The art of poetry is the art of knowing language and people equally well. It is an art whose focus is in two directions at once: toward the inert technical arcana of syllables and sounds and syntax and metaphor as well as toward the animated actualities of human nature and human expectation. The knowledge of the way a reader will react when a technical something is done to him is what controls the poet's manipulation of his technique. To do something to the reader is the end of poetry: a poem is less a notation on a page or a sequence of uttered sounds than a shaped or measured formal effect that impinges upon a reader or hearer. The reality of the poem is its impingement. [. . .] No element of the poem is more basic--and I mean physical--in its effect upon the reader than the metrical element, and perhaps no technical triumphs reveal more readily than the metrical the poet's sympathy with that universal human nature--conceived as a system of physiological and psychological uniformity--which exists outside his own, and to which the fullest understanding of his own is the key. The poet whose metrical effects actually work upon a reader reveals that he has attained an understanding of what man in general is like. It is thus possible to suggest that a great metrical achievement is more than the mark of a good technician: it is something like the signature of a great man.
from Paul Fussell's Poetic Meter and Poetic Form