Solidarity of causes in the world, 216. The human mind abstracts in order to explain, 219. Different cycles of operation in Nature, 220. Darwin's distinction between causes that produce and causes that preserve a variation, 221. Physiological causes produce, the environment only adopts or preserves, great men, 225. When adopted they become social ferments, 226. Messrs. {xvii} Spencer and Allen criticised, 232. Messrs. Wallace and Gryzanowski quoted, 239. The laws of history, 244. Mental evolution, 245. Analogy between original ideas and Darwin's accidental variations, 247. Criticism of Spencer's views, 251. THE IMPORTANCE OF INDIVIDUALS . . . . . . . . . . . . . . . . . 255 Small differences may be important, 256. Individual differences are important because they are the causes of social change, 259. Hero-worship justified, 261. ON SOME HEGELISMS . . . . . . . . . . . . . . . . . . . . . . . 263 The world appears as a pluralism, 264. Elements of unity in the pluralism, 268. Hegel's excessive claims, 273. He makes of negation a bond of union, 273. The principle of totality, 277. Monism and pluralism, 279. The fallacy of accident in Hegel, 280. The good and the bad infinite, 284. Negation, 286. Conclusion, 292.--Note on the Anaesthetic revelation, 294. WHAT PSYCHICAL RESEARCH HAS ACCOMPLISHED . . . . . . . . . . . . 299 The unclassified residuum, 299. The Society for Psychical Research and its history, 303. Thought-transference, 308. Gurney's work, 309. The census of hallucinations, 312. Mediumship, 313. The 'subliminal self,' 315. 'Science' and her counter-presumptions, 317. The scientific character of Mr. Myers's work, 320. The mechanical-impersonal view of life versus the personal-romantic view, 324. INDEX . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 329 {1} ESSAYS IN POPULAR PHILOSOPHY. THE WILL TO BELIEVE.[1] In the recently published Life by Leslie Stephen of his brother, Fitz-James, there is an account of a school to which the latter went when he was a boy. The teacher, a certain Mr. Guest, used to converse with his pupils in this wise: "Gurney, what is the difference between justification and sanctification?--Stephen, prove the omnipotence of God!" etc. In the midst of our Harvard freethinking and indifference we are prone to imagine that here at your good old orthodox College conversation continues to be somewhat upon this order; and to show you that we at Harvard have not lost all interest in these vital subjects, I have brought with me to-night something like a sermon on justification by faith to read to you,--I mean an essay in justification _of_ faith, a defence of our right to adopt a believing attitude in religious matters, in spite of the fact that our merely logical {2} intellect may not have been coerced. 'The Will to Believe,' accordingly, is the title of my paper.