Philosophy is a more intense sort of experience than common life is, just as pure and subtle music, heard in retirement, is something keener and more intense than the howling of storms or the rumble of cities. For this reason philosophy, when a poet is not mindless, enters inevitably into his poetry, since it has entered into his life; or rather, the detail of things and the detail of ideas pass equally into his verse, when both alike lie in the path that has led him to his ideal. To object to theory in poetry would be like objecting to words there; for words, too, are symbols without the sensuous character of the things they stand for; and yet it is only by the net of new connections which words throw over things, in recalling them, that poetry arises at all. Poetry is an attenuation, a rehandling, an echo of crude experience; it is itself a theoretic vision of things at arm's length.
George Santayana, Three Philosophical Poets, p. 124