Online research in philosophy

This is a reply to a paper by Graham Oppy in the July, 1999 issue of this journal, “Koons’ Cosmological Argument.” Recent work in defeasible or nonmonotonic logic means that the cosmological argument can be cast in such a way that it does not presuppose that every contingent situation, without exception, has a cause. Instead, the burden of proof is shifted to the skeptic, who must produce positive reasons for thinking that the cosmos is an exception to the (...) class='Hi'>defeasible law of causality. I show how Oppy’s critique can be turned into a plausible rebuttal of my argument. However, this rebuttal can be set aside when the original argument is supplemented by a plausible account of the nature of causal priority. Several independent lines of argument in support of this account are outlined. (shrink)

An introduction to the motivations and mechanics of John Pollock's theory of defeasible reasoning, from a lecture at the Northern Institute of Philosophy in 2010.

This paper argues that some traditional fallacies should be considered as reasonable arguments when used as part of a properly conducted dialog. It is shown that argumentation schemes, formal dialog models, and profiles of dialog are useful tools for studying properties of defeasible reasoning and fallacies. It is explained how defeasible reasoning of the most common sort can deteriorate into fallacious argumentation in some instances. Conditions are formulated that can be used as normative tools to judge (...) whether a given defeasible argument is fallacious or not. It is shown that three leading violations of proper dialog standards for defeasible reasoning necessary to see how fallacies work are: (a) improper failure to retract a commitment, (b) failure of openness to defeat, and (c) illicit reversal of burden of proof. (shrink)

In this paper two theories of defeasible reasoning, Pollock's account and my theory of ranking functions, are compared, on a strategic level, since a strictly formal comparison would have been unfeasible. A brief summary of the accounts shows their basic difference: Pollock's is a strictly computational one, whereas ranking functions provide a regulative theory. Consequently, I argue that Pollock's theory is normatively defective, unable to provide a theoretical justification for its basic inference rules and thus an independent notion (...) of admissible rules. Conversely, I explain how quite a number of achievements of Pollock's account can be adequately duplicated within ranking theory. The main purpose of the paper, though, is not to settle a dispute with formal epistemology, but rather to emphasize the importance of formal methods to the whole of epistemology. (shrink)

One of the most striking characteristics of human beings is their ability to function successfully in complex environments about which they know very little. In light of our pervasive ignorance, we cannot get around in the world just reasoning deductively from our prior beliefs together with new perceptual input. As our conclusions are not guaranteed to be true, we must countenance the possibility that new information will lead us to change our minds, withdrawing previously adopted beliefs. In this sense, (...) our reasoning is “defeasible”. The question arises how defeasible reasoning works, or ought to work. In particular we need rules governing what a cognizer ought to believe given a set of interacting arguments some of which defeat others. That is what is called a “semantics” for defeasible reasoning, and this chapter will propose a new semantics that avoids certain clear counter-examples to all existing semantics. (shrink)

In this paper we show that any reasoning process in which conclusions can be both fallible and corrigible can be formalized in terms of two approaches: (i) syntactically, with the use of defeasible reasoning, according to which reasoning consists in the construction and assessment of arguments for and against a given claim, and (ii) semantically, with the use of partial structures, which allow for the representation of less than conclusive information. We are particularly interested in the (...) formalization of scientific reasoning, along the lines traced by Lakatos’ methodology of scientific research programs. We show how current debates in cosmology could be put into this framework, shedding light on a very controversial topic. (shrink)

This article argues that: (i) Defeasible reasoning is the use of distinctive procedures for belief revision when new evidence or new authoritative judgment is interpolated into a system of beliefs about an application domain. (ii) These procedures can be explicated and implemented using standard higher-order logic combined with epistemic assumptions about the system of beliefs. The procedures mentioned in (i) depend on the explication in (ii), which is largely described in terms of a Prolog program, EVID, which implements (...) a system for interactive, defeasible reasoning when combined with an application knowledge base. It is shown that defeasible reasoning depends on a meta-level Closed World Assumption applied to the relationship between supporting evidence and a defeasible conclusion based on this evidence. Thesis (i) is then further defended by showing that the EVID explication of defeasible reasoning has sufficient representational power to cover a wide variety of practical applications of defeasible reasoning, especially in the context of decision making. (shrink)

