In this paper I argue that there is a class of attitudes that have questions (rather than propositions or something else) as contents.

This book contains a selection of the papers presented at the Logic, Reasoning and Rationality 2010 conference in Ghent. The conference aimed at stimulating the use of formal frameworks to explicate concrete cases of human reasoning, and conversely, to challenge scholars in formal studies by presenting them with interesting new cases of actual reasoning. According to the members of the Wiener Kreis, there was a strong connection between logic, reasoning, and rationality and that human reasoning is rational in so far (...) as it is based on logic. Later, this belief came under attack and logic was deemed inadequate to explicate actual cases of human reasoning. Today, there is a growing interest in reconnecting logic, reasoning and rationality. A central motor for this change was the development of non-classical logics and non-classical formal frameworks. The book contains contributions in various non-classical formal frameworks, case studies that enhance our apprehension of concrete reasoning patterns, and studies of the philosophical implications for our understanding of the notions of rationality. (shrink)

The book is about logical analysis of natural language. Since we humans communicate by means of natural language, we need a tool that helps us to understand in a precise manner how the logical and formal mechanisms of natural language work. Moreover, in the age of computers, we need to communicate both with and through computers as well. Transparent Intensional Logic is a tool that is helpful in making our communication and reasoning smooth and precise. It deals with all kinds (...) of linguistic context in a fully compositional and anti-contextual way. (shrink)

Needed for such dialogue games as dialectic are appropriate standards of fairness and rationality. The rules of procedure of dialectic must describe a game playable by actual human participants. The present paper centers on certain idealizations of the dialectician that are not allowable.

This paper argues for the idea that the logic of questions should focus its attention on the analysis of arguments in which questions play the role of conclusions. The relevant concepts of validity are discussed and the concept of the logic of questions of a semantically interpreted formalized language is introduced.

The concepta question is reducible to a non-empty set of questions is defined and examined. The basic results are: (1) each question which is sound relative to some of its presuppositions is reducible to some set of binary (i.e. having exactly two direct answers) questions; (b) each question which has a finite number of direct answers is reducible to some finite set of binary questions; (c) if entailment is compact, then each normal question (i.e. sound relative to its presuppositions) is (...) reducible to some finite set of binary questions. (shrink)

In this paper, we propose a decidable single-agent modal logic for reasoning about goal-directed “knowing how”, based on ideas from linguistics, philosophy, modal logic, and automated planning in AI. We first define a modal language to express “I know how to guarantee \ given \” with a semantics based not on standard epistemic models but on labeled transition systems that represent the agent’s knowledge of his own abilities. The semantics is inspired by conformant planning in AI. A sound and complete (...) proof system is given to capture valid reasoning patterns, which highlights the compositional nature of “knowing how”. The logical language is further extended to handle knowing how to achieve a goal while maintaining other conditions. (shrink)

This investigation uses the technique of the profile of dialogue as a tool for the evaluation of arguments from ignorance (also called lack-of-evidence arguments, negative evidence, ad ignorantiam arguments and ex silentio arguments). Such arguments have traditionally been classified as fallacies by the logic textbooks, but recent research has shown that in many cases they can be used reasonably. A profile of dialogue is a connected sequence of moves and countermoves in a conversational exchange of a type that is goal-directed (...) and can be represented in a normative model of dialogue. Selected case studies are used to probe special features of using the profile technique as applied to arguments from ignorance of a kind that occur frequently in everyday conversational exchanges. One of these special features is the use of Gricean implicature. Another is the need to use negative profiles of argument. (shrink)

An Introduction to the Special Issue on Question Processing.

The issue of adequacy of the Turing Test (TT) is addressed. The concept of Turing Interrogative Game (TIG) is introduced. We show that if some conditions hold, then each machine, even a thinking one, loses a certain TIG and thus an instance of TT. If, however, the conditions do not hold, the success of a machine need not constitute a convincing argument for the claim that the machine thinks.

