The word "Verse" is used here as the term most convenient for expressing, and without pedantry, all that is involved in the consideration of rhythm, rhyme, meter, and versification... the subject is exceedingly simple; one tenth of it, possibly may be called ethical; nine tenths, however, appertains to the mathematics.
Poetry, even that of the loftiest, and seemingly, that of the wildest odes, [has] a logic of its own as severe as that of science; and more difficult, because more subtle, more complex, and dependent on more and more fugitive causes. In the truly great poets... there is a reason assignable, not only for every word, but for the position of every word.
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.
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.
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.
You can be a thorough-going Neo-Darwinian without imagination, metaphysics, poetry, conscience, or decency. For 'Natural Selection' has no moral significance: it deals with that part of evolution which has no purpose, no intelligence, and might more appropriately be called accidental selection, or better still, Unnatural Selection, since nothing is more unnatural than an accident. If it could be proved that the whole universe had been produced by such Selection, only fools and rascals could bear to live.
That is what all poets do: they talk to themselves out loud; and the world overhears them. But it's horribly lonely not to hear someone else talk sometimes.
One had a lovely face,
And two or three had charm,
But charm and face were in vain.
Because the mountain grass
Cannot keep the form
Where the mountain hare has lain.
The necessity of poetry has to be stated over and over, but only to those who have reason to fear its power, or those who still believe that language is 'only words' and that an old language is good enough for our descriptions of the world we are trying to transform.