186 THE VARIATION OF ANIMALS IN NATURE 



evolution towards the theory of selection. At the present time 

 some students have a firm conviction as to its validity and are 

 prepared to offer in its support, not the naive and anecdotal 

 evidence offered by a past generation, but the results of critical 

 and intensive investigation, while to others the theory is a 

 ' dead letter ' and an historical curiosity. It is, for example, 

 instructive to compare (e.g.) the attitude of Fisher in this 

 country, who regards the efficacy of selection as an established 

 fact scarcely worth verification, with that of Radl (1930), who 

 dismisses it contemptuously as fundamentally unsound and 

 unworthy of serious consideration. To cite two isolated cases 

 like these does not give an entirely disproportionate picture 

 of the divergence in the minds of biological students as a whole, 

 and the more this divergence is studied the more apparent 

 does it become to our minds that it arises just as much from 

 the lack of any systematic arrangement of the unwieldy mass 

 of data as from prejudice and bias. Candid and scholarly 

 examinations of the evidence have been by no means lacking. 

 The analyses of Kellogg (1907) and Plate (19 13) are of this 

 type. But of recent years their critical and unprejudiced 

 treatment has not been followed up and the mass of observa- 

 tions, inference and assumptions has grown unchecked and 

 little attention has been paid to the logical procedure and the 

 types of evidence required for the purpose of either confirming 

 or destroying the theory. 



Woodger (1929) has indicated the stages by which a 

 scientific doctrine advances from the status of a hypothesis to 

 that of a law. If we ask if Natural Selection has attained the 

 status of a law, the obvious answer is that many students believe 

 it has and others do not. This may mean one of two things — ■ 

 either that judgment of the doctrine is still clouded by prejudice 

 or that the data so far obtained are in fact insufficient to 

 command universal conviction. It would take us too far out 

 of our way to consider the steps by which a scientific theory 

 obtains universal acceptance, the reactions of our minds to 

 evidence and the part played by prejudice in scientific inquiry. 

 It is enough to express the belief that on the evidence available 

 at present Natural Selection has been accepted and its prestige 

 created very largely on the desire for some such hypothesis. 

 No other explanation of the wide acceptance of the theory is 

 forthcoming in face of the guarded and qualified opinions of 



