Inquiry Into Inquiry

Regulation In Biological Systems

Survival

10/6.[concl.]   The same argument will apply, with obvious modifications, to the automatic pilot.  If it is a good regulator the passengers will have a smooth flight whatever the gustiness outside.  They will, in short, be prevented from knowing whether or not it is gusty outside.  Thus a good pilot acts as a barrier against the transmission of that information.

The same argument applies to an air-conditioner.  If I live in an air-conditioned room, and can tell, by the hotness of the room, that it is getting hot outside, then that conditioner is failing as a regulator.  If it is really good, and the blinds are drawn, I shall be unable to form any idea of what the outside weather is like.  The good conditioner blocks the flow inwards of information about the weather.

The same thesis applies to the higher regulations achieved by such activities as hunting for food, and earning one’s daily bread.  Thus while the unskilled hunter or earner, in difficult times, will starve and will force his liver and tissues (the essential variables) to extreme and perhaps unphysiological states, the skilled hunter or earner will go through the same difficult times with his liver and tissues never taken to extremes.  In other words, his skill as a regulator is shown by the fact, among others, that it prevents information about the times reaching the essential variables.  In the same way, the skilled provider for a family may go through difficult times without his family realising that anything unusual has happened.  The family of an unskilled provider would have discovered it.

In general, then, an essential feature of the good regulator is that it blocks the flow of variety from disturbances to essential variables.

Regulation In Biological Systems

Survival

10/6.[cont.]   If is a regulator, the insertion of between and lessens the variety that is transmitted from to   Thus an essential function of as a regulator is that it shall block the transmission of variety from disturbance to essential variable.

Since this characteristic also implies that the regulator’s function is to block the flow of information, let us look at the thesis more closely to see whether it is reasonable.

Suppose that two water-baths are offered me, and I want to decide which to buy.  I test each for a day against similar disturbances and then look at the records of the temperatures;  they are as in Fig. 10/6/1.

Fig. 10/6/1

There is no doubt that is the better;  and I decide this precisely because its record gives me no information, as does about what disturbances, of heat or cold, came to it.  The thermometer and water in bath have been unable, as it were, to see anything of the disturbances

Regulation In Biological Systems

Survival

10/6.   Regulation blocks the flow of variety.   On what scale can any particular mechanism be measured for its value or success as a regulator?  The perfect thermostat would be one that, in spite of disturbance, kept the temperature constant at the desired level.  In general, there are two characteristics required:  the maintenance of the temperature within close limits, and the correspondence of this range with the desired one.  What we must notice in particular is that the set of permissible values, has less variety than the set of all possible values in   for is some set selected from the states of   If is a regulator, the insertion of between and lessens the variety that is transmitted from to   Thus an essential function of as a regulator is that it shall block the transmission of variety from disturbance to essential variable.

Regulation In Biological Systems

Survival

10/5.[concl.]   To make the assumptions clear, here are some simple cases, as illustration.  (Inanimate regulatory systems are given first for simplicity.)

(1) The thermostatically-controlled water-bath.  is its temperature, and what is desired is the temperature range between, say 36° and 37°C.  is the set of all the disturbances that may drive the temperature outside that range — addition of cold water, cold draughts blowing, immersion of cold objects, etc.  is the whole regulatory machinery.  by its action, tends to lessen the effect of on

(2) The automatic pilot.  is a vector with three components — yaw, pitch, and roll — and is the set of positions in which these three are all within certain limits.  is the set of disturbances that may affect these variables, such as gusts of wind, movements of the passengers in the plane, and irregularities in the thrusts of the engines.  is the whole machinery — pilot, ailerons, rudder, etc. — whose action determines how shall affect

(3) The bicycle rider.  is chiefly his angle with the vertical.  is the set of small permissible deviations.  is the set of those disturbances that threaten to make the deviation become large.  is the whole machinery — mechanical, anatomical, neuronic — that determines what the effect of is on

Many other examples will occur later.  Meanwhile we can summarise by saying that natural selection favours those gene-patterns that get, in whatever way, a regulator between the disturbances and the essential variables   Other things being equal, the better is as a regulator, the larger the organism’s chance of survival.

Regulation In Biological Systems

Survival

10/5.[cont.]   Now regard the system as one of parts in communication.  In the previous section the diagram of immediate effects (of cat and mouse) was (or could be regarded as)

We are now considering the case in which the diagram is

in which is the set of essential variables, is the source of disturbance and dangers (such as ) from the rest of the world, and is the interpolated part (shell, brain, etc.) formed by the gene-pattern for the protection of   may also include such parts of the environment as may similarly be used for protection — burrow for rabbit, shell for hermit-crab, pike for pike-man, and sword (as defence) for swordsman.)

For convenience in reference throughout Part III, let the states of the essential variables be divided into a set — those that correspond to “organism living” or “good” — and — those that correspond to “organism not living” or “bad”.  (Often the classification cannot be as simple as this, but no difficulty will occur in principle;  nothing to be said excludes the possibility of a finer classification.)

Regulation In Biological Systems

Survival

10/5.   What is it survives, over the ages?  Not the individual organism, but certain peculiarly well compounded gene-patterns, particularly those that lead to the production of an individual that carries the gene-pattern well protected within itself, and that, within the span of one generation, can look after itself.

What this means is that those gene-patterns are specially likely to survive (and therefore to exist today) that cause to grow, between themselves and the dangerous world, some more or less elaborate mechanism for defence.  So the genes in Testudo cause the growth of a shell;  and the genes in Homo cause the growth of a brain.  (The genes that did not cause such growths have long since been eliminated.)