Not only every great poet, but every genuine, but lesser poet, fulfils once for all some possibility of language, and so leaves one possibility less for his successors.
We may climb into the thin and cold realm of pure geometry and lifeless science, or sink into that of sensation. Between these extremes is the equator of life, of thought, or spirit, or poetry,--a narrow belt.
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.
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.