Piero Scaruffi(Copyright © 2013 Piero Scaruffi | Legal restrictions )
These are excerpts and elaborations from my book "The Nature of Consciousness"
The US mathematician Norbert Wiener (who founded Cybernetics in 1943) first recognized the importance of feedback (a term that he coined) for any meaningful behavior in the environment: a system that has to act in the environment must be able to continuously compare its performed action with the intended action and then infer the next action from their difference. This is what all living organisms do all the time in order to survive.
Feedback is the action of feeding a system its past performance. Given past performance, the system can adjust future performance. All biological systems (animals, plants, ecosystems) exhibit feedback. Feedback is the basis of life. As Bernstein had asserted, we could not even coordinate our limbs if we were not capable of using feedback.
Feedback is crucial for "homeostasis", the phenomenon (first described in the 1930s by the US biologist Walter Cannon) by which an organism tends to compensate variations in the environment in order to maintain its internal stability; i.e., by which an organism adapts to the environment. Homeostasis consists in maintaining a constant internal state in reaction to changes in the environment and through action on the environment. For example, body temperature is controlled by perspiring and shivering (one lowers the temperature and the other one increases it). Homeostasis is crucial for survival.
Given the number of factors that must be taken into account for any type of action in the real world, it is not surprising that the brain evolved to use feedback, rather than accurate computation, to guide motion.
It is not a coincidence that feedback turns out to be as crucial also for the performance of machines in their environment. Beginning with James Watt’s steam engine, machines have been designed so as to be able to control themselves.
A control system is a system that uses feedback to achieve some kind of steady state. A thermostat is a typical control system: it senses the temperature of the environment and directs the heater to switch on or off; this causes a change in the temperature, which in turn is sensed by the thermostat; and so forth. This loop of action and feedback, of sensing and controlling, realizes a control system. A control system is therefore capable of achieving a "goal", is capable of "purposeful" behavior (as opposed to the chaotic behavior that would result if feedback was not used).
Living organisms are control systems. Most machines are also control systems.
Another folk concept that Wiener formalized is “noise”. Wiener emphasized that communication in nature is never perfect: every message carries some involuntary "noise" and in order to understand the communication the original message must be restored. This led to a statistical theory of amount of information.
Wiener understood the essential unity of communication, control and statistical mechanics, which is the same whether the system is an artificial system or a biological system. This unified discipline became "Cybernetics". A cybernetic system is a system that achieves an internal homeostatic control through an exchange of information between its parts.
The British neurologist Ross Ashby also placed emphasis on feedback. Both machines and living beings tend to change in order to compensate variations in the environment, so that the combined system is stable. For living beings this translates into "adaptation" to the environment. The "functioning" of both living beings and machines depends on feedback processes to the extent that feedback allows the system to self-organize. Ashby emphasized the power of self-organizing systems, systems made of a very high number of simple units which can evolve autonomously and adapt to the environment by virtue of their structure.
Ashby believed that in every isolated system that is subject to constant forces "organisms" arise that are capable of adapting to their environment (i.e., that tend towards stationary or quasi-stationary non-equilibrium states). Basically, his principle of self-organization asserts that in any isolated system, life and intelligence inevitably develop.
Back to the beginning of the chapter "Machine Intelligence" | Back to the index of all chapters