ORGANISM AND MECHANISM 131 



increases we do not get appreciably nearer a mechanical 

 description of development. We do, however, recognise more 

 and more that physical and chemical processes are in evi- 

 dence. 



The second answer is that the word mechanical is some- 

 times applied illegitimately to a systematic or connected 

 account which displays a series of events in causal coherence 

 without the intervention of mentality. Given certain prop- 

 erties of organisms in general, of nerve-cells and muscle- 

 fibres in particular, we may give a more or less connected 

 and complete account of a reflex action without dragging 

 in any psychical agency. But this should not be called a 

 mechanical description. It is simply, what it pretends to be, 

 a physiological or biological description, and it implies 

 various non-mechanical concepts. Similarly, given the 

 organism's power of registration and of persistently re- 

 producing its specific organisation, given the cell's mysteri- 

 ous power of dividing of dividing now into similar, and 

 again into dissimilar halves, given the capacity of utilising 

 nurtural stimuli to educe the inherent manifoldness of the 

 germ, and so forth, we can make a show of discovering the 

 connectedness and inevitableness of the successive stages in 

 development. But we cannot without abuse of terms speak 

 of this as a mechanical description. 



7. Difficulty of Applying Mechanistic Formulae to 

 Organic Evolution. 



As a fourth test of the adequacy of mechanistic description 

 in the realm of organisms, we may refer very briefly to 

 evolution, which will engage our attention in detail by and 

 by. Such phrases as ' cosmic evolution ' and ' inorganic 

 evolution ' are apt to suggest the mistaken idea that organic 



