A friend to all is a friend to none.

Since the branch of philosophy on which we are at present engaged differs from the others in not being a subject of merely intellectual interest — I mean we are not concerned to know what goodness essentially is, but how we are to become good men, for this alone gives the study its practical value — we must apply our minds to the solution of the problems of conduct.

Just as at the Olympic games it is not the handsomest or strongest men who are crowned with victory but the successful competitors, so in life it is those who act rightly who carry off all the prizes and rewards.

[I]t is rather the case that we desire something because we believe it to be good than that we believe a thing to be good because we desire it. It is the thought that starts things off.

All communication must lead to change

The shape of the heaven is of necessity spherical; for that is the shape most appropriate to its substance and also by nature primary.

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?