I am slowly working through Thomas Aquinas’ Summa Theologiae. As I do so, I will share quotes that I find intriguing and may want to reference later. I am reading this Latin edition and using Alfred J. Freddoso’s new English translation as needed.
In I, Q1, A6, Aquinas addresses the question of whether sacred doctrine is wisdom–utrum sit sapientia. Thomas affirms, but my interest is less in that as in the statements he makes regarding first principles:
The first principles of other sciences are either self-evident and cannot be proved, or they are proven by some kind of natural reasoning in a different science. But the knowledge proper to the science of sacred doctrine comes through revelation and not through natural reasoning. And so it does not belong to sacred doctrine to prove the first principles of other sciences, but only to pass judgment on them. For whatever in other sciences is found to be contrary to the truth of sacred doctrine is wholly condemned as false. Therefore 2 Corinthians 10:4–5 says: “The weapons of our warfare … destroy counsels and every height that exalts itself against the knowledge of God.”
- Thomas affirms distinctions between various sciences, each of which possess their own distinct first principles (principia). Sacred doctrine is one sort of science with its own principia, but other scientific disciplines have their own principia. There is no need for all kinds of sciences to have the same first principles. Herman Bavinck makes this same point in the Prolegomena to his Reformed Dogmatics.
- The classical understanding of first principles is that they serve as starting points for thought. The principia are the foundational axioms upon which a particular science builds and operates. First principles are not bare presuppositions, assumed without reason. They are either self-evident—per se nota, “known through themselves”—and hence cannot be proven, or they are proven in another science, which itself does not take them as first principles but arrives at them through its own argumentation and proofs. A particular science does not seek to prove its first principles, but rather seeks to prove other things by means of its first principles. (I wrote this last sentence before seeing that Thomas says exactly this in I. Q1, A8, co.)
- The idea that some principia are self-evident tells us something about Thomas’s epistemology. There are some first principles that are not able to be proven or demonstrated in a formal way—something that is self-evident “cannot be proved.” We might consider the first principles of thought as an example. These are not things that are proven through rational argumentation, but are rather those things by which we prove anything else. Our mind comes to apprehend the truth of these principles not by deductive argumentation but by immediate apprehension: in such cases to apprehend the thing is to know the truth of it. Bavinck again affirms something much like this in the chapter “Philosophical Foundations” in his Prolegomena.
- Note that Thomas affirms that the knowledge proper to the science of sacred doctrine does not come through human reason but by divine revelation. This knowledge is so sure that it in fact can judge the first principles of other sciences, rejecting anything in them that is found to be out of accord with it. This may come as a surprise to read, given that in some quarters Thomas has a reputation for denigrating Scripture and elevating the role of human reason in the theological task. But Thomas so far has sought to privilege Scripture above reason in the science of sacred doctrine throughout the first few articles of Question 1, Book 1 of his Summa. In Article 5 he writes: “For it [sacred doctrine] does not receive its first principles from other sciences, but immediately from God through revelation,” and in Article 1 he affirms that “over and beyond the philosophical disciplines discovered by human reason, it was necessary that a sacred doctrine be had through revelation.”