Aristotle, Nicomachean Ethics
H. Rackham, Ed.

Some try to find a more profound and scientific explanation of the nature of affection. Euripides¹ writes that ‘Earth yearneth for the rain’ when dried up, ‘And the majestic Heaven when filled with rain Yearneth to fall to Earth.’ Heracleitus says, ‘Opposition unites,’ and ‘The fairest harmony springs from difference,’ and ‘'Tis strife that makes the world go on.’ Others maintain the opposite view, notably Empedocles, who declares that ‘Like seeks after like.’ 1. [7]

Dismissing then these scientific speculations as not germane to our present enquiry, let us investigate the human aspect of the matter, and examine the questions that relate to man's character and emotions: for instance, whether all men are capable of friendship, or bad men cannot be friends; and whether there is only one sort of friendship or several. Those who hold that all friendship is of the same kind because friendship admits of degree, are relying on an insufficient proof, for things of different kinds also can differ in degree. But this has been discussed before.² 2.

Perhaps the answer to these questions will appear if we ascertain what sort of things arouse liking or love. It seems that not everything is loved, but only what is lovable, and that this is either what is good, or pleasant, or useful. But useful may be taken to mean