And it is here that Burroughs stands as a dominating figure. He was the first of American critics to insist without compromise that poetry is poetry only when it is the voice of life--genuine, spontaneous, inevitable. "How rare," he complained in later years, "are real poems--poems that spring from real feeling, a real throb of emotion, and not from a mere surface itching for expression." This has been the key to all his criticism: literature is life, the voicing of a man's soul. Moreover, it is a voicing of the national life, the expression of a nation's soul: All the great imaginative writers of our century have felt, more or less, the stir and fever of the century, and have been its priests and prophets. The lesser poets have not felt these things. Had Poe been greater or broader he would have felt them, so would Longfellow. Neither went deep enough to touch the formative currents of our social or religious or national life. In the past the great artist has always been at ease in Zion; in our own day only the lesser artists are at ease, unless we except Whitman, a man of unshaken faith, who is absolutely optimistic, and whose joy and serenity come from the breadth of his vision and the depth and universality of his sympathies.[83] The literary criticism of Burroughs--four volumes of it in the final edition, or nearly one-fourth of his whole output--may be classed with the sanest and most illuminating critical work in American literature. Lowell's criticism, brilliant as it is at times, is overloaded with learning. He belongs to the school of the early reviewers, ponderous and discursive. He makes use of one-third of his space in his essay on Thoreau before he even alludes to Thoreau. He is self-conscious, and self-satisfied; he poses before his reader and enjoys the sensation caused by his brilliant hit after hit. Stedman, too, is often more literary than scientific. Often he uses epithet and phrase that have nothing to commend them save their prettiness, their affectation of the odd or the antique. He is an appreciator of literature rather than critic in the modern sense. Burroughs, however, is always simple and direct. He is a scientific critic who compares and classifies and seeks causes and effects. He works not on the surface but always in the deeper currents and always with the positive forces, those writers who have turned the direction of the literature and the thinking of their generation. In marked contrast with Stedman, he can place Longfellow and Landor among the minor singers: "Their sympathies were mainly outside their country and their times." He demands that the poet have a message for his age. He says of Emerson: "Emerson is a power because he partakes of a great spiritual and intellectual movement of his times; he is unequivocally of to-day and New England."