible. (I do not think one needs this to acquire prima facie justification from one of the standard basic sources.)

This is not to imply that just any tactual belief is better justified than any conflicting visual one. Matters are far more complicated, but need not be pursued in detail here.

This is not to deny that there may be justified beliefs of logical truths so luminous that the justification of these beliefs cannot be overridden. The point is that doxastic justification grounded in reflection can be overridden by factors that are at least not entirely a priori. That can be so even when the beliefs in question are true. For further discussion of this issue see Laurence BonJour, In Defense of Pure Reason (Cambridge: Cambridge University Press, 1997), and my “Self‐Evidence,” cited in note 10 .

Another possibility is that there are other basic sources which are comparatively weak, so that although they may add to the justification available through the standard sources, they are not sufficient to yield belief that is justified on balance (roughly, justified to a degree ordinarily sufficient to render a true belief knowledge). On the other hand, if they can add to justification from the standard sources, then they could render a belief that would not ordinarily defeat the justification of another belief able to do so. This would limit the self‐sufficiency of the basic sources. We should surely be cautious about affirming even the de facto self‐sufficiency of the sources, and I leave it open.

A brief treatment of externalism is provided in my Epistemology ; for a more extensive treatment see Ernest Sosa, Knowledge in Focus, Skepticism Resolved (forthcoming from Princeton University Press), and chapter 8 in the present volume.

For two major accounts see Keith Lehrer, Knowledge (Oxford: Oxford University Press, 1974 ), and Laurence BonJour, The Structure of Empirical Knowledge (Cambridge, Mass.: Harvard University Press, 1985 ); and for much discussion see John Bender, ed., The Current State of the Coherence Theory (Dordrecht: Kluwer, 1989). It should be noted that in “The Dialectic of Foundationalism and Coherentism,” in John Greco and Ernest Sosa, eds., The Blackwell Guide to Epistemology (Oxford: Blackwell, 1999 ), BonJour has since abandoned coherentism.

This is suggested and to some degree argued in my Belief, Justification, and Knowledge (Belmont, Calif.: Wadsworth, 1988) and The Architecture of Reason (Oxford: Oxford University Press, 2001).

If it is taken to be an internal relation among beliefs, their content does not matter, nor does their fit with experience. This sort of thing has been widely noted; see Moser, Knowledge and Evidence , and John Bender, The Current State of the Coherence Theory (Dordrecht: Kluwer, 1989 ), for some relevant points and many references.

An approach to understanding the inferential extension of justification and knowledge is developed in chap. 6 of Epistemology . Testimonial extension of justification and knowledge is approached in my “The Place of Testimony.”

For helpful comments on an earlier version of this article (which derives, in part, from chap. 1 of my Architecture of Reason and from my paper on testimony, cited above), I heartily thank Paul Moser and Richard Swinburne.

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Essay On Sources Of Knowledge

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Intellectualism is the factor of being intellect or intelligent. The idea of what it means to be educated can be interpreted many different ways by different people. Some think it’s having a 4.0 and going to Harvard, while others believe in the idea of having common sense. In the essay, “Hidden Intellectualism,” Gerald Graff reflects how lack of education is viewed negatively in society. On top of that, a question also lies what it means to educated. In order to be truly educated, a person should be well rounded not in just tests of intelligence, but the tests of life as well.

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A teenage girl Mary Shelly wrote Frankenstein in the 18th century. A Gothic novel Frankenstein deals with two genres, Gothicism and science fiction. Victor, one of Mary Shelly’s characters represents man’s pursuit of knowledge which ultimately leads towards the path of destruction while another character Robert Walton implemented his knowledge wisely to get benefits for the society. Mary is indicating to the society that mankind has to pay full attention to science and scientific innovations in order to avoid the catastrophic events due to misuse of knowledge. The search for knowledge is arduous, to utilize knowledge wisely can be blessings, but

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During the Elizabethan times, superstitions and folk tales were very popular and were spread all throughout England, and impacted almost everything. Life, sickness, and many beliefs were affected by superstitions that branched from other ideas. For example, astrology and medicine helped construct many of these beliefs. In some ways the church also had an impact because church affected how the common people reacted to these ideas. A religious church man would talk down upon superstitions opposed to an individual who is open minded to the ideas. This was normal during this time, to have such a controversial topic be embedded into the minds of the common citizen in England. Despite the fact that superstitions were controversial to the church, they had a huge impact during the Elizabethan era. Superstitions shaped daily life, affected illnesses, and impacted modern beliefs in the form of folk tales.

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The proposal that adolescents’ interest in literature has diminish in America is clearly voiced by Dana Gioia, in the article, “Why Literature Matters”. Although, Gioia used different methods to persuade his readers, one way he tried to persuade is by indicating the disadvantages of not reading in society today.

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Essay On Value Of Knowledge

“Without application in the world, the value of knowledge is greatly diminished.” Consider this claim with respect to two areas of knowledge.

The Importance Of The Pursuit Of Knowledge

Whilst the knower’s perspective is always essential in the pursuit of knowledge, it’s essence is greater in some areas of knowledge than others. Perspective shapes both what we pursue in knowledge and it affects how we interpret pursued knowledge. Whilst the latter has greater influence over subjective areas such as the arts and history, the former affects even the pursuit of knowledge in more objective areas such as the natural sciences and maths. What’s more, for knowledge to be knowledge, there must be a knower. Each individual knower gains knowledge through the ways of knowing reason and emotion (amongst others); these ways of knowing shape and are shaped by our perspective. More often than not, the knowledge that we pursue has been given to us by another knower, especially in areas of knowledge like history; in this case the previous knowers perspective also shapes our pursuit of knowledge. Thus, in areas of knowledge where shared knowledge is pivotal we draw upon a shared perspective, not just that of the individual knower. Due to perspective affecting knowledge in such a magnitude of ways, it is essential in all areas of knowledge. Through exploring the pursuit of knowledge in three different areas of knowledge: the arts, history and the natural sciences, it becomes apparent, that although to different extents, perspective is essential in shaping each.

What I Learned In College Essay

College is full of experience and to get that experience students need to get involved in campus and use all the resources that their campus offer. For my first semester at university I learned lots of information that helped me go through my first semester and I will keep using this resources until I graduate. and these resources are not just for school but also for my personal life.

More about Essay On Sources Of Knowledge

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Sources of Knowledge (Essay Sample)

The task on the paper was to identify other sources of knowledge apart from books and scientific observation. The paper has two sources which are books. The paper is double spaced.

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Essay on Knowledge

“Learning gives creativity, Creativity leads to thinking, Thinking provides knowledge, and Knowledge makes you great”. These lines had been said by our former president and great scientist Dr. A.P.J. Abdul Kalam focusing on the importance of knowledge. It is the power of knowledge that made human beings become civilized and work for their betterment from an uncivilized early man.

Short and Long Essays on Knowledge in English

Knowledge is considered to be the greatest wealth of human beings that help in attaining success which in turn makes the society and nation progress. Hope these essays will be useful for you.

Knowledge Essay 10 Lines (100 - 150 Words)

1) Knowledge is man’s greatest asset.

2) Knowledge is important to decide good and bad for ourselves.

3) Knowledge helps people to attain success.

4) Time and experience are the major sources of knowledge.

5) We need knowledge for performing every task in our life.

6) Books, education, and people help us to acquire knowledge.

7) Knowledge helps in developing a good personality.

8) Knowledgeable people are respected everywhere.

9) Knowledge is the base of invention and development.

10) Knowledge grows by sharing, so we should always make positive use of our knowledge.

Essay 1 (250 Words) - Knowledge


Knowledge can be defined as the facts and information that a person comes to learn in his whole life. Different people have different levels of knowledge. Knowledge is mainly concerned with what we see and recognize.

What is Knowledge?

We try to know about different things and that tendency to know and learn about different things, events, or phenomenon is called knowledge. Knowledge about anything helps us in understanding things from our own perspective. The main aspect is that we should know about that thing.

Knowledge helps us in understanding the difference between right and wrong. We learn and acquire knowledge throughout our life. The knowledge acquired is based on experience. People who have lived for more years have more access to everything. They have attained the information as a result of their experience. We can judge a person’s knowledge by the way it is applied in any situation. We can be called knowledgeable if we have information about most things.

People who are having knowledge can understand the problems in a better way and further by the power of their understanding can find out the solution. Merely having knowledge about anything does not mean that we can get success in that field. It depends upon this thing that how we are applying the same. A person without knowledge is unable to understand many things. Knowledge helps us in calculations, solving puzzles, riding a bike, driving a car, etc.

Knowledge makes a person act sensibly and wisely. It helps a person in the development of his personality.

