means of guessing whether it took a million of years, or ten millions, or a hundred millions, or a thousand millions of years, to give rise to that series of change. A biologist has no means of arriving at any conclusion as to the amount of time which may be needed for a certain quantity of organic change. He takes his time from the geologist. The geologist, considering the rate at which deposits are formed and the rate at which denudation goes on upon the surface of the earth, arrives at more or less justifiable conclusions as to the time required for the deposit of a certain thickness of rocks; and if he tells me that the Tertiary formations required 500,000,000 years for their deposit, I suppose he has good ground for what he says, and I take that as a measure of the duration of the evolution of the horse from the Orohippus up to its present condition. And, if he is right, undoubtedly evolution is a very slow process, and requires a great deal of time. But suppose, now, that an astronomer or a physicist -for instance, my friend, Sir William Thomson-tells me that my geological authority is quite wrong; and that he has weighty evidence to show that life could not possibly have existed upon the surface of the earth 500,000,000 years ago, because the earth would have then been too hot to allow of life, my reply is: That is not my affair; settle that with the geologist, and when you have come to an agreement among yourselves, I will adopt your conclusion.' We take our time from the geologists and physicists; and it is monstrous that, having taken our time from the physical philosopher's clock, the physical philosopher should turn round upon us, and say we are too fast or too slow. What we desire to know is, is it a fact that evolution took place? As to the amount of time which evolution may have occupied, we are in the hands of the physicists and astronomers, whose business it is to deal with those questions." 6 Abstractions, 45 Abstract terms, 54 Aikins, 163, 205 Amphibology, 73 INDEX Classification, 6, 32, 49, 79, 195; Comparison of quantities, 210 Contradictory propositions, 114 Contrary propositions, 114 Correlation, 191 Counteracting causes, 97, 193 Cross-division, 41 Curves, 226 Cuvier, 12 Darwin, 248, 249 Deduction, 110; a part of scientific method, 2 Definition, 57; defects of, 60 Deviations from an average, 205 Dilemma, The, 159 Discrimination, 45 Disjunctive reasoning, 157 Distributive terms, 56 Distribution of terms, 71 Division, 37; dichotomous, 38; Euler's Method, 72, 120 Exceptive propositions, 76 Explanation, 237; general, 240; Fallacies, formal, 138, 173; of Fowler, 90 Fundamentun divisionis, 34, 41 Facts, 13 Galton, 203 Generalization, 79 General terms, 52 Genus, 41 Geology, 264 Geometry, 258 Hadley, 249 Hearsay evidence, 278 Hobhouse, 240, 253 Induction, 2, 79; perfect, 85; Inference, 6, 14, 15, 29 Laws of thought, 1, 10 Linnaeus, 34 Locke, 4, 9, 76 Lotze, 223 Material facts, 266 Median error, 206 Mendel's Law, 263 Methods, inductive, 88 Mill, 84, 86, 91, 95, 96, 101, 102, 105 Minto, 251, 255 Mode, the, 201 Moods of the syllogism, 140 Natural classifications, 33 Natural science, 4, 12 Newton, 247 Observation, 18, 48, 79, 88; mistakes of, 18 Obversion, 121 Opposition of propositions, 114 Pearson, 32, 192, 208 Predicate, 68 Plurality of causes, 94, 193 Premises, 126 Presuppositions of knowledge, 9 Seignobos, Langlois and, 250, 266, 269, 279 Self-evident propositions, 79 Species, 41 Statistics, 189; collection of, Subcontraries, 114 Subject, 68; grammatical, 68; Sui generis, 42 Syllogism, 111; criticism of, Symbols, 47 Systematic knowledge, 111 Terms, 49; distribution of, 71; Testing inductive inference, 83, Testing perceptions, 23 Variety, 42 Veblen, 258 Verification, 8, 81, 86, 110 Voltaire, 274 Washburn, 253 Witness, The, 269 Wilson, Sedgwick and, 35 Yerkes, 263 Young, 197 |