354 Problems of Organic Adaptation 



and which is more inexplicable than the phenomena it is 

 supposed to explain. To account for the phenomena of life 

 by ascribing them to vitalism is no more helpful or intel- 

 ligible than to explain the properties of water as due to 

 hydrism or of light to photism. These are merely names 

 without intelligible meaning. Explanations that explain must 

 be in terms of other and better known phenomena. 



In contrasting vitalism and mechanism it should be under- 

 stood that the term "mechanism" is not used in the sense of 

 philosophical "materialism" nor of "mechanics" in its nar- 

 rower physical meaning, but rather to connote the regular 

 and invariable sequence of cause and effect, or the principle 

 of causality. Furthermore, it is the function of science to 

 classify but not to give ultimate explanations of phenomena; 

 , to explain phenomena only in the sense of reducing them to 

 common causes, to deal only with proximate causes and 

 never with final ones. For example, the law of gravity does 

 not explain the ultimate causes and mysteries of falling 

 bodies, but it reduces a thousand causes and mysteries to one. 

 Scientific explanations of life or of anything else attempt 

 nothing more than this. 



The biologist is often asked, either naively or scornfully, 

 "What is life?" One might as well ask, "What is matter, 

 mind, energy?" No final and complete answer to such ques- 

 tions is possible; these fundamentals can be defined only in 

 terms of their properties and proximate causes. Life is a 

 complex of many structures and functions associated with 

 peculiar conditions of matter. It is never manifested except 

 in connection with protoplasm, "the physical basis of life," 

 and this is an organization of many parts. The universal 

 form of protoplasmic organization is the cell, which is the 

 smallest unit of structure and function capable of indepen- 

 dent existence. The most general and distinctive proper- 



