Plutarch, De capienda ex inimicis utilitate
Frank Cole Babbitt, Ed.

Primitive men were quite content if they could escape being injured by strange and fierce animals, and this was the aim and end of their struggles against the wild beasts ; but their successors, by learning, as they did, how to make use of them, now profit by them through using their flesh for food, their hair for clothing, their gall and colostrum as medicine, and their skins as armour, so that there is good reason to fear that, if the supply of wild beasts should fail man, his life would become bestial, helpless, and uncivilized.¹ Since, then, it is enough for most people if they can avoid suffering ill-treatment at the hands of their enemies, and since Xenophon ² asserts that men of sense will even derive profit from those who are at variance with them, we must not refuse him credence, but rather try to discover the system and the art through which this admirable advantage is to be gained by those who find it impossible to live without an enemy.

The farmer cannot domesticate every tree, nor can the huntsman tame every beast; and so they have sought to derive profit from these in ways to meet their other needs : the farmer from the trees that bear no fruit and the huntsman from the Wild animals. The water of the sea is unfit to drink and tastes vile ; yet fish thrive in it, and it is a medium for the dispatch and conveyance of travellers everywhere. The Satyr, at his first sight of fire, wished to kiss and embrace it, but Prometheus said, [p. 9]

You, goat, will mourn your vanished beard,³

for fire burns him who touches it, yet it furnishes light and heat, and is an instrument of every craft for those who have learned to use it. So look at your enemy, and see whether, in spite of his being in most respects harmful and difficult to manage, he does not in some way or other afford you means of getting hold of him and of using him as you can use no one else, and so can be of profit to you. Many of the circumstances of life are unkindly and hateful and repellent to those who have to meet them ; yet you observe that some have employed their attacks of bodily illness for quiet resting, and trials which have fallen to the lot of many have but strengthened and trained them. Some, too, have made banishment and loss of property a means of leisure and philosophic study, as did Diogenes⁴ and Crates.⁵ And Zeno,⁶ on learning that the ship which bore his venture had been wrecked, exclaimed, ‘A real kindness, O Fortune, that thou, too, dost join in driving us to the philosopher's cloak !’ For just as those animals which have the strongest and soundest stomachs can eat and digest snakes and scorpions, and there are some even that derive nourishment from stones and shells (for they transmute such things by reason of the vigour and heat of their spirit), while fastidious and sickly persons are nauseated if they partake of bread and wine, so fools spoil even their friendships, while wise men are able to make a fitting use even of their enmities.