Abstract

The basic hypothesis of cybernetics is that the chief mechanism of the central nervous system is one of negative feed-back. The field of study is not, however, restricted to feed-backs of the negative kind. Secondly, cybernetics makes the hypothesis that the negative feed-back mechanism explains purposive and adaptive behaviour. Broadly speaking what the cybernetic model does for our outlook is to make us understand how purposive behaviour can be manifested by a machine, for purposive can now be defined in terms of negative feed-back. An anti-aircraft gun is purposive in the sense that it is able by means of radar to follow its target.1 Predictive behaviour is also accounted for by the same mechanism, as illustrated by a gun firing not at a point where an aeroplane is but at a point where it will bejust as a cat chasing a mouse extrapolates the mouse's path. Support for this striking hypothesis, which is of fundamental importance, is to be found both in rather general resemblances between organisms and electronic machines and in resemblances of more special kinds