RESULTS AND LIMITS OF SCIENTIFIC METHOD. 461 



effects of a constantly acting tendency. Even man, 

 according to these theories, is no distinct creation, but 

 rather an extreme specimen of brain development. His 

 nearest cousins are the apes, and his pedigree extends 

 backwards until it joins that of the lowliest zoophytes. 



The theories of Darwin and Spencer are doubtless not 

 demonstrated ; they are to some extent hypothetical, just 

 as all the theories of physical science are to some extent 

 hypothetical, and open to doubt. But I venture to look 

 upon the theories of evolution and natural selection in 

 their main features as two of the most probable hypo- 

 theses ever proposed, harmonizing and explaining as they 

 do immense numbers of diverse facts } I question whether 

 any scientific works which have appeared since the * Prin- 

 cipia' of Newton, are comparable in importance with those 

 of Darwin and Spencer, revolutionizing as they do all 

 our views of the origin of bodily, mental, moral, arid social 

 phenomena. 



Granting all this/ 1 cannot for a moment admit that 

 the theory of evolution will alter our theological views. 

 That theory embraces several laws or uniformities which 

 are observed to be true in the production of living forms ; 

 but these laws do not determine the size and figure of 

 living creatures, any more than the law of gravitation 

 determines the magnitudes and distances of the planets. 

 Suppose that Dai win is correct in saying that man is 

 descended from the Ascidians : yet the precise form of 

 the human body must have been influenced by an infinite 

 train of circumstances affecting the reproduction, growth, 

 and health of the whole chain of intermediate beings. 

 No doubt, the circumstances being what they were, man 

 could not be otherwise than he is, and if in any other 

 part of the universe an exactly similar earth, furnished, 

 with exactly similar germs of life, existed, a race must 

 have grown up there exactly similar to the human race. 



