"Let no one be slow to seek wisdom when he is young nor weary in the search of it when he has grown old. For no age is too early or too late for the health of the soul. And to say that the season for studying philosophy has not yet come, or that it is past and gone, is like saying that the season for happiness is not yet or that it is now no more. Therefore, both old and young alike ought to seek wisdom, the former in order that, as age comes over him, he may be young in good things because of the grace of what has been, and the latter in order that, while he is young, he may at the same time be old, because he has no fear of the things which are to come. So we must exercise ourselves in the things which bring happiness, since, if that be present, we have everything, and, if that be absent, all our actions are directed towards attaining it."

“Those who were best able to provide themselves with the means of security against their neighbors, being thus in possession of the surest guarantee, passed the most agreeable life in each other's society; and their enjoyment of the fullest intimacy was such that, if one of them died before his time, the survivors did not mourn his death as if it called for sympathy. (40)”

“Where without any change in circumstances the things held to be just by law are seen not to correspond with the concept of justice in actual practice, such laws are not really just; but wherever the laws have ceased to be advantageous because of a change in circumstances, in that case the laws were for that time just when they were advantageous for the mutual dealings of the citizens, and subsequently ceased to be just when they were no longer advantageous. (38)”

“Among the things held to be just by law, whatever is proved to be of advantage in men's dealings has the stamp of justice, whether or not it be the same for all; but if a man makes a law and it does not prove to be mutually advantageous, then this is no longer just. And if what is mutually advantageous varies and only for a time corresponds to our concept of justice, nevertheless for that time it is just for those who do not trouble themselves about empty words, but look simply at the facts. (37)”

“It is impossible for a man who secretly violates the terms of the agreement not to harm or be harmed to feel confident that he will remain undiscovered, even if he has already escaped ten thousand times; for until his death he is never sure that he will not be detected. (35)”

“Those animals which are incapable of making binding agreements with one another not to inflict nor suffer harm are without either justice or injustice; and likewise for those peoples who either could not or would not form binding agreements not to inflict nor suffer harm. (32)”

“Natural justice is a symbol or expression of usefulness, to prevent one person from harming or being harmed by another. (31)”