3/14 DESIGN FOR A BRAIN 



S. 2/8 ? There is no difficulty. Given a species, we observe 

 what follows when members of the species are started from a 

 variety of initial states. We shall find that large initial changes 

 in some variables are followed in the system by merely transient 

 deviations, while large initial changes in others are followed by 

 deviations that become ever greater till the ' machine ' changes 

 to something very different from what it was originally. The 

 results of these primary operations will thus distinguish, quite 

 objectively, the essential variables from the others. This dis- 

 tinction may not be quite clear, for an animal's variables cannot 

 be divided sharply into ' essential ' and ' not essential ' ; but 

 exactness is not necessary here. All that is required is the ability 

 to arrange the animal's variables in an approximate order of 

 importance. Inexactness of the order is not serious, for nowhere 

 will we use a particular order as a basis for particular deductions. 

 We can now define ' survival ' objectively and in terms of a 

 field : it occurs when a line of behaviour takes no essential variable 

 outside given limits. 



References 



Bartlett, F. C. The measurement of human skill. British Medical Journal, 



1, 835 ; 14 June 1947. 

 Jennings, H. S. Behavior of the lower organisms. New York, 1906. 

 Morgan, C. Lloyd. Habit and instinct. London, 1896. 

 Rein, H. Die physiologischen Grundlagen des Kreislaufkollapses. Archiv 



fur klinische Chirurgie, 189, 302 ; 1937. 

 Starling, E. H. Principles of human physiology. London, 6th edition, 1933. 



42 