Essay 2 (400 Words) - Knowledge is a Lifelong Process and Leads to Inventions

Knowledge is like an ornament. As ornament adds beauty, the same way knowledge makes us wise and adds beauty to our personality. Knowledge is attained by experience. It depends on us whether we have the capability of learning or not. When we have information about anything then only we can further make the judgment. Debates, group interactions, people around us, and several books are different ways by which we can acquire learning and enhance our knowledge.

Knowledge is a Lifelong Process

Knowledge is not acquired at an instant. The whole life we learn and gain knowledge. Knowledge increases day by day. We work on the process of learning to gain more knowledge. We should have a good reading habit to get new ideas and information. The application of our knowledge in the right direction leads us to become successful. We must keep our senses open to perceive and learn different things from our surroundings.

Knowledge is the greatest wealth that one can have. It cannot be stolen neither it fades; instead, it increases day by day. It makes us understand different things, and therefore we can differentiate between right and wrong. Children do not know everything by birth but slowly and slowly learn different activities. Many of us have studied from different subjects but in reality, we do not have good knowledge about the subject. The people with good knowledge are successful in life as they are humble and helping in the same way as a tree overloaded with fruits bends down showing modesty and respect.

Knowledge can Lead to Inventions

The knowledge we possess is turned to the invention is applied in a better way. The different technologies, machinery, and the development we see around us are the results of the application of knowledge or ideas of human beings. We are blessed to have a brain that differentiates us from animals. We have the ability to think, speak, and remember many things in our life. Education is one of the ways to gain knowledge. The development of interest in any particular aspect makes us find more information about that thing. Further, if the information is used up by human beings wisely in a creative manner will lead to the betterment of the society and nation.

Knowledge is a valuable asset to mankind. Knowledge helps people in achieving the goal of their life along with the inculcation of moral values. The people who are learned help in the betterment of society and nation and are respected by all.

Essay 3 (500 - 600 Words) – Knowledge: Source, Advantages and Disadvantages

Knowledge is basically what one learns and understands in their daily life. Every one of us performs several activities in our daily life. We learn about those activities and understand them well, this is also the knowledge. The level of knowledge depends upon our age experience and profession. The perspective of a scientist will be different from a student and a normal person. Knowledge helps in the building of our personality and helps us in getting a good profession.

Source of Knowledge

Knowledge is not attained in one day but it is a lifelong process. People keep on learning about different things from birth until death. There are many sources from where we can get a lot of information and hence it will help us in the process of constant learning and gaining knowledge.

Advantages and Disadvantages of Knowledge

Everything has both positive and negative effects. In the same way, knowledge has many of the better impacts but negative too. The whole thing depends upon the way it is utilized and applied. The advantages and disadvantages of knowledge are enlisted below:


Practice Reading to Gain Knowledge

The regular habit of reading benefits us with different ideas, facts, and information. Reading also helps in the building of our vocabulary which is also the enhancement in our knowledge. It is necessary to inculcate the habit of reading in students from a very young age. It will be beneficial to them as they will develop the capability of problem-solving and recognizing the facts from the very beginning.

Knowledge helps us in correlating things that bring in us a better understanding. Knowledge remains with us throughout our life and makes us better human beings.

FAQs: Frequently Asked Questions

Ans . Knowledge is to know or understand something by studying or experience.

Ans . The word knowledge has been derived from the Greek word Gnosis which means knowing through observation.

Ans . Epistemology is the name given to the philosophical study of knowledge.

Ans . Knowledge makes us intelligent and increases our problem-solving capability.

Ans . Knowledge applied in a negative way becomes dangerous for society and the nation.

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Ankita Yadav

Ankita has completed her master's degree from Banaras Hindu University (BHU). She is interested in blogs and articles writing very creatively and elaborating her ideas and views on different topics for her readers. She is a nature lover along with the spirit to save the environment from destruction. She loves traveling and explores her creative ideas in her writings.

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Show More As early as 1854, Florence Nightingale demonstrated the importance of research in the delivery of nursing care. Two major approaches originate from different philosophical perspectives and use different methods for collection and analysis of data. There are several important steps in the conduct of research, and each of these requires decision making by the researcher. Nurses use various sources of knowledge to make clinical decisions. Intuition, trial and error, tradition, authority, and clinical experience are often used as sources of knowledge in clinical settings, however, not all sources of knowledge are reliable. Thus, it is important to comment on the qualifications of the authors to find out if information are useful , valid, and accurate. Qualifications of the authors The first author: Cheryl Tatano Beck, is a distinguished professor at the University of Connecticut School of nursing . She received a Master's degree in maternal-newborn nursing from Yale University. She holds doctorate of Nursing science degree from Boston University. The second author Sue Watson, is chairperson at Trauma and Birth Stress in Auckland, New Zealand.The first …show more content… At personal level, psychological birth trauma can also affects the father, the child, family member, and the society. It can decrease bounding and lactation period and provokes subsequent health issues to the child. This can trigger emotional insecurity and self doubt and cause a myriad of intra familial communication problems, which can traumatize the whole family. Professionally, nurses must provide support, counseling, and a safe environment to mothers who had a traumatic childbirth experience, which may later develop some emotional and behavioral disorder . Therefore, nurses must also be well knowledgeable to prepare women for hospitalizations by decreasing their fears related to childbirth

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May 4 • Final Philosophy for Lunch of Semester • “Where Does Knowledge Come From?”

Posted in: P4L , Philosophy for Lunch

essay on sources of knowledge

May 4, 2023 – Final Philosophy for Lunch of Semester – “Where Does Knowledge Come From?”

Description: What is the source of knowledge? Traditionally, philosophers have given an either/or answer: knowledge is acquired with the body or the mind. In this week’s P4L, we will examine one of the most influential arguments that knowledge is acquired by the mind alone: the one put forward by René Descartes. In the Meditations , Descartes famously argues that the only way to provide a secure foundation for knowledge is to ground it upon the certainty of one’s own existence not as a sensing and feeling embodied being, but as a ‘thinking thing’. Reading key passages from the Meditations , we will reflect upon those features of human experience that Cartesian knowledge includes, and those that it leaves behind. (Image: Wikimedia Commons, CC BY 4.0)

Where? Schmitt Hall, Room 104

When? 11:30AM –12:30PM EST—every Thursday. Come early.

Zoom? This is an in-person event, but you can also participate in the event virtually, live, via Zoom, using this link: https://montclair.zoom.us/meeting/register/tZIqcuqsqzgpHdfjjf3m9lJRFHwz0l6mezTD

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essay on sources of knowledge

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How to use sources in an essay

In this article you can find out:

  • What a source is
  • The importance of using reliable sources in your essay writing

How to evaluate a source

This resource is suitable for broadly discursive essay writing for S1, S2 and S3 (Third and Fourth Level Curriculum for Excellence).

What is a source?

After you have chosen a topic for your broadly discursive essay , you will need to research to make sure you have relevant information to support the key points in your essay.

You can get information from a variety of sources . For example, you might find information from:

  • print media , such as books, newspapers and magazines
  • broadcast media , such as television and radio
  • online media , such as websites and social media

The importance of using reliable sources

Just because something has been posted online or in print does not make it wholly reliable as a source of information.

When you are conducting research (whether for an essay for English, Art, Science or another subject) you should aim to access the best quality sources possible. This will require you to evaluate the source that you are reading and to decide quickly whether or not the information within this source will support and improve your essay.

To evaluate a source, begin by asking yourself:

  • Who has written/published the information?
  • What information are we being given?
  • Why has this information been written/published?

Evaluating a source gives you confidence in the quality of the information that you are being given.


We are surrounded by many different sources of information, not all of it is accurate or reliable. In particular, anyone can post information online, so it is important to be able to work out who we should be listening to/believing.

Which of the listed people or organisations in the box below are considered reliable sources of information?

  • A journalist
  • An expert in the field
  • A registered organisation or charity (an organisation/charity that has been legally registered with the government and follows certain rules and regulations)
  • A government agency
  • An anonymous author
  • As a general rule, vloggers and bloggers are not considered reliable sources of information. They do not have to justify their views by calling on research findings and their content does not usually go through an editorial process . An editorial process is a series of steps used to ensure the accuracy and quality of a piece of writing. For example, the editorial process often includes a check for plagiarism and a peer review .
  • A reviewer might be a brilliant reviewer, but we should also consider whether or not they are impartial. For example, are they being paid to promote a particular product? A reviewer is also giving their opinion , rather than objective facts.
  • Anonymous contributors are problematic as we do not know who they are, why they are writing or what their information is based on. We cannot hold them accountable for the information provided.
  • We would expect sources produced by registered organisations , such as NHS or Oxfam, to be accurate and produced by experts.
  • The views of an expert in a particular field ought to be reliable, given that they have extensively researched that area and are incredibly knowledgeable on the topic.
  • While journalists must uphold standards, content in newspapers or online news sites might lean towards particular political opinions or parties (depending on the company’s ownership). You need to consider if the information presented is biased.

