SERIAL ADAPTATION 17/1 



The pressure on the Paramecium's anterior end varies as a part- 

 function. 



4 The animal may strike against stones.' 

 Similar part-functions. 



4 Our animal comes against a decayed, softened, leaf.' 



More part-functions. 



4 . . . till it comes to a region containing more carbon dioxide 

 than usual.' 



Concentration of carbon dioxide, being generally uniform with 

 local increases, will vary as a part-function. 



4 Finally it comes to the source of the carbon dioxide — a large 

 mass of bacteria, embedded in zoogloea.' 



Another part-function due to contact. 



It is clear that the ecological world of Paramecium contains 

 many part-functions, and so too do the worlds of most living 

 organisms. 



A total environment, or universe, that contains many part- 

 functions will show dispersion, in that the set of variables active 

 at one moment will often be different from the set active at another. 

 The pattern of activity will therefore tend, as in S. 14/15, to be 

 fluctuating and conditional rather than invariant. As an animal 

 interacts with its environment, the observer will see that the 

 activity is limited now to this set, now to that. If one set per- 

 sists active for a long time and the rest remains inactive and in- 

 conspicuous, the observer may, if he pleases, call the first set 4 the ' 

 environment. And if later the activity changes to another set he 

 may, if he pleases, call it a 4 second ' environment. It is the 

 presence of part-functions and dispersion that makes this change of 

 view reasonable. 



An organism that tries to adapt to an environment composed 

 largely of part-functions will find that the environment is com- 

 posed of subsystems which sometimes have individuality and inde- 

 pendence but which from time to time show linkage. The alter- 

 nation is shown clearly when one learns to drive a car. The 

 beginner has to struggle with several subsystems : he has to learn 

 to control the steering-wheel and the car's relation to pavement 

 and pedestrian ; he has to learn to control the accelerator and 

 its relation to engine-speed, learning neither to race the engine nor 



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