Argumentation Without Arguments

A well-known ambiguity in the term ‘argument’ is that of argument as an inferential structure and argument as a kind of dialogue. In the first sense, an argument is a structure with a conclusion supported by one or more grounds, which may or may not be supported by further grounds. Rules for the construction and criteria for the quality of arguments in this sense are a matter of logic. In the second sense, arguments have been studied as a form of dialogical interaction, in which human or artificial agents aim to resolve a conflict of opinion by verbal means. Rules for conducting such dialogues and criteria for their quality are part of dialogue theory. Usually, formal accounts of argumentation dialogues in logic and artificial intelligence presuppose an argument-based logic. That is, the ways in which dialogue participants support and attack claims are modelled as the construction of explicit arguments and counterarguments (in the inferential sense). However, in this paper formal models of argumentation dialogues are discussed that do not presuppose arguments as inferential structures. The motivation for such models is that there are forms of inference that are not most naturally cast in the form of arguments (such as abduction, statistical reasoning and coherence-based reasoning) but that can still be the subject of argumentative dialogue. Some recent work in artificial intelligence is discussed which embeds non-argumentative inference in an argumentative dialogue system, and some general observations are drawn from this discussion.     

From Games to Truth Functions: A Generalization of Giles’s Game

Motivated by aspects of reasoning in theories of physics, Robin Giles defined a characterization of infinite valued ?ukasiewicz logic in terms of a game that combines Lorenzen-style dialogue rules for logical connectives with a scheme for betting on results of dispersive experiments for evaluating atomic propositions. We analyze this game and provide conditions on payoff functions that allow us to extract many-valued truth functions from dialogue rules of a quite general form. Besides finite and infinite valued ?ukasiewicz logics, also Meyer and Slaney’s Abelian logic and Cancellative Hoop Logic turn out to be characterizable in this manner.     

Logic for dialogue games

The purpose of this paper is to work toward an explicit logic and semantics for a game theoretically inspired theory of action. The purpose of the logic is to explicate the conceptual machinery implicit in the dialogue-game model of rational discourse developed in Carlson (1983).A variety of ideas and techniques of modal and philosophical logic are used to define a model structure that generalizes the game theoretical notion of a game in extensive form (von Neumann and Morgenstern, 1944). Relative to this model structure, semantic characterizations are given to the action-theoretic notions oftime, possibility, belief, preference, ability, intention, action, andrationality. The unification of these characterizations under the game-theoretical paradigm leads to insights about the logical interdependences between these concepts.The resulting theory of rational interaction is applied to the explication of rational dialogue. The main benefit of the enterprise for a theory of rational dialogue is that concepts and results of game theory become accessible to the explication of dialogue. In particular, the task of proving the logical coherence of a discourse is reduced to the task of showing the rationality of strategy choices made in an associated dialogue game.     

The Place of Dialogue Theory in Logic,Computer Science and Communication Studies

Dialogue theory, although it has ancient roots, was put forward in the 1970s in logic as astructure that can be useful for helping to evaluate argumentation and informal fallacies.Recently, however, it has been taken up as a broader subject of investigation in computerscience. This paper surveys both the historical and philosophical background of dialoguetheory and the latest research initiatives on dialogue theory in computer science. The main components of dialogue theory are briefly explained. Included is a classification of the main types of dialogue that, it is argued, should provide the central focus for studying many important dialogue contexts in specific cases. Following these three surveys, a concluding prediction is made about the direction dialogue theory is likely to take in the next century, especially in relation to the growing field of communication studies.     

Dialogue Games for Many-Valued Logics — an Overview

An overview of different versions and applications of Lorenzen’s dialogue game approach to the foundations of logic, here largely restricted to the realm of manyvalued logics, is presented. Among the reviewed concepts and results are Giles’s characterization of ?ukasiewicz logic and some of its generalizations to other fuzzy logics, including interval based logics, a parallel version of Lorenzen’s game for intuitionistic logic that is adequate for finite- and infinite-valued Gödel logics, and a truth comparison game for infinite-valued Gödel logic.     

The three bases for the enthymeme: A dialogical theory

In traditional logic, an enthymeme is said to be an argument, or chain of argumentation, with one or more missing (implicit) premises or conclusions. In this paper a new theory of enthymemes, based on recent developments in argumentation technology including argumentation schemes, argument visualization tools and formal dialogue systems, is put forward. The dialogical theory hypothesizes three bases for the enthymeme in a formal dialogue system CBVK: (1) the participants' commitment sets, (2) sets of argumentation schemes (especially including presumptive schemes) shared by both participants, and (3) a set of propositions representing common knowledge shared by both participants. The formal dialogue system CBVK is the backbone of the theory of enthymemes into which these three components are built. Three examples of enthymemes of a kind commonly found in everyday conversational argumentation are used to show how the theory applies.     

