CHAPTER LXVI—Against those who suppose Intellect and Sense to be the same

SENSE is found in all animals, but animals other than man have no intellect: which is proved by this, that they do not work, like intellectual agents, in diverse and opposite ways, but just as nature moves them fixed and uniform specific activities, as every swallow builds its nest in the same way.

2. Sense is cognisant only of singulars, but intellect is cognisant of universals.

3. Sensory knowledge extends only to bodily things, but intellect takes cognisance of things incorporeal, as wisdom, truth, and the relations between objects.

4. No sense has reflex knowledge of itself and its own activity: the sight does not see itself, nor see that it sees. But intellect is cognisant of itself, and knows that it understands.³⁶²³⁶²   A fifth argument is alleged from Aristotle, De anima, III, iv, 6, which comes to this: — A sensory organ is damaged by meeting with its object in a high degree: vivid light is seen, and crashing sounds are heard, but to the damage of eye and ear; whereas a highly intellectual object, — Aristotelian psychology, for example, — if understood at all, is understood to the improvement of the understanding; the understanding, as such, not working through any bodily organ.
   St Thomas however is far from confining dumb animals to mere sensation. He allows them sense memory, phantasy, a sort of judgement called vis aestimativa (notes pp. 122, 125), and a certain power of self-determination (Chap. XLVIII, n. 2). He denies in the intellect, free will, the powers of forming general concepts and determining their own judgements, and the immortality of their souls.