10/5 AN INTRODUCTION TO CYBERNETICS 



10/5. What is it survives, over the ages? Not the individual 

 organism, but certain peculiarly well compounded gene-patterns, 

 particularly those that lead to the production of an individual that 

 carries the gene-pattern well protected within itself, and that, within 

 the span of one generation, can look after itself. 



What this means is that those gene-patterns are specially likely 

 to survive (and therefore to exist today) that cause to grow, between 

 themselves and the dangerous world, some more or less elaborate 

 mechanism for defence. So the genes in Testudo cause the growth 

 of a shell ; and the genes in Homo cause the growth of a brain. (The 

 genes that did not cause such growths have long since been elim- 

 inated.) 



Now regard the system as one of parts in communication. In 

 the previous section the diagram of immediate effects (of cat and 

 mouse) was (or could be regarded as) 



We are now considering the case in which the diagram is 



D 



F 



in which E is the set of essential variables, D is the source of 

 disturbance and dangers (such as C) from the rest of the world, and 

 F is the interpolated part (shell, brain, etc.) formed by the gene- 

 pattern for the protection of E. (F may also include such parts 

 of the environment as may similarly be used for £"s protection — 

 burrow for rabbit, shell for hermit-crab, pike for pike-man, and 

 sword (as defence) for swordsman.) 



For convenience in reference throughout Part III, let the states of 

 the essential variables E be divided into a set rj — those that correspond 

 to "organisms living" or "good" — and not-r; — those that corres- 

 pond to "organism not living" or "bad". (Often the classification 

 cannot be as simple as this, but no difficulty will occur in principle; 

 nothing to be said excludes the possibility of a finer classification.) 



To make the assumptions clear, here are some simple cases, as 

 illustration. (Inanimate regulatory systems are given first for 

 simplicity.) 



(1) The therniostatically-controlled water-bath. E is its tempera- 

 ture, and what is desired (17) is the temperature range between, say 

 36° and 37 C. D is the set of all the disturbances that may drive 

 the temperature outside that range — addition of cold water, cold 

 draughts blowing, immersion of cold objects, etc. F is the whole 



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