DESIGN FOR A BRAIN 11/11 



This is the point. If the method of ultrastability is to succeed 

 within a reasonably short time, then partial successes must be 

 retained. For this to be possible it is necessary that certain parts 

 should not communicate to, or have an effect on, certain other parts. 



11/11. Now we can see where the Homeostat was misleading. 

 From the beginning of the book (from S. 1/7) we have treated the 

 brain and the environment as richly joined, each within its own 

 parts and each to the other. Thus the Homeostat was built so 

 that every unit did in fact interact with every other unit. In this 

 way we developed the theory of the system that is integrated 

 totally. 



By working throughout with systems which were always assumed 

 to be as richly connected as the reader cared to think them, we 

 avoided the possibility of talking much about integration, and 

 then discussing a mechanism that, in fact, really worked in 

 separate parts. The reacting parts and the environments that we 

 have discussed have so far been integrated in the extreme. 



11/12. Nevertheless, it is now clear that one can go too far in 

 this direction. The Homeostat goes too far; it is too well inte- 

 grated, cannot accumulate adaptations, and thereby takes a quite 

 un-brainlike time in reaching adaptation. What we must discuss 

 now is a system similar to the Homeostat in its ultrastability, 

 but not so richly cross-joined. To what degree, then, should it 

 be cross- joined if it is to resemble the nervoils system ? 



The views held about the amount of internal connexion in the 

 nervous system — its degree of ' wholeness ' — have tended to range 

 from one extreme to the other. The ' reflexologists ' from Bell 

 onwards recognised that in some of its activities the nervous 

 system could be treated as a collection of independent parts. They 

 pointed to the fact, for instance, that the pupillary reflex to light 

 and the patellar reflex occur in their usual forms whether the 

 other reflex is being elicited or not. The coughing reflex follows 

 the same pattern whether the subject is standing or sitting. And 

 the acquirement of a new conditioned response might leave a pre- 

 viously established response largely unaffected. On the other 

 hand, the Gestalt school recognised that many activities of the 

 nervous system were characterised by wholeness, so that what 

 happened at one point was conditional on what was happening at 



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