response; the baring of the teeth in anger gives a substantial hint of that tearing of the enemy to pieces which used to be the natural termination of such a beginning.[1] "Forms of thought" like the perception of space and time, or the notions of quantity and cause, which Kant supposed innate, are merely instinctive ways of thinking; and as instincts are habits acquired by the race but native to the individual, so these categories are mental habits slowly acquired in the course of evolution, and now part of our intellectual heritage.[2] All these age-long puzzles of psychology can be explained by "the inheritance of continually-accumulating modifications."[3]—It is of course just this all-pervading assumption that makes so much of these laborious volumes questionable, and perhaps vain.
With sociology the verdict is quite different. These stout volumes, whose publication ranged over twenty years, are Spencer's masterpiece: they cover his favorite field, and show him at his best in suggestive generalization and political philosophy. From his first book, Social Statics, to the last fascicle of The Principles of Sociology, over a stretch of almost half a century, his interest is predominantly in the problems of economics and government; he begins and ends, like Plato, with discourses on moral and political justice. No man, not even Comte (founder of the science and maker of the word), has done so much for sociology.
In a popular introductory volume, The Study of Sociology (1873), Spencer argues eloquently for the recognition and development of the new science. If determinism is correct in psychology, there must be regularities of cause and effect in social phenomena; and a thorough student of man and society will not be content with a merely chronological history, like
