THE MECHANISTIC CONCEPTION OF LIFE 163 



But that would be Descartes' first matter, the exceedingly 

 fine dust resulting from the attrition of the primitive matter 

 which fills up all tEe interstices between the other molecules. 

 Since the universe was originally quite full, it must have remained] 

 full, even when its motions had evolved the three elements.' 

 Therefore there is continuity and yet a particular structure, and 

 that seems to be what the Planck theory of energy requires. 

 After many vicissitudes, therefore, physics returns to what seems, 

 in essentials, to be the Cartesian cosmogony. 



And, of course, our physico-chemical mechanism reverts to 

 that of Descartes. There is nothing but matter and its con- 

 figurations and motions, and this is true whether we think about 

 Descartes' matter or the Newtonian matter, or the modern 

 matter of electro-magnetic theory. The Cartesian matter was 

 extension, but what is the matter of to-day ? We are gradually 

 accustoming ourselves to think about it as immaterial. Atoms 

 are merely systems of electrons, but electrons are pure energy, 

 and energy, as we have seen, is something about the " nature " 

 of which we do not know anything all that we know is that it 

 is a measure of causality, and that we can measure it in terms 

 of work done, and that, we have seen, comes in the long-run to 

 measuring a distance or space. So our matter is extension, just 

 as was that of Descartes, and we ought now to call it substance 

 in the philosophic sense of the term. 



Anyhow, our mechanism of the organism has come again to a 

 crisis. First of all it was a mechanical explanation of life, and 

 that being insufficient biology resorted to a physico-chemical 

 explanation, which was also insufficient, since physics and 

 chemistry are again becoming mechanical. Looking about for 

 the new conception that biology has now again to borrow from 

 physics, we have little difficulty in finding it, and it would appear 

 as if it were really something new. The concept is given to us 

 in the physical notion of statistical mechanics, and to this we 

 shall return presently. 



