^16 THE MECHANISM OF LIFE 



physical phenomena do occur; there are in the universe 

 differences of intensity of energy, and these differences tend, of 



♦ themselves, to become levelled down. As the process of reduc- 

 tion of intensity difference takes place, energy transformations 

 occur and entropy increases. But, as we have seen, the concept 

 of the second law proves inadequate as an explanation in the 

 universal sense, and we are compelled, even in the treatment of 

 inorganic, cosmic systems, to postulate another concept, that of 

 the second law of thermo-dynamics reversed in sign. Somewhere 

 or some time entropy must decrease instead of increasing. 



If this reversal were to happen, the results would be unex- 

 pected, fantastic, and paradoxical. But a physicist would not 

 be incredulous. He would, probably, seek to be very sure that 

 he was not mistaken, and that his observations were trust- 

 worthy; then, having satisfied himself upon these points, he 

 would accept the result. But, as a matter of fact, the reversal 

 does not occur, and every energy transformation that the physi- 

 cists and chemists can observe and investigate happen because, 

 in this part of the universe known to us, entropy always tends to 

 increase. Therefore the concept which he utilises in order to 

 explain physical happeniilgs is this — energy differences tend, of 

 themselves, to become abolished. 



Now it is quite clear that this concept (which is, of course, only 

 another way of stating the second law) does not fully explain 



^/Organic happening, for in such processes energy differences do 

 not tend, of themselves, to become abolished. Again, we must 

 be very precise in our statement of this result; we do not mean 

 to say that the animal physico-chemical system, or body, does 

 not " obey " the second law. We recall here the caution sug- 

 gested in the first part of Chapter II., that we must not seek for 



' absolute distinctions anywhere in nature, since these are logical 

 constructions only. There are no such things as mathematical 

 points, straight lines, or planes, for the points and lines and 



' planes which we observe and measure are only approximations. 

 Let a very small spot become smaller and smaller, and " in the 

 limit " it becomes a mathematical point, and so on. Logically, 

 then, we can construct a conceptual world in which there are 

 absolute distinctions between inorganic and organic, and between 

 processes which tend to entropy increase and others which tend 

 to entropy decrease, but what we do actually observe are only the 



tendencies which, in reasoning, we carry towards their limits. 



