1 8 Psychophysical Evolution 



to see certain of the aniecedents because they are not 

 physical, or because their physical counterpart is not 

 known, or the reverse, that is, to observe only the mental 

 antecedents of the fact in question, is suicidal to genetic 

 science. It not only omits facts from its formulations, but 

 it actually does violence to facts. For with the omission 

 goes the commission of the positive error of arriving at an 

 interpretation which is false.^ 



A remarkable instance illustrating the necessity of 

 recognizing both orders of facts is to be found in the 

 theory — and the history of the theory — of 'warning 

 colours.' As preliminary to the theory there is the fact of 

 coloration, which is distinctly physical. The question is as 

 to its origin. The theory holds it to be due to the warning 

 given to other individuals that a particular colouring is dis- 

 tasteful or poisonous. Now, in order that this warning 

 be given, the biologists tell us there is necessary a cer- 

 tain education of the hostile individuals. The creatures 

 have to learn the meaning of the coloration; and this 

 learning involves profiting by experience. If each creature 

 made the same experiment each time instead of profiting 

 by his own experience, or if each had to learn for himself, 

 instead of profiting by the experience of others through 

 imitation, etc., of course there would be no utility in the 

 colouring as giving warning. Here is as distinctly a mental 

 process involved as any one might cite. To refuse to 

 recognize it would be to throw away what is generally 

 recognized as the true theory of these cases of coloration. 



1 Cf. the criticism of Professor James' theory of the separateness of the 

 psychological and physiological ' cycles ' in my Social and Ethical Interpre- 

 tations, Sect. 42. See also the further discussion in Chap. XIX. on 

 ' Genetic Modes,' below. 



