4/15 AN INTRODUCTION TO CYBERNETICS 



In this case the whole is less richly connected internally, for one of 

 the actions, or channels, is now missing. 



The lessening can continue. We may find that the diagram of 

 immediate effects is simply 



so that the whole consists really of two parts that are functionally 

 independent. In this case the whole is said to be reducible. The 

 importance of this concept will be referred to later (S. 13/21). 



Ex.: Of the systems in Ex. 4/12/1, which are reducible? 



4/15. Materiality. The reader may now like to test the methods 

 of this chapter as an aid to solving the problem set by the following 

 letter. It justifies the statement made in S.1/2 that cybernetics is 

 not bound to the properties found in terrestrial matter, nor does it 

 draw its laws from them. What is important in cybernetics is the 

 extent to which the observed behaviour is regular and reproducible. 



''Graveside" 

 Wit's End 

 Haunts. 

 Dear Friend, 



Some time ago I bought this old house, but found it to be 

 haunted by two ghostly noises— a ribald Singing and a 

 sardonic Laughter. As a result it is hardly habitable. 

 There is hope, however, for by actual testing I have found 

 that their behaviour is subject to certain laws, obscure but 

 infallible, and that they can be affected by my playing the 

 organ or burning incense. 



In each minute, each noise is either sounding or silent— 

 they show no degrees. What each will do during the ensuing 

 minute depends, in the following exact way, on what has been 

 happening during the preceding minute : 



The Singing, in the succeeding minute, will go on as it was 

 during the preceding minute {sounding or silent) unless there 

 was organ-playing with no Laughter, in which case it will 

 change to the opposite {sounding to silent, or vice versa). 



As for the Laughter, if there was incense burning, then it 

 will sound or not according as the Singing was sounding or 

 not {so that the Laughter copies the Singing a minute later). 

 If however there was no incense burning, the Laughter will do 

 the opposite of what the Singing did. 



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