“Our great difference from the scholastic,” William James remarks in The Will to Believe, “lies in the way we face.” That is, James thinks the scholastic faces backwards to indubitable principles of knowledge, whereas the pragmatist faces forward toward the practical results of his opinions. James might be right about some scholastics, but if he is thinking about St. Thomas he is certainly wrong. St. Thomas is not a Cartesian style rationalist, who deduces everything from certain indubitable first truths. First principles do indeed have an important place in St. Thomas’s philosophy, but not first principles in the sense of explicit propositions (‘proper conceptions’), but rather in the sense of the first movements of the intellect in which it receives the world in an indistinct, confused, but very certain manner. That is to say, philosophy begins with the things as we indistinctly know them, and it tries to come to a more distinct knowledge of them through a discourse that always looks back to the things.
As Elliot Milco shows in his brilliant thesis comparing Michel Foucault and Thomism, there is a circularity to the project of philosophy: it begins with the essence of a thing confusedly grasped, and then proceeds by investigation and comparison to return to the essence of the thing now more distinctly grasped. From this Milco concludes that St. Thomas’s does not share the main defects of Cartesian rationalism:
An investigation always grounded in the contemplation of things does not fall victim easily to Kantian fears about runaway logical deduction. If one’s philosophical investigation is always already oriented toward things, toward the disclosure of the essences of things and the adequation of thought to reality, the chances of any early errors of principle fundamentally corrupting one’s work are fairly slim. On the other hand, if one operates like Descartes, or Kant himself, and attempts, while suspending the exercise of one’s capacities as a knower of things, to describe the pure principles of thought by which knowledge is possible, then parvus error in principio will indeed, as St. Thomas says, be magnus in fine. (pp. 67-68)
A consequence that Milco draws from this is that one can freely admit the fact that one’s own approach to reality will always be influenced by cultural habits of thought that incline one to pay attention to certain aspects of things more than others. Such an admission would be fatal to an attempt to construct a complete Cartesian system of knowledge, but it is merely what is to be expected if our knowledge is posterior to things, and dependent on sense experience:
[…] the teacher cannot communicate the essences he has received directly to the minds of his students […] pedagogy directs the mind to the truth, rather than supplying its objects directly. Shifts in pedagogical order, omissions or erasures in the body of transmitted knowledge, deprive new minds of the inclination to discover certain causal connections or aspects of being which others may have found in the past. […] the history of knowledge is not analogous to the development of an individual intellect. Where the intellect always returns to possessed ideas to perfect and develop them, in history death and contingency continually intervene to mar the transmission of acquired knowledge, so that each generation tends to represent more a set of variations on the intuited order of things than the perfection of previously held knowledge. […] to study the history of ideas would be to study the history of pedagogy and the changing forces of human society which incite us to attend to some objects and neglect others.