If, then, there is some end of the things we do, which we desire for its own sake (everything else being desired for the sake of this), and if we do not choose everything for the sake of something else (for at that rate the process would go on to infinity, so that our desire would be empty and vain), clearly this must be the good and the chief good.

Before you heal the body you must first heal the mind

A man who examines each subject from a philosophical standpoint cannot neglect them: he has to omit nothing, and state the truth about each topic.

Friendship is a single soul dwelling in two bodies.

Any change of government which has to be introduced should be one which men, starting from their existing constitutions, will be both willing and able to adopt, since there is quite as much trouble in the reformation of an old constitution as in the establishment of a new one, just as to unlearn is as hard as to learn.

A good character carries with it the highest power of causing a thing to be believed.

The secret to humor is surprise.