The intellectual animal

Properly interpreted, Aquinas supports a transformative rather than an additive understanding of how the human intellect relates to the capacities human beings share with other animals, an understanding founded in a metaphysics. The soul (‘life‐form’) is the substantial form that maintains an organism as a single being throughout life, and Aquinas holds that the human soul is the only substantial form in the human being. He respects the variety of appetitive and apprehensive capacities displayed by different animals, and has a high view of the perceptive (even inductive) powers of the higher animals: they ‘share somewhat in reason’. It is no surprise that we cannot easily identify a rigid boundary between our intellectual powers and the cognitive and conative powers we share with other animals; rather, the powers not only interact, they qualify each other. As Stephen Brock put it, ‘Rationality is a mode of intellect … intrinsically connected to the life of the senses, and therefore to the sense‐organs … and to matter itself.’