132 PROBLEMS OF EVOLUTION 



exactly similar plan after the pulling down of the building ? 

 Conjugation, no less, necessitates variation. Two nearly, but 

 not quite, similar structures are somehow combined in one ; 

 sometimes there is a fusion of characters, often one organism 

 has a prepotent influence. The details of the structure are un- 

 known to us, and we can only infer their complexity from the 

 complexity of the organisms that result : from a fertilised ovum 

 is developed a man. When such is the character of the two 

 structures which combine, we can only wonder at the likeness 

 of child to parent : the differences are accounted for. And yet, 

 as I shall show, the range of variation grows less as the organ- 

 ism grows more complex. The grander and more elaborate the 

 building, the smaller the structural fault that will make it topple 

 down. 



How far Darwinism is often spoken of as a handing over of the universe, 

 - or, at any rate, of the organic world to " blind chance." But this 

 cording to is an altogether false accusation, and seems to reveal an ignorance 

 wnat i s meant by chance, and also of the nature and results of 



upon scientific discoveries. The word chance is used in two distinct 

 senses. To take that which is perhaps the commoner use first, 

 though everything that happens is due to a cause or causes, yet 

 when, owing to our ignorance of the forces at work, we cannot 

 predict what will happen in a particular case, there is what we 

 call chance. It is only ignorance that prevents the falling of a 

 penny, heads or tails, from being perfectly calculable. In such 

 cases, therefore, the term blind chance expresses only our own 

 ignorance. Science, for her part, annexes one region after 

 another, mastering the law that reigns there, and thus reduces 

 more and more the domain of chance. Darwin's work, no less 

 than Newton's, was the introduction of law into regions where 

 it seemed there was none ; evolution possibly or probably, but 

 no one could explain how. So far from introducing chance, he 

 extended the empire of law. But chance in the other sense 

 in the sense of coincidence was esssential to evolution as he 

 understood it. 



Coincidence is the meeting of two independent forces. For 

 example, A, while walking in a wood, happens to be in the line 



