CHAyxv.] RECAPITULATION. 



267 



CHAPTER XV. 



EECAPITULATION AND CONCLUSION. 



Recapitulation of the objections to the theory of Natural Selection 

 —Recapitulation of the general and special circumstances in its 

 favour— Causes of the general belief in the immutability of 

 species— How far the theory of Natural Selection may be ex- 

 tended-Effects of its adoption on the study of Natural History 

 — Concluding Remarks. 



As this whole volume is one long argument, it may 

 be convenient to the reader to have the leading facts 

 and inferences briefly recapitulated. 



That many and serious objections may be advanced 

 against the theory of descent with modification through 

 variation and natural selection, I do not deny. I have 

 endeavoured to give to them their full force. Nothing 

 at first can appear more difficult to believe than that 

 the more complex organs and instincts have been per- 

 fected,' not by means superior to, though analogous with, 

 human reason, but by the accumulation of innumerable 

 slight variations, each good for the individual possessor. 

 Nevertheless, this difficulty, though appearing to our 

 imagination insuperably great, cannot be considered 

 real if we admit the following propositions, namely, 

 that all parts of the organisation and instiacts offer, at 

 least, individual differences — that there is a struggle for 

 existence leading to the preservation of profitable devia- 

 tions of structure or instinct — and, lastly, that grada- 



