When the conceptions of an individual mind are expressed in a permanent form of words, we get literature. The sum total of all the permanent forms of expression in one language make up the literature of that language; and if no one has given his conceptions a form which has been preserved, the language is without a literature. There are then two things essential to a literary work: first, the conceptions of an individual mind; second, a permanent form of expression. Hence it follows that the domain of literature is distinct from the domain of natural or mathematical science. Science does not give us the conceptions of an individual mind, but it tells us what every rational person who studies the subject must think. And science is entirely independent of any form of words: a proposition of Euclid is science; a sonnet of Wordsworth’s is literature. We learn from Euclid certain truths which we should have learnt from some one else if Euclid had never existed, and the propositions may be conveyed equally well in different forms of words and in any language. But a sonnet of Wordsworth’s conveys thought and feeling peculiar to the poet; and even if the same thought and feeling were conveyed to us in other words, we should lose at least half of what he has given us. Poetry is indeed only one kind of literature, but it is the highest kind; and what is true of literary works in verse, is true also in a measure of literary works in prose. So great is the difference between science and literature, that in literature, as the first Lord Lytton said, the best books are generally the oldest; in science they are the newest. § 8. At present we are concerned with literature only. There are two ways in which a work of literature may excite our admiration and affect our minds. These are, first, by the beauty of the conceptions it conveys to us; and second, by the beauty of the language in which it conveys them. In the greatest works the two excellences will be combined.[4]