This article begins with an introduction to defeasible (nonmonotonic) reasoning and a brief description of a computer program, EVID, which can perform such reasoning. I then explain, and illustrate with examples, how this program can be applied in computational representations of ordinary dialogic argumentation. The program represents the beliefs and doubts of the dialoguers, and uses these propositional attitudes, which can include commonsense defeasible inference rules, to infer various changing conclusions as a dialogue progresses. It is (...) proposed that computational representations of this kind are a useful tool in the analysis of dialogic argumentation, and, in particular, demonstrate the important role of defeasible reasoning in everyday arguments using commonsense reasoning. (shrink)

Proceedings of the 2008 AAAI Spring Symposium on Architectures for Intelligent Theory-Based Agents. “OSCAR is a fully implemented architecture for a cognitive agent, based largely on the author’s work in philosophy concerning epistemology and practical cognition. The seminal idea is that a generally intelligent agent must be able to function in an environment in which it is ignorant of most matters of fact. The architecture incorporates a general-purpose defeasible reasoner, built on top of an efficient natural deduction reasoner for (...) first-order logic. It is based upon a detailed theory about how the various aspects of epistemic and practical cognition should interact, and many of the details are driven by theoretical results concerning defeasible reasoning.”. (shrink)

The general conditions of epistemic defeat are naturally represented through the interplay of two distinct kinds of entailment, deductive and defeasible. Many of the current approaches to modeling defeasible reasoning seek to define defeasible entailment via model-theoretic notions like truth and satisfiability, which, I argue, fails to capture this fundamental distinction between truthpreserving and justification-preserving entailments. I present an alternative account of defeasible entailment and show how logic programming offers a paradigm in which the (...) distinction can be captured, allowing for the modeling of a larger range of types of defeat. This is possible through a natural extension of the declarative and procedural semantics of Horn clauses. (shrink)

HANDBOOK OF DEFEASIBLE REASONING AND UNCERTAINTY MANAGEMENT SYSTEMS EDITORS: DOV M. ... and A. Hunter Volume 3: Belief Change Edited by D. Dubois and H. Prade HANDBOOK OF DEFEASIBLE REASONING AND ...

In this paper I attempt to cast the current program verification debate within a more general perspective on the methodologies and goals of computer science. I show, first, how any method involved in demonstrating the correctness of a physically executing computer program, whether by testing or formal verification, involves reasoning that is defeasible in nature. Then, through a delineation of the senses in which programs can be run as tests, I show that the activities of testing and formal (...) verification do not necessarily share the same goals and thus do not always constitute alternatives. The testing of a program is not always intended to demonstrate a program's correctness. Testing may seek to accept or reject nonprograms including algorithms, specifications, and hypotheses regarding phenomena. The relationship between these kinds of testing and formal verification is couched in a more fundamental relationship between two views of computer science, one properly containing the other. (shrink)

This paper points out some problems with two recent logical systems – one due to Prakken and Sartor, the other due to Kowalski and Toni – designedfor the representation of defeasible arguments in general, but with a specialemphasis on legal reasoning.

The question addressed in this paper is how the degree of justification of a belief is determined. A conclusion may be supported by several different arguments, the arguments typically being defeasible, and there may also be arguments of varying strengths for defeaters for some of the supporting arguments. What is sought is a way of computing the “on sum” degree of justification of a conclusion in terms of the degrees of justification of all relevant premises and the strengths of (...) all relevant reasons. (shrink)

One of the most important developments over the last twenty years both in logic and in Artificial Intelligence is the emergence of so-called non-monotonic logics. These logics were initially developed by McCarthy [10], McDermott & Doyle [13], and Reiter [17]. Part of the original motivation was to provide a formal framework within which to model cognitive phenomena such as defeasible inference and defeasible knowledge representation, i.e., to provide a formal account of the fact that reasoners can reach conclusions (...) tentatively, reserving the right to retract them in the light of further information. (shrink)

This is a reply to a paper by Graham Oppy in the July, 1999 issue of this journal, “Koons’ Cosmological Argument.” Recent work in defeasible or nonmonotonic logic means that the cosmological argument can be cast in such a way that it does not presuppose that every contingent situation, without exception, has a cause. Instead, the burden of proof is shifted to the skeptic, who must produce positive reasons for thinking that the cosmos is an exception to the (...) class='Hi'>defeasible law of causality. I show how Oppy’s critique can be turned into a plausible rebuttal of my argument. However, this rebuttal can be set aside when the original argument is supplemented by a plausible account of the nature of causal priority. Several independent lines of argument in support of this account are outlined. (shrink)

