The triplicity of the word, as sound, image, meaning, provides a certain justification for the variety of tastes in poetry, and accounts for the difficulty of setting up a single universal standard. There is an unstable equilibrium between the three aspects of words; hence poetry tends to become predominantly music or painting or thought, yet can never succeed in becoming completely any one of these. And it is inevitable that some people should be more sensitive to one rather than to another of the aspects of words, preferring therefore the more musical, or the more thoughtful, or the more pictorial poetry. And so we have poems that would be music, and others that would be pictures, and still others that would be epigrams. And each kind has a certain right and beauty; but no kind has the unique beauty that is poetical. We do not ask their makers not to produce them, nor do we condemn the pleasures which they afford us, but we cannot commend them without reservation. For the best poems achieve a synthesis of the elements of words,--they are at once musical and imaginative and thoughtful. Yet with difficulty; for there is an antagonism among the elements: when the music is insistent, the thought is obscured; when the images are elaborate, their meaning is lost to sight; when the thought is subtle or profound, it rejects the image and is careless of sound. Swinburne's poetry is full of philosophy, but is so sensuous and musical that we miss its thoughts; Browning is too subtle a thinker to be a musician. The complexity of poetry is the source of its strength, lending it something of the inwardness of music and the plasticity of the pictorial arts; but is also the source of its weakness. Seldom does it achieve the technical purity and perfection of music and painting and sculpture. Music has a clear and simple medium, painting and sculpture work with colors and forms which almost are what they represent; but word-sounds are not what they mean, and what they mean is not precisely the same as the images which they evoke; too often the correspondence is factitious and artificial, rarely is there fusion. Yet, as I have tried to show, when meaning is made central, sound may fit it closely, and when the meaning is emotional, the music of sound may echo its cry, and the image, instead of rebelling, may serve. Emotional thought is the essence of poetry and the link between its music and its pictures.