When someone admits one and rejects another which is equally in accordance with the appearances, it is clear that he has quitted all physical explanation and descended into myth.

Necessity is an evil; but there is no necessity for continuing to live subject to necessity.

Neither one should hesitate about dedicating oneself to philosophy when young, nor should get tired of doing it when one's old, because no one is ever too young or too old to reach one's soul's healthy.

In a philosophical dispute, he gains most who is defeated, since he learns most.

Let no one be slow to seek wisdom when he is young nor weary in the search of it when he has grown old. For no age is too early or too late for the health of the soul.

Those desires that do not bring pain if they are not satisfied are not necessary; and they are easily thrust aside whenever to satisfy them appears difficult or likely to cause injury.

We must, therefore, pursue the things that make for happiness, seeing that when happiness is present, we have everything; but when it is absent, we do everything to possess it.