BIO-DYNAMICS 85 



and a consequent margin of structural variations ; that it is 

 possible rapidly to push functional and structural changes 

 towards the extreme of this margin in any direction, both in 

 an individual and in a race; but that to push these changes 

 further in any direction, and so to alter the organism as to 

 bring its mean state up to the extreme of the margin in that 

 direction, is a comparatively slow process." 



Here the great synthetic philosopher adds, parenthetically, 

 he is assuming that " modifications of structure produced by 

 modifications of function, are transmitted to offspring," the 

 necessities of the argument having obliged him to assume the 

 conclusion reached in a subsequent chapter. 



With the facts, so far set before us, we are, of course, 

 familiar, but seeing that they are deduced without regard to 

 the concomitant bio-economic facts, i.e., seeing that the 

 organism is taken out from its ensemble, we are already on our 

 guard against conclusions that are too mechanical. 



So far as species-formation is concerned, the problem of 

 problems, according to Spencer, is to achieve decided steps in 

 any direction by a group of individuals, and that by involving 

 them in a set of special actions and reactions of sufficient 

 permanence and strength to bring about the necessarily slow 

 process of raising the mean state up to the extreme of the 

 margin in that direction. How is this done? 



Spencer says: "Study the laws of organic modification." 



"A right understanding of the laws of organic modifica- 

 tion underlies a right understanding of the great question of 

 species." 



This is a somewhat similar statement to Samuel Butler's 

 that " modification, like charity, begins at home " ; except that 

 Butler's view more pertinently points to the autonomous 

 factor, to effort and work. That Spencer, notwithstanding his 

 rig-id mechanics, felt driven to admit or imply this factor, will 

 be clear from the following. But for the fact that his general 

 biological views were too mechanical, he might easily have 

 discovered the wider dynamics underlying the web of life, for 