The next step on evaluating a source is thinking about what information we are given in it.

Here are some examples of types of information we might come across

Type of informationDefinitionExample
StatisticsCollecting, analysing, organising and presenting data. (Source: Statista)
Views of expertInformation from a person with specific knowledge of a topic or field.
AdvertisementMedia that encourage you to buy things or have a particular point of view. Remember, advertisements will often give positive information that will require balance.
Factual informationInformation that deals with facts, not opinions. For example, factual information could come from an encyclopaedia entry.

If you find a statistic you want to use, think carefully about how you are going to use that statistic to add value to what your own argument.

In your essay, you will have to explain the importance of the evidence that you have found. Make sure that you fully understand:

  • what is being conveyed
  • why a writer has included it

A final consideration we must make in evaluating a source is thinking about why that source has been produced.

NHS leafletTo inform patients about conditions/procedures etc
A government reportTo present findings of research/enquiry
A blogTo convey personal response/opinions

Test your knowledge

Challenge: check your sources.

How reliable are the sources you are using for your essay research?

Once you have a list of sources for your essay, evaluate each source quickly using the three step who/what/why method .

Discursive, persuasive and informative writing

How to find the right angle for an essay.

How to carry out essay research and note-making

How to use tone in an essay

essay on sources of knowledge

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  • What Are Credible Sources & How to Spot Them | Examples

What Are Credible Sources & How to Spot Them | Examples

Published on August 26, 2021 by Tegan George . Revised on December 7, 2022.

A credible source is free from bias and backed up with evidence. It is written by a trustworthy author or organization.

There are a lot of sources out there, and it can be hard to tell what’s credible and what isn’t at first glance.

Evaluating source credibility is an important information literacy skill. It ensures that you collect accurate information to back up the arguments you make and the conclusions you draw.

Table of contents

Types of sources, how to identify a credible source, the craap test, where to find credible sources, evaluating web sources, frequently asked questions.

There are many different types of sources , which can be divided into three categories: primary sources , secondary sources , and tertiary sources .

Primary sources are often considered the most credible in terms of providing evidence for your argument, as they give you direct evidence of what you are researching. However, it’s up to you to ensure the information they provide is reliable and accurate.

You will likely use a combination of the three types over the course of your research process .

Type Definition Example
Primary First-hand evidence giving you direct access to your research topic
Secondary Second-hand information that analyzes, describes, or (primary)
Tertiary Sources that identify, index, or consolidate primary and secondary sources

There are a few criteria to look at right away when assessing a source. Together, these criteria form what is known as the CRAAP test .

  • The information should be up-to-date and current.
  • The source should be relevant to your research.
  • The author and publication should be a trusted authority on the subject you are researching.
  • The sources the author cited should be easy to find, clear, and unbiased.
  • For web sources, the URL and layout should signify that it is trustworthy.

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essay on sources of knowledge

The CRAAP test is a catchy acronym that will help you evaluate the credibility of a source you are thinking about using. California State University developed it in 2004 to help students remember best practices for evaluating content.

  • C urrency: Is the source up-to-date?
  • R elevance: Is the source relevant to your research?
  • A uthority: Where is the source published? Who is the author? Are they considered reputable and trustworthy in their field?
  • A ccuracy: Is the source supported by evidence? Are the claims cited correctly?
  • P urpose: What was the motive behind publishing this source?

The criteria for evaluating each point depend on your research topic .

For example, if you are researching cutting-edge scientific technology, a source from 10 years ago will not be sufficiently current . However, if you are researching the Peloponnesian War, a source from 200 years ago would be reasonable to refer to.

Be careful when ascertaining purpose . It can be very unclear (often by design!) what a source’s motive is. For example, a journal article discussing the efficacy of a particular medication may seem credible, but if the publisher is the manufacturer of the medication, you can’t be sure that it is free from bias. As a rule of thumb, if a source is even passively trying to convince you to purchase something, it may not be credible.

Newspapers can be a great way to glean first-hand information about a historical event or situate your research topic within a broader context. However, the veracity and reliability of online news sources can vary enormously—be sure to pay careful attention to authority here.

When evaluating academic journals or books published by university presses, it’s always a good rule of thumb to ensure they are peer-reviewed and published in a reputable journal.

What is peer review?

The peer review process evaluates submissions to academic journals. A panel of reviewers in the same subject area decide whether a submission should be accepted for publication based on a set of criteria.

For this reason, academic journals are often considered among the most credible sources you can use in a research project– provided that the journal itself is trustworthy and well-regarded.

What sources you use depend on the kind of research you are conducting.

For preliminary research and getting to know a new topic, you could use a combination of primary, secondary, and tertiary sources.

  • Encyclopedias
  • Websites with .edu or .org domains
  • News sources with first-hand reporting
  • Research-oriented magazines like ScienceMag or Nature Weekly .

As you dig deeper into your scholarly research, books and academic journals are usually your best bet.

Academic journals are often a great place to find trustworthy and credible content, and are considered one of the most reliable sources you can use in academic writing.

  • Is the journal indexed in academic databases?
  • Has the journal had to retract many articles?
  • Are the journal’s policies on copyright and peer review easily available?
  • Are there solid “About” and “ Scope ” pages detailing what sorts of articles they publish?
  • Has the author of the article published other articles? A quick Google Scholar search will show you.
  • Has the author been cited by other scholars? Google Scholar also has a function called “Cited By” that can show you where the author has been cited. A high number of “Cited By” results can often be a measurement of credibility.

Google Scholar is a search engine for academic sources. This is a great place to kick off your research. You can also consider using an academic database like LexisNexis or government open data to get started.

Open Educational Resources , or OERs, are materials that have been licensed for “free use” in educational settings. Legitimate OERs can be a great resource. Be sure they have a Creative Commons license allowing them to be duplicated and shared, and meet the CRAAP test criteria, especially in the authority section. The OER Commons is a public digital library that is curated by librarians, and a solid place to start.

A few places you can find academic journals online include:
Science + Mathematics
Social Science + Humanities

It can be especially challenging to verify the credibility of online sources. They often do not have single authors or publication dates, and their motivation can be more difficult to ascertain.

Websites are not subject to the peer-review and editing process that academic journals or books go through, and can be published by anyone at any time.

When evaluating the credibility of a website, look first at the URL. The domain extension can help you understand what type of website you’re dealing with.

  • Educational resources end in .edu, and are generally considered the most credible in academic settings.
  • Advocacy or non-profit organizations end in .org.
  • Government-affiliated websites end in .gov.
  • Websites with some sort of commercial aspect end in .com (or .co.uk, or another country-specific domain).

In general, check for vague terms, buzzwords, or writing that is too emotive or subjective . Beware of grandiose claims, and critically analyze anything not cited or backed up by evidence.

  • How does the website look and feel? Does it look professional to you?
  • Is there an “About Us” page, or a way to contact the author or organization if you need clarification on a claim they have made?
  • Are there links to other sources on the page, and are they trustworthy?
  • Can the information you found be verified elsewhere, even via a simple Google search?
  • When was the website last updated? If it hasn’t been updated recently, it may not pass the CRAAP test.
  • Does the website have a lot of advertisements or sponsored content? This could be a sign of bias.
  • Is a source of funding disclosed? This could also give you insight into the author and publisher’s motivations.

Social media posts, blogs, and personal websites can be good resources for a situational analysis or grounding of your preliminary ideas, but exercise caution here. These highly personal and subjective sources are seldom reliable enough to stand on their own in your final research product.

Similarly, Wikipedia is not considered a reliable source due to the fact that it can be edited by anyone at any time. However, it can be a good starting point for general information and finding other sources.

Checklist: Is my source credible?

My source is relevant to my research topic.

My source is recent enough to contain up-to-date information on my topic.

There are no glaring grammatical or orthographic errors.

The author is an expert in their field.

The information provided is accurate to the best of my knowledge. I have checked that it is supported by evidence and/or verifiable elsewhere.

My source cites or links to other sources that appear relevant and trustworthy.

There is a way to contact the author or publisher of my source.

The purpose of my source is to educate or inform, not to sell a product or push a particular opinion.

My source is unbiased, and offers multiple perspectives fairly.

My source avoids vague or grandiose claims, and writing that is too emotive or subjective.

[For academic journals]: My source is peer-reviewed and published in a reputable and established journal.

[For web sources]: The layout of my source is professional and recently updated. Backlinks to other sources are up-to-date and not broken.

[For web sources]: My source’s URL suggests the domain is trustworthy, e.g. a .edu address.

Your sources are likely to be credible!

A credible source should pass the CRAAP test  and follow these guidelines:

  • The information should be up to date and current.
  • For a web source, the URL and layout should signify that it is trustworthy.

