A review of: “LOGIC AND PHILOSOPHY IN THE LVOV-WARSAW SCHOOL”, by Jan Woleński,Kluwer, Dordrecht (The Netherlands) and Boston, 1989. xiv + 364 pages.

Qualitative methodology plays an important role within computer simulation; modeling and analysis of complex systems require qualitative methods since humans think naturally in qualitative and linguistic terms. The critical interface for simulationists exploring qualitative simulation should rely on an unambiguous mathematical formalism or method with foundations in systems theory. Currently, many ad hoc formalisms exist for encoding uncertain or qualitative simulation knowledge; however, we have found that fuzzy set theory provides for a formalism where linguistic variables can be encoded as state, parameter, input and output information in the model. Fuzzy numbers, in particular, are useful when population statistics are unavailable—usually due to cost factors. We have constructed fuzzy simulation programs based on our C-based SimPack library and we use fuzzy simulation to hypothesize qualitative system models reflecting real system behavior, and to specify qualitative versions of systems.