If a man knows what it is right to do, he does not require a formal reason. And a person that has been thus trained, either possesses these first principles already, or can easily acquire them.

Perhaps then we must begin with such facts as are known to us from individual experience. It is necessary therefore that the person who is to study, with any tolerable chance of profit, the principles of nobleness and justice and politics generally, should have received a good moral training.

And surely to know what this good is, is of great importance for the conduct of life, for in that case we shall be like archers shooting at a definite mark, and shall be more likely to do what is right. But, if this is the case, we must try to comprehend, in outline at least, what it is and to which of the sciences it belongs.

If, then, in the sphere of action there is some one end which we desire for its own sake, and for the sake of which we desire every thing else; and if we do not choose every thing for the sake of something else, for this would go on without limit, and our desire would be idle and futile, it is clear that this must be the supreme good, and the best thing of all.

But it is clear there is a difference in the ends proposed: for in some cases they are activities, and in others results beyond the mere activities, and where there are certain ends beyond and beside the actions, the results are naturally superior to the activities. Now, as there are numerous kinds of actions and numerous arts and sciences, it follows that the ends are also various. Thus the end of the healing art is health, of ship-building ships, of strategy victory, of economy wealth.

Every art, and every system, and in like manner every action and purpose aims, it is thought, at some good; for which reason a common and by no means a bad description of the good is, ‘that at which all things aim.’

Those who assert that the mathematical sciences say nothing of the beautiful or the good are in error. For these sciences say and prove a great deal about them; if they do not expressly mention them, but prove attributes which are their results or definitions, it is not true that they tell us nothing about them. The chief forms of beauty are order and symmetry and definiteness, which the mathematical sciences demonstrate in a special degree.

That which is desirable on its own account and for the sake of knowing it is more of the nature of wisdom than that which is desirable on account of its results.

For it is owing to their wonder that men both now begin and at first began to philosophize; they wondered originally at the obvious difficulties, then advanced little by little and stated difficulties about the greater matters, e.g. about the phenomena of the moon and those of the sun and of the stars, and about the genesis of the universe. And a man who is puzzled and wonders thinks himself ignorant (whence even the lover of myth is in a sense a lover of Wisdom, for the myth is composed of wonders); therefore since they philosophized order to escape from ignorance, evidently they were pursuing science in order to know, and not for any utilitarian end.

But as more arts were invented, and some were directed to the necessities of life, others to recreation, the inventors of the latter were naturally always regarded as wiser than the inventors of the former, because their branches of knowledge did not aim at utility. ... This is why the mathematical arts were founded in Egypt; for there the priestly caste was allowed to be at leisure.