Peer review is a process of evaluating submissions to an academic journal. Utilizing rigorous criteria, a panel of reviewers in the same subject area decide whether to accept each submission for publication. For this reason, academic journals are often considered among the most credible sources you can use in a research project– provided that the journal itself is trustworthy and well-regarded.

The CRAAP test is an acronym to help you evaluate the credibility of a source you are considering using. It is an important component of information literacy .

The CRAAP test has five main components:

  • Currency: Is the source up to date?
  • Relevance: Is the source relevant to your research?
  • Authority: Where is the source published? Who is the author? Are they considered reputable and trustworthy in their field?
  • Accuracy: Is the source supported by evidence? Are the claims cited correctly?
  • Purpose: What was the motive behind publishing this source?

Academic dishonesty can be intentional or unintentional, ranging from something as simple as claiming to have read something you didn’t to copying your neighbor’s answers on an exam.

You can commit academic dishonesty with the best of intentions, such as helping a friend cheat on a paper. Severe academic dishonesty can include buying a pre-written essay or the answers to a multiple-choice test, or falsifying a medical emergency to avoid taking a final exam.

To determine if a source is primary or secondary, ask yourself:

  • Was the source created by someone directly involved in the events you’re studying (primary), or by another researcher (secondary)?
  • Does the source provide original information (primary), or does it summarize information from other sources (secondary)?
  • Are you directly analyzing the source itself (primary), or only using it for background information (secondary)?

Some types of source are nearly always primary: works of art and literature, raw statistical data, official documents and records, and personal communications (e.g. letters, interviews ). If you use one of these in your research, it is probably a primary source.

Primary sources are often considered the most credible in terms of providing evidence for your argument, as they give you direct evidence of what you are researching. However, it’s up to you to ensure the information they provide is reliable and accurate.

Always make sure to properly cite your sources to avoid plagiarism .

Cite this Scribbr article

If you want to cite this source, you can copy and paste the citation or click the “Cite this Scribbr article” button to automatically add the citation to our free Citation Generator.

George, T. (2022, December 07). What Are Credible Sources & How to Spot Them | Examples. Scribbr. Retrieved May 5, 2023, from https://www.scribbr.com/working-with-sources/credible-sources/

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Google shared AI knowledge with the world — until ChatGPT caught up

For years the tech giant published scientific research that helped jump-start its competitors. but now it’s lurched into defensive mode..

In February, Jeff Dean, Google’s longtime head of artificial intelligence, announced a stunning policy shift to his staff: They had to hold off sharing their work with the outside world.

For years Dean had run his department like a university, encouraging researchers to publish academic papers prolifically; they pushed out nearly 500 studies since 2019, according to Google Research’s website .

But the launch of OpenAI’s groundbreaking ChatGPT three months earlier had changed things. The San Francisco start-up kept up with Google by reading the team’s scientific papers, Dean said at the quarterly meeting for the company’s research division. Indeed, transformers — a foundational part of the latest AI tech and the T in ChatGPT — originated in a Google study .

Things had to change. Google would take advantage of its own AI discoveries, sharing papers only after the lab work had been turned into products, Dean said, according to two people with knowledge of the meeting, who spoke on the condition of anonymity to share private information.

The policy change is part of a larger shift inside Google. Long considered the leader in AI, the tech giant has lurched into defensive mode — first to fend off a fleet of nimble AI competitors , and now to protect its core search business, stock price, and, potentially, its future, which executives have said is intertwined with AI.

In op-eds, podcasts and TV appearances, Google CEO Sundar Pichai has urged caution on AI. “On a societal scale, it can cause a lot of harm,” he warned on “60 Minutes” in April, describing how the technology could supercharge the creation of fake images and videos.

But in recent months, Google has overhauled its AI operations with the goal of launching products quickly, according to interviews with 11 current and former Google employees, most of whom spoke on the condition of anonymity to share private information.

It has lowered the bar for launching experimental AI tools to smaller groups, developing a new set of evaluation metrics and priorities in areas like fairness. It also merged Google Brain, an organization run by Dean and shaped by researchers’ interests, with DeepMind, a rival AI unit with a singular, top-down focus, to “accelerate our progress in AI,” Pichai wrote in an announcement. This new division will not be run by Dean, but by Demis Hassabis, CEO of DeepMind, a group seen by some as having a fresher, more hard-charging brand.

At a conference earlier this week, Hassabis said AI was potentially closer to achieving human-level intelligence than most other AI experts have predicted. “We could be just a few years, maybe … a decade away,” he said.

Google’s acceleration comes as a cacophony of voices — including notable company alumnae and industry veterans — are calling for the AI developers to slow down, warning that the tech is developing faster than even its inventors anticipated. Geoffrey Hinton, one of the pioneers of AI tech who joined Google in 2013 and recently left the company, has since gone on a media blitz warning about the dangers of supersmart AI escaping human control. Pichai, along with the CEOs of OpenAI and Microsoft, will meet with White House officials on Thursday, part of the administration’s ongoing effort to signal progress amid public concern, as regulators around the world discuss new rules around the technology.

Meanwhile, an AI arms race is continuing without oversight, and companies’ concerns of appearing reckless may erode in the face of competition .

“It’s not that they were cautious, they weren’t willing to undermine their existing revenue streams and business models,” said DeepMind co-founder Mustafa Suleyman, who left Google in 2022 and launched Pi, a personalized AI from his new start-up Inflection AI this week. “It’s only when there is a real external threat that they then start waking up.”

Pichai has stressed that Google’s efforts to speed up does not mean cutting corners. “The pace of progress is now faster than ever before,” he wrote in the merger announcement. “To ensure the bold and responsible development of general AI, we’re creating a unit that will help us build more capable systems more safely and responsibly.”

One former Google AI researcher described the shift as Google going from “peacetime” to “wartime.” Publishing research broadly helps grow the overall field, Brian Kihoon Lee, a Google Brain researcher who was cut as part of the company’s massive layoffs in January, wrote in an April blog post. But once things get more competitive, the calculus changes.

“In wartime mode, it also matters how much your competitors’ slice of the pie is growing,” Lee said. He declined to comment further for this story.

“In 2018, we established an internal governance structure and a comprehensive review process — with hundreds of reviews across product areas so far — and we have continued to apply that process to AI-based technologies we launch externally,” Google spokesperson Brian Gabriel said. “Responsible AI remains a top priority at the company.”

Pichai and other executives have increasingly begun talking about the prospect of AI tech matching or exceeding human intelligence, a concept known as artificial general intelligence, or AGI. The once fringe term , associated with the idea that AI poses an existential risk to humanity, is central to OpenAI’s mission and had been embraced by DeepMind, but was avoided by Google’s top brass.

To Google employees, this accelerated approach is a mixed blessing. The need for additional approval before publishing on relevant AI research could mean researchers will be “scooped” on their discoveries in the lightning-fast world of generative AI. Some worry it could be used to quietly squash controversial papers , like a 2020 study about the harms of large language models, co-authored by the leads of Google’s Ethical AI team, Timnit Gebru and Margaret Mitchell.

But others acknowledge Google has lost many of its top AI researchers in the last year to start-ups seen as cutting edge. Some of this exodus stemmed from frustration that Google wasn’t making seemingly obvious moves, like incorporating chatbots into search, stymied by concerns about legal and reputational harms.

On the live stream of the quarterly meeting, Dean’s announcement got a favorable response, with employees sharing upbeat emoji, in the hopes that the pivot would help Google win back the upper hand. “OpenAI was beating us at our own game,” said one employee who attended the meeting.

For some researchers, Dean’s announcement at the quarterly meeting was the first they were hearing about the restrictions on publishing research. But for those working on large language models, a technology core to chatbots, things had gotten stricter since Google executives first issued a “Code Red” to focus on AI in December, after ChatGPT became an instant phenomenon.

Getting approval for papers could require repeated intense reviews with senior staffers, according to one former researcher. Many scientists went to work at Google with the promise of being able to continue participating in the wider conversation in their field. Another round of researchers left because of the restrictions on publishing.

Shifting standards for determining when an AI product is ready to launch has triggered unease. Google’s decision to release its artificial intelligence chatbot Bard and implement lower standards on some test scores for experimental AI products has triggered internal backlash, according to a report in Bloomberg.

But other employees feel Google has done a thoughtful job of trying to establish standards around this emerging field. In early 2023, Google shared a list of about 20 policy priorities around Bard developed by two AI teams: the Responsible Innovation team and Responsible AI. One employee called the rules “reasonably clear and relatively robust.”

Others had less faith in the scores to begin with and found the exercise largely performative. They felt the public would be better served by external transparency, like documenting what is inside the training data or opening up the model to outside experts.

Consumers are just beginning to learn about the risks and limitations of large language models, like the AI’s tendency to make up facts. But El Mahdi El Mhamdi, a senior Google Research scientist, who resigned in February over the company’s lack of transparency over AI ethics, said tech companies may have been using this technology to train other systems in ways that can be challenging for even employees to track.

