18/6 DESIGN FOR A BRAIN 



genes have biochemical effects, the acquisition of many a new 

 favourable mutation has meant that a harmonious set of bio- 

 chemical reactions has had to be reorganised to allow the incor- 

 poration of the new reaction. 



Evolution has thus had to cope, phylogenetically, with all the 

 difficulties of integration that beset the individual ontogenetically. 

 The tendency to ' chaos ', described in S. 18/2, thus occurs in the 

 species as well as in the individual. In the species, the co-ordinat- 

 ing power of natural selection has shown itself stronger than the 

 tendency to chaos. 



Natural selection is effective in proportion to the number of 

 times that the selection occurs : in a single generation it is negli- 

 gible, over the ages irresistible. And if the unrepeated action of 

 ultrastability seems feeble, might it not become equally irresistible 

 if the nervous system was subjected to its action on an equally 

 great number of occasions ? 



How often does it act in the life of, say, the average human 

 being ? I suggest that in those reactions where interaction is 

 important and extensive, the total duration of the learning process 

 is often of ' geological ' duration when compared with the duration 

 of a single incident, in that the total number of incidents contri- 

 buting to the final co-ordination is very large. I will give a single 

 example. Consider the adult's ability to make a prescribed move- 

 ment without hitting a given object — to put the cap on a fountain- 

 pen, say, without damaging the nib. This skill demands co- 

 ordinated activity, but the co-ordination has not been developed 

 by a single experience. Here are some of the incidents that will 

 probably have contributed to this particular skill : 



Putting the finger into the mouth (without hitting lips or teeth) ; 

 putting the finger into the handle of a cup (without striking the 

 handle) ; dipping pen into inkwell (without striking the rim) ; 

 putting button into button-hole ; passing a shoe-lace through its 

 hole ; inserting a collar-stud into the neck-band ; putting pen-nib 

 into pen ; making a knot by passing an end through a loop ; 

 replacing the cork in a bottle ; putting a key into a key-hole ; 

 threading a needle ; placing a gramophone record on the turn- 

 table's central pin ; putting the finger into a ring ; inserting a 

 funnel into a flask ; putting a cigarette into a holder ; putting 

 a cuff-link into a cuff ; inserting a pipe-cleaner ; putting a screw 

 into a nut ; and so on. 



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