Now, the causes being four, it is the business of the student of nature to know about them all, and if he refers his problems back to all of them, he will assign the "why" in the way proper to his science-the matter, the form, the mover, that for the sake of which.

Every virtue is a mean between two extremes, each of which is a vice.

It is Homer who has chiefly taught other poets the art of telling lies skillfully.

Man by Nature desires to know.

Perfect friendship is the friendship of men who are good, and alike in excellence; for these wish well alike to each other qua good, and they are good in themselves.

If there is any kind of animal which is female and has no male separate from it, it is possible that this may generate a young one from itself. No instance of this worthy of any credit has been observed up to the present at any rate, but one case in the class of fishes makes us hesitate. No male of the so-called erythrinus has ever yet been seen, but females, and specimens full of roe, have been seen. Of this, however, we have as yet no proof worthy of credit.

Virtue means doing the right thing, in relation to the right person, at the right time, to the right extent, in the right manner, and for the right purpose. Thus, to give money away is quite a simple task, but for the act to be virtuous, the donor must give to the right person, for the right purpose, in the right amount, in the right manner, and at the right time.