When he uses Google Translate and YouTube, “I already see the volatility and instability that could only be explained by the use of,” these models and data sets, El Mhamdi said.

Many companies have already demonstrated the issues with moving fast and launching unfinished tools to large audiences.

“To say, ‘Hey, here’s this magical system that can do anything you want,’ and then users start to use it in ways that they don’t anticipate, I think that is pretty bad,” said Stanford professor Percy Liang, adding that the small print disclaimers on ChatGPT don’t make its limitations clear.

It’s important to rigorously evaluate the technology’s capabilities, he added. Liang recently co-authored a paper examining AI search tools like the new Bing. It found that only about 70 percent of its citations were correct.

Google has poured money into developing AI tech for years. In the early 2010s it began buying AI start-ups , incorporating their tech into its ever-growing suite of products. In 2013, it brought on Hinton, the AI software pioneer whose scientific work helped form the bedrock for the current dominant crop of technologies. A year later, it bought DeepMind, founded by Hassabis, another leading AI researcher, for $625 million.

Soon after being named CEO of Google, Pichai declared that Google would become an “AI first” company, integrating the tech into all of its products. Over the years, Google’s AI research teams developed breakthroughs and tools that would benefit the whole industry. They invented “transformers” — a new type of AI model that could digest larger data sets. The tech became the foundation for the “large language models” that now dominate the conversation around AI — including OpenAI’s GPT3 and GPT4.

Despite these steady advancements, it was ChatGPT — built by the smaller upstart OpenAI — that triggered a wave of broader fascination and excitement in AI. Founded to provide a counterweight to Big Tech companies’ takeover of the field, OpenAI faced less scrutiny than its bigger rivals and was more willing to put its most powerful AI models into the hands of regular people.

“It’s already hard in any organizations to bridge that gap between real scientists that are advancing the fundamental models versus the people who are trying to build products,” said De Kai, an AI researcher at University of California Berkeley who served on Google’s short-lived outside AI advisory board in 2019. “How you integrate that in a way that doesn’t trip up your ability to have teams that are pushing the state of the art, that’s a challenge.”

Meanwhile, Google has been careful to label its chatbot Bard and its other new AI products as “experiments.” But for a company with billions of users, even small-scale experiments affect millions of people and it’s likely much of the world will come into contact with generative AI through Google tools. The company’s sheer size means its shift to launching new AI products faster is triggering concerns from a broad range of regulators, AI researchers and business leaders.

The invitation to Thursday’s White House meeting reminded the chief executives that President Biden had already “made clear our expectation that companies like yours must make sure their products are safe before making them available to the public.”

This story has been updated to clarify that De Kai is researcher at the University of California Berkeley.

  • Google shared AI knowledge with the world — until ChatGPT caught up Just now Google shared AI knowledge with the world — until ChatGPT caught up Just now
  • AI pioneer quits Google to warn humanity of the tech’s existential threat May 2, 2023 AI pioneer quits Google to warn humanity of the tech’s existential threat May 2, 2023
  • Say what, Bard? What Google’s new AI gets right, wrong and weird. March 21, 2023 Say what, Bard? What Google’s new AI gets right, wrong and weird. March 21, 2023
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The Gravest Threats to Campus Speech Come From States, Not Students

A close-up of a bill on the desk of Gov. Ron DeSantis of Florida, with only his right arm visible. The paper in front of him bears his signature and the large letters “CRT” (for critical race theory) with a traffic sign-style red bar through the letters.

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By Christina Paxson

Ms. Paxson is the president of Brown University.

America is facing a fundamental threat‌, and it echoes a dark past.

In 1633, Galileo was forced to renounce the “false opinion” that the Earth circled the sun since it collided with the prevailing beliefs of the Catholic Church.

Shortly after publication in 1859, Charles Darwin’s “On the Origin of Species ” was banned from the library of Trinity College, Cambridge.

And in the early 1950s, during the McCarthy era, many university professors were subject to “loyalty hearings,” and some lost their positions because of defamation campaigns and indiscriminate allegations of Communist leanings.

Each of these episodes of censorship and repression of knowledge reflected the unique social and political tensions of its time. But the proponents of censorship and repression all had one thing in common: they were on the wrong side of history.

‌The mistakes of the past are being repeated in this country, right now. The State Senate in Texas last week advanced one of three bills aimed at public colleges that would ban diversity, equity and inclusion activities, end tenure, and fire professors accused of indoctrinating their students. Several states, including Georgia , Idaho and most notably Florida , have passed varying laws making it easier to ban books and limit what American educators can teach.

Dozens of other bills are pending in state legislatures around the country with the promise of affecting what tens of millions of students will or won’t be allowed to learn, and exerting a chilling effect on educators who fear for their jobs. The recent actions take aim at teaching about so-called “divisive concepts,” including the history of slavery in America and its legacy in modern times, structural racism, evolving concepts of gender identity, sexuality and L.G.B.T.Q. issues, and anything to do with diversity, however defined. ‌They are just as dangerous and misguided as attempts to outlaw the teaching of evolution, or Joseph McCarthy’s persecution of people for their political beliefs.

Like their forebears, the proponents of these laws are on the wrong side of history. They are acting out of political expediency, ‌exploiting convenient political wedge issues. They are mounting a direct and dangerous attack on America’s longstanding commitment to free expression, democracy and education. Legislating toward a future where the state decrees what ideas may be taught and debated upends a bedrock principle of this country.

I am the president of a private, nonprofit university in Rhode Island, a state founded on the values of freedom and tolerance. Brown University is not immediately threatened by new or pending laws affecting public education in Arizona, Florida, Texas, or the numerous other states where similar legislation has been introduced. I am free to speak against what’s happening, but the educational leaders in the states in question, particularly those at the helm of public institutions, are in very different positions. The new laws censor their voices as well as those of their faculty and students.

Proponents of these laws attempt to justify them by repeating claims that universities are places where political correctness runs rampant and students are intolerant of alternative viewpoints. In my experience, these problems are much less pervasive than media coverage suggests, but they do exist. Students should not ‌violate university policies and ‌shout down speakers they don’t agree with. And peer pressure, like cancel culture in the larger world, is unfortunate and sometimes suppresses debate. Universities ‌work hard to prevent and address these problems. We need to support‌ open inquiry and debate both inside and outside of classrooms.

But ‌‌it is ludicrous to claim that state-sponsored censorship — which carries the full force of the government and can even entail criminal penalties — is justified by student misconduct or peer pressure.

The ironic truth is that laws that prohibit the teaching of “divisive concepts” are themselves attempts to indoctrinate students into seeing the world through one lens. This is exactly the opposite of what colleges and universities should do. College campuses are a place for controversial issues and emerging ideas to be taught, discussed and debated. This is how we fulfill our missions of advancing knowledge and understanding in a democratic society.

The very project of democracy means bringing together people who have different values and objectives, and helping them find a way to work toward common goals. This project is messy but essential. If we can’t get it right on college campuses, then where?

Consider that, over the centuries, students across this country have been free to confront controversial issues such as the abolition of slavery, women’s rights and the involvement of the U.S. in military actions around the world. We should be thankful that‌‌ no limits or laws were in place to prevent students from considering such important questions.

One hundred years from now, the ideas and theories about American history, race and gender that are currently being suppressed may survive, or not. No one reading this column will be alive to know the answer, any more than Galileo knew if his belief that positioned the sun as the center of the universe would be accepted in the centuries ahead.

I hope that in his years of house arrest, ending only in his death, Galileo understood and took comfort in the truth that ideas survive or perish after having been subject to rigorous and open intellectual inquiry. In the long run, misguided laws that censor ideas and suppress the advancement of knowledge fail, and their architects fail with them.

Christina H. Paxson is the president of Brown University and a frequent public voice on issues of academic freedom and freedom of expression.

The Times is committed to publishing a diversity of letters to the editor. We’d like to hear what you think about this or any of our articles. Here are some tips . And here’s our email: [email protected] .

Follow The New York Times Opinion section on Facebook , Twitter (@NYTopinion) and Instagram .

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Latest national test results underscore declining knowledge of U.S. history and civics

Covid could be just one factor for nationwide in 8th grade naep scores, john fensterwald, may 3, 2023.

Scores nationwide testing eighth  graders’ understanding of U.S. history continued a decade of decline in 2022  and fell for the first time in civics , according to data released Tuesday.

Only 13% of students scored proficient in history and only 22% scored proficient in civics on the National Assessment of Educational Progress; 40% of students scored below the basic level of knowledge in U.S. history, a decline from 34% in 2018.

The implication is a large proportion of students lacking a strong foundation and understanding of the subjects are entering high schools where civics and history are facing highly politicized debates over content and instruction. Some California teachers are toning down or avoiding vigorous discussions to avoid contention.

