what he thinks the good for man is: the good, he says, is "mental, activity--where such activity is of an excellent kind, or, if there are several different kinds of excellent mental activity, that which has the best and most perfect kind of excellence; and also" (he significantly adds) "mental activity which lasts through a sufficiently long life." The word which I have here translated "excellence" is what is commonly translated "virtue"; but it does not mean quite the same as we mean by "virtue," and that in a very important respect. "Virtue" has come to mean exclusively _moral_ excellence; and if that were all Aristotle meant, you might think that what he means by "good" came very near being a moral idea. But it turns out that he includes among "excellences," intellectual excellence, and even that he thinks that the best and most perfect excellence of which he speaks is a particular kind of intellectual excellence, which no one would think of calling a moral quality, namely, the sort of excellence which makes a man a good philosopher. And as for the word which I have translated "activity," the meaning of this can be best brought out by mentioning the reason which Aristotle himself gives for saying that mere excellence itself is not (as some of the Greeks had said) the good for man. He says, truly enough, that a man may possess the greatest excellence--he may be a very excellent man--even when he is asleep, or is doing nothing; and he points out that the possession of excellence when you are asleep is not a thing that is desirable _for its own sake_--obviously only for the sake of the effects it may produce when you wake up. It is not therefore, he thinks, mere mental excellence, but the _active exercise_ of mental excellence--the state of a man's mind, when he not only possesses excellent faculties, moral or intellectual, but is actively engaged in using them, which really constitutes the human good.