This is a title on the foundations of defeasible logic, which explores the formal properties of everyday reasoning patterns whereby people jump to conclusions, reserving the right to retract them in the light of further information. Although technical in nature the book contains sections that outline basic issues by means of intuitive and simple examples. This book is primarily targeted at philosophers interested in the foundations of defeasible logic, logicians, and specialists in artificial intelligence and theoretical computer (...) science. (shrink)

There was a long tradition in philosophy according to which good reasoning had to be deductively valid. However, that tradition began to be questioned in the 1960’s, and is now thoroughly discredited. What caused its downfall was the recognition that many familiar kinds of reasoning are not deductively valid, but clearly confer justification on their conclusions. Here are some simple examples.

In this paper, the Carneades argumentation system is extended to represent a procedural view of inquiry in which evidence is marshalled to support or defeat claims to knowledge. The model is a sequence of moves in a collaborative group inquiry in which parties take turns making assertions about what is known or not known, putting forward evidence to support them, and subjecting these moves to criticisms. It is shown how this model of evaluating evidence in an inquiry is based on (...) a defeasible logic using forms of argument that admit exceptions. It is contended that reasoning from absence of knowledge is as important to inquiry as positive reasoning from evidence to knowledge. The philosophical conflict between this view of reasoning about knowledge and the true-belief-plus view is explored by airing objections and replies on both sides. (shrink)

Heuristics can be regarded as justifying the actions and beliefs of problem-solving agents. I use an analysis of heuristics to argue that a symbiotic relationship exists between traditional epistemology and contemporary artificial intelligence. On one hand, the study of models of problem-solving agents usingquantitative heuristics, for example computer programs, can reveal insight into the understanding of human patterns of epistemic justification by evaluating these models'' performance against human problem-solving. On the other hand,qualitative heuristics embody the justifying ability of defeasible (...) rules, the understanding of which is provided by traditional epistemology. (shrink)

This paper compares two ways of formalising defeasible deontic reasoning, both based on the view that the issues of conflicting obligations and moral dilemmas should be dealt with from the perspective of nonmonotonic reasoning. The first way is developing a special nonmonotonic logic for deontic statements. This method turns out to have some limitations, for which reason another approach is recommended, viz. combining an already existing nonmonotonic logic with a deontic logic. As an example of this method (...) the language of Reiter's default logic is extended to include modal expressions, after which the argumentation framework in default logic of [20, 22] is used to give a plausible logical analysis of moral dilemmas and prima facie obligations. (shrink)

Modeling legal argumentation is one of the most important research in AI and Law, and a lot of models have been proposed. However, most research has not treated value judgement and debate. In this paper, we introduce a legal reasoning model which covers various aspects of legalreasoning such as making argument, selecting argument and debate.Furthermore, we present how criminal law is described and reasoned inthis model.

Contextual type theories are largely explored in their applications to programming languages, but less investigated for knowledge representation purposes. The combination of a constructive language with a modal extension of contexts appears crucial to explore the attractive idea of a type-theoretical calculus of provability from refutable assumptions for non-monotonic reasoning. This paper introduces such a language: the modal operators are meant to internalize two different modes of correctness, respectively with necessity as the standard notion of constructive verification and possibility (...) as provability up to refutation of contextual conditions. (shrink)

One might ask of two or more texts—what can be inferred from them, taken together? If the texts happen to contradict each other in some respect, then the unadorned answer of standard logic is EVERYTHING. But it seems to be a given that we often successfully reason with inconsistent information from multiple sources. The purpose of this paper is to attempt to develop an adequate approach to accounting for this given.

The explanation of the suppression of Modus Ponens inferences within the framework of linguistic pragmatics and of plausible reasoning (i.e., deduction from uncertain premises) is defended. First, this approach is expounded, and then it is shown that the results of the first experiment of Byrne, Espino, and Santamar a (1999) support the uncertainty explanation but fail to support their counterexample explanation. Second, two experiments are presented. In the first one, aimed to refute one objection regarding the conclusions observed, the (...) additional conditional premise ( if N, C ) was replaced with a statement of uncertainty ( it is not certain that N ); the answers produced by the participants remained qualitatively and quantitatively similar in both conditions. In the second experiment, a fine-grained analysis of the responses to and justifications for an evaluation task was performed. The results of both experiments strongly supported the uncertainty explanation. (shrink)

The cosmological argument for God’s existence has a long history, but perhaps the most influential version of it has been the argument from contingency. This is the version that Frederick Copleston pressed upon Bertrand Russell in their famous debate about God’s existence in 1948 (printed in Russell’s 1957 Why I am not a Christian). Russell’s lodges three objections to the Thomistic argument.