“There are a number of schools implementing outstanding history and civics programs for youth in California and across the nation. But sadly, they are the exception and not the norm,” said Michelle Herczog, coordinator of history and social science instruction for the Los Angeles County Office of Education. “The dismal NAEP findings need to be a call to action for every American school, beginning in kindergarten, to energize the teaching of U.S. history and civics in non-partisan ways, as an educational priority.” 

Said Leslie Muldoon, executive director of the National Assessment governing board, an independent body that sets policy for NAEP:  “ Schools at all grade levels have a core role to play in instruction around citizenship, knowledge and skills.”   

The drop in results was not surprising; 2022 scores released last fall in math and reading plummeted in four th and eigh th grade nationally and, to a lesser extent, in California.

“Given what we already know about how Covid affected students’ reading and math skills, I think it’s important to emphasize the disruption caused by the pandemic,” said Martin West, the academic dean at the Harvard Graduate School of Education and a member of NAEP’s governing board.

But, he said, noting that U.S.  history scores fell by a similar amount between 2014 and 2018, “I think it would be a mistake to say that this is all about the pandemic and not try to identify other factors that could be affecting students’ performance.”

While more than 100,000 students nationwide took the 2022 NAEP math and reading tests, only 7,800 eighth graders from 410 schools took the test in civics, and 8,000 eighth-graders from 410 schools took the history test — too few to provide results by state.

Based on a scale of 300 points, the average civics score of 150 in 2022 was 2 points lower than in 2018 and equal to the score in 1998, the first year for civics using the current framework. It is 28 points below the level designating proficiency.

Based on a scale of 500 points, the average eighth-grader’s U.S. history score was 258, a significant 5-point drop from 263 in 2018  and not significantly different from 259 in 1994, the first year the test was given. It is also 36 points below the level designating proficiency.

Lower scores in history especially were widespread and profound, covering all racial and ethnic groups and all student achievement groups except for the highest achievers, the top 10% of performers. Their scores in history and civics held steady, another indication of the widening gap of achievement between the lowest and highest performing students that also were prevalent in math and reading. In civics, scores of students in the lowest 10 th and 25 th percentiles of performance fell, while scores didn’t drop among the top quarter of students.

  “The top half of students are OK by the historical measure of bad performance, but the bottom half got worse, dragging down the distribution,” said another NAEP board member, Eric Hanushek, an economist and senior fellow with the Hoover Institution at Stanford University . “This reinforces our concern about polarization in general knowledge and views of civics and history among the next generation.”

Several factors could be at play. NEAP assessments, West said, “are always much better at telling us what’s happening with students than why.”

Low scores could point to weak comprehension skills. “Schools must focus on literacy from the earliest grades and sustain reading and background knowledge through middle school and beyond,” said Muldoon.

In 2022, there was a small drop in the proportion of eighth grade students who took a course primarily focused on U.S. history compared with four years earlier. Those students scored 12 points higher than students who took a course with only some U.S. history and 14 points higher than students who didn’t take a U.S. history course.

“We also know that there have been various pressures on schools that have unfortunately led elementary schools in particular to spend more instructional time on reading and math,  less on science and social studies,” West said. Instead, schools should recognize that “building students’ background knowledge in areas like history and civics is crucial for their development as readers.”

“Especially in elementary school, instructional time on different subjects is not a zero-sum game,” he said.

Los Angeles Unified Superintendent Alberto Carvahlo, who also services on the NAEP board, agreed.  

“I think there’s been a preponderance of emphasis on literacy and numeracy at the expense of other areas such as civics, such as technology. So I don’t think it’s surprising that we are looking at pretty dismal data, ” he said.

What the tests measure 

The U.S. history assessment measures eighth graders’ knowledge of four themes: change and continuity in American democracy; interactions of peoples, cultures and ideas; economic and technological changes and their impacts on society; and the changing role of America in the world.

The civics assessment measures knowledge about government and civil society; participatory skills essential for informed, effective and responsible citizenship; and civic dispositions that contribute to the individual effectiveness and the common good.

The assessment presents both multiple-choice and open-ended questions requiring written responses.

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On the 2022 U.S. history assessment, 84% of students picked correctly on a multiple-choice question asking about working conditions in a 19th-century  factory. But only 6% got the full credit, needed for a proficient score , asking what two ideas from the Constitution or Declaration of Independence that Martin Luther King might have referred to in a less-known passage from his 1963 “I Have a Dream” speech.

Hanushek acknowledged that scoring proficient on NAEP U.S history reflects a high standard, requiring a deeper understanding of knowledge, while scoring basic does not – equivalent to naming the functions of the Legislature. Scoring below basic means you cannot talk about U.S. government functions, and “that should be a concern.”

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rob 1 day ago 1 day ago

Dont take it so personal…. the entire USA has fallen off a cliff in Mathematics, Science, and English as well!

Erik Kengaard 1 day ago 1 day ago

Only those of limited perspective react to averages of an extremely heterogenous population

Dr. Bill Conrad 6 hours ago 6 hours ago

The canary is long dead on the mine floor and in rigor mortis!

Frances O'Neill Zimmerman 2 days ago 2 days ago

When regular teaching of civics and History is interrupted, devalued and diminished, as has been happening in K-12 public schools over the past decade or longer, it is no surprise that students quickly become know-nothings. Those same students become ignorant adults, susceptible to social media and other propaganda. They are easily influenced because they have no background to counter spurious sources of "news" and "facts." If we care about maintaining and strengthening this democracy, … Read More

When regular teaching of civics and History is interrupted, devalued and diminished, as has been happening in K-12 public schools over the past decade or longer, it is no surprise that students quickly become know-nothings. Those same students become ignorant adults, susceptible to social media and other propaganda. They are easily influenced because they have no background to counter spurious sources of “news” and “facts.” If we care about maintaining and strengthening this democracy, we will restore civics and history to their full place in the curriculum, and we might even revive the discontinued high school exit exam.

Elizabeth Silva 2 days ago 2 days ago

I think part of the reason for this decline is a reflection of the increasing disrespect our society has for the founding fathers and the documents that made this country. This has been going on for years. Our history has become irrelevant and even shameful to more and more people. Just today I saw a video a restaurant patron in Fallbrook, California, made of fellow diners standing for the national anthem. Apparently the restaurant owners … Read More

I think part of the reason for this decline is a reflection of the increasing disrespect our society has for the founding fathers and the documents that made this country. This has been going on for years. Our history has become irrelevant and even shameful to more and more people.

Just today I saw a video a restaurant patron in Fallbrook, California, made of fellow diners standing for the national anthem. Apparently the restaurant owners play the national anthem daily at noon. It was the “scariest thing” she’d ever seen, she said. The ignorance of people like this, and their unwillingness to recognize the good in our history as well as the bad, is unforgivable.

Bob Becker 2 days ago 2 days ago

And we have no idea how California is doing because we do not participate in NAEP Civics testing, and when we abandoned California’s STAR system we ended any statewide histroy-social science assessments.

John Fensterwald 2 days ago 2 days ago

Bob, as far as I know, the Civics test is a national assessment only. Do you know otherwise?

Tom Adams 2 days ago 2 days ago

While NAEP provides good information about history- social science education, it only comes every 4 years. CA did have a standards-based test for history-social science but it was discontinued. Unfortunately, no additional source of information exists to inform policy discussions and to provide a portrait of the state of social studies teaching and learning.

Dr. Bill Conrad 2 days ago 2 days ago

When almost 50 million 4th grade students score below proficient on the Reading NAEP over 20 years, you may have found a strong contributor to low proficiency scores in history.

Hopefully, educators have seen the failure of their ways in pursuing the Balanced Reading boondoggle, and will now pursue evidence and science- based approaches to teaching reading! It might help!

Reading must be Job #1 in California.

It would be nice if our state education leaders would weigh in! No?

John Trasvina, CA Senior Advisor 2 days ago 2 days ago

California’s State Seal of Civic Engagement recognizes high school students who have the academic training in civics and history and apply what they learn to participate in their communities.

Generation Citizen backs Assembly Member Mia Bonta’s AB 1520 that paves the way to equip more school districts and to train teachers to offer programs to advance civic learning. The NAEP report underscores the need for concerted action.

Erik Kengaard 2 days ago 2 days ago

Generalizations with reference to student performance in California are irritating, misleading and a turnoff. Performance varies by community, and meaningful reporting requires analysis at the community level.

Dr. Lisa Lace 2 days ago 2 days ago

Did we expect anything else? California keeps pushing for fake history to be taught to demonize the history of the United States. If we want test scores to go up, we need to put fake questions about the fake history we are forced to teach! Or we could go back to teaching actual US History?

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Gender pay gap in u.s. hasn’t changed much in two decades.

