All human happiness and misery take the form of action.

A thing chosen always as an end and never as a means we call absolutely final. Now happiness above all else appears to be absolutely final in this sense, since we always choose it for its own sake and never as a means to something else.

It is clear that those constitutions which aim at the common good are right, as being in accord with absolute justice; while those which aim only at the good of the rulers are wrong.

Man is the metre of all things, the hand is the instrument of instruments, and the mind is the form of forms.

A young man is not a proper hearer of lectures on political science; for he is inexperienced in the actions that occur in life, but its discussions start from these and are about these; and, further, since he tends to follow his passions, his study will be vain and unprofitable, because the end that is aimed at is not knowledge but action. And it makes no difference whether he is young in years or youthful in character.

I say that habit's but a long practice, friend, and this becomes men's nature in the end.

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.