DESIGN FOR A BRAIN 2/11 



the system may be changed by the inclusion of new variables 

 or by the omission of old; the initial state may be changed; 

 or the surrounding states may be changed. By applying these 

 variations systematically, in different patterns and groupings, the 

 different responses may be interrelated to yield relations. 



By further orderly variations, these relations may be further 

 interrelated to yield secondary, or hyper-, relations ; and so on. 

 In this way the 'machine' may be made to yield more and more 

 complex information about its inner organisation. 



What is fundamental about this method is that the transition 

 is a purely objective and demonstrable fact. By basing all our 

 later concepts on jthe properties of transitions we can be sure that 

 the more complex concepts involve no component other than the 

 objective and demonstrable. All our concepts will eventually be 

 denned in terms of this method. For example, ' environment ' is 

 so defined in S. 3/8, ' adaptation ' in S. 5/3, and ' stimulus ' in 

 S. 6/5. If any have been omitted it is by oversight; for I hold 

 that this procedure is sufficient for their objective definition. 



Phase-space and Field 



2/11. Often the experimenter, while controlling the external 

 conditions, allows the system to pass from state to state without 

 interrupting its flow, so that if he started it at state A and it went 

 to B, he allows it then to proceed from B to C, from C to Z), 

 and so on. 



A line of behaviour is specified by a succession of states and the 

 time-intervals between them. The first state in a line of behaviour 

 will be called the initial state. Two lines of behaviour are equal 

 if all the corresponding pairs of states are equal, and if all the 

 corresponding pairs of time-intervals are equal. 



2/12. There are several ways in which a line of behaviour may 

 be recorded. 



The graphical method is exemplified by Figure 2/12/1. The 

 four variables form, by definition, the system that is being 

 examined. The four simultaneous values at any instant define 

 a state. And the succession of states at their particular intervals 

 constitute and specify the line of behaviour. The four traces 

 specify one line of behaviour. 



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