The gender gap in pay has remained relatively stable in the United States over the past 20 years or so. In 2022, women earned an average of 82% of what men earned, according to a new Pew Research Center analysis of median hourly earnings of both full- and part-time workers. These results are similar to where the pay gap stood in 2002, when women earned 80% as much as men.

A chart showing that the Gender pay gap in the U.S. has not closed in recent years, but is narrower among young workers

As has long been the case, the wage gap is smaller for workers ages 25 to 34 than for all workers 16 and older. In 2022, women ages 25 to 34 earned an average of 92 cents for every dollar earned by a man in the same age group – an 8-cent gap. By comparison, the gender pay gap among workers of all ages that year was 18 cents.

While the gender pay gap has not changed much in the last two decades, it has narrowed considerably when looking at the longer term, both among all workers ages 16 and older and among those ages 25 to 34. The estimated 18-cent gender pay gap among all workers in 2022 was down from 35 cents in 1982. And the 8-cent gap among workers ages 25 to 34 in 2022 was down from a 26-cent gap four decades earlier.

The gender pay gap measures the difference in median hourly earnings between men and women who work full or part time in the United States. Pew Research Center’s estimate of the pay gap is based on an analysis of Current Population Survey (CPS) monthly outgoing rotation group files ( IPUMS ) from January 1982 to December 2022, combined to create annual files. To understand how we calculate the gender pay gap, read our 2013 post, “How Pew Research Center measured the gender pay gap.”

The COVID-19 outbreak affected data collection efforts by the U.S. government in its surveys, especially in 2020 and 2021, limiting in-person data collection and affecting response rates. It is possible that some measures of economic outcomes and how they vary across demographic groups are affected by these changes in data collection.

In addition to findings about the gender wage gap, this analysis includes information from a Pew Research Center survey about the perceived reasons for the pay gap, as well as the pressures and career goals of U.S. men and women. The survey was conducted among 5,098 adults and includes a subset of questions asked only for 2,048 adults who are employed part time or full time, from Oct. 10-16, 2022. Everyone who took part is a member of the Center’s American Trends Panel (ATP), an online survey panel that is recruited through national, random sampling of residential addresses. This way nearly all U.S. adults have a chance of selection. The survey is weighted to be representative of the U.S. adult population by gender, race, ethnicity, partisan affiliation, education and other categories. Read more about the ATP’s methodology .

Here are the questions used in this analysis, along with responses, and its methodology .

The  U.S. Census Bureau has also analyzed the gender pay gap, though its analysis looks only at full-time workers (as opposed to full- and part-time workers). In 2021, full-time, year-round working women earned 84% of what their male counterparts earned, on average, according to the Census Bureau’s most recent analysis.

Much of the gender pay gap has been explained by measurable factors such as educational attainment, occupational segregation and work experience. The narrowing of the gap over the long term is attributable in large part to gains women have made in each of these dimensions.

Related: The Enduring Grip of the Gender Pay Gap

Even though women have increased their presence in higher-paying jobs traditionally dominated by men, such as professional and managerial positions, women as a whole continue to be overrepresented in lower-paying occupations relative to their share of the workforce. This may contribute to gender differences in pay.

Other factors that are difficult to measure, including gender discrimination, may also contribute to the ongoing wage discrepancy.

Perceived reasons for the gender wage gap

A bar chart showing that Half of U.S. adults say women being treated differently by employers is a major reason for the gender wage gap

When asked about the factors that may play a role in the gender wage gap, half of U.S. adults point to women being treated differently by employers as a major reason, according to a Pew Research Center survey conducted in October 2022. Smaller shares point to women making different choices about how to balance work and family (42%) and working in jobs that pay less (34%).

There are some notable differences between men and women in views of what’s behind the gender wage gap. Women are much more likely than men (61% vs. 37%) to say a major reason for the gap is that employers treat women differently. And while 45% of women say a major factor is that women make different choices about how to balance work and family, men are slightly less likely to hold that view (40% say this).

Parents with children younger than 18 in the household are more likely than those who don’t have young kids at home (48% vs. 40%) to say a major reason for the pay gap is the choices that women make about how to balance family and work. On this question, differences by parental status are evident among both men and women.

Views about reasons for the gender wage gap also differ by party. About two-thirds of Democrats and Democratic-leaning independents (68%) say a major factor behind wage differences is that employers treat women differently, but far fewer Republicans and Republican leaners (30%) say the same. Conversely, Republicans are more likely than Democrats to say women’s choices about how to balance family and work (50% vs. 36%) and their tendency to work in jobs that pay less (39% vs. 30%) are major reasons why women earn less than men.

Democratic and Republican women are more likely than their male counterparts in the same party to say a major reason for the gender wage gap is that employers treat women differently. About three-quarters of Democratic women (76%) say this, compared with 59% of Democratic men. And while 43% of Republican women say unequal treatment by employers is a major reason for the gender wage gap, just 18% of GOP men share that view.

Pressures facing working women and men

Family caregiving responsibilities bring different pressures for working women and men, and research has shown that being a mother can reduce women’s earnings , while fatherhood can increase men’s earnings .

A chart showing that about two-thirds of U.S. working mothers feel a great deal of pressure to focus on responsibilities at home

Employed women and men are about equally likely to say they feel a great deal of pressure to support their family financially and to be successful in their jobs and careers, according to the Center’s October survey. But women, and particularly working mothers, are more likely than men to say they feel a great deal of pressure to focus on responsibilities at home.

About half of employed women (48%) report feeling a great deal of pressure to focus on their responsibilities at home, compared with 35% of employed men. Among working mothers with children younger than 18 in the household, two-thirds (67%) say the same, compared with 45% of working dads.

When it comes to supporting their family financially, similar shares of working moms and dads (57% vs. 62%) report they feel a great deal of pressure, but this is driven mainly by the large share of unmarried working mothers who say they feel a great deal of pressure in this regard (77%). Among those who are married, working dads are far more likely than working moms (60% vs. 43%) to say they feel a great deal of pressure to support their family financially. (There were not enough unmarried working fathers in the sample to analyze separately.)

About four-in-ten working parents say they feel a great deal of pressure to be successful at their job or career. These findings don’t differ by gender.

Gender differences in job roles, aspirations

A bar chart showing that women in the U.S. are more likely than men to say they're not the boss at their job - and don't want to be in the future

Overall, a quarter of employed U.S. adults say they are currently the boss or one of the top managers where they work, according to the Center’s survey. Another 33% say they are not currently the boss but would like to be in the future, while 41% are not and do not aspire to be the boss or one of the top managers.

Men are more likely than women to be a boss or a top manager where they work (28% vs. 21%). This is especially the case among employed fathers, 35% of whom say they are the boss or one of the top managers where they work. (The varying attitudes between fathers and men without children at least partly reflect differences in marital status and educational attainment between the two groups.)

In addition to being less likely than men to say they are currently the boss or a top manager at work, women are also more likely to say they wouldn’t want to be in this type of position in the future. More than four-in-ten employed women (46%) say this, compared with 37% of men. Similar shares of men (35%) and women (31%) say they are not currently the boss but would like to be one day. These patterns are similar among parents.

Note: This is an update of a post originally published on March 22, 2019. Anna Brown and former Pew Research Center writer/editor Amanda Barroso contributed to an earlier version of this analysis. Here are the questions used in this analysis, along with responses, and its methodology .

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What is the gender wage gap in your metropolitan area? Find out with our pay gap calculator

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When negotiating starting salaries, most u.s. women and men don’t ask for higher pay, the enduring grip of the gender pay gap, most popular.

About Pew Research Center Pew Research Center is a nonpartisan fact tank that informs the public about the issues, attitudes and trends shaping the world. It conducts public opinion polling, demographic research, media content analysis and other empirical social science research. Pew Research Center does not take policy positions. It is a subsidiary of The Pew Charitable Trusts .

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What I Learned From Justice Stevens' Papers on Kelo v. City of New London

There are several interesting revelations, including an unpublished dissent by justice antonin scalia..

Ilya Somin | 5.5.2023 12:51 AM

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In my last post , I outlined some things I hoped to learn from Justice John Paul Stevens' papers about Kelo v. City of New London , the controversial 5-4 decision in which the Supreme Court ruled that the condemnation of homes for "private economic development" is permissible under the Takings Clause of the Fifth Amendment (which only allows takings that are for a "public use"). Stevens wrote the majority opinion. Kelo was an important decision that drew a massive political backlash (over 80% of the public opposed the ruling, and 45 states enacted eminent domain reform laws in reaction to it) and remains contentious to this day.

There are two big revelations. First, there was no vote switch. Five justices intended to uphold the takings from the beginning of the Court's deliberations. However, Stevens did apparently worry that he might lose the support of key swing voter Justice Anthony Kennedy. Second, Justice Antonin Scalia wrote a draft dissent, which he eventually chose not to publish (though he did join Sandra Day O'Connor's dissenting opinion). I will post Justice Scalia's draft dissent in a separate post, along with my comments on it.

