Meditações - o relógio como metáfora cibernética

A bacteriological culture that has just been inoculated will increase in “number of organisms present” from hour to hour. If at first the numbers double in each hour, the number in the culture will change in the same way hour by hour as n is changed in successive powers of the transformation n' = 2n. If the organism is somewhat capricious in its growth, the system’s behaviour, i.e. what state will follow a given state, becomes somewhat indeterminate So “determinateness” in the real system evidently corresponds’ in the transformation, to the transform of a given operand being single-valued.

Next consider a clock, in good order and wound, whose hands, pointing now to a certain place on the dial, will point to some determinate place after the lapse of a given time. The positions of its hands correspond to the transformation’s elements. A single transformation corresponds to the progress over a unit interval of time; it will obviously be of the form n' = n + k. In this case, the “operator” at work is essentially undefinable for it has no clear or natural bounds. It includes everything that makes the clock go: the mainspring (or gravity), the stiffness of the brass in the wheels, the oil on the pivots, the properties of steel, the interactions between atoms of iron, and so on with no definite limit. As we said in S.2/3, the “operator” is often poorly defined and somewhat arbitrary—a concept of little scientific use. The transformation, however, is perfectly well defined, for it refers only to the facts of the changes, not to more or less hypothetical reasons for them.

A series of changes as regular as those of the clock are not readily found in the biological world, but the regular courses of some diseases show something of the same features. Thus in the days before the sulphonamides, the lung in lobar pneumonia passed typically through the series of states: Infection, consolidation, red hepatisation, grey hepatisation, resolution, health. Such a series of states corresponds to a transformation that is well defined, though not numerical.

W. Ross Ashby, An Introduction to Cybernetics