This interdisciplinary work is a collection of major essays on reasoning: deductive, inductive, abductive, belief revision, defeasible (non-monotonic), cross cultural, conversational, and argumentative. They are each oriented toward contemporary empirical studies. The book focuses on foundational issues, including paradoxes, fallacies, and debates about the nature of rationality, the traditional modes of reasoning, as well as counterfactual and causal reasoning. It also includes chapters on the interface between reasoning and other forms of thought. In general, this (...) last set of essays represents growth points in reasoning research, drawing connections to pragmatics, cross-cultural studies, emotion and evolution. (shrink)

Peter Gärdenfors has proved (Philosophical Review, 1986) that the Ramsey rule and the methodologically conservative Preservation principle are incompatible given innocuous-looking background assumptions about belief revision. Gärdenfors gives up the Ramsey rule; I argue for preserving the Ramsey rule and interpret Gärdenfors's theorem as showing that no rational belief-reviser can avoid reasoning nonmonotonically. I argue against the Preservation principle and show that counterexamples to it always involve nonmonotonic reasoning. I then construct a new formal model of belief revision (...) that does accommodate nonmonotonic reasoning. (shrink)

In concrete applications of probability, statistical investigation gives us knowledge of some probabilities, but we generally want to know many others that are not directly revealed by our data. For instance, we may know prob(P/Q) (the probability of P given Q) and prob(P/R), but what we really want is prob(P/Q&R), and we may not have the data required to assess that directly. The probability calculus is of no help here. Given prob(P/Q) and prob(P/R), it is consistent with the probability calculus (...) for prob(P/Q&R) to have any value between 0 and 1. Is there any way to make a reasonable estimate of the value of prob(P/Q&R)? A related problem occurs when probability practitioners adopt undefended assumptions of statistical independence simply on the basis of not seeing any connection between two propositions. This is common practice, but its justification has eluded probability theorists, and researchers are typically apologetic about making such assumptions. Is there any way to defend the practice? This paper shows that on a certain conception of probability — nomic probability — there are principles of “probable probabilities” that license inferences of the above sort. These are principles telling us that although certain inferences from probabilities to probabilities are not deductively valid, nevertheless the second-order probability of their yielding correct results is 1. This makes it defeasibly reasonable to make the inferences. Thus I argue that it is defeasibly reasonable to assume statistical independence when we have no information to the contrary. And I show that there is a function Y(r,s,a) such that if prob(P/Q) = r, prob(P/R) = s, and prob(P/U) = a (where U is our background knowledge) then it is defeasibly reasonable to expect that prob(P/Q&R) = Y(r,s,a). Numerous other defeasible inferences are licensed by similar principles of probable probabilities.. (shrink)

This paper studies the modelling of legal reasoning about evidence within general theories of defeasible reasoning and argumentation. In particular, Wigmore's method for charting evidence and its use by modern legal evidence scholars is studied in order to give a formal underpinning in terms of logics for defeasible argumentation. Two notions turn out to be crucial, viz. argumentation schemes and empirical generalisations.

A rational agent (artificial or otherwise) residing in a complex changing environment must gather information perceptually, update that information as the world changes, and combine that information with causal information to reason about the changing world. Using the system of defeasible reasoning that is incorporated into the OSCAR architecture for rational agents, a set of reasonschemas is proposed for enabling an agent to perform some of the requisite reasoning. Along the way, solutions are proposed for the Frame (...) Problem, the Qualification Problem, and the Ramification Problem. The principles and reasoning described have all been implemented in OSCAR. (shrink)

This technical report describes the construction of an experimental planner that finds plans by reasoning about them defeasibly rather than by running a search algorithm. The need for such a planner is defended in the paper “The Logical Foundations of Goal-Regression Planning”.

