The study of defeasible reasoning unites epistemologists with those working in AI, in part, because both are interested in epistemic rationality. While it is traditionally thought to govern the formation and (with)holding of beliefs, epistemic rationality may also apply to the interrogative attitudes associated with our core epistemic practice of inquiry, such as wondering, investigating, and curiosity. Since generally intelligent systems should be capable of rational inquiry, AI researchers have a natural interest in the norms that govern interrogative attitudes. Following (...) its recent coinage, we use the term ``zetetic'' to refer to the properties and norms associated with the capacity to inquire. In this paper, we argue that zetetic norms can be modeled via defeasible inferences to and from questions---a.k.a erotetic inferences---in a manner similar to the way norms of epistemic rationality are represented by defeasible inference rules. We offer a sequent calculus that accommodates the unique features of ``erotetic defeat" and that exhibits the computational properties needed to inform the design of zetetic agents. The calculus presented here is an improved version of the one presented in Millson (2019), extended to cover a new class of defeasible erotetic inferences. (shrink)

In this essay, we extend earlier inferentialist-expressivist treatments of traditional logical, semantic, modal, and representational vocabulary (Brandom 1994, 2008, 2015; Peregrin 2014) to explanatory vocabulary. From this perspective, Inference to the Best Explanation (IBE) appears to be an obvious starting point. In its simplest formulation, IBE has the form: A best explains why B, B; so A. It thereby captures one of the central inferential features of explanation. An inferentialist-expressivist treatment of “best explains” would treat it as a logical operator. (...) Analogous to the inferentialist-expressivist treatment of other logical operators, this essay aims to provide introduction and elimination rules for “best explains.” Indeed, by exhibiting a form of detachment, IBE superficially looks like an elimination rule. The sequent calculus LEA+, described in Section 5 below, makes good on this intuition. By showing how “A best explains why B” is related to the underlying, scientific inference “A, so B,” we can purchase the inference ticket of IBE for no more than the cost of science’s material inferences. (shrink)

Robert Brandom’s normative-pragmatic theory is intended to represent the minimal set of practical abilities whose exhibition qualifies creatures as speaking a language. His model of a minimally discursive practice (MDP) is one in which participants, devoid of logical vocabulary, are only capable of making assertions and drawing inferences. This paper argues that Brandom’s purely assertional practices are not MDPs and that speech acts of asking questions (queries) must be included in any practice that counts as an MDP. The upshot of (...) the argument is support for the claim that the normative pragmatic analysis of assertions requires a corresponding analysis of queries and vice versa. (shrink)

It’s commonly thought that, in conversation, speakers accept and reject propositions that have been asserted by others. Do speakers accept and reject questions as well? Intuitively, it seems that they do. But what does it mean to accept or reject a question? What is the relationship between these acts and those of asking and answering questions? Are there clear and distinct classes of reasons that speakers have for acceptance and rejection of questions? This chapter seeks to address these issues. Beyond (...) their intrinsic interest to those working on the nature of questions, solutions to these problems may aid the extension of inferentialist approaches to logic and language. Inferentialists who think that inferences should be conceived in terms of the norms we are subject to in virtue of both the sentences we accept or assert as well as those we reject or deny are known as bilateralists. A coherent account of accepting and rejecting questions raises the prospects for a bilateralism that interprets question-involving or erotetic inferences according to these additional primitives. While a full-blown bilateralism for erotetic inferences and ultimately for question-forming operators themselves far exceeds this chapter’s scope, the work presented here does sketch the first steps in that direction. (shrink)

Robert Brandom's normative-pragmatic theory is intended to represent the minimal set of practical abilities whose exhibition qualifies creatures as speaking a language. His model of a minimally discursive practice (MDP) is one in which participants, devoid of logical vocabulary, are only capable of making assertions and drawing inferences. This dissertation argues that Brandom's purely assertional practices are not MDPs and that speech acts of asking questions (queries) must be included in any practice that counts as an MDP. I propose several (...) novel alternations to Brandom's deontic scorekeeping model of discourse, which I then utilize to generate a normative-pragmatic analysis of inquisitive practices. This analysis supports the claim that agents who can assert need to be able to ask questions and vice versa. The upshot is that intentionality belongs to those who can ask and answer questions. (shrink)

Many epistemologists take Inference to the Best Explanation (IBE) to be “fundamental.” For instance, Lycan (1988, 128) writes that “all justified reasoning is fundamentally explanatory reasoning.” Conee and Feldman (2008, 97) concur: “fundamental epistemic principles are principles of best explanation.” Call them fundamentalists. They assert that nothing deeper could justify IBE, as is typically assumed of rules of deductive inference, such as modus ponens. However, logicians account for modus ponens with the valuation rule for the material conditional. By contrast, fundamentalists (...) account for IBE with an ill-defined set of relations that happen to furnish their favorite set of inductive inferences. To our eye, this seems a little too convenient—there is too much room for ad hoc, just-so stories about the “striking” correspondence between our explanatory and inductive practices. We will argue that the (explanatory) pluralism adopted by the leading theorists of the best explanation—philosophers of science—undermines fundamentalism. Section 1 clarifies fundamentalism’s key tenets. Section 2 presents pluralism’s challenge to fundamentalism. Section 3 considers a potential fundamentalist reply to this challenge. Sections 4 through 6 canvass the leading candidates for developing this fundamentalist reply, showing each to be unsatisfactory. (shrink)