16/4 ADAPTATION IN THE MULTISTABLE SYSTEM 



might make the spot also move off the screen. The attempt to 

 bring it back might alter its rate of sweep and start it oscillating 

 vertically. An attempt to correct this might make its line of 

 sweep leave the horizontal; and so on. This system's variables 

 (brightness of spot, rate of sweep, etc.) were dynamically linked 

 in a rich and complex manner. Attempts to control it through 

 the available parameters were difficult precisely because the 

 variables were richly joined. 



16/4. How long will an ultrastable system that includes such 

 an environment take to get adapted ? 



This is the question of S. 11/2. Unless a large fraction of the 

 outcomes are acceptable, the time taken tends to be like T x of 

 S. 11/5. As the system is made larger, so does the time of 

 adaptation tend to increase beyond all bounds of what is practical; 

 in other words, the ultrastable system probably fails. But this 

 failure does not discredit the ultrastable system as a model of 

 the brain (S. 8/17), for such an environment is one that is also 

 likely to defeat the living brain. That the living organism is 

 notoriously apt to find such environments difficult or impossible 

 for adaptation is precisely the reason why the combination lock 

 is relied on for protection. 



Even when a skilled thief defeats the combination lock he 

 supports, rather than refutes, the thesis. Thus if he can hear, as 

 each dial moves, a tumbler fall into position, then the environ- 

 ment is to him a serial one (S. 15/8); for he can get the first dial- 

 setting right without reference to the others, then the second, and 

 so on. The time of its opening is thus made vastly shorter. 

 Thus the skilled thief does not really adapt successfully to the 

 richly joined environment — he demonstrates that what to others 

 is richly joined is to him joined serially. 



Thus the first answer to the question : how does the ultrastable 

 system, or the brain, adapt to a richly joined environment ? is — it 

 doesn't. After the reasonableness of this answer has been made 

 clear, we may then notice that sometimes there are ways in 

 which an environment, apparently too complex for adaptation, 

 may eventually be adapted to; perhaps by the discovery of 

 ways of getting through the necessary trials much faster, or 

 perhaps by the discovery that the environment is not really as 

 complex as it looks. (/. to C, S. 13/4, discusses the matter.) 



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