Since its inception, situation theory has been concerned with the situated nature of meaning and cognition, a theme which has also recently gained some prominence in Artificial Intelligence. Channel theory is a recently developed framework which builds on concepts introduced in situation theory, in an attempt to provide a general theory of information flow. In particular, the channel theoretic framework offers an account of fallible regularities, regularities which provide enough structure to an agent's environment to support efficient cognitive processing but (...) which are limited in their reliability to specific circumstances. This paper describes how this framework can lead to a different perspective on defeasible reasoning: rather than being seen as reasoning with incomplete information, an agent makes use of a situated regularity, choosing to use the regularity that seems best suited (trading off reliability and simplicity) to the circumstances it happens to find itself in. We present a formal model for this task, based on the channel theoretic framework, and sketch how the model may be used as the basis for a methodology of defeasible situated reasoning, whereby agents reason with simple monotonic regularities but may revise their choice of regularity on learning more about their circumstances. (shrink)

Inferences from desired ends to intended necessary means seem to be among the most unproblematic elements of practical reasoning. A closer look dissolves this appearance, however, when we see that such inferences are defeasible. We can nevertheless understand such inferences as leading to the adoption of plans, by analogy with inferences leading to explanations. Plans should satisfy at least some important ends desired by the agent, be consistent with the satisfaction of other desired ends, and be inconsistent with (...) as few desired ends as possible. A rational plan may rule out the satisfaction of some desires, however, and this feature explains the defeasibility of such inferences. (shrink)

Inspired by legal reasoning, this paper presents a formal framework for assessing conflicting arguments. Its use is illustrated with applications to realistic legal examples, and the potential for implementation is discussed. The framework has the form of a logical system for defeasible argumentation. Its language, which is of a logic-programming-like nature, has both weak and explicit negation, and conflicts between arguments are decided with the help of priorities on the rules. An important feature of the system is that (...) these priorities are not fixed, but are themselves defeasibly derived as conclusions within the system. Thus debates on the choice between conflicting arguments can also be modelled.The proof theory of the system is stated in dialectical style, where a proof takes the form of a dialogue between a proponent and an opponent of an argument. An argument is shown to be justified if the proponent can make the opponent run out of moves in whatever way the opponent attacks. Despite this dialectical form, the system reflects a declarative, or relational approach to modelling legal argument. A basic assumption of this paper is that this approach complements two other lines of research in AI and Law, investigations of precedent-based reasoning and the development of procedural, or dialectical models of legal argument. (shrink)

This paper gives a new, proof-theoretic explanation of partial-order reasoning about time in a nonmonotonic theory of action. The explanation relies on the technique of lifting ground proof systems to compute results using variables and unification. The ground theory uses argumentation in modal logic for sound and complete reasoning about specifications whose semantics follows Gelfond and Lifschitz’s language . The proof theory of modal logic A represents inertia by rules that can be instantiated by sequences of time steps (...) or events. Lifting such rules introduces string variables and associates each proof with a set of string equations; these equations are equivalent to a set of partial-order tree-constraints that can be solved efficiently. The defeasible occlusion of inertia likewise imposes partial-order constraints in the lifted system. By deriving an auxiliary partial order representation of action from the underlying logic, not the input formulas or proofs found, this paper strengthens the connection between practical planners and formal theories of action. Moreover, the general correctness of the theory of action justifies partial-order representations not only for forward reasoning from a completely specified start state, but also for explanatory reasoning and for reasoning by cases. (shrink)

Two notions from philosophical logic and linguistics are brought together and applied to the psychological study of defeasible conditional reasoning. The distinction between disabling conditions and alternative causes is shown to be a special case of Pollock's (1987) distinction between 'rebutting' and 'undercutting' defeaters. 'Inferential' conditionals are shown to come in two varieties, one that is sensitive to rebutters, the other to undercutters. It is thus predicted and demonstrated in two experiments that the type of inferential conditional used (...) as the major premise of conditional arguments can reverse the heretofore classic, distinctive effects of defeaters. (shrink)

The paper starts by describing and clarifying what Williamson calls the consequence fallacy. I show two ways in which one might commit the fallacy. The first, which is rather trivial, involves overlooking background information; the second way, which is the more philosophically interesting, involves overlooking prior probabilities. In the following section, I describe a powerful form of sceptical argument, which is the main topic of the paper, elaborating on previous work by Huemer. The argument attempts to show the impossibility of (...) defeasible justification, justification based on evidence which does not entail the (allegedly) justified proposition or belief. I then discuss the relation between the consequence fallacy, or some similar enough reasoning, and that form of argument. I argue that one can resist that form of sceptical argument if one gives up the idea that a belief cannot be justified unless it is supported by the totality of the evidence available to the subject—a principle entailed by many prominent epistemological views, most clearly by epistemological evidentialism. The justification, in the relevant cases, should instead derive solely from the prior probability of the proposition. A justification of this sort, that does not rely on evidence, would amount to a form of entitlement, in (something like) Crispin Wright’s sense. I conclude with some discussion of how to understand prior probabilities, and how to develop the notion of entitlement in an externalist epistemological framework. (shrink)

