are reconcilable with the hypothesis of evolution, and some of them yield strong support,—­especially the near relationship existing between the living and extinct types in each great geographical area.  Thus of these four categories of evidence, each furnishes several arguments which point to the same conclusion.  This coincidence would give to the induction a very high degree of probability, even were it not enforced by deduction.  As a matter of fact, the conclusion deductively reached is in harmony with the inductive conclusion.  Mr. Spencer has deductively shown that, by its lineage and its kindred, the evolution-hypothesis is as closely allied with the proved truths of modern science as is the antagonist hypothesis, that of special creation, with the proved errors of ancient ignorance.  He has shown that, instead of being a mere pseud-idea, it admits of elaboration into a definite conception, so showing its legitimacy as an hypothesis.  Instead of positing a purely fictitious process, the process which it alleges proves to be one actually going on around us.  To which may be added that the evolution-hypothesis presents no radical incongruities from a moral point of view.  On the other hand, the special-creation hypothesis is shown to be not even a thinkable hypothesis, and, while thus intellectually illusive, to have moral implications irreconcilable with the professed beliefs of those who hold it.

Passing from the evidence that Evolution has taken place to the question—­How has it taken place?—­Mr. Spencer finds in known agencies and known processes adequate causes of its phenomena.  In astronomic, geologic, and meteorologic changes, ever in progress, ever combining in new and more involved ways, we have a set of inorganic factors to which all organisms are exposed; and in the varying and complicated actions of organisms on one another we have a set of organic factors that alter with increasing rapidity.  Thus, speaking generally, all members of the Earth’s flora and fauna experience perpetual rearrangements of external forces.  Each organic aggregate, whether considered individually or as a continuously existing species, is modified afresh by each fresh distribution of external forces.  To its pre-existing differentiations new differentiations are added; and thus that lapse to a more heterogeneous state, which would have a fixed limit were the circumstances fixed, has its limits perpetually removed by the perpetual change of the circumstances.  These modifications upon modifications, which result in evolution, structurally considered, are the accompaniments of those functional alterations continually required to re-equilibrate inner with outer actions.  That moving equilibrium of inner actions corresponding with outer actions, which constitutes the life of an organism, must either be overthrown by a change in the outer actions or must undergo perturbations that cannot end until there is a readjusted balance of functions and correlative