Lehrer, Keith (1936–)

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Keith Lehrer was born January 10, 1936, in Minneapolis, Minnesota. He attended the University of Minnesota from 1953 to 1957, earning his BA in Philosophy magna cum laude. His teachers at Minnesota included Alan Donagan, John Hospers, Michael Scriven, Mary Shaw, May Brodbeck, Herbert Feigel, and Wilfred Sellers. Lehrer went on earn his AM in 1959 and his PhD in 1960, both in philosophy, at Brown University, where his teachers included Roderick Chisholm, John Ladd, John Lenz, Stephan K(rner, Vincent Thomas, Wesley Salmon, and Richard Taylor. Chisholm supervised Lehrer's master's thesis on epistemology, and Taylor supervised Lehrer's doctoral dissertation on free will. Chisholm's and Taylor's continuing support were not due to Lehrer's agreement with their positions: Lehrer was then and continues to be a coherence theorist in epistemology, whereas Chisholm was a foundationalist, and Lehrer has always endorsed compatibilism, whereas Taylor was a libertarian.

Lehrer is best known for his work on free will, theory of knowledge, rational consensus, and the philosophy of Thomas Reid. His earliest philosophical works clearly reflect the ordinary language and common sense approaches to philosophy that he learned first from Hospers at Minnesota, and then through the influence of Reid, partly gained indirectly from Reid's influence on both Chisholm and Taylor. Lehrer's first published article (1960) was a common sense defense of the claim that humans can know they have free will simply through introspection.

Despite his lifelong commitment to compatibilism, many of Lehrer's earliest works were critical of various analyses of freedom intended to defend that viewparticularly hypothetical analyses of freedom (e.g., that S is free to do X just in case S would do X if S tries to do X). Lehrer's argument against such analyses is that the conditional might apply to S, but S might lack some advantage necessary for exemplifying the antecedent of the conditional. So, for example, it could be true that S would do X if S tried to do X, but because of some phobia or other disadvantage, S could never actually try to do X. One may thus have control over external circumstances, but not have control over oneself, and such a disadvantage leaves one unfree.

His own first defenses of the compatibility of freedom and determinism were based upon a possible worlds analysis of freedom. His work in the late twentieth and early twenty-first centuries analyzes freedom in terms of a power preference that is a preference for having the preference structure one has concerning an action. To insure freedom, one must have that power preference because one prefers to have it. The preference for the preference structure must be the primary explanation of one's having it.

Lehrer is one of the best known proponents of a coherence theory of knowledge. On Lehrer's view, coherence consists in a cognitive system that is able to meet critical objections to the acceptance of a target proposition. Although his first analyses included a standard belief condition, Lehrer later argues that acceptance rather than belief should constitute the relevant condition, partly because the former involves a decision one makes. One's epistemic mission is to accept what is true and not to accept what is false. One cannot decide what to believe at a given moment; but one can decide what to accept in the pursuit of one's epistemic mission.

The ability of a background system to meet critical objections to the accepting of something one accepts provides personal justification. Lehrer first construed this background system as consisting only in states of acceptance designed to pursue the subject's epistemic mission; he expanded this view of the background system, which he later calls the "evaluation system," to include preferences and reasonings.

Much of Lehrer's earliest work in epistemology critiqued various attempts to solve the Gettier problem. The Gettier problem shows that one can have convincing justification of a true belief and yet not have knowledge because some part of the justification is false, where if that part were removed or replaced by the truth, one would no longer qualify as justified. Where such problems in justification exist, the justification is "defeated," and defeasibility theorists seek to solve the Gettier problem by formulating and explicating as a necessary condition the stipulation that one who knows has undefeated justification for what one knows. Defeasibility remains a central concern in Lehrer's most recent work in epistemology, Theory of Knowledge (2000), according to which knowledge is the product of true belief that is personally justified on the basis of coherence with the evaluation system, where such justification is undefeated. Undefeated justification, according to Lehrer, is a kind of justification that cannot be refuted by pointing out errors in the evaluation system (2000).