In this paper, the defeasible argumentation scheme for practical reasoning (Walton 1990) is revised. To replace the old scheme, two new schemes are presented, each with a matching set of critical questions. One is a purely instrumental scheme, while the other is a more complex scheme that takes values into account. It is argued that a given instance of practical reasoning can be evaluated, using schemes and sets of critical questions, in three ways: by attacking one (...) or more premises of the argument, by attacking the inferential link between the premises and conclusion, or by mounting a counter-argument. It is argued that such an evaluation can be carried out in many cases using an argument diagram structure in which all components of the practical reasoning in the case are represented as premises, conclusions, and inferential links between them that can be labeled as argumentation schemes. This system works if every critical question can be classified as a assumption of or an exception to the original argument. However, it is also argued that this system does not work in all cases, namely those where epistemic closure is problematic because of intractable disputes about burden of proof. (shrink)

Fixpoint semantics are provided for ambiguity blocking and propagating variants of Nute’s defeasible logic. The semantics are based upon the well-founded semantics for logic programs. It is shown that the logics are sound with respect to their counterpart semantics and complete for locally finite theories. Unlike some other nonmonotonic reasoning formalisms such as Reiter’s default logic, the two defeasible logics are directly skeptical and so reject floating conclusions. For defeasible theories with transitive priorities on defeasible (...) rules, the logics are shown to satisfy versions of Cut and Cautious Monotony. For theories with either conflict sets closed under strict rules or strict rules closed under transposition, a form of Consistency Preservation is shown to hold. The differences between the two logics and other variants of defeasible logic—specifically those presented by Billington, Antoniou, Governatori, and Maher—are discussed. (shrink)

The applicability of Bayesian conditionalization in setting one’s posterior probability for a proposition, α, is limited to cases where the value of a corresponding prior probability, PPRI(α|∧E), is available, where ∧E represents one’s complete body of evidence. In order to extend probability updating to cases where the prior probabilities needed for Bayesian conditionalization are unavailable, I introduce an inference schema, defeasible conditionalization, which allows one to update one’s personal probability in a proposition by conditioning on a proposition that represents (...) a proper subset of one’s complete body of evidence. While defeasible conditionalization has wider applicability than standard Bayesian conditionalization (since it may be used when the value of a relevant prior probability, PPRI(α|∧E), is unavailable), there are circumstances under which some instances of defeasible conditionalization are unreasonable. To address this difficulty, I outline the conditions under which instances of defeasible conditionalization are defeated. To conclude the article, I suggest that the prescriptions of direct inference and statistical induction can be encoded within the proposed system of probability updating, by the selection of intuitively reasonable prior probabilities. (shrink)

Regress arguments have convinced many that reasoning cannot require beliefs about what follows from what. In this paper I argue that this is a mistake. Regress arguments rest on dubious (although deeply entrenched) assumptions about the nature of reasoning—most prominently, the assumption that believing p by reasoning is simply a matter of having a belief in p with the right causal ancestry. I propose an alternative account, according to which beliefs about what follows from what play a (...) constitutive role in reasoning. (shrink)

Do other people's arguments tie you in knots? Do you lack the confidence in your ability to reason? Do you assume that everything written in newspapers must be true? We all engage in the process of reasoning, but we don't always pay attention to whether we are doing it well. This book offers the opportunity to practice reasoning in a clear-headed and critical way, with the aims of developing an awareness of the importance of reasoning well, and (...) of improving the reader's skill in analyzing and evaluating arguments. In this second edition of the highly successful Critical Reasoning , Anne Thomson has updated and revised the book to include new and topical examples which will guide students through the processes of critical reasoning in a clear and engaging way. (shrink)

Following Burge, many anti-individualists suppose that a subject can possess a concept even if she incompletely understands it. While agreeing that this is possible, I argue that there is a limit on the extent to which a subject can incompletely understand the set of concepts she thinks with. This limit derives from our conception of our ability to reflectively evaluate our own thoughts or, as Burge puts it, our ability to engage in critical reasoning. The paper extends Burge's own (...) work on critical reasoning. He argued that critical reasoning imposes a limit on the extent to which we can be mistaken about what thoughts we are having; in general, we can know non-empirically what we are thinking (Burge, "Our Entitlement to Self-Knowledge", Proceedings of the Aristotelian Society XCVI, 1996). He does not explicitly consider whether critical reasoning also imposes a limit on incomplete understanding of thoughts. (shrink)

