3/14 THE ORGANISM AS MACHINE 



chew without biting his own tongue ; functionally both bread and 

 tongue are part of the environment of the cerebral cortex. But 

 the environments with which the cortex has to deal are sometimes 

 even deeper in the body than the tongue: the child has to learn 

 how to play without exhausting itself utterly, and how to talk 

 without getting out of breath. 



These remarks are not intended to confuse, but to show that 

 later arguments (in Chapters 15 and 16) are not unreasonable. 

 There it is intended to treat one group of neurons in the brain 

 as the environment of another group. These divisions, though 

 arbitrary, are justifiable because we shall always treat the system 

 as a whole, dividing it into parts in this unusual way merely for 

 verbal convenience in description. 



It should be noticed that from now on ' the system ' means 

 not the nervous system but the whole complex of the organism 

 and its environment. Thus, if it should be shown that ' the 

 system ' has some property, it must not be assumed that this 

 property is attributed to the nervous system: it belongs to the 

 whole; and detailed examination may be necessary to ascertain 

 the contributions of the separate parts. 



3/13. In some cases the dynamic nature of the interaction 

 between organism and environment can be made intuitively more 

 obvious by using the device, common in physics, of regarding the 

 animal as the centre of reference. In locomotion the animal 

 would then be thought of as pulling the world past itself. Pro- 

 vided we are concerned only with the relation between these two, 

 and are not considering their relations to any third and inde- 

 pendent body, the device will not lead to error. It was used in 

 the ' rider and bicycle ' example. 



By the use of animal-centred co-ordinates we can see that the 

 animal has much more control over its environment than might at 

 first seem possible. Thus, while ^a frog cannot change air into 

 water, a frog on the bank of a stream can, with one small jump, 

 change its world from one ruled by the laws of mechanics to one 

 ruled by the laws of hydrodynamics. 



Essential variables 

 3/14. The biologist must view the brain, not as being the seat of 

 the 4 mind ', nor as something that 4 thinks ', but, like every other 



41 



