This passage occurs in the second book of the _Advancement of Learning_ (1605), where Bacon has briefly stated his theory of poetry. His point of view does not differ essentially from that of Sidney, though the expression is more compact and logical. The human understanding, according to Bacon, includes the three faculties of memory, imagination, and reason, and each of these faculties finds typical expression in one of the three great branches of learning, memory in history, reason in philosophy, and imagination in poetry.[485] The imagination, not being tied to the laws of matter, may join what nature has severed and sever what nature has joined; and poetry, therefore, while restrained in the measure of words, is in all things else extremely licensed. It may be defined as feigned history, and in so far as its form is concerned, may be either in prose or in verse. Its source is to be found in the dissatisfaction of the human mind with the actual world; and its purpose is to satisfy man's natural longing for more perfect greatness, goodness, and variety than can be found in the nature of things. Poetry therefore invents actions and incidents greater and more heroic than those of nature, and hence conduces to magnanimity; it invents actions more agreeable to the merits of virtue and vice, more just in retribution, more in accordance with revealed providence, and hence conduces to morality; it invents actions more varied and unexpected, and hence conduces to delectation. "And therefore it was ever thought to have some participation of divineness, because it doth raise the mind, by submitting the shows of things to the desires of the mind; whereas reason doth buckle and bow the mind unto the nature of things."[486] For the expression of affections, passions, corruptions, and customs, the world is more indebted to poets than to the works of philosophers, and for wit and eloquence no less than to orators and their orations. It is for these reasons that in rude times, when all other learning was excluded, poetry alone found access and admiration. This is pure idealism of a romantic type; but in his remarks on allegory Bacon was foreshadowing the development of classicism, for from the time of Ben Jonson the allegorical mode of interpreting poetry ceased to have any effect on literary criticism. The reason for this is obvious. The allegorical critics regarded the plot, or fable,--to use a simile so often found in Renaissance criticism--as a mere sweet and pleasant covering for the wholesome but bitter pill of moral doctrine. The neo-classicists, limiting the sense and application of Aristotle's definition of poetry as an imitation of life, regarded the fable as the medium of this imitation, and the more perfect according as it became more truly and more minutely an image of human life. In criticism, therefore, the growth of classicism is more or less coextensive with the growth of the conception of the fable, or plot, as an end in itself.