PROBABILISTIC ASPECTS OF THE HUMAN CYBERNETIC MACHINE* VAN RENSSELAER POTTERf Men who know they are machines should be able to bring a higher degree of objectivity to bear on their problems than machines that think they are men.—D. E. Wooldridge [Mechanical Man, p. 204] I have been working in the field of cancer research for over 30 years, and it has become increasingly apparent to me that the biological world has many probabilistic aspects. This view is a direct result of my experience in the cancer field, in which one of the chief products of my own research has been the demonstration of the diversity of chemical patterns that are compatible with malignancy. I should make clear what I mean by "probabilistic aspects" of cancer, or of life, or of the world. I will define "probabilistic" to mean "uncertain as to time of occurrence." This definition is my own and differs from any previous definitions by introducing time into the discussion. I will try to develop the significance of this new definition as I go along. First, I would remind you of the accepted definitions, which are permissive for my own. Probabilutic is given as (1) of or relating to probabilism and (2) of, relating to, or based on probability. Probabilism: a theory that certainty is impossible, especially in the sciences, and that probability suffices to govern belief and action. Probability: a mathematical basis for prediction that, for an exhaustive set of outcomes, is the ratio of outcomes that would produce a given event to the total number of possible outcomes. In plain words, this means that the probability of drawing an ace of spades from a standard deck of cards is one in 52. In this simple example, time is not mentioned because the action and result are immediate and there is no obvious intervention by modulating influences if an honest deck is used. However, it will be my purpose ?Paper presented at the Institute for Theological Encounter with Science and Technology, Saint Louis, April 1973. Cybernetics is the science of communication and control within organized systems. tMcArdle Laboratory, Medical School, University of Wisconsin, Madison, Wisconsin 53706. 164 I Van Rensselaer Potter » Human Cybernetic Machine to argue that in most real-life situations, we will find probabilistic aspects involving time as one ofthe variables. When time enters into probability, there is an opportunity for factors other than a "first cause" to moderate the outcome. These factors may involve feedback from the system itself, or they may be external. A classic example ofan event that is apparently probabilistic in the sense of having a most probable but uncertain "time of occurrence" is the decay of a radioactive element. In this case there is a "most probable time" for decay precisely because the event is not modulated by any external influence as far as is known. In speaking of probabilistic aspects of life, I did not, you will note, prejudice my case by speaking about the probabilutic nature of life, because I will emphasize that life is highly organized but that it has probabilistic aspects. On the other hand, I might with some justification talk about the probabilistic nature of cancer, which is very disorganized, although organized enough to proliferate. Thus, I might say that among the probabilistic aspects of life is the phenomenon ofcancer. The cancer problem may be dominated by the probabilistic nature of cancer causation , cancer progression, and cancer therapy, but life is not. Life is characterized by the exquisite organization of living organisms, whether they are single cells or human beings consisting of millions upon millions ofindividual cells combined into a fabulous cybernetic system. Organization includes organization in space, which is structure, and organization in time and space, which isfunction. A computer is also organized in time and space. An automated machine can be built around a computer to produce a cybernetic machine that will carry out certain functions according to a desired program in an environment with specified raw materials, but it is not comparable to a living organism, which can operate adaptively over a wider range of unexpected events. Perhaps such a combination of devices should not be called a cybernetic machine but, rather...
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