From Apollonius I learned freedom of will and undeviating steadiness of purpose; and to look to nothing else, not even for a moment, except to reason; and to be always the same, in sharp pains, on the occasion of the loss of a child, and in long illness.

We are born for cooperation

The healthy eye ought to see all visible things and not to say, I wish for green things; for this is the condition of a diseased eye.

We are too much accustomed to attribute to a single cause that which is the product of several, and the majority of our controversies come from that.

I am called to man's labour; why then do I make a difficulty if I am going out to do what I was born to do and what I was brought into the world for?

All things are in the act of change; thou thyself in ceaseless transformation and partial decay, and the whole universe with thee.

Men seek out retreats for themselves in the country, by the seaside, on the moutains . . . But all this is unphilosophical to the last degree . . . when thou canst at a moment's notice retire into thyself.