Metaphysics -- Book I -- 1. All men by nature desire to have knowledge. An indication of this is the delight that we take in the senses; quite apart from the use that we make of them, we take delight in them for their own sake, and more than of any other this is true of the sense of sight. For not only when we want to do something, but even when we have no intention of doing anything at all, we prefer sight to practically every other sense. The reason for this is that, more than any other sense, it enables us to get to know things, and it reveals a number of differences between things.