That poetry must be metrical or even rhythmical in movement, however, is what some have denied. Here we touch at once the very root of the subject. Aristotle seems to have assumed that the indispensable basis of poetry is invention; and perhaps the first critic who tacitly revolted against the dictum that substance, and not form, is the indispensable basis of poetry was Dionysius of Halicarnassus, whose treatise upon the arrangement of words is really a very fine piece of literary criticism.
By the poets themselves metre was for long considered to be the one indispensable requisite of a poem, though, as regards criticism, even in the time of the appearance of the Waverley Novels, the Quarterly Review would sometimes speak of them as "poems"; and perhaps even later the same might be said of romances so concrete in method and diction, and so full of poetic energy, as Wuthering Heights and Jane Eyre, where we get ab solutely all that Aristotle requires for a poem. However, at all events this at least may be said, that the division between poetical critics is not now between Aristotelians and others ; it is of a different kind altogether. While one group of critics may still perhaps say with Dryden that "a poet is a maker, as the name signifies" and that "he who cannot make (that is, invent) has his name for nothing," another group contends that it is not the invention but the artistic treatment, the form, which de termines whether an imaginative writer is a poet or a writer of prose—contends, in short, that emotion is the basis of all true poetic expression, whatever be the subject-matter, that thoughts must be expressed in an emotional manner before they can be brought into poetry, and that this emotive expression demands even yet something else, viz., style and form.
Although many critics are now agreed that "L'art est une forme," that without metre and without form there can be no poetry, there are few who would contend that poetry can exist by virtue of any one of these alone, or even by virtue of all these combined. Quite independent of verbal melody, though mostly accompanying it, and quite independent of "composition" there is an atmosphere floating around the poet through which he sees everything, an atmosphere which stamps his utterances as poetry. This atmosphere is what we call poetic imagination.
For, notwithstanding all that may be said upon poetry as a fine art, it is in the deepest sense of the word an "inspiration." No man can write a line of genuine poetry without having been "born again" (or as the true rendering of the text says, "born from above") ; and then the mastery over those highest reaches of form which are beyond the ken of the mere versifier comes to him as a result of the change.
It might almost be said, indeed, that Sincerity and Conscience, the two angels that bring to the poet the wonders of the poetic dream, bring him also the deepest, truest delight of form. It might almost be said that by aid of sincerity and conscience the poet is enabled to see more clearly than other men the eternal limits of his own art—to see with Sophocles that nothing, not even poetry itself, is of any worth to man, invested as he is by the whole army of evil, unless it is in the deepest and highest sense good, unless it comes linking us all together by closer bonds of sympathy and pity, strengthening us to fight the foes with whom Fate and even Nature, the mother who bore us, sometimes seem in league—to see with Milton that the high quality of man's soul which in English is expressed by the word virtue is greater than even the great poem he prized, greater than all the rhythms of all the tongues that have been spoken since Babel—and to see with Shakespeare and with Shelley that the high passion which in English is called love is lovelier than all art, lovelier than all the marble Mercuries that "await the chisel of the sculptor" in all the marble hills.