Emmanuel J. Genot

The game of inquiry: the interrogative approach to inquiry and belief revision theory

I. Levi has advocated a decision-theoretic account of belief revision. We argue that the game-theoretic framework of Interrogative Inquiry Games, proposed by J. Hintikka, can extend and clarify this account. We show that some strategic use of the game rules (or ‘policies’) generate Expansions, Contractions and Revisions, and we give representation results. We then extend the framework to represent explicitly (multiple) sources of answers, and apply it to discuss the Recovery Postulate. We conclude with some remarks about the potential extensions of interrogative games, with respect to some issues in the theory of belief change.

Unity, Truth and the Liar

The Liar Paradox challenges logicians’ and semanticists’ theories of truth and meaning. Modern accounts of paradoxes in formal semantics offer solutions through the hierarchy of object language and metalanguage. Yet this solution to the Liar presupposes that sentences have unique meaning. This assumption is non-controversial in formal languages, but an account of how “hidden meaning” is made explicit is necessary to any complete analysis of natural language. Since the Liar Paradox presents itself as a sentence uniting contradictory meanings, appreciating how they can be united in a single sentence may provide new insights into this and other paradoxes. This volume includes a target paper, taking up the challenge to revive, within a modern (formal) framework, a medieval solution to the Liar Paradox which did not assume Uniqueness of Meaning. Stephen Read, author of the target paper, attempts to formally state a theory of truth that dates back to the 14th century logician Thomas Bradwardine; the theory offers a solution to the Liar Paradox in which the Liar sentence turns out to be false. The rest of the volume consists of papers discussing and/or challenging Read’s – and Bradwardine’s -- views one the one hand, and papers addressing the doctrinal and historical background of medieval theories of truth on the other hand. It also includes a critical edition of Heytesbury’s treatise on insolubles, closely related to Bradwardine’s view. Including formal, philosophical and historical discussions, this volume intends to renew the debate about paradoxes and theory of truth, and to show that the interest of earlier medieval work is not merely historical but, on the contrary, still relevant for modern, formal semantic theory. It is of interest for both professional philosophers and advanced students of philosophy.

Strategies of inquiry : The ‘Sherlock Holmes sense of deduction’ revisited

This paper examines critically the reconstruction of the ‘Sherlock Holmes sense of deduction’ proposed jointly by M.B. Hintikka (1939–1987) and J. Hintikka (1929–2016) in the 1980s, and its successor, the interrogative model of inquiry (imi) developed by J. Hintikka and his collaborators in the 1990s. The Hintikkas’ model explicitly used game theory in order to formalize a naturalistic approach to inquiry, but the imi abandoned both the game-theoretic formalism, and the naturalistic approach. It is argued that the latter better supports the claim that the imi provides a ‘logic of discovery’, and safeguards its empirical adequacy. Technical changes necessary to this interpretation are presented, and examples are discussed, both formal and informal, that are better analyzed when these changes are in place. The informal examples are borrowed from Conan Doyle’s The Case of Silver Blaze, a favorite of M.B. and J. Hintikka.

The interrogative model of inquiry and inquiry learning

Hakkarainen and Sintonen (Sci Educ 11(1):25–43, 2002) praise the descriptive adequacy of Hintikka’s Interrogative Model of Inquiry (imi) to describe children’s practices in an inquiry-based learning context. They further propose to use the imi as a starting point for developing new pedagogical methods and designing new didactic tools. We assess this proposal in the light of the formal results that in the imi characterize interrogative learning strategies. We find that these results actually reveal a deep methodological issue for inquiry-based learning, namely that educators cannot guarantee that learners will successfully acquire a content, without limiting learner’s autonomy, and that a trade-off between success and autonomy is unavoidable. As a by-product of our argument, we obtain a logical characterization of serendipity.

The Best of All PossibleWorlds: Where Interrogative Games Meet Research Agendas

Erik J. Olsson and David Westlund have recently argued that the standard belief revision representation of an epistemic state is defective.1 In order to adequately model an epistemic state one needs, in addition to a belief set (or corpus, or theory, i.e. a set closed under deduction) \(\underline{\textrm K}\) and (say) an entrenchment relation E, a research agenda \(\underline{\textrm A}\), i.e. a set of questions satisfying certain corpus-relative preconditions (hence called \(\underline{\textrm K}\)-questions) the agent would like to have answers to. Informally, the preconditions guarantee that the set of potential answers represent a partition of possible expansions of \(\underline{\textrm K}\), hence are equivalent to well-behaved sets of alternative hypotheses.

The brain attics: the strategic role of memory in single and multi-agent inquiry

M. B. Hintikka (1939–1987) and J. Hintikka (1929–2016) claimed that their reconstruction of the ‘Sherlock Holmes sense of deduction’ can “serve as an explication for the link between intelligence and memory” ( 1983 , p. 159). The claim is vindicated, first for the single-agent case, where the reconstruction captures strategies for accessing the content of a distributed and associative memory; then, for the multi-agent case, where the reconstruction captures strategies for accessing knowledge distributed in a community. Moreover, the reconstruction of the ‘Sherlock Holmes sense of deduction’ allows to conceptualize those strategies as belonging to a continuum of behavioral strategies .

Inquiry and Deliberation in Judicial Systems: The Problem of Jury Size

We raise the question whether there is a rigorous argument favoring one jury system over another. We provide a Bayesian model of deliberating juries that allows for computer simulation for the purpose of studying the effect of jury size and required majority on the quality of jury decision making. We introduce the idea of jury value (J-value), a kind of epistemic value which takes into account the unique characteristics and asymmetries involved in jury voting. Our computer simulations indicate that requiring more than a > 50 % majority should be avoided. Moreover, while it is in principle always better to have a larger jury, given a > 50 % required majority, the value of having more than 12–15 jurors is likely to be negligible. Finally, we provide a formula for calculating the optimal jury size given the cost, economic or otherwise, of adding another juror.