THE PROBLEM 1/10 



the survival of the fittest) is fixed, yet its influence has an infinite 

 variety when applied to an infinite variety of particular organisms 

 in particular environments. 



A final example is given in the body by the process of inflam- 

 mation. The function-rules which govern the process are gene- 

 tically determined and are constant in one species. Yet these 

 rules, when applied to an infinite variety of individual injuries, 

 provide an infinite variety in the details of the process at particular 

 points and times. 



Our aim is now clear : we must find the function-rules. They 

 must be few in number, much fewer than 50,000, and we must 

 show that these few function-rules, when applied to an almost 

 infinite number of circumstances and to 10,000,000,000 neurons, 

 are capable of directing adequately the events in all these circum- 

 stances. The function-rules must be fixed, their applications 

 flexible. 



(The gene-pattern is discussed again in S. 9/9.) 



Restrictions on the concepts to be used 



1/10. Throughout the book I shall adhere to certain basic 

 assumptions and to certain principles of method. 



The nervous system, and living matter in general, will be 

 assumed to be identical with all other matter. So no use of any 

 1 vital ' property or tendency will be made, and no deus ex machina 

 will be invoked. No psychological concept will be used unless 

 it can be shown in objective form in non-living systems ; and 

 when used it will be considered to refer solely to its objective 

 form. Related is the restriction that every concept used must 

 be capable of objective demonstration. In the study of man 

 this restriction raises formidable difficulties extending from the 

 practical to the metaphysical. But as most of the discussion 

 will be concerned with the observed behaviour of animals and 

 machines, the peculiar difficulties will seldom arise. 



No teleological explanation for behaviour will be used. It 

 will be assumed throughout that a machine or an animal behaved 

 in a certain way at a certain moment because its physical and 

 chemical nature at that moment allowed it no other action. Never 

 will we use the explanation that the action is performed because 

 it will later be advantageous to the animal. Any such explanation 



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