Page:Popular Science Monthly Volume 50.djvu/463

Rh of the homogeneous, the multiplication of effects, and segregation—are exhibited as corollaries from the ultimate law, as inevitable results of the persistence of force under its forms of matter and motion. In this way the circle of induction and deduction is made complete.

In this connection it will be interesting to say something about the course of thought by which Mr. Spencer was gradually led to the fundamental principles above summarized. I am fortunate in having before me as I write a letter in which he was kind enough to outline for me the important stages in his progress toward the great doctrines of the synthetic philosophy. If, in following his account and in occasionally reproducing, as I shall venture to do, his own words, I am forced to touch again upon points already brought out, this will scarcely be deemed ground for regret, since the slight repetition involved will serve perhaps to throw the whole subject into clearer relief.

The simple nucleus of his philosophic system first made its appearance in Social Statics, where, in the chapter entitled General Considerations, mention is made of the biological truth that low types of animals are composed of many like parts not mutually dependent, while higher animals are composed of parts that are unlike and are mutually dependent. This, he writes, "was an induction which I had reached in the course of biological studies—mainly, I fancy, while attending Professor Owen's lectures on the Vertebrate Skeleton." With this was joined the statement that the same is true of societies, "which begin with many like parts not mutually dependent and end with many like parts that are mutually dependent." This also was an induction. "And then in the joining of these came the induction that the individual organism and the social organism followed this law." Thus the radical conception of the entire system took shape before Mr, Spencer had become acquainted with von Baer's law, which, as we have seen, did not occur till two years later. This law, though applying to the unfolding of the individual only, had none the less its use. In furnishing the expression "from homogeneity to heterogeneity," it presented a more convenient intellectual implement. "By its brevity and its applicability to all orders of phenomena, it served for thinking much better than the preceding generalization, which contained the same essential thought." The essays which followed Social Statics were marked by the establishment of various separate inductions in which other groups of