Keats was more of the artist than any of his English brother poets. He troubled himself less about principles than any of them. There is no groundwork of patriotism in his poetry as there is in Scott's and Moore's; no message of liberty, as in Shelley's and Byron's; it is pure art, owing its origin to nothing but the power of imagination. It was one of his favourite sayings, that the poet should have no principles, no morality, _no self_. Why? Because the true poet enjoys both light and shade--has as much delight in conceiving an Iago as an Imogen. All poets who have forgotten themselves in the theme of their flights of fancy, have, when engaged in production, to the best of their ability banished their private peculiarities and preferences. Few have managed to make such a clean sweep as Keats of their personal hopes, enthusiasms, and principles. His study was, as one of his admirers has said, "a painter's studio with very little in it besides the easel."
Keats's poetical indifference to theories and principles was, however, in itself a theory and a principle--was the philosophy which has its foundation in poetic worship of nature. To the consistent pantheistic poet all forms, all shapes, all expressions of life on earth which engage the imagination, are precious, and all equally precious. Keats, as poet, recognises no truth of the kind that means improvement or exclusion; but he has an almost religious faith in imagination as the source of truth. In one of his letters he expresses himself thus:--"I am certain of nothing but of the holiness of the heart's affections, and the truth of Imagination. What the Imagination seizes as Beauty must be Truth, whether it existed before or not;--for I have the same idea of all our passions as of Love: they are all, in their sublime, creative of essential Beauty.... The Imagination may be compared to Adam's dream; he awoke and found it truth." He enlarges on the difference between this kind of truth and the truth arrived at by consecutive reasoning, and concludes with an exclamation which is a key to the whole of his poetry:--"However it may be, O for a life of sensations rather than of thoughts!"
He led in great part a life of passive sensation, of pleasure and pain through the senses. "Take," says Masson, "a book of physiology and go over the so-called classes of sensations one by one--the sensations of the mere muscular states; the sensations connected with such vital processes as circulation, alimentation, respiration, and electrical intercommunication with surrounding bodies; the sensations of taste; those of odour; those of hearing; and those of sight--and Keats will be found to have been unusually endowed in them all."