18/6 AMPLIFYING ADAPTATION 



Some ancillary regulations may be adjusted by the gene-pattern 

 at one remove. In this case the gene-pattern would establish 

 values that would result in the appearance of a mechanism, 

 actually a regulator, that would then proceed, by its own action, 

 to bring the parameters to appropriate values. 



Other ancillary regulators might be adjusted by the gene- 

 pattern at two removes ; but we need not trace the matter further, 

 as real systems will seldom be arranged neatly in distinct levels 

 (S. 17/9). All we need notice here is that adaptation can be 

 achieved by the gene-pattern either directly or indirectly. 



Amplifying adaptation 



18/6. The method of adaptation by learning is the only way of 

 achieving adaptation when what is adaptive is constant for too 

 short a time for adaptation of the gene-pattern to be achieved. 

 For this reason alone we would expect the more advanced organ- 

 isms to show it. The method, however, has also a peculiar 

 advantage that is worth notice, particularly when we consider 

 the limitation implied by the law of requisite variety, and ask 

 how much regulation the gene-pattern can achieve in the two cases. 



Direct and indirect regulation occur as follows. Suppose an 

 essential variable X has to be kept between limits x' and x" . 

 Whatever acts directly on X to keep it within the limits is regu- 

 lating directly. It may happen, however, that there is a mechan- 

 ism M available that affects X, and that will act as a regulator 

 to keep X within the limits x' and x" provided that a certain 

 parameter P (parameter to M) is kept within the limits p' andp". 

 If, now, any selective agent acts on P so as to keep it between 

 p' and p", the end result, after M has acted, will be that X is 

 kept between x' and x" . 



Now, in general, the quantities of regulation required to keep 

 P in p' and p" and to keep X in x' to x" are independent. The 

 law of requisite variety does not link them. Thus it may happen 

 that a small amount of regulation supplied to P may result in a 

 much larger amount of regulation being shown by X. 



When the regulation is direct, the amount of regulation that 

 can be shown by X is absolutely limited to what can be supplied 

 to it (by the law of requisite variety) ; when it is indirect, however, 

 more regulation may be shown by X than is supplied to P. Indirect 



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