Main trends of research in the social and human ... - unesdoc - Unesco

General problems of interdisciplinary research and common mechanisms 505
of economics is of particular interest, in the first place because of the convergence
between these models and classical concepts such as that of the economic
circuit and, secondly, because the generalized nature of economic mechanisms
is already becoming apparent, some of their central aspects recurring in the
fields of biology, psychology and even of linguistics.
The advantage of loop systems is that they confer a clearly defined status on
some of the innumerable situations in which concepts of interaction and circular
causality have to be substituted for the concept of a linear causal sequence. In
physics the principle of action and reaction, the existence of many systems which
retain their balance by compensation of the various equivalent efforts which they
allow, and Le Chfitelier’s law (or the law of equilibrium displacements in the
direction opposite to that of the initial disturbance) show the impossibility of
reducing certain forms of causality to a linear sequence pattern. In biology the
very fact of organization and its conservation through successive adjustments
involving on each occasion a set of gains and losses makes the consideration of
loop systems more and more indispensable, and even in the case of apparently
simple effects of an environment on an organism (phenotypical modifications
or selection with genetic effects) it is increasingly believed that the organism
chooses and modifies its environment as much as it depends upon it, which
suggests the relevance of cybernetic circuits. In the sphere of the human scien-
ces, where interactions are always accompanied by automatic or more or less
intentional regulations, the notion of circuits is even more obviously applicable
and it is becoming increasingly apparent that even the general pattern S- R
(stimulus-reaction) is itself circular in nature, for a subject reacts to a stimulus
only if he is sensitized to it, and he is sensitized to it only as a function of the
pattern which determines the response, without it being possible to interpret the
latter in turn independently of the habitual stimuli.
In the field of economics, which offers the advantage of allowing extensive
measurements, a certain number of notions which have gained currency pre-
pared the way for cybernetic models. Such a notion, for instance, is the some-
what intuitive one, but one essential to economic thought, of a ‘variable which
is self-influencing by means of other variables dependent upon it’. Such also is
the notion of the ‘economic circuit’, for instance in the relations between pro-
duction, consumption and investment, which constitute numerous cases of
circular causality. Such too are the notions of multiplicator and accelerator,
frequently used by economists, which can furnish examples of simple trans-
formations in a loop system.
Let us, for the sake of concreteness, give an elementary example (taken from
L. Solari) of the translation in feedbacks of an economic circuit. Let us suppose
that this model refers to a closed national economy (without exchanges with
other countries) and let us assume only three variables, as follows: Y(t) =
national product, eft) = global consumption and I(t) = global investment.
These variables are continuous functions of time (t) ; they represent monetary
flows within an interval t, t + dt. We then obtain the accounting relationship:
Yft) = I(t) + C(t)
which may be completed, e.g. by the introduction of the two behaviour laws