IS THE ORGANISM A MECHANISM? 655 



our imaginar}' decilitre of gas. Physical inertia is " normal," 

 that is, it is the most probable condition of a dynamical system 

 in the general sense. But in small regions of the entire universe, 

 and for infinitesimal periods of duration, the improbable con- 

 dition may obtain. It does occur in regions of a decilitre of 

 gas, if we take these regions small enough. Here and there 

 there are certainly small groups of molecules, in which, for a 

 very small time, the mean linear velocity, and therefore the 

 temperature, is greater than in adjacent regions. 



Such an universe, one in which there was physical activity, 

 as there is in our universe, would be passing from an improbable 

 towards a more probable phase. The most probable phase 

 would be that in which entropy had attained its maximum 

 value ; the least probable phase would be that of zero entropy. 

 The phase of physical activity would be preceded by a phase 

 of restoration of available energy, that is, a passage from the 

 most probable to the least probable condition. Time would 

 have a double sign. The passage from the improbable towards 

 the probable conditions would occur in our time, that is from 

 the past to the future. But in the period of restoration of 

 available energy the scale of time would be reversed, and the 

 passage from the most probable to the least probable phase 

 would occur in time which moved from the future back into 

 the past. Conscious organisms in such a phase of an individual 

 universe would possess knowledge of the future but not of 

 the past. 



What this discussion leads up to is the consideration of the 

 second law of thermodynamics as a probability only. The law 

 states that inorganic phenomena tend in one way — towards 

 increase of entropy. But the sign of the law may be changed, 

 that is, events may also conceivably take place in such a way 

 as to lead to diminution of entropy. It is more probable that 

 entropy increases than that it should diminish. 



Unless we postulate that the entire universe is passing from 

 an initial determined state towards a final definitive state, we 

 cannot regard the second law of thermodynamics, as it is 

 usually stated, as true. 



We can define an organism as an autonomous physico- 

 chemical system ; possessing specific form ; maintaining its 

 specific form in the midst of an environment which undergoes 



