So far, we've examined the three faculties of perception and the three faculties of conception. Next we must examine attention, comparison, abstraction, generalization, judgment, and reasoning.

Attention is the faculty that allows the mind to concentrate on a particular object. Condillac argued that attention is but another word for an intense sensation, but this confuses the conditions of the phenomenon with the phenomenon itself. We often ignore an object unless it is striking, of course, but sensations are effects that the mind passively receives from things, while attention is by nature fundamentally active. So we shouldn't confuse the two. Moreover, strong sensations often result from the application of attention. When an object strikes us, we pay attention to it, and the sensation grows stronger and stronger. For these reasons, Condillac's theory is unacceptable.

What most distinguishes attention is that it's the work of our will. Attention takes two forms. In the first, it's the object that attracts the mind, the will intervening hardly at all, while in the second, attention is wholly voluntary as we direct our mind toward the object. In the first form, where attention is barely voluntary, the mind doesn't exercise much control. It's the spectacle of the object that commands our attention and keeps us from turning away. Obsession – a variety of attention in which the mind has difficulty shaking itself loose – is precisely the same phenomenon as it occurs in our inner life.