We have seen that Shelley, being unteachable, could never put together any just idea of the world:  he merely collected images and emotions, and out of them made worlds of his own.  His poetry accordingly does not well express history, nor human character, nor the constitution of nature.  What he unrolls before us instead is, in a sense, fantastic; it is a series of landscapes, passions, and cataclysms such as never were on earth, and never will be.  If you are seriously interested only in what belongs to earth you will not be seriously interested in Shelley.  Literature, according to Matthew Arnold, should be criticism of life, and Shelley did not criticise life; so that his poetry had no solidity.  But is life, we may ask, the same thing as the circumstances of life on earth?  Is the spirit of life, that marks and judges those circumstances, itself nothing?  Music is surely no description of the circumstances of life; yet it is relevant to life unmistakably, for it stimulates by means of a torrent of abstract movements and images the formal and emotional possibilities of living which lie in the spirit.  By so doing music becomes a part of life, a congruous addition, a parallel life, as it were, to the vulgar one.  I see no reason, in the analogies of the natural world, for supposing that the circumstances of human life are the only circumstances in which the spirit of life can disport itself.  Even on this planet, there are sea-animals and air-animals, ephemeral beings and self-centred beings, as well as persons who can grow as old as Matthew Arnold, and be as fond as he was of classifying other people.  And beyond this planet, and in the interstices of what our limited senses can perceive, there are probably many forms of life not criticised in any of the books which Matthew Arnold said we should read in order to know the best that has been thought and said in the world.  The future, too, even among men, may contain, as Shelley puts it, many “arts, though unimagined, yet to be.”  The divination of poets cannot, of course, be expected to reveal any of these hidden regions as they actually exist or will exist; but what would be the advantage of revealing them?  It could only be what the advantage of criticising human life would be also, to improve subsequent life indirectly by turning it towards attainable goods, and is it not as important a thing to improve life directly and in the present, if one has the gift, by enriching rather than criticising it?  Besides, there is need of fixing the ideal by which criticism is to be guided.  If you have no image of happiness or beauty or perfect goodness before you, how are you to judge what portions of life are important, and what rendering of them is appropriate?