316 THE PHILOSOPHY OF BIOLOGY 



dust by radiation pressure, apparently insurmount- 

 able difficulties arise. All such hypotheses as we have 

 indicated assume material substance and modes of 

 energy-transformation similar to those that we study 

 in laboratory processes, and all such hypotheses involve 

 the notion of the degradation of energy. So long as 

 we suppose that all cosmic processes are transforma- 

 tions of extended systems of material substances we 

 must assume that energy is dissipated at every stage 

 of the transformation, and whenever we assume this 

 we admit that the processes are irreversible ones, and 

 that the material universe as a whole tends towards a 

 condition of inertia. Yet this, we see, cannot be true, 

 for the universe teems with diversity. Is the progress 

 towards the ultimate state of inertia an asymptotic 

 one, as Ward suggests ? This does not help us, since all 

 that the suggestion does is to misapply a mathematical 

 device of service only in the treatment of the problems 

 for v/hich it was developed. Somewhere or other, it 

 has been said, the second law of thermodynamics must 

 be evaded in our universe. 



How can it be evaded ? That movement or pro- 

 gress which we call inorganic is a movement of energy- 

 transformations in one direction — towards their cessa- 

 tion. It is a movement which we can easily reverse 

 in imagination. A cigarette consumed by a smoker 

 represents the downfall of energy : the cellulose and 

 oils of the tobacco burn with the liberation of heat, 

 and the formation of water, carbon dioxide, and some 

 soot ; and this is what happens when potential energy 

 contained in an organised substance becomes converted 

 into kinetic energy. Now, the opposite process can 

 clearly be conceived — it can even be pictured. If we 

 make a kinematographic record of the smoking of the 

 cigarette and then reverse the direction of motion of the 



