xx SUMMARY AND CONCLUSIONS 271 



tendings of Mr. C. W. Williams * are relevant. Though 

 it offers very little guidance in detail, yet this assertion 

 demands to be looked at. It can be held, and is, apart 

 from any claim to knowledge of the factors of evolution. 



We do not attempt to say anything further regard- 

 ing merely physical evolution. In spite of Mr. Spencer, 

 we doubt the possibility of laying down laws a priori for 

 that process. But we must consider, in the first place, 

 biological evolution, or the evolution of species. And 

 secondly, we shall pass on to speak of evolution in 

 human history. 



If we might assume natural selection to be the 

 key to organic evolution, we should have a good deal 

 of reason for identifying evolution with progress. 

 " Natural selection " seems to imply the transforming 

 of minute random variations into definite serviceable 

 changes. If everywhere there is movement, the move- 

 ment ought everywhere to result in progressive 

 efficiency or adaptedness. Yet the assertion is a difficult 

 one. 



First of all, there is one very plain condition, which 

 presumably no critic will question, but which ought to 

 be made explicit. If evolution is to mean progress, it 

 must at least imply continuous adjustment to a constant 

 environment. If the environment changes, if there is 

 no continuity in the definition of " fitness," there can 

 be no real progress. Dissatisfied with my dwelling, I 

 build myself a house exactly suited to my personal 

 needs. That is a real improvement. But forthwith I 

 have to accept an appointment in a different town, and 

 must sell my new house at a loss for whatever it will 

 fetch. The improvement due to building for myself is 

 forfeited, and turns to the opposite. Now in the far-off 



1 Review of the Systems of Ethics founded on Evolution. 



