Simulating Non-Deductive Reasoning

This paper is intended to draw attention to a literature in Philosophy that would be of great use and interest to researchers attempting to simulate non-deductive reasoning. Two models of such reasoning are discussed, and the kernel role of the concept of explanation common to them both is revealed. Finally, the relevance of the conceptual insights to computing by appealing to Scriven's comprehension theorem which facilitates a link between the concepts of explanation, understanding and processing efficiency under certain constraints. 1. Introduct ion A fairly recent survey found that researchers in Artificial Intelligence considered Philosophy of more immediate relevance to their work than Psychology (Newell, 1980). This is a plausible attitude toward a discipline that is traditionally preoccupied with the mental, with knowledge and with reasoning. It is a reasonable hope that the body of philosophic ruminations about these domains, though are univocal, will help the formulation of precise characterizations of the properties intelligent programs are supposed to exhibit, i.e., specifications of the behavior to be simulated. The first two of the three philosophic preoccupations mentioned above have fairly old titles, philosophy of mind and epistomology, respectively. The third concern, the characterization of reasoning properly belongs to logic. In what follows, however, I wish to call attention to and draw upon a literature that is not precisely at home in any one titled field of philosophy. The literature in question is one concerned at a conceptual and not a psychological level with the characterization of reasoning, ordinary reasoning fro