The Condition of Civilization and of Thought at the Close of the Nineteenth Century--Progress of Our Knowledge of Nature, of the Organic and Inorganic Sciences--The Law of Substance and the Law of Evolution--Progress of Technical Science and of Applied Chemistry--Stagnancy in other Departments of Life: Legal and Political Administration, Education, and the Church--Conflict of Reason and Dogma--Anthropism--Cosmological Perspective--Cosmological Theorems--Refutation of the Delusion of Man's Importance--Number of "World-Riddles"--Criticism of the "Seven" Enigmas--The Way to Solve Them--Function of the Senses and of the Brain--Induction and Deduction--Reason, Sentiment, and Revelation--Philosophy and Science--Experience and Speculation--Dualism and Monism The close of the nineteenth century offers one of the most remarkable spectacles to the thoughtful observer. All educated people are agreed that it has in many respects immeasurably outstripped its predecessors, and has achieved tasks that were deemed impracticable at its commencement. An entirely new character has been given to the whole of our modern civilization, not only by our astounding theoretical progress in sound knowledge of nature, but also by the remarkably fertile practical application of that knowledge in technical science, industry, commerce, and so forth. On the other hand, however, we have made little or no progress in moral and social life, in comparison with earlier centuries; at times there has been serious reaction. And from this obvious conflict there have arisen, not only an uneasy sense of dismemberment and falseness, but even the danger of grave catastrophes in the political and social world. It is, then, not merely the right, but the sacred duty, of every honorable and humanitarian thinker to devote himself conscientiously to the settlement of that conflict, and to warding off the dangers that it brings in its train. In our conviction this can only be done by a courageous effort to attain the truth, and by the formation of a clear view of the world--a view that shall be based on truth and conformity to reality.