Epistemology and Metaphysics
Epistemology and Metaphysics
Without providing a fuller development of Thomas’s overall epistemological commitments, this might be a good place to notice a certain kind of foundationalism in Thomas’s epistemological thought, but with an important codicil. Foundationalism is an epistemological structure in which certain immediate, or basic, propositions are affirmed as “foundational” to our knowledge, and then other propositions, if they are to be believed, must first be demonstrated on the basis of those immediate, or basic, propositions.
Foundationalism has been pictured, at times, as a pyramid.19 The base of the pyramid pictures those immediate propositions that can be known apart from any demonstration. The sides of the pyramid picture those propositions that can only be known by way of demonstration from the immediate propositions known. This propositional structure comports, at least to some extent, with Thomas’s view.
According to Thomas, “demonstration,” by which he means syllogistic reasoning, must “proceed from principles that are immediate either straightway or through middles.”20 It is necessary, therefore, for our reasoning process, that the beliefs gained thereby rest on beliefs (or knowledge) that are not inferred. In this, Thomas is classifying our beliefs as either inferred or immediate.
But there is a difference in what Thomas is saying from what many modern foundationalists want to affirm.21 It is certainly the case that Thomas affirms propositions that are analytic; the predicate is somehow contained in the subject. Such is his meaning of immediate propositions. If propositions were in need of demonstration, they would not, therefore, be immediate. They would be mediated by way of demonstration.
Immediate propositions, then, are those in which “the predicate is included within the notion of its subject.”22 These propositions are known by virtue of themselves, and not by virtue of any inference from subject to predicate. Thus, immediate propositions are stronger than mediate ones, and are known with more certainty.
For Thomas, however, unlike contemporary foundationalism, immediate propositions are not simply epistemic grounds for other, mediate propositions, but, even more importantly, propositions which themselves are grounded metaphysically.
So, according to Scott MacDonald, “Immediate propositions, then, are capable of being known by virtue of themselves and are, therefore, proper objects of non-derivative knowledge.”23 This much could be said by virtually any foundationalist. What is more significant, however, is the following sentence: “But their actually being known by virtue of themselves requires that one be acquainted with the facts expressed by those propositions which requires that one conceive the terms of those propositions.”24
In other words, one of the key elements necessary for a proposition to be immediate is that there be a particular structure to reality. Which propositions are immediate depends on the nature of the world:
Which propositions are immediate, then, depends solely on what real natures there are and what relations hold among them, that is, on the basic structure of the world, and on the psychology or belief-structure of any given epistemic subject.25
This emphasis marks a significant and useful difference between what Aquinas argues with respect to our beliefs and what is typically assumed in current epistemological discussions. Typically, epistemology is discussed as if it can stand on its own, without reference to, or need of, a proper understanding of reality. Not so for Thomas. For Thomas, the nature of that which is known is centrally important; the “pyramid” itself is in need of something on which to rest. Thus, says MacDonald,
Propositions are immediate by virtue of expressing what might be called metaphysically immediate relationships or facts, the relationships that hold between natures and their essential constituents.26
Thomas, therefore, sees a necessary and direct link between what we believe and the nature of the world. This important addition gives our beliefs their proper epistemological ground. It recognizes that in order for there to be a justification of knowledge, a metaphysical structure must be assumed such that facts, natures and their constituents, and the relationships between them, exist and are known—and are known immediately. In other words, justification not only is epistemological, but also includes the metaphysical structure of the world. The things known are known by virtue of their mode of existence. Contrary to post-Enlightenment discussions of epistemology, in which it is thought to be separate from metaphysics, Thomas recognizes that the disciplines must be inextricably linked:
This metaphysical picture allows us to see the kind of objectivist requirement Aquinas incorporates into the theory of demonstration. When he claims that the first principles of demonstration must be immediate and indemonstrable, he is claiming that they must express metaphysically immediate propositions and not just propositions that are epistemically basic and unprovable for some particular epistemic subject. That a given proposition P happens to be indemonstrable for some person S because there are no other propositions in S’s belief-structure on the basis of which S would be justified in holding P is no guarantee that P is, on Aquinas’s view, an immediate, indemonstrable proposition. The structure of demonstration, then, is isomorphic with the metaphysical structure of reality: immediate, indemonstrable propositions express metaphysically immediate facts, whereas mediate, demonstrable propositions express metaphysically mediate facts.27
As we will see below, this inextricable link between epistemology and metaphysics is radically premodern; it predates the severing of epistemology and metaphysics in virtually all post-Kantian thought. More importantly, in Thomas’s affirmation of the link between the two, he comes closer to a Christian understanding of epistemology and metaphysics and of the proper relation between them, than Kant and his progeny have been able to come.