Robert Batterman examines a form of scientific reasoning called asymptotic reasoning, arguing that it has important consequences for our understanding of the scientific process as a whole. He maintains that asymptotic reasoning is essential for explaining what physicists call universal behavior. With clarity and rigor, he simplifies complex questions about universal behavior, demonstrating a profound understanding of the underlying structures that ground them. This book introduces a valuable new method that is certain to fill explanatory gaps across (...) disciplines. (shrink)

This book is an accessible introduction that will enable students, through practical exercises, to develop their own skills in reasoning about ethical issues, including analyzing and evaluating arguments used in discussions of ethical issues; analyzing and evaluating ethical concepts, such as utilitarianism; making decisions on ethical issues; and learning how to approach ethical issues in a fair minded way. The issues discussed in the book include abortion, euthanasia, capital punishment, animal rights, the environment and war. The book will be (...) essential reading for students studying all aspects of ethics. (shrink)

In this important new collection, Gilbert Harman presents a selection of fifteen interconnected essays on fundamental issues at the center of analytic philosophy. The book opens with a group of four essays discussing basic principles of reasoning and rationality. The next three essays argue against the once popular idea that certain claims are true and knowable by virtue of meaning. In the third group of essays Harman presents his own view of meaning and the possibility of thinking in language (...) The final three essays investigate the nature of mind, developing further the themes already set out. Reasoning, Meaning, and Mind offers an integrated presentation of this rich and influential body of work. which Harman has developed over thirty years. (shrink)

Practical Reasoning and Ethical Decision presents an account of practical reasoning as a process that can explain action, connect reasoning with intention, ...

This chapter examines the extent to which there are continuities between the cognitive processes and epistemic practices engaged in by human hunter-gatherers, on the one hand, and those which are distinctive of science, on the other. It deploys anthropological evidence against any form of 'no-continuity' view, drawing especially on the cognitive skills involved in the art of tracking. It also argues against the 'child-as-scientist' accounts put forward by some developmental psychologists, which imply that scientific thinking is present in early infancy (...) and universal amongst humans who have sufficient time and resources to devote to it. In contrast, a modularist kind of 'continuity' account is proposed, according to which the innately channelled architecture of human cognition provides all the materials necessary for basic forms of scientific reasoning in older children and adults, needing only the appropriate sorts of external support, social context, and background beliefs and skills in order for science to begin its advance. (shrink)

The importance of situational constraint for moral evaluations is widely accepted in philosophy, psychology, and the law. However, recent work suggests that this relationship is actually bidirectional: moral evaluations can also influence our judgments of situational constraint. For example, if an agent is thought to have acted immorally rather than morally, that agent is often judged to have acted with greater freedom and under less situational constraint. Moreover, when considering interpersonal situations, we judge that an agent who forces another to (...) act immorally (versus morally) uses more force. These two features can result in contradictory response patterns in which participants judge both that (1) a forcer forced a forcee to act and (2) the forcee was not forced by the forcer to act. Here, we characterize potential psychological mechanisms, in particular, “moral focus” and counterfactual reasoning that account for this paradoxical pattern of judgments. (shrink)

This paper starts from an assumption defended in the author's previous work. This is that distinctivelyhuman flexible and creative theoretical thinking can be explained in terms of the interactions of a variety of modular systems, with the addition of just a few amodular components and dispositions. On the basis of that assumption it is argued that distinctively human practical reasoning, too, can be understood in modular terms. The upshot is that there is nothing in the human psyche that requires (...) any significant retreat from a thesis of massively modular mental organization. (shrink)

The view to be defended in this paper is intended to be a novel and compelling model of instrumental practical reasoning, reasoning aimed at determining how to act in order to achieve a given end in a certain set of circumstances. On standard views of instrumental reasoning, the end in question is the object of a particular desire that the agent has, a desire which, when combined with the agent’s beliefs about what means are available to him (...) or her in order to satisfy that desire, can cause the formation of an independent desire or intention to engage in the relevant means. One of the main goals in what follows is to show that such views provide an inadequate understanding of instrumental practical reasoning when it comes to the practical lives of agents. (shrink)

