For he is at unity in himself, and with every part of his soul he desires the same objects; and he wishes for himself both what is, and what he believes to be, good; and he does it (it being characteristic of the good man to work at what is good), and for the sake of himself, inasmuch as he does it for the sake of his Intellectual Principle which is generally thought to be a man’s Self.
– Aristotle, Nicomachean Ethics