Tarde thinks that civilization results from an increase of similarity among the members of a group through generations of mutual imitation; here the movement of evolution is conceived as a progress towards homogeneity. Gothic architecture is surely more complex than that of the Greeks; but not necessarily a higher stage of artistic evolution. Spencer was too quick to assume that what was earlier in time was simpler in structure; he underrated the complexity of protoplasm, and the intelligence of primitive man.[1] Finally, the definition fails to mention the very item which in most minds today is inalienably associated with the idea of evolution—namely, natural selection. Perhaps (imperfect though this too would be) a description of history as a struggle for existence and a survival of the fittest—of the fittest organisms, the fittest societies, the fittest moralities, the fittest languages, ideas, philosophies—would be more illuminating than the formula of incoherence and coherence, of homo- and heterogeneity, of dissipation and integration?
"I am a bad observer of humanity in the concrete," says Spencer, "being too much given to wandering into the abstract."[2] This is dangerous honesty. Spencer's method, of course, was too deductive and à priori, very different from Bacon's ideal or the actual procedure of scientific thought. He had, says his secretary, "an inexhaustible faculty of developing à priori and à posteriori, inductive and deductive, arguments in support of any imaginable proposition;[3] and the à priori arguments were probably prior to the others. Spencer began, like a scientist, with observation; he proceeded, like a scientist, to make hypotheses; but then, unlike a scientist, he resorted not to experiment, nor to impartial observation, but to the selective accumulation of favorable data. He had no nose at all for "negative instances." Contrast the procedure of Darwin, who, when he came upon data unfav-