Profiles of Dialogue for Evaluating Arguments from Ignorance

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.     

Weak Rejection

Linguistic evidence supports the claim that certain, weak rejections are less specific than assertions. On the basis of this evidence, it has been argued that rejected sentences cannot be premisses and conclusions in inferences. We give examples of inferences with weakly rejected sentences as premisses and conclusions. We then propose a logic of weak rejection which accounts for the relevant phenomena and is motivated by principles of coherence in dialogue. We give a semantics for which this logic is sound and complete, show that it axiomatizes the modal logic KD45 and prove that it still derives classical logic on its asserted fragment. Finally, we defend previous logics of strong rejection as being about the linguistically preferred interpretations of weak rejections.     

The force and the content of judgment

This essay explores what it means to reject Frege's distinction of force and content: the rejection completes Frege's anti‐psychologism as it leaves no space for a psychological concept of judgment distinct from the logical concept, which is the concern of no empirical science, but of logic. It emerges that logic, as the science of judgement, is — not a metaphysics of judgement, but — metaphysics. And it emerges that the opposition of subject to subject — the elementary nexus of thinker to thinker in dialogue — is contained within the logical concept of judgment.     

Peter Winch on ‘Aristotelian’ and ‘Socratic’ Reasoning

Peter Winch often returned to questions about the nature of logic. In the context of his work on Wittgenstein and political philosophy in the 1990s, Winch described a contrast between ‘Aristotelian’ and ‘Socratic’ reasoning. Aristotelian conceptions of reasoning, attributed to Frege and Russell, would see logic as a formal science and rationality as consistency with pre‐existent rules of inference. The Socratic conception, attributed to Wittgenstein, understands rational argument as a form of socially embedded dialogue that involves moral relationships and a dimension of depth. Rational persuasion may also involve use of persuasive images and examples.     

Reconceiving the Boundaries of Home: The ‘Oikology’ of Ephesians

This article offers a reading of Ephesians in repair of a modern liberal inclusivism that unwittingly perpetuates an oppressive colonialist logic. It delineates the dynamic of dwelling, building and inhabitation present in Ephesians via the oik‐ root, coining the term ‘oikology’ to capture its inseparable economy and ecology. Willie James Jennings is a key dialogue partner in the articulation of the colonialist logic to be overcome. The particular species of modern inclusivism in view is that which is exhibited by New Testament scholars associated with the New Perspective on Paul, which I argue remains captive to a supersessionist logic. The article offers a non‐supersessionist reading of Ephesians, arguing that Israel, rather than being replaced, remains the wider habitat in which the gentile Ephesians find their home. In this way the article seeks a reading of the cosmic Christology of Ephesians as an instantiation not of colonial inclusivism but of true catholicity.     

Formal systems of dialogue rules

Section 1 contains a survey of options in constructing a formal system of dialogue rules. The distinction between material and formal systems is discussed (section 1.1). It is stressed that the material systems are, in several senses, formal as well. In section 1.2 variants as to language form (choices of logical constants and logical rules) are pointed out. Section 1.3 is concerned with options as to initial positions and the permissibility of attacks on elementary statements. The problem of ending a dialogue, and of infinite dialogues, is treated in section 1.4. Other options, e.g., as to the number of attacks allowed with respect to each statement, are listed in section 1.5. Section 1.6 explains the concept of a chain of arguments.From section 2 onward four types of dialectic systems are picked out for closer study: D, E, Di and Ei. After a preliminary section on dialogue sequents and winning strategies, the equivalence of derivability in intuitionistic logic and the existence of a winning strategy (for the Proponent) on the strength of Ei is shown by simple inductive proofs.Section 3 contains a — relatively quick — proof of the equivalence of the four systems. It follows that each of them yields intuitionistic logic.     

Giles’s Game and the Proof Theory of Łukasiewicz Logic

In the 1970s, Robin Giles introduced a game combining Lorenzen-style dialogue rules with a simple scheme for betting on the truth of atomic statements, and showed that the existence of winning strategies for the game corresponds to the validity of formulas in Łukasiewicz logic. In this paper, it is shown that ‘disjunctive strategies’ for Giles’s game, combining ordinary strategies for all instances of the game played on the same formula, may be interpreted as derivations in a corresponding proof system. In particular, such strategies mirror derivations in a hypersequent calculus developed in recent work on the proof theory of Łukasiewicz logic. Presented by Daniele Mundici     

The ad Hominem argument as an informal fallacy

This article outlines criteria for the evaluation of the argumentum ad hominem (argument against the person, or personal attack in argument) that is traditionally a part of the curriculum in informal logic. The argument is shown to be a kind of criticism which works by shifting the burden of proof in dialogue through citing a pragmatic inconsistency in an arguer's position. Several specific cases of ad hominem argumentation which pose interesting problems in analyzing this type of criticism are studied.     

