How fully Browning was a representative of the thought of this time, combining as he did an intuitional with a scientific outlook has already been shown. Evolution means for him the progress toward the infinite, and is full of beauty and promise. The failures in nature and life which fill Tennyson with despair furnish to Browning's mind a proof of the existence of the absolute, or a somewhere beyond, where things will be righted. Observation shows him everywhere in the universe the existence of power and mystery. The mystery is either that of the incomprehensibleness of causes, or is emphasized in the existence of evil. The first leads to awe and wonder, and is a constant spur to mankind to seek further knowledge, but the poet insists that the knowledge so accumulated is not actual gain, but only a means to gain in so far as it keeps bringing home to the human mind the fact of its own inadequacy in the discovery of truth. The existence of evil leads to the constant effort to overcome it, and to sympathy and pity, and as the failure of knowledge proves a future of truth to be won, so the failure of mankind to attain perfection in moral action proves a future of goodness to be realized. All this may be found either explicitly or implied in the synthetic philosophy of Herbert Spencer, whose fundamental principles, despite the fire of criticism to which he has been subjected from all sides--science, religion, metaphysics, each of which felt it could not claim him exclusively as its own, yet resenting his inclusion of the other two--are now, in the first decade of the twentieth century, receiving the fullest recognition by such masters of the history of nineteenth-century thought as Theodore Merz and Émile Boutroux. People often forget that while Spencer spent his life upon the knowledge or scientific side of human experience, he frequently asserted that there was in the human consciousness an intuition of the absolute which was the only certain knowledge possessed by man. Here again Browning was at one with Spencer. Discussing the problem of a future life in "La Saisiaz," he declares that God and the soul are the only facts of which he is absolutely certain: "I have questioned and am answered. Question, answer presuppose Two points: that the thing itself which questions, answers--_is_, it knows; As it also knows the thing perceived outside itself--a force Actual ere its own beginning, operative through its course, Unaffected by its end--that this thing likewise needs must be; Call this--God, then, call that--soul, and both--the only facts for me. Prove them facts? That they o'erpass my power of proving, proves them such."