Yet man becomes comprehensible as soon as we apply scientific methods to the study of his nature. He has indeed numerous faculties, seeing and hearing, imagination and feeling, reproduction and concentration. These, however, do not oppose each other, but stand side by side, supplementing each other, as everything on earth consists of parts which supplement each other. The fundamental laws of human life are the same as those which we find in the higher animals. But man’s ability to elaborate momentary sense impressions is immensely increased: there is no limit to the associative and selective combination of the elementary impressions. Thus man establishes his power over all other animals and the inanimate world, realizing the general purposes common to all organisms by incomparably higher and richer constructions. But these, however we esteem them, are derived from the same fundamental forces of nature, only differing in measure and in their proportions. Mind is not like an unclean pot in which noble seeds are planted, so that the plants growing from them do not fit the vessel containing them and unending discord must result. Mind is a unitary organism which, unfolding its capacities, adjusts itself more and more perfectly to the circumstances of chance or of its own creation. As the same atmosphere brings forth out of wind and water and warmth now fertile rains, now destructive hail storms, beautiful clouds above, dangerous fog below, so the same mind by the same natural laws brings forth error and truth, desireful pleasure and desireless joy, selfishness and morality. INDEX Abstraction, 126, 133, 140, 151. Adaptation, 74. Affection, 162. Afferent, 35, 38. After-image, 74. Anemia, 27. Animals, 27, 37, 65, 75, 128, 151, 197. Apes, 27. Apperception, 119. Arborization, 33. Architecture, 202. Aristotle, 3, 10, 17. Art, 14, 24, 196. Association, 10, 11, 12, 14, 93, 144, 164. Attention, 11, 12, 87, 115, 121, 125, 144, 151. Audition, 74, 76. Auditory, 62, 98. Automatic, 101. Axiom, 152. Beats, 64. Beethoven, 14. Belief, 152, 156, 158. Bessel, 20. Biology, 16. Bismarck, 180. Blind born, 67. Boycott, 136. Brain, 21, 22, 23, 27, 28. Brewster, 17. Broca, 21. Buffon, 11. Bulb, 38. Cæsar, 136. Catholic church, 205. Causality, 5, 7, 8, 9, 177. Center, 35, 36, 37, 107, 111. Cerebellum, 38, 39. Cerebrum, 38, 41. Christ, 209. Cicero, 159. Coherent thought, 142. Collateral, 32. Color, 58. Color-blind, 60, 76. Color mixture, 61. Conduct, 162, 176. Conscience, 206. Consciousness, 41. Conservation of energy, 45. Copernican system, 161. Cortex, 38, 40, 41. Corti, 76. Crime, 97. Cutaneous, 52, 73. Davy, 121. Definition, 141. Dendrite, 31. Desire, 109. Determinism, 181. Difference tone, 64. Discrimination, 100. Distance, 116. Dream, 142, 156. Drugs, 27. Duration, 68. Education, 24, 97. Efferent, 35, 38. Emotion, 168. Enlightenment, 11. Esthetics, 14, 185, 197, 202. Evolution, 5, 16.