3.5 The Integrating Rôle of Directive Correlation

23

Fig. 3.2 Directive correlation (after Sommerhoff 1950). The arrows indicate causal connexions. In

this drawing, four correlated variables (upper EE andupper RR) are involved. See the text for explanation of the

symbols

is called the coenetic variable, underlying the fact that it is a common causal deter-

minant of both upper EE and upper RR. Directive correlation is this special relationship between

upper EE and upper RR (Fig. 3.2). Its existence renders the goal independent of upper DD. Adaptation is

thus a tetradic relationship amongupper DD (which may be a prior occurrence ofupper EE),upper EE,upper RR,

and upper GG. Furthermore, it is not necessary to restrict the coenetic variable to specific

environmental stimuli that evoke an organic response; it can also be a general factor

that determines the specific nature of an action. It may also be remarked that the

general purpose of sensory organs is to establish those causal connexions that will

enable environmental variables to become the coenetic variables of adapted organic

behaviour.

The degree upper MM of directive correlation can be defined as the range of variation

of the coenetic variable over which directive correlation can be maintained, and the

range upper NN of directive correlation can be defined as the number of correlated (upper EE and

upper RR) or coenetic (upper DD) variables involved. The degree is especially important because it

is related to the minimum probability that the goal will be achieved.

3.5

The Integrating Rôle of Directive Correlation

Although the ultimate goal of any organism is survival, the functions of most of the

individual organs are very subordinate to that ultimate goal. The goal of a subordinate

function may simply be the maintenance of the physiological conditions required to

keep the coenetic variable of a higher function within its maximum permissible