Alvin Plantinga’s Warrant and Proper Function offers a detailed version of a very widely accepted (and strongly disputed) analysis of knowledge. In this analysis, knowledge, for a person, is not to have evidence of his or her beliefs but rather for these beliefs to have been formed properly, for these beliefs to be the result of a reliable process of belief formation operating in a congenial environment under circumstances in which its operation is aimed at truth (rather than, for example, survival or convenience).

This book is the second of three books that form a trilogy in the theory of knowledge. The other two are Warrant: The Current Debate (1993) and Warranted Christian Belief (1999). Warrant examines in detail the debate concerning the nature of knowledge, asking what exactly it means for a person to know something. Plantinga attempts to analyze the claim “Jane knows that so-and-so is true if and only if . . . ,” where the blank is filled in with a statement of the conditions that must be satisfied. The analysis is intended to be general so that regardless whether what Jane knows is that her shoes are white, that ten is greater than nine, that God exists, that it is wrong to torture for pleasure, or that quantum mechanics has replaced classical Newtonian mechanics, the analysis will fit perfectly. The analysis is intended to cover every actual and every possible case of knowing. Warrant examines various analyses of knowledge and rejects them in favor of Plantinga’s analysis. Warranted Christian Belief discusses the relevance of the analysis offered in Warrant and Proper Function to questions of religious, particularly Christian, belief.

Internalism vs. Externalism

Warrant was written to show that internalist theories of knowledge are mistaken, and that while externalist theories of knowledge are the right sort of analyses, only Plantinga’s externalist analysis has a certain very desireable feature and is not subject to refuting counter-examples. Warrant and Proper Function presents an in-depth examination of the theories set out in the first book, and an understanding of these theories is necessary to place the second work in its context.

The internalist versus externalist dispute occurs among philosophers who agree on at least two things. (1) A person can know something only if that something is true. It is what might be called propositional knowledge, or knowledge of what is expressed by true statements, that is under analysis, not knowledge by acquaintance or awareness of either external objects such as trees or internal items such as pains. Thus, these philosophers must agree that “Jane knows that P” entails “P is true.” (2) For a person to know something, the individual must believe it. Knowledge must include true belief, but true belief is not enough for knowledge. If Jane believes that the most expensive tea in the world costs twenty thousand dollars an ounce and believes this because she read about a twenty-thousand-dollar car while she was drinking a cup of tea, even if the most expensive tea in the world does happen to cost twenty thousand dollars an ounce, Jane has just luckily stumbled onto a...

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Plantinga’s Externalism

According to Plantinga, for Jane to know that some proposition is true—that her hair is properly brushed or that seventeen is a prime number or whatever—is for her to have the belief that this proposition is true when it is and under conditions in which her faculties that produced the belief in question are functioning properly in a congenial environment where those faculties operate in accord with a design plan that orients them toward truth seeking and where the design plan is good (such that if our faculties follow it, the plan will typically yield true beliefs). Plantinga contends that reference to a design plan is crucial in offering any defensible version of externalism. He also argues, by critically considering various accounts that lack this feature, that the design plan must be more than simply metaphorical or used for convenience.

His view is that if our cognitive faculties simply developed in a naturalistic or creatorless evolutionary environment, there would be no reason to think that their functioning properly relative to survival would also involve their functioning reliably relative to truth (and in particular, there would be no reason to think that they do so relative to beliefs about matters not related to survival such as evolutionary theory and the nature of knowledge). He contends that if we are to have an externalist account of knowledge such that we can know the account of knowledge to be the correct one, we need an externalist account in which our cognitive faculties are objectively likely to yield true beliefs. This, he contends, will be the case only for a monotheistic externalist account in which God has made people in a way that they are knowers, an account in which God has established a design plan for people’s cognitive faculties and an environment in which these faculties congenially operate so that their results (people’s actual beliefs) are likely to be true beliefs and hence (given their manner of production) to constitute knowledge.


Additional Reading

Alston, William. Perceiving God. Ithaca, N.Y.: Cornell University Press, 1991. Offers a discussion of a wide variety of perspectives in the theory of knowledge by way of embracing the view that a theistic practice of belief formation can reasonably be believed to be reliable.

Dancy, Jonathan, and Ernest Sosa, eds. Blackwell Companions to Philosophy: A Companion to Epistemology. Oxford: Blackwell, 1992. A series of discussions of a wide variety of perspectives, theories, ideas, and arguments in theory of knowledge, including internalism and externalism.

Kvanvig, Jonathan L., ed. Warrant in Contemporary Epistemology: Essays in Honor of Plantinga’s Theory of Knowledge. Lanham, Md: Rowman and Littlefield, 1996. This collection of essays examines Plantinga’s views on warrant and proper function and his theory of knowledge. Includes bibliography and index.

Sosa, Ernest. Collected Essays in Epistemology. Cambridge, England: Cambridge University Press, 1991. Defends an account of knowledge in which one is justified within an environment and relative to a community of believers.

Tomberlin, James, and Peter van Inwagen, eds. Alvin Plantinga. Dordrecht: D. Reidel, 1985. Collection of essays on various aspects of Plantinga’s work, including the work that provided the background for the trilogy on warrant.