82 THE PHILOSOPHY OF BIOLOGY 



guide to reasoning only. On the other hand we see 

 that all naturally occurring physical processes are 

 irreversible and in their sum tend to complete degrad- 

 ation of energy. Mechanistic biology isolates physico- 

 chemical processes in the functioning of the organism, 

 and sees that they conform to the law of dissipation, 

 as well as to that of the conservation of energy. 



Yet the organism as a whole, that is, life as a whole, 

 on the earth, does not conform to the law of dissipation. 

 That which is true of the isolated processes into which 

 physiology decomposes life is not true of life. In all 

 inorganic happenings energy becomes unavailable for 

 the performance of work. Solar radiation falling on 

 sea and land fritters itself away in waste irrecoverable 

 heat, but falling on the green plant accumulates in the 

 form of available chemical energy. The total result 

 of life on the earth in the past has been the accumula- 

 tion of enormous stores of energy in the shape of 

 coal and other substances. By its agency degradation 

 has been retarded. Whenever, says Bergson, energy 

 descends the incline indicated by Carnot's law, and 

 where a cause of inverse direction can retard the 

 descent, there we have life. 



