It is clear, then, that wisdom is knowledge having to do with certain principles and causes. But now, since it is this knowledge that we are seeking, we must consider the following point: of what kind of principles and of what kind of causes is wisdom the knowledge?
There are three things that are the motives of choice and three that are the motives of avoidance; namely, the noble, the expedient, and the pleasant, and their opposites, the base, the harmful, and the painful. Now in respect of all these the good man is likely to go right and the bad to go wrong, but especially in respect of pleasure; for pleasure is common to man with the lower animals, and also it is a concomitant of all the objects of choice, since both the noble and the expedient appear to us pleasant.
To die, and thus avoid poverty or love, or anything painful, is not the part of a brave man, but rather of a coward; for it is cowardice to avoid trouble, and the suicide does not undergo death because it is honorable, but in order to avoid evil.
Some men turn every quality or art into a means of making money; this they conceive to be the end, and to the promotion of the end all things must contribute.
If thinking is like perceiving, it must be either a process in which the soul is acted upon by what is capable of being thought, or a process different from but analogous to that. The thinking part of the soul must therefore be, while impassable, capable of receiving the form of an object; that is, must be potentially identical in character with its object without being the object. Mind must be related to what is thinkable, as sense is to what is sensible.