LECTURE XLVII. 

 PRESENT BATTLE-GROUNDS OF EVOLUTION. 



Discussion of Disputed Questions in Evolution from 

 the Standpoint of Science. 



Science is knowledge set in order. Disputed ques- 

 tions are those (1) in which facts are not sufficient 

 for a decision, and (2) in which search for such facts 

 may hope to be rewarded. Science does not concern 

 itself with insoluble problems, nor does it dispute over 

 solved problems. The best men in science work in 

 fruitful fields. A theory in science may be valuable 

 as indicating a direction for work, giving opportunity 

 for decisive tests. Scientific ,use of the imagination. 

 A theory, no matter how plausible, is valueless for 

 any other purpose. Science cares nothing for guesses, 

 even though marvelously shrewd. The logic of science 

 is a deduction from facts. It is impersonal, unemo- 

 tional, and might be made by an automatic logic 

 machine. " Nature abhors a generalization." Science 

 can recognize only those generalizations which are so 

 supported by facts that the conclusions are evident to 

 all who know the facts. A hypothesis valueless if 

 nothing can be said against it ; that is, if incapable of 

 verification. Hence science differs from speculative 

 philosophy. Helmholtz says that the latter deals 

 with such "schlechtes Stoff" that its conclusions have 

 no value. Hence such discussions as monism versus 