Dialogue Foundations: A Sceptical Look: Wilfrid Hodges

During the last forty or so years it has become popular to offer explanations of logical notions in terms of games. There is no doubt that many people find games helpful for understanding various logical phenomena. But we ask whether anything is really 'explained' by these accounts, and we analyse Paul Lorenzen's dialogue foundations for constructive logic as an example. The conclusion is that the value of games lies in their ability to provide helpful metaphors and representations, rather than in any true conceptual analysis. In fact some of the standard explanations of logical notions in terms of competitive games simply don't work.     

‘In the Beginning is Relation’: Martin Buber’s Alternative to Binary Oppositions

In this article we develop a relational understanding of sociality, that is, an account of social life that takes relation as primary. This stands in contrast to the common assumption that relations arise when subjects interact, an account that gives logical priority to separation. We will develop this relational understanding through a reading of the work of Martin Buber, a social philosopher primarily interested in dialogue, meeting, relationship, and the irreducibility and incomparability of reality. In particular, the article contrasts Buber??s work with that of poststructuralist theorists who take as their starting point the deconstruction of the Hegelian logic of binary oppositions. Deconstruction understands difference as the excess that undoes the binary, but Buber, we argue, shows how difference derives from the primacy and ontological undefinability of relation. Relational logic does not exclude the logic of separations and oppositions: relation is the primal ground that makes separations possible.     

Varieties of Reasoning: Assessing Adequacy

Helmut Reich's theory of relational and contextual reasoning is a courageous initiative for the resolution of cognitive conflicts between apparently incompatible or incommensurable views. Built upon Piagetian logico‐mathematical reasoning, cognitive complexity theory, and dialectical and analogical reasoning, it includes the development of a both/and logic inclusive of binary either/or logic. Reich provides philosophic, theoretical, and even initial empirical support for the development of this form of reasoning along with a heuristic for its application. A valuable step beyond the limits of binary, static, and formal reasoning, it takes relationship, context, and perspectival variations seriously in an explicitly reflective and iterative system. We can and do address conflicts not resolvable by conventional appeals to logic or evidence, including those at epistemic boundaries or produced by belief‐commitment differences. Although this form of reasoning has real promise, including stepping beyond complementarity in the religion‐science dialogue, it seems better directed to causally explanatory theories than to other forms of rendering meaning. Finally, its coextension requirement may render it problematic where functionally coherent explananda cannot be identified or are themselves produced or constituted by a belief system.     

Formal systems of dialogue rules

Section 1 contains a survey of options in constructing a formal system of dialogue rules. The distinction between material and formal systems is discussed (section 1.1). It is stressed that the material systems are, in several senses, formal as well. In section 1.2 variants as to language form (choices of logical constants and logical rules) are pointed out. Section 1.3 is concerned with options as to initial positions and the permissibility of attacks on elementary statements. The problem of ending a dialogue, and of infinite dialogues, is treated in section 1.4. Other options, e.g., as to the number of attacks allowed with respect to each statement, are listed in section 1.5. Section 1.6 explains the concept of a chain of arguments.From section 2 onward four types of dialectic systems are picked out for closer study: D, E, Di and Ei. After a preliminary section on dialogue sequents and winning strategies, the equivalence of derivability in intuitionistic logic and the existence of a winning strategy (for the Proponent) on the strength of Ei is shown by simple inductive proofs.Section 3 contains a — relatively quick — proof of the equivalence of the four systems. It follows that each of them yields intuitionistic logic.     

Socrates’ wisdom in definition

Why does Socrates favour definitional speech discussion of virtue’s instances and attributes? Why does he take such a dim view of applied ethics? In this article, I criticise the received answers to these questions and offer a different view. I argue that Socrates favours definitional dialogue because it actualises knowledge that the logic of his argument shows to be essential to virtue. By leading the interlocutor to a paradoxical definition of virtue as knowledge, Socrates engenders this knowledge in his soul.     

Paraconsistency And Dialogue Logic Critical Examination And Further Explorations

The first part of this paper presents asympathetic and critical examination of the approachof Shahid Rahman and Walter Carnielli, as presented intheir paper The Dialogical Approach toParaconsistency. In the second part, possibleextensions are presented and evaluated: (a) top-downanalysis of a dialogue situation versus bottom-up, (b)the specific role of ambiguities and how to deal withthem, and (c) the problem of common knowledge andbackground knowledge in dialogues. In the third part,I claim that dialogue logic is the best-suitedinstrument to analyse paradoxes of the Sorites type.All these considerations lead to philosophicallyrelevant observations concerning principles of charityon the one hand, and compactness on the other.