Here is what I have learned about the answers to the five questions outlined in my previous post , plus a few additional revelations:

1. Was there a chance the case could have gone the other way? Did Justice Kennedy flip?

The evidence indicates that five justices, including Justice Kennedy, wanted to uphold the New London condemnations all along. However, Stevens seems to have been concerned that Kennedy might defect. At one point, he sent an e-mail to Roberto Gonzalez, his law clerk working on the Kelo case, saying that "I don't think we need to reply [to Justice Scalia's draft dissent]—of course we do need five votes, but I don't think this reference to Lawrence [v. Texas] is likely to be persuasive to AMK [Justice Kennedy]." This implies that Stevens was on guard about a potential switch by Kennedy, but thought that Scalia's draft dissent was unlikely to sway Kennedy into the dissenters' camp. Yet he also may have worried that some other argument might indeed be "persuasive to AMK."

Kennedy did not agree to join what became Stevens' majority opinion until just a few days before the Court's decision was issued on June 23, 2005. On June 16-17, Kennedy asked Stevens to make a number of changes to the majority draft, in exchange for his support, and Stevens agreed. Kennedy then finally agreed to join, but also authored a solo concurring opinion, which has confused takings lawyers and lower court judges ever since.

I won't go over them in detail here. But, in my view, the changes Kennedy requested mostly concern minor issues, and did little to change the bottom-line reasoning and effect of the Kelo decision. The admittedly limited available evidence suggests Stevens worried about the possibility of Kennedy flipping, but the risk probably wasn't all that high. We may never know for sure how great it actually was, at least not unless Justice Kennedy reveals his papers someday.

2. Why did Justice Sandra Day O'Connor, author of the lead dissenting opinion in Kelo, change her mind about "public use" between 1984 and 2005?

As discussed in my previous post , O'Connor endorsed a very broad view of public use in her opinion for the Court in Hawaii Housing Authority v. Midkiff (1984) , but switched to a much narrower view in her influential lead dissent in Kelo , which garnered the support of four justices. Sadly, the Stevens papers shed no light on this important issue. We may know more when and if Justice O'Connor (who retired in 2005), releases her own papers.

3. Did any of the justices anticipate the massive political reaction against Kelo ? Did it influence the decision in any way?

The files don't reveal any anticipation of the reaction Kelo would generate, on the part of any of the justices. That doesn't prove none of them foresaw it. But, if so, it isn't reflected in their communications with Stevens. I think some significant negative reaction was foreseeable based on the extensive media and public attention the case attracted even before the Court issued its ruling. But the justices may have been oblivious to this, or at least underestimated the extent of public anger.

4. Why didn't Justice Scalia join Clarence Thomas' strong originalist dissent?

As already noted, the Stevens papers reveal that Scalia authored a solo dissent of his own, that he ultimately chose not to publish. I will say more about it in a future post. Here, I will only note that the Scalia dissent says almost nothing about the text and original meaning of the Takings Clause, and therefore doesn't tell us anything about why he chose not to join Thomas. Nor is there anything else in the Stevens papers that bears on this question. Scalia did join Justice O'Connor's mostly non-originalist dissent.

In my view, outlined in my book about Kelo ,  the Thomas dissent is the best of the four opinions in the case. Scalia  apparently had a different view. But we still don't know why.

5. Does anything in the Stevens files strengthen or weaken the case for overruling Kelo ?

Kelo remains a highly controversial decision, and four current Supreme Court justices have expressed interest in overruling or at least revisiting it (I hope they do!). I don't think anything in the Stevens papers is likely to persuade many people to change their minds about the case. Certainly, there's nothing there as dramatic as Stevens' earlier public admissions that he made a "somewhat embarrassing to acknowledge error" in his interpretation of precedent in his majority opinion.

However, it's worth noting that Stevens' claim that the majority's broad view of public use is backed by "more than a century" of precedent figures prominently in all of his draft opinions contained in the files, and may have played an important rule in persuading other justices. This, of course, is the very thing Stevens later admitted he got badly wrong.

In a May 13, 2005 note conveying her decision to join Stevens, Justice Ruth Bader Ginsburg praised the draft opinion for being "as clear and fair as can be in conveying our precedent and where it leads in this case." Would she and others have been so quick to join Stevens' opinion if they knew its analysis of precedent was based on an "embarrassing to acknowledge error"? Impossible to know for sure. But there is at least room for doubt on that score. And it would only have taken one defection to shift the outcome in the case.

In addition to providing insights on two or three of the questions I raised in my earlier post, the Stevens papers also include a few other interesting revelations about the case:

6. "A fine teaching opinion."

In the same note where she praised Justice Stevens' draft for its analysis of precedent, Justice Ginsburg also called it a "fine teaching opinion." And so it was! But not in the way Ginsburg had in mind. Stevens' ruling had the effect of awakening public opinion to the reality that Supreme Court precedent allowed government to condemn private property for almost any reason it wants. That generated the broadest political backlash against any modern Supreme Court opinion. In his 2019 memoir, Stevens called it "the most unpopular opinion that I wrote during my more than thirty-four years on the Supreme Court. Indeed, I think it is the most unpopular opinion that any member of the Court wrote during that period."

In combination with O'Connor's and Thomas' dissents, the Stevens opinion also helped awaken elite legal opinion to some of the serious flaws in the broad view of "public use" and thereby broke the seeming expert consensus on that question .

7. Stevens probably knew the New London redevelopment plan was likely to fail.

The justification for the Kelo condemnations was the need to promote "economic development" in New London, Connecticut by transferring the condemned property to a private developer who would supposedly put it to more productive use. In his opinion for the Court, Stevens highlights New London's "carefully considered development plan" and distinguishes this from cases where there is no such plan, and therefore stronger suspicion that the condemnation was undertaken purely to benefit a private party.

In reality, Stevens had good reason to question whether there really was any "carefully considered" plan. The files contain a memo from Stevens' law clerk Roberto Gonzales, in which he includes several media articles documenting the flaws of the redevelopment plan. "Overall," writes Gonzales, "they present a pretty dim picture of the prospects of the plan," though he also notes that the "'facts'" in the articles "are certainly not before us in this case." This adds to the extensive evidence of the plan's flaws that was in the official record before the Court—including that the trial court had invalidated 11 of the 15 condemnations precisely because the City had no clear plan for how to use the land it was trying to take.

As it turned out, the plan's prospects were indeed "dim." To this day, nothing has been built on the condemned land, and its only regular users are a colony of feral cats .

I don't think this fact by itself proves Stevens got the decision wrong. If you combine a broad definition of "public use" with an ultradeferential approach to government planners' judgment, then it can still make sense to uphold the New London takings. Nonetheless, given what he knew, Stevens should at least not have relied so heavily on the planning process in justifying his decision.

8. Seven of nine justices wanted to hear the case.

Most experts—myself included—were surprised that the Court decided to hear the Kelo case. The conventional wisdom was that the Court had already definitively endorsed a broad definition of public use in Berman v. Parker (1954) and Hawaii Housing Authority v. Midkiff (1984) , and therefore there would be little interest in revisiting the issue. I think Berman was a terrible decision —worse than Kelo . But I too recognize that it endorsed an extremely broad view of public use, even broader than that Stevens ultimately endorsed in his majority opinion. Stevens was wrong to claim his position was backed by "more than a century" of precedent , but right to believe it was supported by Berman and Midkiff .

The Stevens papers suggest the justices may have seen the precedent as less definitive than most outside experts did. They reveal that seven of the nine justices (all but Ginsburg and David Souter) voted to hear the case. Supreme Court rules only require the agreement of four justices to grant a petition for certiorari.

The files also include a September 27, 2004 memo written by Stevens clerk Melissa Beth Arbus, in which she evaluated whether the Court should take the case. Stevens was the one justice, at the time, who did not participate in the "cert pool" in which clerks for the other justices divided up petitions for certiorari and made common recommendations to the Court on whether to grant them. The Kelo cert pool memo isn't in the file, probably because Stevens didn't participate in the pool.

Arbus wrote that Kelo would be a good vehicle for "elaborating or clarifying 'public use' doctrine" and that the justices could potentially vote to strike down the New London takings without overruling Berman and Midkiff , because "neither case directly addressed the particular public purpose at issue here—economic development in a non-blighted area." This distinction, of course, foreshadows the very similar one made in Justice O'Connor's dissenting opinion.

There are also some less significant revelations that I will not cover in this already long post. But I may include them in a future academic article.

In sum, despite the absence of truly earth-shattering revelations, the Stevens papers deepen our knowledge of the case in several ways. I will consider Justice Scalia's draft dissent in a follow-up post. Stay tuned!

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