Abstract
Many criticisms of epistemic logic have centered around its use of devices such as idealized knowers with logical omniscience and perfect self-knowledge. One possible response to such criticisms is to say that these idealizations are normative devices, and that epistemic logic tells us how agents ought to behave. This paper will take a different approach, treating epistemic logic as descriptive, and drawing the analogy between its formal models and idealized scientific models on that basis. Treating it as descriptive matches the way in which some philosophers, including one of its founders, Jaako Hintikka, have thought about epistemic logic early in its history. Further, the analogy between the two fields will give us a way to defuse criticisms that see epistemic logic as unrealistic. For example, criticizing models of epistemic logic in which agents know all propositional tautologies as being unrealistic would be like criticizing frictionless planes in physics for being unrealistic. Each one would certainly be an unsuitable model for studying some kinds of phenomena, but is entirely appropriate for others. After outlining the analogy between epistemic and scientific models, we will discuss some ways in which idealizations are used by different research programs in epistemic logic.
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Notes
And there really does seem to be space to treat epistemic logic as a discipline with both normative and descriptive components. But since the concerns in this paper have principally to do with the accuracy of epistemic logic’s depiction of agents, we will not discuss the normativity issue in any detail.
More contemporary authors such as (Girle 1998) have raised the problem of epistemic logic’s unrealistic features, even accounting for developments in the discipline since (Hintikka 1962). So while our focus will be on Hocutt’s critique, he is certainly not the only one to have made the point that features such as logical and deductive omniscience are deeply unrealistic when we consider actual knowers.
While Hocutt writes that no epistemic logician has suggested such a proposal, we have already seen (Lemmon and Henderson 1959) talking much along these lines.
This is admittedly a complicated claim. (Feldman 1988) considers the issue of doxastic voluntarism, arguing that it does make sense to talk about obligations that we may be incapable of fulfilling. This would mean that even if belief formation is involuntary, we may still have obligations to believe. I will not treat this issue further here, however, instead taking it for granted that a largely descriptive interpretation of epistemic logic is desirable.
(Weisberg 2007) lists other representational ideals, but these have been omitted as being less relevant to the type of modeling in epistemic logic.
The models of epistemic logic we consider are also all research programs in the external approach to knowledge representation. That is, we consider modeling agents from the point of view of an external observer. An internal approach to epistemic logic from the point of view of one of the agents in the situation is given in (Aucher 2010). However, autoepistemic logic is an alternative knowledge representation system we outline that can be seen as an instance of the internal approach.
Though Moore himself attributes the term ‘autoepistemic’ to an unpublished note by Stalnaker.
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Yap, A. Idealization, epistemic logic, and epistemology. Synthese 191, 3351–3366 (2014). https://doi.org/10.1007/s11229-014-0448-8
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DOI: https://doi.org/10.1007/s11229-014-0448-8