EVOLUTION IN GENERAL. 5 



remarked, is not to account for it. No living thinker 

 has yet found it possible to account for Evolution. 

 Mr. Herbert Spencer's famous definition of Evolution 

 as "a change from an indefinite incoherent homogene- 

 ity to a definite coherent heterogeneity through contin- 

 uous differentiations and integrations " 1 — the formula 

 of which the Contemporary Reviewer remarked that 

 " the universe may well have heaved a sigh of relief 

 when, through the cerebration of an eminent thinker, 

 it had been delivered of this account of itself " — is 

 simply a summary of results, and throws no light, 

 though it is often supposed to do so, upon ultimate 

 causes. While it is true, as Mr. Wallace affirms in his 

 latest work, that " Descent with modification is now 

 universally accepted as the order of nature in the 

 organic world," there is everywhere at this moment 

 the most disturbing uncertainty as to how the Ascent 

 even of species has been brought about. The attacks 

 on the Darwinian theory from the outside were never 

 so keen as are the controversies now raging in scien- 

 tific circles, over the fundamental principles of Dar- 

 winism itself. On at least two main points — sexual 

 selection and the origin of the higher mental charac- 

 teristics of man — Mr. Alfred Russel Wallace, co-dis- 

 coverer with Darwin of the principle of Natural Selec- 

 tion though he be, directly opposes his colleague. 

 The powerful attack of Weismann on the Darwinian 

 assumption of the inheritability of acquired characters 

 has opened one of the liveliest controversies of recent 

 years, and the whole field of science is hot with con- 

 troversies and discussions. In his " Germ-Plasm," the 

 German naturalist believes himself to have finally 

 1 Data qf Ethics, p. 65. 



