The Logic of Plausible Reasoning: A Core Theory

Abstract

The paper presents a core theory of human plausible reasoning based on analysis of people's answers to everyday questions about the world. The theory consists of three parts: a formal representation of plausible inference patterns; such as deductions, inductions, and analogies, that are frequently employed in answering everyday questions; a set of parameters, such as conditional likelihood, typicality, and similarity, that affect the certainty of people's answers to such questions; and a system relating the different plausible inference patterns and the different certainty parameters. This is one of the first attempts to construct a formal theory that addresses both the semantic and parametric aspects of the kind of everyday reasoning that pervades. all of human discourse.

Real-world estimation: Estimation modes and seeding effects

“…To this end, I adopt a plausible reasoning architecture as a general processing framework (Collins & Michalski, 1989). I identify two basic estimation modes, the numerical-retrieval mode and the ordinalconversion mode, and describe a number of processes engaged by each of these.…”

Untitled

“…This is similar to the mutual dependency rules introduced by Collins and Michalski (1989) and Michalski (1993), but different from the determination rules introduced by Davies and Russell (1977), which guarantee the truth of the inferred knowledge.…”

“…Although we do not claim that the presented method is a model of human learning, some features are similar to those employed by humans. These are the building of the justification tree of an example by using the justification trees of the previous examples (Wisniewski & Medin, 1991), and the use of multiple lines of reasoning in the justification of a plausible inference step (Collins & Michalski, 1989).…”

“…If no contradiction is found, the inference step is accepted. This method (although quite simple, and definitely a necesssary topic of future research) is related to that employed by humans (Collins & Michalski, 1989). Indeed, Collins and Michalski argue that people solve problems by pursuing different "lines of reasoning."…”

What Should Default Reasoning be, by Default?

“…Good examples of this is the work done by Collins & Michalski (1989) on plausible inferences and Osherson et al (1991) on probabilistic reasoning. Casting the net more widely, work on pragmatic reasoning schemas (e.g., Cheng & Holyoak, 1989) and on the invitation (suppression) of invalid (valid) inferences in everyday language use of the conditional (e.g., Byrne, 1989;Cummins et al, 1991) can provide a different and potentially useful perspective even on the mistakes humans make in making deductive inferences.…”