7/18 AN INTRODUCTION TO CYBERNETICS 



physicist would still find some constraint here). Our terrestrial 

 world, to which the living organism is adapted, is far from presenting 

 such a chaos. Later (S.13/5) it will be suggested that the organism 

 can adapt just so far as the real world is constrained, and no further. 



Ex. : Attempt to count, during the next one minute, all the constraints that are 

 operating in your surroundings. 



7/18. Prediction and constraint. That something is "predictable" 

 implies that there exists a constraint. If an aircraft, for instance, 

 were able to move, second by second, from any one point in the sky 

 to any other point, then the best anti-aircraft prediction would be 

 helpless and useless. The latter can give useful information only 

 because an aircraft cannot so move, but must move subject to 

 several constraints. There is that due to continuity — an aircraft 

 cannot suddenly jump, either in position or speed or direction. 

 There is the constraint due to the aircraft's individuality of design, 

 which makes this aircraft behave like an A- 10 and that one behave 

 like a Z-20. There is the constraint due to the pilot's individuality; 

 and so on. An aircraft's future position is thus always somewhat 

 constrained, and it is to just this extent that a predictor can be useful. 



7/19. Machine as constraint. It will now be appreciated that the 

 concept of a "machine", as developed from the inspection of a 

 protocol (S.6/5), comes froin recognising that the sequence in the 

 protocol shows a particular form of constraint. Were the protocol 

 to show no constraint, the observer would say it was chaotic or 

 unpredictable, like a roulette-wheel. 



When it shows the characteristic form of constraint, the observer 

 can take advantage of the fact. He does this by re-coding the whole 

 protocol into a more compact form, containing only: 



(i) a statement of the transformation 

 and (ii) a statement of the actual input given. 



Subsequently, instead of the discussion being conducted in terms of a 

 lengthy protocol, it is conducted compactly in terms of a succinct 

 transformation ; as we did throughout Part I. 



Thus, use of the transformation is one example of how one can 

 turn to advantage the characteristic constraint on behaviour imposed 

 by its being "machine-like". 



Ex. : If a protocol shows the constraint characteristic of a machine, what does the 

 constraint exclude? 



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