"Together with Warren McCulloch, Norbert Wiener, John von Neumann, and others, Heinz von Foerster was the architect of cybernetics. In particular he developed a second-order cybernetics which focus on self-referential systems and the importance of eigenbehaviors for the explanation of complex phenomena. In von Foerster�s words, it is the �cybernetics of observing systems�. Von Foerster�s famous distinction between trivial and non-trivial machines is a starting point to recognize the complexity of cognitive behavior. A trivial machine is a machine whose operations are not influenced by previous operations. It is analytically determinable, independent from previous operations, and thus predictable. For non-trivial machines, however, this is no longer true as the problem of identification, i.e., deducing the structure of the machine from its behavior, becomes unsolvable. Finally, as long-term director of the Biological Computer Laboratory in Illinois he provided an fruitful platform for studies of complex systems and had essential influence on many cognitive scientists and (radical) constructivists.

Heinz von Foerster was born 1911 in Vienna, Austria, where he studied physics at the Vienna Technical University. 1944 he received a Ph.D. in physics at the University Breslau. After World War II he taught at the University of Illinois at Urbana-Champaign where he hold the professorship for signal engineering from 1951 to 1975. From 1962 to 1975 he also was professor for biophysics and 1958�75 director of the Biological Computer Laboratory. Additionally, 1956�57 and 1963�64 he was Guggenheim-Fellow; 1963�65 president of the Wenner-Gren-Foundation for anthropological research; 1971�72 secretary of the Josiah-Macy-Foundation of the cybernetic program. H. von Foerster wrote a large number of scientific publications.

Heinz von Foerster died on 2 October 2002 in Pescadero, California"

www.univie.ac.at/constructivism/HvF.htm