Nicomachean Ethics by Aristóteles — Read

We must not be satisfied, then, with examining this starting-point or principle of ours as a conclusion from our data, but must also view it in its relation to current opinions on the subject; for all experience harmonizes with a true principle, but a false one is soon found to be incompatible with the facts.

Now, good things have been divided into three classes, external goods on the one hand, and on the other goods of the soul and goods of the body; and the goods of the soul are commonly said to be goods in the fullest sense, and more good than any other.