This principle is the great spring of the activity of our minds, and their chief feeder.
From this principle the direction of the sexual appetite, and all the passions connected with it, take their origin: it is the life of our ordinary conversation; and upon the accuracy with which similitude in dissimilitude, and dissimilitude in similitude are perceived, depend our taste and our moral feelings.

It would not be a useless employment to apply this principle to the consideration of metre, and to show that metre is hence enabled to afford much pleasure, and to point out in what manner that pleasure is produced.

But my limits will not permit me to enter upon this subject, and I must content myself with a general summary.
I have said that poetry is the spontaneous overflow of powerful feelings: it takes its origin from emotion recollected in tranquillity: the emotion is contemplated till, by a species of reaction, the tranquillity gradually disappears, and an emotion, kindred to that which was before the subject of contemplation, is gradually produced, and does itself actually exist in the mind.

In this mood successful composition generally begins, and in a mood similar to this it is carried on; but the emotion, of whatever kind, and in whatever degree, from various causes, is qualified by various pleasures, so that in describing any passions whatsoever, which are voluntarily described, the mind will, upon the whole, be in a state of enjoyment.

If Nature be thus cautious to preserve in a state of enjoyment a being so employed, the Poet ought to profit by the lesson held forth to him, and ought especially to take care, that, whatever passions he communicates to his Reader, those passions, if his Reader's mind be sound and vigorous, should always be accompanied with an overbalance of pleasure.