In opposition to Wordsworth, Coleridge believes that metre is not something superadded but an organic part of poetry. In chapter XVIII of the Biographia Literaria, he discusses in a very subtle manner the origin and effect of metre and its legitimate place in poetry. So far as the powers of metre and the source of that power are concerned, he has nothing to dispute with Wordsworth, but he regrets that Wordsworth has not given an independent and elaborate treatment to this subject. He, therefore, examines and corrects Wordsworth's views and gives them a more philosophical and perspicuous treatment.
Coleridge begins by emphasizing the difference between prose and poetry. "A poem contains the same elements as a prose composition." Both use words. The difference between a poem and a prose composition cannot, then, lie in the medium, for each employs the same medium, words. It must, therefore, "consist in a different combination of them; in consequence of a different object being proposed." A poem combines words differently, because it is seeking to do something different. "Of course, all it may be seeking to do may be to facilitate memory. You may take a piece of prose and cast it into rhymed and metrical form in order to remember it better." And rhyming tags of that kind, with their recurring, "sounds and quantities," yield a particular pleasure too, though not of a very high order. If one wants to give the name of poem to composition of this kind, there is no reason why one should not. "But we should not think that, though such rhyming tags have the charm of metre and rhyme, metre and rhyme have been "superadded." They do not rise from the nature of the content but have been imposed on it in order to make it more easily memorized.
Since the main function of poetry is to give pleasure, the composition in rrietre can provide more natural pleasure than a non-metrical one. He say;, "you cannot derive true and permanent pleasure out of any feature of a work which does not arise naturally from the total nature of that work". If metre be superadded, all other parts must be made consonant with it. Rhyme and metre involve an exact correspondent recurrence of accent and sound. "A poem, therefore, must be an organic unity in the sense that, while we note and appreciate each part, to which regular recurrence of accent and sound draw attention, our pleasure in the whole develops cumulatively out of such appreciation, which is at the same time pleasurable in itself and conducive to an awareness of the total pattern of the complete poem." In a poem the parts mutually support and explain each other, all in their proportion harmonizing with, and supporting, the purpose and known influences of metrical arrangement. In other words, in a metrical composition there must be a perfect union of 'an interpenetration of passion and of will, of spontaneous impulse and of voluntary purpose.' And this union can be best manifested in a language which is picturesque and vivifying, based on a frequent use of forms and figures of speech.
Now, the effects of metre, Coleridge believes that since metre is an organic part of poetry, it is vitally connected with its effects also. Metre in itself tends to increase the vivacity and susceptibility of the reader's mind by producing continual excitement of surprise. For poetic purposes, "metre resembles yeast, worthless or disagreeable by itself, but giving vivacity and spirit to the liquor with which it is proportionately combined." It has the power to liven the language and render it pleasurable. But the pleasure of metre itself is conditional. It is dependent on "the appropriateness of the thoughts and expressions, to which the metrical form is superadded." "Where, therefore, correspondent food and appropriate matter are not provided for the attention and feelings thus roused, there must needs be a disappointment felt; like that of leaping in the dark from the last step of a staircase, when we had prepared our muscles for a leap of three or four…… Neither can 1 conceive any other answer that can be rationally given, short of this; 1 write in metre, because I am about to use a language different from that of prose. Besides where the language is not such, how interesting so ever the reflections are, that are capable of being drawn by a philosophic mind from the thoughts of incident of the poem the metre itself must often become feeble. Here Coleridge's views appear to be somewhat inconsistent. He argues that in itself metre is only an accessory and therefore metrical composition must be accompanied by a rich thought content and poetic diction. But later he pleads that metre is 'the proper form of poetry,' and that poetry is' imperfect and defective without metre.'
In order to justify metre as an essential part of poetic composition, Coleridge, like Wordsworth, refers to the harmonious adjustment of similar and dissimilar elements into an organic unity. "This and the preceding arguments,'" he says, "may be strengthened by the reflection, that the composition of a poem is among the imitative arts; and that imitation, as opposed to copying, consists either in interfusion of the SAME throughout the radically DIFFERENT, or of the different throughout a base radically the same."
And finally, in his zeal to disprove Wordsworth's contention that "there neither is, nor can be, any essential difference between the language of prose and metrical composition." Coleridge appeals to the authority of the best poets of all countries in all ages, who have written in metre to give sanction to his view that 'there may, there is, and ought to be, an essential difference between the language of prose and metrical composition.' Language of poetry differs from prose in the same way as the language of conversation differs from prose. Words in prose and poetry may be the same but their arrangement is different. This arrangement is different because poetry uses metre. Hence there is bound to be an essential difference between the language of poetry and prose.
To conclude, metre is essential to a poem to make it different from a prose piece, to heighten the effect, to enliven pleasure and to help us in memorizing a poem; metre also balances the spontaneous overflow of passion in the poet's mind; metrical language better conveys excitement than prose. Since passion is the property of poetry, metre is organic to poetry. Then anything related to metre is actually related to the spirit of poetry. The metrical pattern tends to increase the vivacity and susceptibility both of the general feelings and of the attention. The effect which it produces is that of the continued excitement of surprise, metre also gives us the sense of musical delight.