The expressiveness of rhythm is like that of music, vague and objectless, for which reason rhythm is properly called the music of verse. Almost everything in a general way which we have said about the expressiveness of music applies to poetic rhythm. This expressiveness cannot be translated into words with any exactness; the most that can be done is to find a set of words into which it will roughly fit, leaving much vacant space of meaning. That the emotional values of rhythms have character is, however, proved by the fact that some rhythms are better vehicles for certain kinds of thought than others are. Yet it often happens that, just as, in song or opera, the same melody is used to express joy or grief, love or religious emotion, so approximately the same rhythmic form is employed in the expression of apparently antagonistic emotions. Nevertheless, this fact is not fatal to expression; for, in the first place, there is much variety of rhythm within a given metrical form, so that what superficially may seem to be the same rhythm is really a different one; and, in the second place, as we have already observed in the case of music, there is much—in form and energy of movement—which contrasting emotions have in common, and this may be expressed in the rhythmic type. Think of the wide sweep of emotions which have been expressed in the sonnet form! Yet consider what varieties of rhythm and speech melodies are possible within this form, and how, nevertheless, there is an identity of character in all sonnets—how they are all thoughtful, all restrained, yet unfaltering in their movement!
Without going into details, which would lie beyond the scope of general sthetics, it is possible to state the following broad facts (compare the similar facts relating to melody) with reference to poetic rhythms: a rising rhythm expresses striving or restlessness; a falling rhythm, quiet, steadfastness. There is, however, no absolute contrast between the two kinds, because a falling rhythm is still a rhythm, and that means a movement which necessarily contains something of instability and unrest. The contrast is sharpest in the anapestic and dactylic, less sharp in the trochaic and iambic. Many a trochaic rhythm becomes in effect iambic when the division of the thought moments and the distribution of the pauses make the rhythm rise after the first few words; and conversely, many an iambic rhythm becomes trochaic through a similar shift in the attention. Within a single line, therefore, there may be both rising and falling pulsations. Much of the rare beauty of poetry comes from such subtle combinations of rhythmic qualities.
Through time and tempo also, poetic rhythm is expressive, much after the manner of music; by these means too, in addition to the mode of stress-undulation, it imitates the temporal and dynamic course of action and emotion, and so tends to arouse congruous types of feeling in the mind; it is swift or slow, gliding or abrupt, retarded or accelerated. Compare the slow and retarded rhythm of "When I have fears that I may cease to be," so well adapted to express the gravity of the thought, with the rapid and accelerated movement of "Hail to thee, blithe spirit!" so full of a quick joyousness. Or compare the light legato movement of "Bird of the wilderness, blithesome and cumberless," with the heavy staccato movement of "Waste endless and boundless and flowerless."
Yet, for all its expressiveness, the music of verse can never stand alone. It is too bare and tenuous by itself to win and keep the attention or to evoke much feeling. It does not possess the purity of color, the loudness, force, or volume of sound that belong to music and make music, almost alone of the arts, capable of existing as mere form. The rhythm of poetry, derived very largely from a rhythm of thought, has need of thought for significance. The thought and the music are one. For this reason poetry is better, I think, when read to oneself than when read aloud; for then the sound and the sense are more intimate; the attention is not drawn off to the former away from the latter. Moreover, try as he will, the poet can never make his word-sounds fully harmonious; some roughness and dissonance will remain; but in silent reading these qualities disappear. However, although by itself of small significance, the musical element in verse makes all the difference between poetry and prose. Through its own vague expressiveness it fortifies the emotional meaning of the poetic language, and, at the same time, sublimates it by scattering it in the medium. And finally it imparts an intimacy, a personal flavor, which also allies poetry with music; for the substance of rhythm is the movement of our own inner processes; the rhythm of thoughts and sounds is a rhythm in our own listening and attending, our own thinking and feeling; the emotional values spring from us as well as from the subject-matter. Hence even narrative and dramatic poetry have a lyrical tone; we ourselves are implicated in the actions and events portrayed.
