The tragic element in poetry is like Saturn in alchemy, the Malevolent, the Destroyer of Nature ; but without it no true Aurum Potabile, or Elixir of Life, can be made.
I take as metaphysical poetry that in which what is ordinarily apprehensible only by thought is brought within the grasp of feeling, or that in which what is ordinarily only felt is transformed into thought without ceasing to be feeling.
What a poem means is as much what it means to others as what it means to the author; and indeed, in the course of time a poet may become merely reader in respect to his own works, forgetting his original meaning.
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.
Poetry may make us from time to time a little more aware of the deeper, unnamed feelings which form the substratum of our being, to which we rarely penetrate; for our lives are mostly a constant evasion of ourselves.