DESIGN FOR A BRAIN 18/2 



world is grossly bi-modal in its forms: either the forms in it are 

 extremely simple, like the run-down clock, so that we dismiss 

 them contemptuously, or they are extremely complex, so that we 

 think of them as being quite different, and say they have Life. 



18/2. Today we can see that the two forms are simply at the 

 extremes of a single scale. The Homeostat made a start at the 

 provision of intermediate forms, and modern machinery, especially 

 the digital computers, will doubtless enable further forms to be 

 interpolated, until we can see the essential unity of the whole range. 



Further examples of intermediate forms are not difficult to 

 invent. Here is one that shows how, in any state-determined 

 dynamic system, some properties will have a greater tendency to 

 persist, or ' survive ', than others. Suppose a computer has a 

 hundred stores, labelled 00 to 99, each of which initially holds one 

 decimal digit, i.e. one of 0, 1, 2, . . . , 9, chosen at random, inde- 

 pendently and equiprobably. It also has a source of random 

 numbers (drawn, preferably, from molecular, thermal, agitation). 

 It now repeatedly performs the following operation: 



Take two random numbers, each of two digits; suppose 82 

 and 07 come up. In this case multiply together the numbers 

 in stores 82 and 07, and replace the digit in the first store 

 (no. 82) by the right-hand digit of the product. 



Now Even x Even gives Even, and Odd x Odd gives Odd; 

 but Odd X Even gives Even, so the number in the first store can 

 change from Odd to Even, but not from Even to Odd. As a 

 result, the stores, which originally contained Odds and Evens in 

 about equal numbers, will change to containing more and more 

 Evens, the Odds gradually disappearing. The biologist might say 

 that in the ' struggle ' to occupy the stores and survive the Evens 

 have an advantage and will inevitably exterminate the Odds. 



In fact, among the Evens themselves there are degrees of 

 ability to survive. For the Zeros have a much better chance 

 than the other Evens, and, as the process goes on, so will the 

 observer see the Zeros spread over the stores. In the end they 

 will exterminate their competitors completely. 



18/3. This example is easily followed, but is uncomfortably close 

 to the trivial. More complex examples could easily be set up, 

 but they would tell us nothing of the principles at work (though 



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