The aims of this paper are to provide a detailed taxonomy of noncanonical uses of interrogative sentences, i.e. when they are used not to ask a question but to convey some information, or to ask a question albeit not that expressed by the interrogative sentence exploited in the act, to identify properties of circumstances where an interrogative sentence is being used in this way, and to propose some maxims that govern the rational use of questions. Four main categories of such (...) cases are presented, and a few further subclasses are differentiated. I show how these types are interrelated, and what logical features differentiate them. I also propose a hypothesis for when an interrogative sentence is not being used in its primary mode. Studies on circumstances in which questions are used in other ways can shed light on maxims that govern asking and questioning in a rational conversation; therefore, some possible maxims of this kind are proposed. (shrink)

In this paper we reexamine the question of whether questions areinherently intensional entities. We do so by proposing a novelextensional theory of questions, based on a re-interpretation of thedomain of t as a bilattice rather than the usual booleaninterpretation. We discuss the adequacy of our theory with respect tothe adequacy criteria imposed on the semantics of questionsby (Groenendijk and Stokhof 1997). We show that the theory is able to account in astraightforward manner for some complex issues in the semantics ofquestions (...) including coordinated questions, combined indicative andinterrogative sentences, questions with quantifiers, and theimpossibility of negating questions. (shrink)

In earlier publications of the first author it was shown that intentional explanation of actions, functional explanation of biological traits and causal explanation of abnormal events share a common structure. They are called explanation by specification (of a goal, a biological function, an abnormal causal factor, respectively) as opposed to explanation by subsumption under a law. Explanation by specification is guided by a schematic train of thought, of which the argumentative steps not concerning questions were already shown to be logically (...) valid (elementary) arguments.Independently, the second author developed a new, inferential approach to erotetic logic, the logic of questions. In this approach arguments resulting in questions, with declarative sentences and/or other questions as premises, are analyzed, and validity of such arguments is defined. (shrink)

We can characterise thought in two different ways. Which is preferred can have implications for important issues about reasoning and the norms that govern cognition. The first, which owes much to the picture of the mind encountered in Descartes' Meditations, observes that paradigmatic examples of thoughts and inferences are events and processes whose special characteristics stem from their being ‘mental’ occurrences. For example they are conscious or, if unconscious, they stand in some special relation to thought processes that are conscious. (...) They typically involve attitudes towards contents or propositions. In general, thoughts have a distinctive onto-logical status and this status depends upon their being mental and typically conscious. The second emphasises that thought is a kind of activity with a definite function. It involves the use of intelligence to solve problems, answer questions, make plans and so on. Thought should be studied as a kind of goal-directed activity. Those interested in the norms that govern thought should attend to the role of responsible disciplined reflection in carrying out this activity. (shrink)

In this paper we sketch a logic of message and reply. The logic is intended for application in a wide variety of situations, not restricted to the two-person, turn-taking situation. Each message has a body and a vector; the vector specifies the from, to, and the like. To reply to a message, it suffices to give either (1) a complete reply to the body or (2) a corrective reply to at least one presumption derivable from the vector. We discuss the (...) problems of achieving effectiveness and completeness with respect to certain aspects of communication. The results are mixed. In section 9 we argue semi-formally that, in a certain sense, dialogue is necessary. Finally we note that this logic is not a rival of other approaches but may be combinable with them. (shrink)

Traditional logical theories are concerned with the characterization of valid reasoning. For such logical theories, the main object of investigation is the notion of entailment, a notion that is construed as a relation between two or more declarative statements, dictating when one of them can be legitimately inferred from the others. In the course of the previous century, however, and especially since the 1970s, the scope of logical theories has become much broader. In particular, logic is no longer only concerned (...) with declarative statements, but also with questions. Accordingly, the field is no longer focusing exclusively on the entailment relation that may hold between two or more statements, but also aims to characterize fundamental relations that may hold between questions, or between questions and statements. For instance, when does a statement resolve a given question? When does a statement evoke a certain question? And when does the resolution of one question depend on the resolu .. (shrink)

Grice's Quantity maxims have been widely misinterpreted as enjoining a speaker to make the strongest claim that she can, while respecting the other conversational maxims. Although many writers on the topic of conversational implicature interpret the Quantity maxims as enjoining such volubility, so construed the Quantity maxims are unreasonable norms for conversation. Appreciating this calls for attending more closely to the notion of what a conversation requires. When we do so, we see that eschewing an injunction to maximal informativeness need (...) not deprive us of any ability to predict or explain genuine cases of implicature. Crucial to this explanation is an appreciation of how what a conversation, or a given stage of a conversation, requires, depends upon what kind of conversation is taking place. I close with an outline of this dependence relation that distinguishes among three importantly distinct types of conversation. (shrink)

