*153* My view, therefore, is that those duties are closer to nature which depend upon the social instinct than those which depend upon knowledge; and this view can be confirmed by the following argument: (1) suppose that a wise man should be vouchsafed such a life that, with an abundance of everything pouring in upon him, he might in perfect peace study and ponder over everything that is worth knowing, still, if the solitude were so complete that he could never see a human being, he would die. And then, the foremost of all virtues is wisdom--what the Greeks call σοφία; for by prudence, which they call φρόνησις, we understand something else, namely, the practical knowledge of things to be sought for and of things to be avoided. (2) Again, that wisdom which I have given the foremost place is the knowledge of things human and divine, which is concerned also with the bonds of union between gods and men and the relations of man to man. If wisdom is the most important of the virtues, as it certainly is, it necessarily follows that that duty which is connected with the social obligation is the most important duty.[AG] And (3) service is better than mere theoretical knowledge, for the study and knowledge of the universe would somehow be lame and defective, were no practical results to follow. Such results, moreover, are best seen in the safe-guarding of human interests. It is essential, then, to human society; and it should, therefore, be ranked above speculative knowledge. *154* Upon this all the best men agree, as they prove by their conduct. For who is so absorbed in the investigation and study of creation, but that, even though he were working and pondering over tasks never so much worth mastering and even though he thought he could number the stars and measure the length and breadth of the universe, he would drop all those problems and cast them aside, if word were suddenly brought to him of some critical peril to his country, which he could relieve or repel? And he would do the same to further the interests of parent or friend or to save him from danger. *155* From all this we conclude that the duties prescribed by justice must be given precedence over the pursuit of knowledge and the duties imposed by it; for the former concern the welfare of our fellow-men; and nothing ought to be more sacred in men's eyes than that.