Aquinas on the Immateriality of the Intellect

AQUINAS ON THE IMMATERIALITY OF THE INTELLECT DAVID RUEL FOSTER Seton Hall University South Orange, New Jersey I. A Controversial Question? HE QUESTION of the immateriailiity of the intelloot s ,an important part of the wider question about the nau11e of the soul. The axgiumen'ts for the immaiteriality of rthe intellect a11e particularly important to Thomas's thought because they undergil1d his argument for the incorruptibility of the soul; the incorruptibiility of the soul, in turn, leads towards the dootrine of the immortaility of the soruJ, a tenet of faith which Thoma.s wants to explain and deifend.1 This article will present Thomas's two most prominent arguments for the immateriality of the intieliteot and critique the first iin light of rthe seoond.2 Whether ,the principle of int~Uectual ilife must, by the very 1 .Arguments for the immateriality of the intellect do not necessarily appear in articles on the incorruptibility of the soul but are always presupposed by them in Thomas. For example, in Summa theologiae I, q. 75, a. 6, "Whether the human soul is incorruptible?" (" Utrum anima humana sit corruptibilis "), Thomas supports the crucial premise in his argument by referring to the ,arguments for the immateriality of the intellect in articles 2 and 5 (" Utrum anima humana sit aliquid subsistens? "; "Utrum anima sit composita ex materia et forma?" Summa theologiae I, q. 75, aa. 2 and 5). 2 Five important instances of the arguments are as follows: In Sententias II, d. 19, q. 1, a. l; Summa contra gentiles II, chapters 49-50; Summa theologiae I, q. 75, aa. 2 and 5; Quaestiones Dis-putatae De anima a. 14; Oompendium theologiae, De fide, chapters 79 and 84. This chronological ordering is based on Weisheipl's catalogue in Friar Thomas D'A.quino, pp. 355-406; and Eschmann's, A Catalogue of St. Thomas's Work, in Gilson's, The Christian Philosophy of St. Thomas Aquinas, pp. 381-439. The dating of the Compendium theologiae is the most problematic. 415 416 DAVID RUEL FOSTER natUJ.1e of its .act, be immaterial is a particularly controrverted question today. Many corutempo~ary thinkers helie¥e that human understanding can be ex:pfained in strictly physical terms. ':Chis was not the case in Thomas's day, and it is important to takie notre of this. Thomas W1as noit foroed by any opponent to sharpen his arguments for the imma.teriality of the inteHect. The major Islamic philosophers, ailithough they disagreed among themselves about aspects of the inbe1iJiect's nature (e.g., the plaice and ro[e of the agent intellect)' md agree thait the intellectual soul was immaterial. Plato and Aristotle, according .to Thomas, agreed on this f.undamental point. In fact, although there were post-Socratic materialists,3 Thoma;s usuru1Jy goes ha;ek to the Pre-Socratics in order rto give an example of someone who taJUght that the inte!IJiectual :act. depends entirely on physicrul principles. Perhaps it is better to s1ay that, because the doctrine of runiversal hylomorphism was so widely accepted in his time, Thomas was not challenged regarding the incorporeality of the intellect. Many of Thoma:s's contemporaries , foililowing the tewching of Awoobroin, held that the intellectuaJ . souil was composed of spiritua.l matter .and the appropriate form,4 hut this was not in opposition to Thomas's arguments for the immateriality of the intellect. II. The Two Most Prominent Arguments A. Type I The first argument (hereaf·ter caUed Type 1) proceeds from the intellect's potential to know all corporeal things. It is justifiably described as Thomas's preferred argument,5 for s For example, the Epicureans. 4 J. Weisheipl, "Albertus Magnus and Universal Hylomorphism: Avicebron ," in Albert the priam rationem formalem, which is :to grasp the essence of the obj,oot. Then Thom!lis draws his conclusion " therefore, ... the inte!llecrbuaJ soul itse[f is an absolute form." The conclusion that the irntellect's mode of being is immaterial, a " form without matter," follows from the premises: majorr premise, the objeclt is ,in the knower in an ahso1uite way, i.e., without matter; minor premise, the object is received in the knower .ruooording to rthe mode of he...