124 THE FOUNDATIONS OF ZOOLOGY 



arated by gaps, and characterized by fitness ? Why is the system 

 of living nature such that we cannot picture it as a circle, spread- 

 ing in all directions from a common centre, and growing wider 

 around its whole circumference ? Why is it such that it is more 

 exactly represented by a number of growing radii, independent at 

 their outer ends ? 



This is the problem which Darwin undertook to solve, by show- 

 ing that it results from extermination according to a standard of 

 fitness. How does the Lamarckian meet it? Sometimes by deny- 

 ing the existence of fitness. Sometimes by asserting, even in the 

 same breath, that fitness is universal and necessary, and that there 

 is no real problem. 



He asserts that it is the outcome or expression of a deeper 

 principle of necessary progress or evolution, which must result in 

 fitness. The tendency to regard natural selection as more or less 

 unnecessary and superfluous, which is so characteristic of our 

 day, seems to grow out of reverence for the all-sufficiency of the 

 philosophy of evolution, and pious belief that the history of 

 living things flows out of this philosophy as a necessary truth or 

 axiom. 



" The inheritance of characters acquired during the life of the 

 individual is an indispensable axiom of the monistic doctrine of 

 evolution." ^ 



The writer yields to no one in admiration of the doctrine of evo- 

 lution. So far as it is a scientific generalization from our know- 

 ledge of nature, it is one of the greatest triumphs of the human 

 mind ; rivalled only by its reciprocal, the doctrine of dissolution. 



Experience seems to show, very clearly, that our system of 

 nature is, on the whole, moving towards what commends itself to 

 our minds as evolution, or progress to greater and greater per- 

 fection. While there is just as much evidence that each step in 

 evolution is also a step toward dissolution, we have the same 

 rational ground for expecting that this movement will continue, 

 without any sudden radical change, that we have for other expec- 

 tations which we base on knowledge of nature. 



So far as the doctrine of evolution is based on knowledge, it is 

 not only a part, but one of the most valuable and suggestive parts 



1 Haeckel, " Monism," p. 96. 



