Abstract

The concept of an 'assumption' is discussed, and it is suggested that the psychological model implied by normal usage is misleading. A new model is proposed which distinguishes between 'assumptions', as constraints upon the thinking process, and 'postulates', as corresponding potential or actual propositional vocalizations. Some evidence for this model is provided, and its implications, particularly for the process of assumption identification, are discussed. It is suggested that assumption identification requires lateral thinking, and needs to be separated from problem-solving. The discussion is offered as an instance of an appropriate type of fusion of psychological and informal-logical approaches