This book illustrates the program of Logical-Informational Dynamics. Rational agents exploit the information available in the world in delicate ways, adopt a wide range of epistemic attitudes, and in that process, constantly change the world itself. Logical-Informational Dynamics is about logical systems putting such activities at center stage, focusing on the events by which we acquire information and change attitudes. Its contributions show many current logics of information and change at work, often in multi-agent settings where social behavior is essential, (...) and often stressing Johan van Benthem's pioneering work in establishing this program. However, this is not a Festschrift, but a rich tapestry for a field with a wealth of strands of its own. The reader will see the state of the art in such topics as information update, belief change, preference, learning over time, and strategic interaction in games. Moreover, no tight boundary has been enforced, and some chapters add more general mathematical or philosophical foundations or links to current trends in computer science. The theme of this book lies at the interface of many disciplines. Logic is the main methodology, but the various chapters cross easily between mathematics, computer science, philosophy, linguistics, cognitive and social sciences, while also ranging from pure theory to empirical work. Accordingly, the authors of this book represent a wide variety of original thinkers from different research communities. And their interconnected themes challenge at the same time how we think of logic, philosophy and computation. Thus, very much in line with van Benthem's work over many decades, the volume shows how all these disciplines form a natural unity in the perspective of dynamic logicians (broadly conceived) exploring their new themes today. And at the same time, in doing so, it offers a broader conception of logic with a certain grandeur, moving its horizons beyond the traditional study of consequence relations. (shrink)

This chapter presents a new semantics for inductive empirical knowledge. The epistemic agent is represented concretely as a learner who processes new inputs through time and who forms new beliefs from those inputs by means of a concrete, computable learning program. The agent’s belief state is represented hyper-intensionally as a set of time-indexed sentences. Knowledge is interpreted as avoidance of error in the limit and as having converged to true belief from the present time onward. Familiar topics are re-examined within (...) the semantics, such as inductive skepticism, the logic of discovery, Duhem’s problem, the articulation of theories by auxiliary hypotheses, the role of serendipity in scientific knowledge, Fitch’s paradox, deductive closure of knowability, whether one can know inductively that one knows inductively, whether one can know inductively that one does not know inductively, and whether expert instruction can spread common inductive knowledge—as opposed to mere, true belief—through a community of gullible pupils. (shrink)

In this dissertation I attempt to develop a better understanding of knowledge and belief. In Chapter 1 I offer an analysis of knowledge-wh . I argue that knowledge-wh ascriptions express that a subject stands in the knowledge relation to a question--where to stand in this knowledge relation to a question is to know an answer to the question. Additionally I adopt a contextualist picture of knowledge- wh . I raise some problems for invariantism about knowledge- wh and I argue that (...) contextualism about knowledge-wh fits nicely with a very natural understanding of the semantics of interrogatives, and the nature of questions. In Chapter 2 consider whether knowledge-how is importantly different from knowledge-wh . I argue that 'knows how' is ambiguous, but on one sense knowledge-how ascriptions should be treated just like the other knowledge ascriptions with interrogative complements. Hence this type of knowledge-how is not fundamentally distinct from knowledge-wh . In Chapter 3 I reconsider various theories about knowledge and knowledge- that ascriptions in light of our conclusions about knowledge- wh ascriptions. It seems that doing so can help adjudicate between contextualism and invariantism about knowledge-that and may help determine which form of contextualism about knowledge-that is the most plausible. In Chapter 4 I consider whether there is some fact about the nature of the attitudes that determines the verb's complement selection. Some have suggested that the embedding behavior of attitude verbs is correlated with the factivity of the attitude verb. I evaluate this suggestion and the possible explanations for the embedding behavior of the various attitude verbs. I attempt to determine the extent to which the factivity of verbs is correlated with their embedding behavior and I attempt to explain why factivity plays such an important role. I argue that these facts can provide important insights into the nature of the attitudes. In Chapter 5 I explore the way in which knowledge and action are related in an important way. I consider the claim that it is appropriate to treat the proposition that p as a reason for action if and only if you know that p . I first present and explain the principle. Next I consider some objections to the proposal, and I argue that none of these objections is successful. I claim that the contrastivist, in particular, has several moves available in the face of the alleged problems with this Reason-Knowledge principle. (shrink)