The Conceptual Structure of HFE
The history of a discipline should logically begin with the conceptual structure (CS) of the discipline, which is the assumptions on which the discipline depends. A discipline cannot be fully understood without examining its foundations (i.e., the assumptions and their implications). Assumptions have a number of attributes, each of which must be examined in turn. Some assumptions are entirely logical, which means that they are required by the logic of the situation. For example, the assumption that HFE is an autonomous discipline is required by logic, or else why are we describing HFE? Other assumptions do not depend on logic, but are personal beliefs of individual professionals. These assumptions may be positive or negative and may have emotion associated with some of them. When a large enough number of professionals (what has been termed a critical mass) develop a set of common personal assumptions, one can speak of them as a professional CS.
The personal beliefs of professionals logically precede those assumptions that characterize the discipline as a whole. A small group of HFE professionals, whom one can term an elite (but only because they are a subset of all professionals), write textbooks and papers; this elite takes the raw material of the professional CS and refines it to form what one can call a disciplinary CS. In the process of this refinement, many (possibly most) professional assumptions are eliminated as being too specific or too negative. The process of refinement is not necessarily deliberate; it may occur subconsciously.
Before progressing further, it is necessary to define what an assumption is. An assumption is a statement of a belief that describes some aspect of the discipline. An assumption can be operationally further defined as a statement that cannot be broken down into more detailed substatements. However,