Mutual perceptual knowledge is a prevalent feature of our everyday lives, yet appears to be exceptionally difficult to characterise in an acceptable way. This paper argues for a renewed understanding of Stephen Schiffer’s iterative approach to mutual knowledge, according to which mutual knowledge requires an infinite number of overlapping, embedded mental states. It is argued that the charge of ‘psychological implausibility’ that normally accompanies discussion of this approach can be offset by identifying mutual knowledge, not with the infinite iterations themselves, (...) but with the finite base which Schiffer proves is capable of generating those iterations. An understanding of this finite base as a primitive, relational property holding between two or more people, allows us to understand the iterations as an implicit and ‘harmless’ intrapersonal feature of what is an interpersonal phenomenon. The paper concludes by relating the account to joint attention in infant interaction. (shrink)

Tarski’s conceptual analysis of the notion of logical consequence is one of the pinnacles of the process of defining the metamathematical foundations of mathematics in the tradition of his predecessors Euclid, Frege, Russell and Hilbert, and his contemporaries Carnap, Gödel, Gentzen and Turing. However, he also notes that in defining the concept of consequence “efforts were made to adhere to the common usage of the language of every day life.” This paper addresses the issue of what relationship Tarski’s analysis, and (...) Béziau’s further generalization of it in universal logic, have to reasoning in the everyday lives of ordinary people from the cognitive processes of children through to those of specialists in the empirical and deductive sciences. It surveys a selection of relevant research in a range of disciplines providing theoretical and empirical studies of human reasoning, discusses the value of adopting a universal logic perspective, answers the questions posed in the call for this special issue, and suggests some specific research challenges. (shrink)

Reasoning about what other people know is an important cognitive ability, known as epistemic reasoning, which has fascinated psychologists, economists, and logicians. In this paper, we propose a computational model of humans’ epistemic reasoning, including higher-order epistemic reasoning—reasoning about what one person knows about another person’s knowledge—that we test in an experiment using a deductive card game called “Aces and Eights”. Our starting point is the model of perfect higher-order epistemic reasoners given by the framework of dynamic epistemic logic. We (...) modify this idealized model with bounds on the level of feasible epistemic reasoning and stochastic update of a player’s space of possibilities in response to new information. These modifications are crucial for explaining the variation in human performance across different participants and different games in the experiment. Our results demonstrate how research on epistemic logic and cognitive models can inform each other. (shrink)

In this paper we consider the potential role of metarepresentation—the representation of another representation, or as commonly considered within cognitive science, the mental representation of another individual's knowledge and beliefs—in mediating definite reference and common ground in conversation. Using dialogues from a referential communication study in which speakers conversed in succession with two different addressees, we highlight ways in which interlocutors work together to successfully refer to objects, and achieve shared conceptualizations. We briefly review accounts of how such shared conceptualizations (...) could be represented in memory, from simple associations between label and referent, to “triple co-presence” representations that track interlocutors in an episode of referring, to more elaborate metarepresentations that invoke theory of mind, mutual knowledge, or a model of a conversational partner. We consider how some forms of metarepresentation, once created and activated, could account for definite reference in conversation by appealing to ordinary processes in memory. We conclude that any representations that capture information about others' perspectives are likely to be relatively simple and subject to the same kinds of constraints on attention and memory that influence other kinds of cognitive representations. (shrink)

This paper advances the following criticisms against the received view of implicatures: (1) implicatures are relations of pragmatic implication and not attempts to convey particular speaker meanings; (2) conversational implicatures are non-cancellable; (3) generalised conversational implicatures and conventional implicatures are necessary to preserve the cooperative assumption employing a conversational maxim of conveyability; (4) implicatures should be divided into utterance implicatures and assumption implicatures, not speaker implicatures and sentence implicatures; (5) trivial implicatures are genuine implicatures; (6) Grice’s theory of conversation cannot (...) explain most of his examples of particularised conversational implicatures; (7) the apparent attempts of explicit cancellation of implicatures are apologies, not attempts to avoid misunderstandings. (shrink)

In this paper I provide a theory of the speech act of assertion according to which assertion is a species of joint action. In doing so I rely on a theory of joint action developed in more detail elsewhere. Here we need to distinguish between the genus, joint action, and an important species of joint action, namely, what I call joint epistemic action. In the case of the latter, but not necessarily the former, participating agents have epistemic goals, e.g., the (...) acquisition of knowledge. It is joint epistemic action that assertion is a species of. (shrink)

Speakers often do not state requests directly but employ innuendos such as Would you like to see my etchings? Though such indirectness seems puzzlingly inefficient, it can be explained by a theory of the strategic speaker, who seeks plausible deniability when he or she is uncertain of whether the hearer is cooperative or antagonistic. A paradigm case is bribing a policeman who may be corrupt or honest: A veiled bribe may be accepted by the former and ignored by the latter. (...) Everyday social interactions can have a similar payoff structure (with emotional rather than legal penalties) whenever a request is implicitly forbidden by the relational model holding between speaker and hearer (e.g., bribing an honest maitre d’, where the reciprocity of the bribe clashes with his authority). Even when a hearer’s willingness is known, indirect speech offers higher-order plausible deniability by preempting certainty, gossip, and common knowledge of the request. In supporting experiments, participants judged the intentions and reactions of characters in scenarios that involved fraught requests varying in politeness and directness. (shrink)