Qualitative Reasoning: How we think Our way through the Day

Abstract

Abstract : We have come full circle back to the topic of visualization and the role of the mind's eye and of external visual displays in human thinking. I have tried to survey some of the main tools and processes that seem to be implicated in everyday reasoning -- the kind that carries us through the day, dealing with problems as they arise. The thinking I have described does not look at all like formal logic, and only a little like mathematics. It makes use of a great multitude of inference rules, which are not tautological rules of logic but incorporate much real-world knowledge. It appears to be remarkably unconcerned with questions of sufficiency and necessity. When it deals with quantities, as if often must, it usually handles primarily their ordinal rather than their cardinal properties. For most people, at least, it makes great use of diagrammatic representations, or mental diagrams in the mind's eye, which provide it with powerful inference processes. To compensate for its severe limitations in handling simultaneous relations, it proceeds by successive approximations, and halts when it has satisfied. By the standards of formal logic, it is a jerry-built structure. But it gets us through the day.