COMPARATIVE psychology has arrived. We have had our Descartes and our psychic epiphenomenalists; and their descendants, the vital mechanicians, are still with us. And no Luther has arisen to shatter at a stroke their gods (of tin and other artificers' materials) and proclaim the reformation of psychology in a single revolutionary coup. No Darwin has struck off a hypothesis of psychogenesis full grown and puissant to drive its decadent rivals from the field by virtue of its own all-assimilating vitality. But the leaven of Darwinism has been slowly permeating, even into the dusty meal bins of speculative psychology. In spite of fervid anathemas from the citadels of the categorical intuitionalists, the steady growth of genetic ideas has by natural process begun to corrode the very foundations of these strongholds of conservatism; for have we not already begun our natural history of the intuitions and their genesis?
It has been pointed out as a most hopeful sign that this new psychology (unlike that sometimes falsely so called) does not come bearing as its ikons a glittering array of brass instruments of precision and tomes of statistics; but, like the kingdom of Heaven, it cometh not with observation, as a change of mental attitude among both psychologists and naturalists.
There is apparently no general recognition of the revolutionary character of this feature, which is implicit in many movements now current in science and philosophy—movements bearing as diverse labels in the philosophical vernacular of the day as 'experimental evolution' 'genetic psychology' (in a score of mutually antagonistic forms), 'pragmatism,' 'functional philosophy,' 'paidology,' 'dynamic monism' etc., etc. So far as the genetic element in these systems is true, it is destined to outlive its ephemeral and sometimes bizarre setting, and the day when we shall have a generally accepted doctrine of psychogenesis and psychic evolution is certainly not far off, though it would be folly to assert that this day has yet dawned.
One of the most valuable features of the remarkable book by Stanley Hall on the psychology of adolescence is the emphasis which he places on the study of the past of mind as a corrective to the morbid speculations on its future which comprise the larger part of