Regulation In Biological Systems

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 like 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 “lifeless” state.  What we see today in the biological world are these “autocatalytic” processes showing all the peculiarities 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 million years’ attrition.  Any form in any way defective in its power of survival has been eliminated;  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.