LIFE 337 



It is this transition from science as a conceptual descrip- 

 tion of the sequences of sense-impressions to metaphysics 

 as a discussion of the imperceptible substrata of sense- 

 impressions, which mars biological as well as physical 

 literature. But the physicist is here to blame, for he has 

 projected without perceptual evidence his molecule and 

 atom into the phenomenal world, and the biologist only 

 follows the physicist's example when he asserts the reality 

 of gemmule or germ-plasm. Finding the ground behind 

 sense-impressions already occupied by molecule and atom, 

 by matter and force, he not unnaturally gives his meta- 

 physical products molecular or atomic structure ; he 

 endows them with force and " explains " life by mechanism. 

 In the theories of both Darwin and Weismann a meta- 

 physical element seems to enter owing to a misinterpreta- 

 tion of the concepts of physics.^ Only when we have 

 fully recognised that physical science is solely a conceptual 

 description, that matter as that which moves and force as 

 the why of its motion are meaningless, will this recognition 

 begin to react on the fundamental conceptions of biology. 

 Our object hitherto has been to suggest that if the 

 physicist withdraws, as we trust he may do, from the 

 metaphysical limbo beyond sense- impression, then the 

 biologist who has followed him there will retreat also. 

 The problem as to whether life is or is not a mechanism 

 will then have to be restated. We shall then have to ask 

 whether organic and inorganic phenomena are capable of 

 being described by the same conceptual shorthand. In 

 order to understand more clearly the exact nature of this 

 question we must stay for a moment to consider what we 

 mean when we speak of organic and inorganic phenomena. 

 What groups of sense-impressions do we classify as living, 

 what groups as lifeless ? 



1 There are still stronger metaphysical aspects in Weismann's doctrine. 

 That a substance which possesses continuity and sameness should indetinitely 

 reproduce itself, or if it increases by absorption of foreign substances should 

 remain the same, and this owing to a definite molecular structure, can hardly 

 be looked upon even as a conceptual limit to any perceptual experience. We 

 may ask, as Weismann does of Darwin's gemmule, whether 'it does not 

 compel us " to suspend all known physical and physiological conceptions"? 



O 2 



