Plutarch De Amore Prolis 5

[5] Now both this and miny other excellences are obscured by vice, as a thicket springs up beside seeds planted in a garden. Or are we to say that man has no natural love for himself just because many men cut their throats or hurl themselves from precipices? And Oedipus ¹ and Hegesias ² by the eloquence of his reasoning persuaded many of his hearers to starve themselves to death.

But these are like those diseases and morbid states of the soul which drive men from their natural condition, as they themselves testify against themselves. For if a sow tears to pieces her suckling pig, or a bitch her puppy, men grow despondent and disturbed and offer to the gods sacrifices to avert the evil, and consider it a portent on the ground that Nature prescribes to all creatures that they should love and rear their offspring, not destroy them. Moreover, as in mines the gold, though mingled and covered with much earth, yet gleams through, so Nature, even in characters and passions which are themselves perverted, reveals their love for their offspring. For when poor men do not rear their children it is because they fear that if they are educated less well than is befitting ⁴ they will become servile and boorish and destitute of all the virtues; since they consider poverty the worst of evils, they cannot endure to let their children share it with them, as though it were a kind of disease, serious and grievous....

[5] But this natural affection, like many other good qualities in men, may be choked and obscured by vices; as when a wild forest is sown with garden-seeds. Can we say that man loves not himself, because some hang themselves, others break their own necks, Oedipus put out his own eyes, ¹ and Hegesias, by his disputation, persuaded many of his auditors to pine themselves to death? But all these things are disease and craziness of mind, transporting a man out of his own nature; and in this men testify against themselves. For if a sow or a bitch kill the young they have brought forth, men look dejected, are disturbed, sacrifice to the Gods to avert the mischief, and do account it a miracle; because men know that Nature has implanted in all creatures the love of their young, so that they should feed them and not kill them. For as among metals gold, though mixed with much rubbish, will appear; so Nature, even in vicious deeds and affection, declares the love to posterity. For poor people do not rear their children, fearing that, if they should not be well educated, they would prove slavish, clownish, and destitute of all things commendable; since they cannot endure to entail poverty, which they look upon as the worst of all evils or diseases, upon their posterity.