12/16 AN INTRODUCTION TO CYBERNETICS 



process by which the values in Fisher and Yates' Table of Random 

 Numbers acted as determinants (as they certainly did). If now we 

 ignore (i.e. take for granted) the resistors on the switches, then we 

 can regard part B (of S.5/14) as being composed of a relay and a 

 channel only, to which comes values from the Table. We now regard 

 B as having two inputs. 



Relay 



Channel 



B 



Table 



5's state is still a vector of two components— a value provided by the 

 Table and the state of the relay (whether energised or not). To an 

 Observer who cannot observe the Table, B is Markovian (compare 

 S.12/9). Its input from A has two states, ^ and y; and it has been 

 built so that at ^3 no state is equilibrial, and at y every state is. 

 Finally it is coupled as in S.5/14. 



The whole is now Markovian (so long as the Table is not observed). 

 It goes to an equilibrium (as in S.5/14), but will now seem, to this 

 Observer, to proceed to it by the process of hunt and stick, searching 

 apparently at random for what it wants, and retaining it when it 

 gets it. 



It is worth noticing that while the relay's input is at ^, variety 

 in the Table is transmitted to A ; but when the input comes to y, the 

 transmission is stopped. The relay thus acts as a "tap" to the flow 

 of variety from the Table to A. The whole moves to a state of 

 equilibrium, which must be one in which the entry of variety from 

 the Table is blocked. It has now gone to a state such that the entry 

 of variety from the Table (which would displace it from the state) is 

 prevented. Thus the whole is, as it were, self-locking in this condi- 

 tion. (It thus exemplifies the thesis of S.4/22.) 



12/16. The example of the previous section showed regulation 

 occurring in a system that is part determinate (the interactions 

 between the magnets in A) and part Markovian (the values taken 

 by the channel in part B). The example shows the essential 

 uniformity and generality of the concepts used. Later we shall want 



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