8 EVOLUTION OF TO-DAY. 



ever be demonstrated. All that can be done is to 

 discuss the question from theoretical grounds. 

 There is then a break at the beginning of life, since 

 spontaneous generation can be neither proved nor 

 disproved. This fact makes it far preferable for the 

 present at least to confine the term evolution, in our 

 ordinary discussion, as Darwin did, to the develop- 

 ment of life, without including any theory as to its 

 origin ; realizing all the while that as thus stated 

 the theory is not complete. If we do confine the 

 term to these limits we have a theory which is open 

 to investigation, and which may some time be ap- 

 proximately demonstrated. But if we attempt to 

 include all that Spencer understands by the term, 

 there is little hope that we can advance beyond 

 hypothesis. Scientists, therefore, as a rule, restrict 

 the term to the development of living organisms. 

 It is the object of the following pages to discuss the 

 question in this sense, as a scientific theory, there- 

 fore, without reference to the deeper metaphysical 

 problems underlying the more comprehensive signi- 

 ficance of evolution as applied to the origin of the 

 universe. Whenever the term evolution is used in 

 the following pages, it is in the sense above indicated, 

 and is synonymous with the terms organic evolution 

 and the theory of descent. 



Are there any other breaks in the chain of con- 

 tinuity which may make it wise to limit still further 

 the meaning of evolution ? It is claimed by many 

 that such a break is found in man ; not so far as his 

 body is concerned, but because he represents a new 

 order, in intellect and morality. This question is 



