74 The Unity of the Organism 



The Relation of Ideas and Observations as Exemplified in 

 the Discussions of This Chapter 



I would have this discussion stand as one example of the 

 general method of interpretation which underlies our whole 

 undertaking: while interpretation of biological phenomena 

 is wholly impossible without ideas, some of which take the 

 form of hypotheses and theories, equally true is it that 

 hypothesis and theory are wholly dependent upon observa- 

 tion for validity. To this every biologist in whatever field 

 of research and of whatever manner of thinking, would as- 

 sent. But I go farther and assert that no hypothesis is 

 proved, nor can be elevated to the rank of a general theory 

 or doctrine until it is brought into acciord with all relevant 

 and fully verified observational knowledge. To this no ele- 

 mentalist assents in practice even though he may in words. 

 Measured by this standard our final constructive discussion 

 will reveal the fact that such conceptions as those of Weis- 

 mann's germ-plasm and DeVries' pangens are not legitimate 

 scientific theories at all. The^^ are not because they can be 

 maintained only by positively refusing to admit as evidence 

 many of the demonstrable relevant obser\^ational facts. 



REFERENCE INDEX 



1. McMiirrich 79 8. Goette 63 



2. Minot 250 9. Weismann ('83) 42 



3. Ritter ('9()) 183 10. Hargitt 24« 



4. Harmer 514 11. Goette 63 



5. Weismann ('12) . 190 12. Weismann ('83) 284 



6. Weismann ('12) xiii 13. Goette 301 



7. Weismann ('04) 400 



