Wherefore, as vice has not such power as to afford a justifying cause for voluntary death, it is evident that it is the duty even of fools, and of those too who are miserable, to remain in life, if they are surrounded by a preponderance of those things which we call according to nature. And since such a man is equally miserable, whether departing from life, or abiding in it, and since the duration of misery is not any the more a cause for fleeing from life, therefore it is not a causeless assertion, that those men who have the power of enjoying the greatest number of natural goods, ought to abide in life.
XIX. But they think it is very important with reference to this subject, that it should be understood that it is the work of nature, that children are beloved by their parents; and that this is the first principle from which we may trace the whole progress of the common society of the human race. And that this may be inferred, in the first place, from the figure and members of the body, which of themselves declare that a due regard for everything connected with generation has been exhibited by nature; nor can these two things possibly be consistent with one another, that nature should desire that offspring should be propagated, and yet take no care that what is propagated should be loved. But even in beasts the power of nature may be discerned; for when we see such labour bestowed upon the bringing forth and bearing of their offspring, we seem to be hearing the voice of nature herself. Wherefore, as it is evident that we are by nature averse to pain; so also it is clear that we are impelled by nature herself to love those whose existence we have caused. And from this it arises that there is such a recommendation by nature of one man to another, that one man ought never to appear unfriendly to another, for the simple reason that he is a man.
For as among the limbs some appear to be created for themselves as it were, as the eyes and ears; others assist the rest of the limbs, as the legs and hands; so there are some monstrous beasts born for themselves alone: but that fish which floats in an open shell and is called the pinna, and that other which swims out of the shell, and, because it is a guard to the other, is called the pinnoteres, and when it has withdrawn within the shell again, is shut up in it, so that it
