Memory is of past things. But the past is referred to by reference to a definite time. Memory therefore is a way of knowing things in reference to a definite time, which is to say that it knows things by reference to here and now. But such knowledge is the province of the senses, not of intellect. So memory belongs not to the intellectual part of the soul, but to the same part as the senses.

All our knowledge begins with the senses, proceeds thence to understanding, and ends with reason, beyond which nothing higher can be discovered in the human mind for elaborating the matter of intuition and subjecting it to the highest unity of thought.

In order to distinguish what is clear in this connection from what is obscure, we must be very careful to note that pain and colour and so on are clearly and distinctly perceived when they are regarded merely as sensations or thoughts. But when they are judged to be certain things existing outside our mind, there is no way of understanding what sort of things they are.

All men naturally desire knowledge. An indication of this is our esteem for the senses; for apart from their use we esteem them for their own sake, and most of all the sense of sight. Not only with a view to action, but even when no action is contemplated, we prefer sight, generally speaking, to all the other senses. The reason of this is that of all the senses sight best helps us to know things, and reveals many distinctions.