# Rational analysis, intractability, and the prospects of ‘as if’-explanations

*Synthese*195 (2):491–510 (2018)

**Abstract**

The plausibility of so-called ‘rational explanations’ in cognitive science is often contested on the grounds of computational intractability. Some have argued that intractability is a pseudoproblem, however, because cognizers do not actually perform the rational calculations posited by rational models; rather, they only behave as if they do. Whether or not the problem of intractability is dissolved by this gambit critically depends, inter alia, on the semantics of the ‘as if’ connective. First, this paper examines the five most sensible explications in the literature, and concludes that none of them actually circumvents the problem. Hence, rational ‘as if’ explanations must obey the minimal computational constraint of tractability. Second, this paper describes how rational explanations could satisfy the tractability constraint. Our approach suggests a computationally unproblematic interpretation of ‘as if’ that is compatible with the original conception of rational analysis.

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Archival date: 2019-03-29

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References found in this work BETA

Re-Engineering Philosophy for Limited Beings. Piecewise Approximations to Reality.Wimsatt, William C.

Précis of Bayesian Rationality: The Probabilistic Approach to Human Reasoning.Oaksford, Mike & Chater, Nick

Rational Approximations to Rational Models: Alternative Algorithms for Category Learning.Sanborn, Adam N.; Griffiths, Thomas L. & Navarro, Daniel J.

Computers and Intractability. A Guide to the Theory of NP-Completeness.Garey, Michael R. & Johnson, David S.

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2019-01-25

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