46 THE POPULAR SCIENCE MONTHLY. 



age of reproduction, could enable the varied individual to clear 

 the field of all competitors, either by slaughtering or starving them 

 out. But unless the struggle for existence took this summary 

 and internecine character, there would be nothing but mere chance 

 to secure that the advantageously varied bridegroom at one end 

 of the wood should meet the bride who by a happy contingency 

 had been advantageously varied in the same direction at the same 

 time at the other end of the wood. It would be a mere chance if 

 they ever knew of each other's existence a still more unlikely 

 chance that they should resist on both sides all temptations to a 

 less advantageous alliance. But unless they did so, the new breed 

 would never even begin, let alone the question of its perpetuation 

 after it had begun. I think Prof. Weismann is justified in sajdng 

 that we can not, either with more or less ease, imagine the process 

 of natural selection. 



It seems strange that a philosopher of Prof. Weismann's pene- 

 tration should accept as established a hypothetical process the 

 truth of which he admits that he can not demonstrate in detail, 

 and the operation of which he can not even imagine. The reason 

 that he gives seems to me instructive of the great danger scien- 

 tific research is running at the present time the acceptance of 

 mere conjecture in the name and place of knowledge, in prefer- 

 ence to making frankly the admission that no certain knowledge 

 can be attained. " We accept natural selection," he says, " be- 

 cause we must because it is the only possible explanation that 

 we can conceive." As a politician, I know that argument very 

 well. In political controversy it is sometimes said of a disputed 

 proposal that it "holds the field," that it must be accepted be- 

 cause no possible alternative has been suggested. In politics there 

 is occasionally a certain validity in the argument, for it some- 

 times happens that some definite course must be taken, even 

 though no course is free from objection. But such a line of rea- 

 soning is utterly out of place in science. We are under no obli- 

 gation to find a theory, if the facts will not provide a sound one. 

 To the riddles which Nature propounds to us the profession of 

 ignorance must constantly be our only reasonable answer. The 

 cloud of impenetrable mystery hangs over the development and 

 still more over the origin of life. If we strain our eyes to pierce 

 it, with the foregone conclusion that some solution is and must 

 be attainable, we shall only mistake for discoveries the figments 

 of our own imagination. Prof. Weismann adds another reason 

 for his belief in natural selection, which is certainly characteris- 

 tic of the time in which we live. " It is inconceivable," he says, 

 "that there should be another principle capable of explaining the 

 adaptation of organisms without assuming the help of a principle 

 of design." The whirligig of time assuredly brings its revenges. 



