184 PART IV. PREPARATORY STAGE. 



struggle for existence; that affection and mutual aid occupy a 

 prominent place in the development process ; that evolutionary 

 progress is "essentially through the subordination of individual 

 struggle and development to species-maintaining ends" (Geddes); 

 that acquired characteristics are not inherited ; and that human 

 progress is cultural and not biological. Finally, the Mendelians 

 are furnishing certain reasons for surmising that many so-called 

 variations are post-natal and are not inherited ; that true varia- 

 tions are frequently due to a re-shuffling of unit characters; 

 that variations are more likely to be sudden, large, and definite, 

 than slow, small, and intermediate in form; and that other 

 factors, besides the natural selection of favourable variations, 

 require to be considered in accounting for the evolution of 

 living forms. 1 Hence it transpires that Darwin effected little 

 more than to marshal in a persuasive form the evidence in 

 favour of the theory that the variety of living forms is intimately 

 related, and that natural forces could be conceived explaining 

 the metamorphosis of species. 2 This case eloquently illustrates 

 the folly of tracing world-moving ideas to the fortuitous dis- 

 covery of some preternaturally endowed individual. 



In conformity with this Conclusion, then, the scientific worker 

 should seek to extend some particular field of labour, or, if he 

 inaugurates some new science, it should not be one which 

 depends materially on other not yet developed sciences. In 

 any case, he would not think of investigating a problem where 

 the facts are at once decidedly complicated and very imperfectly 

 known to men of science. It may be said that the order of 

 fruitful investigation is the order of the sciences as commonly 

 classified at the present day, beginning somewhere with mathe- 

 matics and terminating somewhere with applied ethics. 



We might epitomise the Conclusion in the following rule: 

 "In initiating an enquiry, begin with what is scientifically deter- 

 mined; but if nothing relevant is thus determined, ascertain 

 the commencement of the simplest relevant elements, and pro- 

 ceed thence in a forward direction, unless the beginnings lie far 

 back or are complicated, in which case abandon the enquiry." 

 In connection with this rule these two sub-rules may prove 

 useful: (a) "Only that is to be regarded as well-ascertained 

 which has been investigated and tested scientifically." (b) "All 

 commonly accepted statements, not the outcome of scientific 



1 Two of the leading modern works on organic evolution are E. Weismann. 

 The Evolution Theory, 1904, which aims at disproving the inheritance of 

 acquired characteristics, and Hugo de Vries, The Mutation Theory, 1910-1911, 

 which argues in favour of sudden, large, and definite organic variations. 

 Bateson's Mendel's Principles of Heredity, 1909, ably expounds and develops 

 the new principles of heredity. 



"The commanding superiority and wide scientific influence of Darwin 

 among naturalists are of course popularly, though groundlessly, associated 

 with the origin instead of the final popularisation of the conception of 

 descent." (Article "Biology", in Chambers' Encyclopaedia, 1908.) 



