ABSTRACT
Not only systems may be observed, but they can observe also. This was latent even in the first steps of cybernetics (Wiener 1948). Even feedback involves the observation, at every instant, of the gap between what is realised and what is desired. This implies an “observation operator (Vallée 1951) acting, in the most general case, on the past and present of the signal showing the gap to be filled. A cybernetic system observes its environment and also itself. Based on the result of this observation, a decision is taken and consequent action occurs. So even in early cybernetics, not only observation but also decision were present, involving decision operators. In more general cybernetic systems we have the same situation.
