202 THE PROBLEM OF EVOLUTION 



inexplicable,, 1 he himself maintained that, in the case 

 of these interior forces also, the demand for their 

 quantitative determination must hold good. The 

 word Vitalism was in bad odour in scientific circles, 

 but, nevertheless, he would to some extent acknow- 

 ledge himself to be a vitalist. Those interior forces 

 might be designated by any name we might call 

 them physical energy, if we liked ; but for this form 

 of energy, as for all other forms, the demand held 

 good, that it should admit of quantitative determina- 

 tion. 



If Dr. Thesing meant that, in order to be 

 scientifically explicable, a thing must admit of 

 quantitative determination, I cannot agree with 

 him. There are in nature qualitative differ- 

 ences also, and we discover these in the course of 

 our observation of vital processes, in as far 

 as they are really such. 



The growth of a tree may be measured 

 quantitatively, it is true, but living growth 

 is something differing in quality from a mere 

 addition of new to old atoms. Further, the 

 word 'Vitalism' is in bad odour, not among 

 scientists, but among materialists. Dr. Thesing, 

 in acknowledging himself to be a vitalist, does 

 so in company with Driesch, Reinke, and other 

 eminent biologists; nevertheless, the opinion 



1 I have no idea where I am supposed to have said that the interior 

 laws of evolution affecting organic life were ' a part of the divine Will or 

 of the Deity.' Cf. my second lecture, pp. 29, 35. 