Lehrer has also offered a number of criticisms of recent "naturalistic" or externalist approaches to knowledge and justification, on the general ground that reliable cognitive mechanisms or ways of believing that track truth without cognitive self-evaluation are insufficient for knowledge. Lehrer's development of this element of his epistemology derives from his interest in the philosophy of Thomas Reid. Lehrer noted within Reid's system a metaprinciple according to which our faculties and the principles thereof are trustworthy. Lehrer applies this same principle to allow the knower to meet critical and skeptical objections, while also immunizing his own analysis of knowledgedespite its requirement for cognitive self-evaluationagainst the KK-regress (namely, that one's knowing requires knowing that one knows, that one knows that one knows one knows, and so on ad infinitum) (1990, 2000).

The theory of rational consensus, which Lehrer developed with Carl Wagner (1981), was an attempt to incorporate a social component into the theory of rationalityanother echo of Reid's common sense approach to philosophy. Social rationality, in Lehrer's and Wagner's theory, results from the evaluations people make of others, expressed mathematically as weights. They argue that under plausible conditions of evaluation social convergence would yield rational consensus. Lehrer went on to unify his work on justification and preference in Self Trust (1997), in which he sought to explain the trustworthiness of the self in terms of rationality, theoretical and practical as well as personal and social. In this and in his epistemology, Lehrer claims that complete explanation will contain a loop of the sort Lehrer first found in Reid's philosophy. There is a fundamental choice, according to Lehrer, between starting with unexplained first principles or, instead, maximizing explanation by including a principle of trustworthiness, which explains both why people are justified in accepting everything else that they accept and also why people are justified in accepting the principle itself. The effectiveness of the explanation depends on the wider system of explanation as well, and not simply on the "keystone principle" of self-trust.

See also Chisholm, Roderick; Coherentism; Determinism and Freedom; Epistemology; Epistemology, History of; Freedom; Reid, Thomas; Salmon, Wesley; Self; Sellars, Wilfrid.


Bogdan, Radu, ed. Keith Lehrer. Dordrecht, Netherlands: D. Reidel, 1980. Several essays by various authors on various aspects of Lehrer's philosophy, with a single essay in reply as well as a 101-page self-profile by Lehrer himself.

Brandl, Johannes, et al., eds. Metamind, Knowledge, and Coherence: Essays on the Philosophy of Keith Lehrer. Amsterdam: Rodopi, 1991. Several essays by various authors on various aspects of Lehrer's philosophy, each with a reply by Lehrer.

Lehrer, Keith. "Can We Know that We Have Free Will by Introspection?" The Journal of Philosophy 57 (1960): 145157. A defense of freedom on the ground that human possession of freedom is entirely obvious from introspection.

Lehrer, Keith. Metamind. Oxford: Clarendon Press, 1990. A study of ways in which people's epistemic and preference assessments can also apply at metalevels, and to themselves.

Lehrer, Keith. Self Trust: A Study of Reason, Knowledge and Autonomy. Oxford: Clarendon Press, 1997. Brings together into one theoretical presentation most of Lehrer's views about knowledge, justification, rationality, and preference.

Lehrer, Keith. Theory of Knowledge. 2nd ed. Boulder, CO: Westview Press, 2000. Explicates and critiques several different conceptions of knowledge and justification, and argues for Lehrer's own version of the coherence theory.

Lehrer, Keith, and Carl Wagner. Rational Consensus in Science and Society. Dordrecht, Netherlands: D. Reidel, 1981. Argues that rational consensus can be reached by assigning weights to others' evaluations.

Olsson, Erik J., ed. The Epistemology of Keith Lehrer. Dordrecht, Netherlands: Kluwer, 2003. Essays by various authors with a reply by Lehrer.

Nicholas D. Smith (2005)

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Lehrer, Keith (1936–)

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