Chemical formulas represent concepts not sounds, 95 Chemistry, 20, 47, 55; significance of, 160 ff. Chinese script based on direct co-ordination, 93 Civilization, 184 ff. Classification, not definite, 2; purpose of, 2-4 Classification of the sciences, 53 ff. Collective activity, 181 Combination, sequence in, 73 ff. Combinations, theory of, 71 Combinatory schematization, 73; in chemistry, 71 ff.; in physics, 72 Communication, 181 Community among plants and animals, 179 Comparison, 82 Comte, Auguste, 54 Concept, the most general, 61 ff. Concepts, arbitrary, 23; complex, 23; complex empirical, 23; definition of, 16; empirical, 18; formation of, 19; general, 26; in ceaseless flux, 88; science of, 15 ff., 122; simple, 20; simple and complex, 19 ff. Conclusion, the, 24 ff.; analytic, 66; scientific, 27, 30, 66 ff. Concrete and abstract, 16 ff. Conjugacy, most general concept in formal sciences, 56 Conscious action, 174 Conscious thinking, willing, and acting, 178 Conservation of energy, the law of the, 135 ff. Conservation of matter, 138 Conservation of the sum of work and kinetic energy, the law of the, 134 Conservation of work, the law of the, 130 Conservation, quantitative, 131 Continuity, 101 ff.; the law of, 113 ff. Co-ordinated signs, change in, 88 ff. Co-ordination, 80 ff.; a means of obtaining facts without dealing directly with the corresponding realities, 87; between concept and word not unambiguous, 89; between concept and written sign, direct and indirect, 92 ff.; identity the limit case in, 82; integral numbers the best basis of, 85; in use among primitive men and higher animals, 87; its importance, 85; methodology of the sciences based upon, 85; of numbers with signs, 90 ff.; possibility of unambiguous, 88 Copernican theory, 117 ff. Copernicus, 117, 141 Corpuscular theory of light, 5, 157 Counting, 85 ff.; defined, 85; purpose of, 86 Culture, see Civilization Darwin, his fundamental theory, 173 Deduction, 40 ff.; the process of, 41 ff. Deductive sciences, 38 Determinateness, absolute, only in ideal world, 50 Determinateness of things, the, 47 ff. Determinism, 48, 51 Differential Calculus, see Differentials Differentials, 112 Double numbers or double points in a group, 82 Dynamics, 128 ff.; definition of, 139 Elasticity, 145 Elastic undulatory theory of light, see Wave theory of light Electricity, principal source of, 156 Electricity and magnetism, 154 ff. Electromagnetic theory of light, 157 ff. Electrotechnics, 156 Empirical sciences, 38 Energetic mechanics, 138 ff.