The demands made by the form of poetry upon its substance are similar to those made by music upon the words in a song, only less stringent. The content must be emotional and significant; it cannot be trite and cold. The meaning of words would permit the poet to bring before the mind all possible objects, events, and ideas, but the music of words would be incongruous with most of them. Events narrated must be stirring, thoughts uttered must be emotionally toned, things described must be related to human life and action. Poetry may desert the royal themes of long ago—arma virumque cano, maenin aeide thea—and relate the lowly life of common folk, even the sordid life of the poor and miserable, but when doing so throws over it the musical glamour of verse and arouses the heat of sympathy and passion. Although, since it makes use of words, poetry should always have a meaning, it need not have the definiteness of meaning of logical thought; it may suggest rather than explicate; its music is compatible with vagueness. But vagueness is not obscurity; the poet should always make us feel that we understand him; he should not seek to mystify us, or keep us guessing at his meaning. Yet, since the poet operates with words and not with mere sounds, great subtlety and precision of thought are possible in poetry, although not argument and dialectic. Poetry may express the results of reflection, so far as they are of high emotional value, but cannot well reproduce its processes; the steps of analysis and inference are too cold and hard for the muse to climb.
On the other hand, poetry does not permit of the development and iteration of pure feeling which we find in music; for poetic rhythms and melodies lack the variety and fluency of the musical. Yet poetry is capable, where music is not, of expressing brief, quick outbursts of feeling; for a few words, by referring to the causes and conditions of feeling, may adequately express what music needs time and many tones to convey. Poetry wins beauty by concentration, whereas music gains by expansion. There is also a similar relation between prose and poetry in this respect; the severity of the form imposes upon poetry a simplicity which contrasts with the breadth and complexity of prose. As Schopenhauer remarked, every good poem is short; long poems always contain stretches either of unmusical verse or unpoetic music. Yet, in comparison with prose, the tempo of music is slow; we have to linger in the medium in order that its rhythmic and tonal beauties may impress us, and this slowness of movement is imparted to the thought; even narrative and dramatic poetry suffer retardation; for which reason the poetic form must be abandoned if great rapidity of expression is sought.
From our study of the materials and forms of its expression, it becomes clear how the subject-matter of poetry is the inner life of mood and striving and passionate human action. Emotions may be poured forth in words, and, by means of words, actions may be described. But neither passion nor action appear in poetry as they are lived and enacted; for the poet, working in a medium of words, has to translate them into thoughts. Words cannot embody the real experiences which they express; experience is fleeting and falls away from the words, which retain only an echo of what they mean. Only what can be relived in memory can be contained in a word, and not even all of that; for a word is not a mere embodiment of an experience, but a communication also, and only its public and universal content can pass from a speaker to a hearer. Now, this socialized content of a word is a thought. Even passion the most spontaneous and lyrical has to be translated into thought,—not the abstract thought of scientific expression, but the emotionally toned thought of art, thought which, while condensing experience, still keeps its values. Emotional thought is the substance of poetry. However, albeit an image of the inner life, poetry does not volatilize it into pure feeling as music does, but distinguishes its objects and assigns its causes. Poetry is concrete and articulate where music is abstract and blind. Since words, through their meanings and associated images, can express things as well as man's reactions to them, poetry can also reflect the natural environment of life, its habitat and seat. And yet, because the poet has to translate things into ideas, nature never appears in poetry as it is in itself, but as it is implicated in mind. For the poet, sea and sky, the woods and plains and rivers, birds and flowers, are the symbols of human destiny or the loci of human action. Emotion overflows into nature, but this involves the taking up of nature into man. Not nature, but man's thoughtful life is the poet's theme.
If the foregoing statement is correct, emotional thought rather than imagery is the substance of poetry. For poetry, as music with a meaning, can be quite free of definite images. "In la sua volantade e nostra pace" (In his will is our peace) [Footnote: Dante: Paradiso, 3, 85.] is beautiful poetry, yet there is no image. The thought formulates a mood and finds a sensuous embodiment in musical language, and that suffices for beauty. And yet in poetry, as has been observed, thought tends to descend into imagery. By being connected with a sensuous material, a thought acquires a firmer support for feeling than it could possess of itself as a mere concept. Especially effective is the descent to the lower senses; for they are closest to the roots of emotion. Let me recall again the Shakespearean lyric which I have quoted before in a similar connection, omitting the last lines of each stanza:—
Blow, blow, thou winter wind,
Thou art not so unkind
As man's ingratitude;
Thy tooth is not so keen
Because thou art not seen,
Although thy breath be rude.