The "second order cyberneticians" claimed that knowledge is a biological phenomenon (Maturana, 1970), that each individual constructs his or her own "reality" (Foerster, 1973) and that knowledge "fits" but does not "match" the world of experience (von Glasersfeld, 1987).

Stuart A. Umpleby (1994) The Cybernetics of Conceptual Systems. p. 3