Language, color, form, and religious and civil habits of action, are all the instruments and materials of poetry; they may be called poetry by that figure of speech which considers the effect as a synonym of the cause. But poetry in a more restricted sense expresses those arrangements of language, and especially metrical language, which are created by that imperial faculty, whose throne is curtained within the invisible nature of man. And this springs from the nature itself of language, which is a more direct representation of the actions and passions of our internal being, and is susceptible of more various and delicate combinations, than color, form, or motion, and is more plastic and obedient to the control of that faculty of which it is the creation. For language is arbitrarily produced by the imagination, and has relation to thoughts alone; but all other materials, instruments, and conditions of art have relations among each other, which limit and interpose between conception and expression. The former is as a mirror which reflects, the latter as a cloud which enfeebles, the light of which both are mediums of communication. Hence the fame of sculptors, painters, and musicians, although the intrinsic powers of the great masters of these arts may yield in no degree to that of those who have employed language as the hieroglyphic of their thoughts, has never equalled that of poets in the restricted sense of the term; as two performers of equal skill will produce unequal effects from a guitar and a harp. The fame of legislators and founders of religions, so long as their institutions last, alone seems to exceed that of poets in the restricted sense; but it can scarcely be a question, whether, if we deduct the celebrity which their flattery of the gross opinions of the vulgar usually conciliates, together with that which belonged to them in their higher character of poets, any excess will remain.
We have thus circumscribed the word poetry within the limits of that art which is the most familiar and the most perfect expression of the faculty itself. It is necessary, however, to make the circle still narrower, and to determine the distinction between measured and unmeasured language; for the popular division into prose and verse is inadmissible in accurate philosophy.
Sounds as well as thoughts have relation both between each other and towards that which they represent, and a perception of the order of those relations has always been found connected with a perception of the order of the relations of thoughts. Hence the language of poets has ever affected a certain uniform and harmonious recurrence of sound, without which it were not poetry, and which is scarcely less indispensable to the communication of its influence, than the words themselves, without reference to that peculiar order. Hence the vanity of translation; it were as wise to cast a violet into a crucible that you might discover the formal principle of its color and odor, as seek to transfuse from one language into another the creations of a poet. The plant must spring again from its seed, or it will bear no flower—and this is the burden of the curse of Babel.
An observation of the regular mode of the recurrence of harmony in the language of poetical minds, together with its relation to music, produced metre, or a certain system of traditional forms of harmony and language. Yet it is by no means essential that a poet should accommodate his language to this traditional form, so that the harmony, which is its spirit, be observed. The practice is indeed convenient and popular, and to be preferred, especially in such composition as includes much action: but every great poet must inevitably innovate upon the example of his predecessors in the exact structure of his peculiar versification. The distinction between poets and prose writers is a vulgar error. The distinction between philosophers and poets has been anticipated. Plato was essentially a poet—the truth and splendor of his imagery, and the melody of his language, are the most intense that it is possible to conceive. He rejected the measure of the epic, dramatic, and lyrical forms, because he sought to kindle a harmony in thoughts divested of shape and action, and he forebore to invent any regular plan of rhythm which would include, under determinate forms, the varied pauses of his style. Cicero sought to imitate the cadence of his periods, but with little success. Lord Bacon was a poet. [See the “Filum Labyrinthi,” and the “Essay on Death” particularly.—Shelley] His language has a sweet and majestic rhythm, which satisfies the sense, no less than the almost superhuman wisdom of his philosophy satisfies the intellect; it is a strain which distends, and then bursts the circumference of the reader’s mind, and pours itself forth together with it into the universal element with which it has perpetual sympathy. All the authors of revolutions in opinion are not only necessarily poets as they are inventors, nor even as their words unveil the permanent analogy of things by images which participate in the life of truth; but as their periods are harmonious and rhythmical, and contain in themselves the elements of verse; being the echo of the eternal music. Nor are those supreme poets, who have employed traditional forms of rhythm on account of the form and action of their subjects, less capable of perceiving and teaching the truth of things, than those who have omitted that form. Shakespeare, Dante, and Milton (to confine ourselves to modern writers) are philosophers of the very loftiest power.