Imagination constrained, imagination constructed

A number of authors have asked what it takes for a course of mental imagery to be epistemically or practically useful. This paper addresses a prior question, namely, the difference between courses of imagination that are realistic and those that are fantastic. One approach, suggested by recent literature concerning the utility of imagery, holds that a course of imagination represents realistically if and only if the course of events represented conforms to certain accepted constraints. Against this it will be argued that the constraints cannot be both permissive enough and restrictive enough. An alternative approach adds as a necessary condition that realistic courses of imagination are constructed in accordance with certain procedures on the basis of remembered perceptions.