Mechanistic Biology 251 



quite compatible with a relative dualism of a Spinozistic type. It 

 is, of course, the common-sense position. And our return to it 

 through centuries of speculation is not the first time that a common- 

 sense view has been proved the most acceptable in the long run, 

 nor will it be the last, 



5. Constructive Thoughts 



In returning to the biological philosophy of Descartes we are 

 making use of a conception which now possesses experimental 

 evidence, though in his time it was only the brilliant guess of a 

 philosopher. The following quotation from the " Traite de 

 r Homme " is unavoidable : 



" All the functions of the body follow naturally from the sole 

 disposition of its organs, just in the same way as the movements of 

 a clock or other self-acting machine or automaton follow from the 

 arrangement of its weights and wheels. So that there is no reason 

 on account of its functions to conceive that there exists in the body 

 any soul whether vegetative or sensitive or any principle of move- 

 ment other than the blood and its animal spirits agitated by the heat 

 of the fire which burns continually in the heart and which does not 

 diflrer in nature from any of the other fires which are met with in 

 inanimate bodies." 



Is there then at the present time any theory of life which 

 will be both philosophically and biologically adequate ? What 

 we have seen above points the way to it. The legitimacy of 

 physico-chemical explanations in the realm of physical life we have 

 seen to be well grounded, but we have also found that as far as 

 mental life is concerned biochemistry and biophysics have no 

 authority. The opinion, therefore, which seems to me to be most 

 justifiable is that life in all its forms is the phenomenal disturbance 

 created in the world of matter and energy when mind comes into 

 it. Living matter is the outward and visible sign of the presence 

 of mind, the splash made by the entry of mental existences into 

 the sea of inert matter. We must observe, however, that there 

 appear to be certain conditions which are necessary for the action 

 of mind in this manner. Biochemical speculation regards the 

 most important of these as the properties of the element carbon. 

 By whatever fundamental characteristics of the electron it comes 

 about that the carbon group in the periodic table is the only 

 one the elements of which possess the power of combining with 



