PRESENT-DAY BIOLOGICAL THOUGHT 59 



modern scientific thought has had on philosophy, 

 adds: 



"Science has progressed in the biological sciences by 

 abandoning a faith in final causes for a faith in the hypo- 

 thesis that works, by draining off every stagnant suspi- 

 cion of ultimateness in explanation, in the light of the 

 conviction — the product of experience — that the ideas 

 that serve us change with our knowledge of object facts. "^ 



And I think that he sums up well the ideas on this 

 matter of the average biologist in the three following 

 paragraphs : 



"For one who seeks a basis of criticism for a contri- 

 bution to science, three obvious tests may be applied. 



"L It may contribute new facts. 



"2. It may contribute a formulation of old facts. 



"3. It may contribute a new idea that, in the presence 

 of facts, may lead to a new point of departure for explora- 

 tions into the unknown. 



"If then, one were to apply these tests to what seem 

 to me to be the two most significant developments in the 

 philosophic thought of today, they might be said to fall, 

 very roughly speaking, under the second and third cate- 

 gories. In the former, might be placed the synthetic phi- 

 losophy of Spencer, an avowedly scientific philosophy 

 whose essential problem was to formulate the known 

 facts of science in terms of principles of evolution. This 

 stupendous project, remarkable alike for the powers of 

 its author and the wide range of his interests, ended in a 



