Building semantic networks

After three people signed it (Ivan was one of them), I went to the Stanford AI project and spent much more time thinking about notebook KiddyKomputers than AI. But there were two AI designs that were very intriguing. The first was Carl Hewitt's PLANNER, a programmable logic system that formed the deductive basis of Winograd's SHRDLU [Sussman 69, Hewitt 69] I designed several languages based on a combination of the pattern matching schemes of FLEX and PLANNER [Kay 70]. The second design was Pat Winston's concept formation system, a scheme for building semantic networks and comparing them to form analogies and learning processes [Winston 70]. It was kind of "object-oriented". One of its many good ideas was that the arcs of each net which served as attributes in AOV triples should themselves be modeled as nets. Thus, for example a first order arc called LEFT-OF could be asked a higher order question such as "What is your converse?" and its net could answer: RIGHT-OF. This point of view later formed the basis for Minsky's frame systems [Minsky 75]. A few years later I wished I had paid more attention to this idea.