Folia Theologica 12. (2001)
Tibor Rászlai: Aquinas ont the Infallibilty of the Intellect
124 T. RASZLAI I. According to Aquinas, human cognition in its natural state begins with and remains tied to sense perception: there must be a conversio ad phantasmata, a turning of sense images, not only for one to form an idea5, such as the idea of triangle, but also to engage in geometrical speculation about the properties of triangles. Yet human, abstract thought, which is of course beyond mere sense perception, also requires the intellect with its natural light. Thomas distinguishes two operations of the intellect.6 In the first operation of the intellect - FOI -, one grasps the essences, or quiddities, of things. There seem to be two stages in the FOI: in the first stage, the receptive intellect receives the intelligible forms that are illumined by the natural light of the intellect in phantasmata: having received this determination, in the second stage the agent intellect can form an abstract idea, a ratio. In the second operation of the intellect - SOI -, one engages in compositio and divisio, positive and negative judgments. In his commentary on Aristotle's De Interpretatione, Thomas distinguishes between two sorts of compositio.7 The first, which I shall call predicative compositio, is present in both the affirmative judgment that Socrates is sitting, and the negative judgment that Socrates is not sitting; it is also present in the wish and the command, as well as in entertaining the thought, that Socrates is sitting. It is simply that joining of one idea to another which is involved in each of these mental acts. In the second sort of compositio, on the other hand, what are „joined", as it were, are the mental synthesis and reality in an affirmation; that is, one not only forms a mental synthesis, but judges that there is some real composition corresponding to it. I shall call that second sort judgmental compositio. In its complement, divisio, one denies the existence of the corresponding composition in a negative judgment. Compositio and divisio are each forms of assent. Truth and falsity enter into judgmental compositio 5 I use ‘idea’ to translate ‘ratio’, which is the nature or essence of the thing abstractly considered, with materia communa but with materia signata. Such rationes are the objects of abstract thought. 6 In Periherm., prooemium. I. 7 In Periherm., I., III., 26.
