NATURAL SELECTION 69 



tion. A complete theory of evolution by secondary 

 agencies alone demands an explanation of the causes 

 of variation. 



It may be that the causes of variation are purely 

 secondary, or it may be that variations are produced 

 by secondary agencies under the direct control of the 

 Creator, or they may be produced by special fiats. 

 It is evident that with these alternatives the evolu- 

 tionist has no right to urge the theory of secondary 

 causes alone, and this is especially true if, by second- 

 ary causes, is meant causes that may work independ- 

 ently of the direct control of the Creator, for the use 

 of the expression, secondary causes, implies the ex- 

 istence of a Primary Cause, and known facts do not 

 justify us in assuming that any part of the Universe 

 can run itself if severed from the Primary Cause. 

 That every event must have an efficient cause there 

 can be no doubt, but there may be grave doubts as to 

 whether a cause is to be regarded as secondary or 

 primary. 



The following closing paragraph of " The Origin of 

 Species " contains a general summary of Darwin's 

 theory. " It is interesting to comtemplate a tangled 

 bank, clothed with many plants of many kinds, with 

 birds singing on the bushes, with various insects flit- 

 ting about, and with worms crawling through the 

 damp earth, and to reflect that these elaborately con- 

 structed forms, so different from each, and depend- 

 ent on each other in so complex a manner, have 

 all been produced by laws acting around us. These 

 laws, taken in the largest sense, being Growth with 

 Eeproduction; Inheritance, which is almost implied 

 by reproduction; Variability from the indirect and 

 direct action of the conditions of life, and from use 

 and disuse ; a Ratio of Increase so high as to lead to a 

 struggle for life, and as a consequence to Natural 



