DESIGN FOR A BRAIN 



2/14 



S. 2/9, by reference exclusively to the observed values of the 

 variables and to the results of primary operations on them. It 

 is therefore a wholly objective property of the system. 



The concept of 4 field ' will be used extensively. It defines the 

 characteristic behaviour of the system, replacing the vague con- 

 cept of what a system ' does ' or how it ' behaves ' (often describ- 

 able only in words) by the precise construct of a ' field '. Further 



5 10 15 



Weight of dog (kg.) 



Figure 2/14/1 : Arrow-heads show the direction of movement of the 

 representative point ; cross-lines show the positions of the representative 

 point at weekly intervals. 



it presents all a system's behaviours (under constant conditions) 

 frozen into one unchanging entity that can be thought of as a 

 unit. Such entities can readily be compared and contrasted, and 

 so we can readily compare behaviour with behaviour, on a basis 

 that is as complete and rigorous as we care to make it. 



The reader may at first find the method unusual. Those who 

 are familiar with the phase-space of mechanics will have no 

 difficulty, but other readers may find it helpful if at first, whenever 

 the word ' field ' occurs, they substitute for it some phrase like 

 4 typical way of behaving '. 



24 



