20 - Thomas Aquinas  pp. 422-460

Thomas Aquinas

By Janet Coleman

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One of the crucial points of difference between Aquinas and many of his Christian predecessors and contemporaries was over the role of man's body both in perception and intellection. Here, he was indebted to Averroes and to an extremely close reading of Aristotle. Aquinas forthrightly argued against all dualist theories of man, especially those of Avicenna, his Franciscan contemporary Bonaventure, and all the other neo-Platonists including the pseudo-Augustinian author of the De Spiritu et Anima. Man's nature is composite; he is a being made up of both body and soul, so that intellect always owes a debt to sensation. The whole world of sensory experience, the external world which leaves phantasms or impressions in the soul, is not only necessary for man's development and essential to his very nature, but also he achieves blessedness through it. The body is not merely the soul's garment or its prison. The soul does not merely use corpora. Sensation, rather, belongs to the soul and body conjoined and this makes man a kind of hybrid. Averroes had similarly emphasised this, but had not satisfactorily individuated men within the species. In the Summa Theologiae where Aquinas begins his so-called ‘treatise on man’, he wrote that man must be considered a compound whose substance is both spiritual and corporeal (Ia q. 75). Writing this between 1266–8, roughly at the same time as his commentary on Aristotle's De Anima, Aquinas argued that the soul has no activity without the body, not even the act of understanding.