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?
Truthfulness. He will never willingly tolerate an untruth, but will hate it as much as he loves truth... And is there anything more closely connected with wisdom than truth?
Thus, cases of injustice, and oppression, and tyranny, and the most extravagant bigotry, are in constant occurrence among us every day. It is the custom to trumpet forth much wonder and astonishment at the chief actors therein setting at defiance so completely the opinion of the world; but there is no greater fallacy; it is precisely because they do consult the opinion of their own little world that such things take place at all, and strike the great world dumb with amazement.
To know people is wisdom, but to know yourself is enlightenment. to master people takes force, but to master yourself takes strength. to know contentment is wealth, and to live with strength resolve. to never leave whatever you are is to abide, and to die without getting lost- that is to live on and on.
And tell him it's quite true that the best of the philosophers are of no use to their fellows; but that he should blame, not the philosophers, but those who fail to make use of them.