Abstract: The objective of this disclosure is to propose a method of designing an intelligent system assuring autonomy in problem solving to the largest extent. An architecture of a general purpose problem solving system and also a new modeling scheme for representing an object which may include human activity are discussed first. Then a special purpose problem solving system dedicated for a given problem is generated. It is extracted from a general purpose system using the object model as a template. Several new concepts are included in this disclosure to achieve this goal; a multi-level function structure and its corresponding knowledge structure, multiple meta-level operations, a level manager for building general purpose problem solving systems, a concept of multi-strata model to represent objects including human activity, and a method of extracting a special purpose system from a general purpose system and so on.