Observation of the sense-organs and their employment reveals a distinction between the impassibility of the sensitive and that of the faculty of thought. After strong stimulation of a sense we are less able to exercise it than before, as e.g. in the case of a loud sound we cannot hear easily immediately after, or in the case of a bright colour or a powerful odour we cannot see or smell, but in the case of thought thinking about an object that is highly thinkable renders it more and not less able afterwards to think objects that are less thinkable: the reason is that while the faculty of sensation is dependent upon the body, thought is separable from it.
– Aristotle, On the Soul Book III
I understand the deductive logic at work here, but it seems clear to me that a simple rejection of the premises that “mental exhaustion in the face of much abstract thinking is impossible” is quite an easy jump to make. However, perhaps Aristotle had something else in mind regarding thoughts that are “highly thinkable.” After all, what, in the realm of thought, would correspond to a bright light or a sound at a high decibel level? The latter appear to have their noted deleterious effect byoverpowering the sense-faculty, whereas the only form of the argument which makes sense for Aristotle is one that claims that such a “highly thinkable” object renders the faculty of thought stronger by virtue of its rational simplicity or clarity. But then it what sense can the highly thinkable be considered analogous to the highly see-able or highly taste-able? Basically, it can’t, and that’s why this argument makes no sense to me. Any clues?