In the introduction to his study of contemporary epistemology, Alvin Plantinga asserts that the "ahistoricism" of analytic philosophy has proven an impediment to progress in epistemology; what we need, he urges, is "history and hermeneutics."(1) In its turning to history, epistemology is beginning to resemble recent ethical theory, which has readily availed itself of the history of philosophy as a means of enriching its discourse and circumventing seemingly insoluble debates. There are other similarities between contemporary epistemology and recent ethical theory. The standard division in contemporary epistemology pits internalism against externalism.(2) The former demands that individuals have cognitive access to (all) the justifying conditions of their belief and that the belief be formed in accord with appropriate rules.(3) The latter drops the requirement of internal access but demands that a belief be formed by a process, reliably aimed at the production of truth. Internalism's accentuation of epistemic rights and duties calls to mind ethical deontology, while the externalist emphasis on the production of true beliefs is akin to moral consequentialism. Lately, virtue epistemology has emerged to counter the two dominant theories of knowledge, just as virtue ethics arose as an alternative to deontology and utilitarianism.(4)
There is little consensus, however, about where we should locate the most influential figures in the history of philosophy along the spectrum of contemporary positions.(5) Descartes, who thought all knowledge needed to be justified by reference to, and grounded in, clear and distinct ideas, is often cited as a paradigmatic internalist, while Thomas Reid, who thought such a project quixotic and instead grounded knowledge in the reliable operation of faculties, is often classified as an externalist. Beyond this, there is ample room for dispute, especially when one turns to pre-modern thinkers. The theory of knowledge of Thomas Aquinas, for example, has been called internalist, externalist, and, most recently, a virtue theory. In what follows, I want to consider the strengths and weaknesses of each of these interpretations of Aquinas. Since any attempt to understand past thinkers in terms of current categories risks comic anachronism, we shall have to spend some time clarifying each thesis in relationship to Aquinas. It turns out that none of the theories meshes neatly with Aquinas's position and that all are likely to overlook important features of his account.
Part of the problem is that the meanings of internalism and externalism are fluid. John Greco provides a useful catalogue of the most prominent senses. He first sets out the "standard" uses. Concerning the "accessibility of the criteria for justification or warrant to the consciousness of the believer," internalism requires that all criteria be accessible while externalism denies this and holds that some are not. A less standard distinction has internalism insisting that some of the criteria are accessible and externalism, that none are. The standard view contrasts a strong internalism with a weak externalism, while the less standard comparison is between a weak internalism and a strong externalism. In light of these criteria, where should we locate Aquinas? Given the complexity of Aquinas's position, it seems impossible that his account of knowledge should conform to an extreme version of either internalism or externalism. So, according to the first, so-called standard use of the terms, Aquinas is an externalist, while on the second use, he is an internalist. This will have to suffice as an initial statement of our thesis.
Some recent work purporting to be Thomistic illustrates how strong the grip of the internalist model can be. I am thinking of Scott MacDonald's piece on Aquinas's "Theory of Knowledge," in the Cambridge Companion to Aquinas, wherein Thomas is simply and crudely conflated with Cartesian internalism. …