10/3 AN INTRODUCTION TO CYBERNETICS 



yet to be written the book, much larger in size, that shall show how 

 all the organism's exteriorly-directed activities — its "higher" 

 activities — are all similarly regulatory, i.e. homeostatic. In this 

 chapter I have had to leave much of this to the reader's imagination, 

 trusting that, as a biologist, he will probably already be sufficiently 

 familiar with the thesis. The thesis in any case has been discussed 

 to some extent in Design for a Brain. 



The chief purpose of this chapter is to tie together the concepts 

 of regulation, information, and survival, to show how intimately 

 they are related, and to show how all three can be treated by a 

 method that is entirely uniform with what has gone before in the 

 book, and that can be made as rigorous, objective, and unambiguous 

 as one pleases. 



10/3. The foundation. Let us start at the beginning. The most 

 basic facts in biology are that this earth is now two thousand 

 million years old, and that the biologist studies mostly that which 

 exists today. From these two facts follow a well-known deduction, 

 which I would hke to restate in our terms. 



We saw in S.4/23 that if a dynamic system is large and composed 

 of parts with much repetition, and if it contains any property that is 

 autocatalytic, i.e. whose occurrence at one point increases the 

 probability that it will occur again at another point, then such a 

 system is, so far as that property is concerned, essentially unstable 

 in its absence. This earth contained carbon and other necessary 

 elements, and it is a fact that many combinations of carbon, nitrogen, 

 and a few others are self-reproducing. It follows that though the 

 state of "being lifeless" is almost a state of equilibrium, yet this 

 equilibrium is unstable (S.5/6), a single deviation from it being 

 sufficient to start a trajectory that deviates more and more from the 

 "hfeless" state. What we see today in the biological world are these 

 "autocatalytic" processes showing all the pecuHarities that have 

 been imposed on them by two thousand million years of elimination 

 of those forms that cannot survive. 



The organisms we see today are deeply marked by the selective 

 action of two thousand miUion years' attrition. Any form in any 

 way defective in its power of survival has been ehminated ; and today 

 the features of almost every form bear the marks of being adapted 

 to ensure survival rather than any other possible outcome. Eyes, 

 roots, cilia, shells and claws are so fashioned as to maximise the 

 chance of survival. And when we study the brain we are again 

 studying a means to survival. 



196 