In this paper I am concerned with the question of whether degrees of belief can figure in reasoning processes that are executed by humans. It is generally accepted that outright beliefs and intentions can be part of reasoning processes, but the role of degrees of belief remains unclear. The literature on subjective Bayesianism, which seems to be the natural place to look for discussions of the role of degrees of belief in reasoning, does not address the question (...) of whether degrees of belief play a role in real agents’ reasoning processes. On the other hand, the philosophical literature on reasoning, which relies much less heavily on idealizing assumptions about reasoners than Bayesianism, is almost exclusively concerned with outright belief. One possible explanation for why no philosopher has yet developed an account of reasoning with degrees of belief is that reasoning with degrees of belief is not possible for humans. In this paper, I will consider three arguments for this claim. I will show why these arguments are flawed, and conclude that, at least as far as these arguments are concerned, it seems like there is no good reason why the topic of reasoning with degrees of belief has received so little attention. (shrink)

In this book the author gives a broad overview of different areas of research in nonmonotonic reasoning, and presents some new results and ideas based on his research. The guiding principles are: clarification of the different research activities in the area, which have sometimes been undertaken independently of each other; and appreciation of the fact that these research activities often represent different means to the same ends, namely sound theoretical foundations and efficient computation. The book begins with a discussion (...) of the various types of nonmonotonic reasoning, their applications and their logics. Theorem proving techniques for these logics are also described. The following chapters deal with formulations of nonmonotonic inheritance, and nonmonotonic reasoning based on nonmonotonic rules. The final chapter discusses the achievements in the field in the light of the Yale shooting example. The book will be welcomed by researchers in theoretical computer science and artificial intelligence. (shrink)

This paper addresses an argument offered by John Hawthorne gainst the propriety of an agent’s using propositions she does not know as premises in practical reasoning. I will argue that there are a number of potential structural confounds in Hawthorne’s use of his main example, a case of practical reasoning about a lottery. By drawing these confounds out more explicitly, we can get a better sense of how to make appropriate use of such examples in theorizing about norms, (...) knowledge, and practical reasoning. I will conclude by suggesting a prescription for properly using lottery propositions to do the sort of work that Hawthorne wants from them. (shrink)

Change, Choice and Inference develops logical theories that are necessary both for the understanding of adaptable human reasoning and for the design of intelligent systems. The book shows that reasoning processes - the drawing on inferences and changing one's beliefs - can be viewed as belonging to the realm of practical reason by embedding logical theories into the broader context of the theory of rational choice. The book unifies lively and significant strands of research in logic, philosophy, economics (...) and artificial intelligence. It elaborates on the relevant theories and provides a mathematically precise foundation for the thesis that large parts of theoretical reason can be subsumed under practical reason. (shrink)

Reasoning Practically deals with a classical philosophical topic, the link between thought and action--how we think about what we do or ought to do, and how we move from thinking to doing. The essays by such renowned contributors as Donald Davidson, Barry Stroud, Cass R. Sunstein, Seyla Benhabib, and Gerald Dworkin, cover a range of issues raised when we link reason and practice. This collection connects state-of-the-art philosophical work with concrete issues in social life and political practice, making it (...) of interest not only to philosophers, but to political theorists, legal scholars, and any researcher interested in the practical application of reason. (shrink)

This book by one of the world's foremost philosophers in the fields of epistemology and logic offers an account of suppositional reasoning relevant to practical deliberation, explanation, prediction and hypothesis testing. Suppositions made 'for the sake of argument' sometimes conflict with our beliefs, and when they do, some beliefs are rejected and others retained. Thanks to such belief contravention, adding content to a supposition can undermine conclusions reached without it. Subversion can also arise because suppositional reasoning is ampliative. (...) These two types of nonmonotonic logic are the focus of this book. A detailed comparison of nonmonotonicity appropriate to both belief contravening and ampliative suppositional reasoning reveals important differences that have been overlooked. (shrink)

The articles in this volume consider at what stage of legal reasoning should a judge or lawyer make specifically moral judgments.

This book is about Relational and Contextual Reasoning (RCR), a new theory of the human mind that addresses key areas of human conflict, such as the ideological conflict between nations, in close relationships and between science and religion. K. Helmut Reich provides a clear and accessible introduction to the RCR way of thinking that encourages an inclusive rather than oppositional approach to conflict and problem-solving.

Scepticism, Knowledge, and Forms of Reasoning is an attempt to resolve how best to respond to such vexing arguments, a matter on which there is no consensus ...

Reasoning About Knowledge is the first book to provide a general discussion of approaches to reasoning about knowledge and its applications to distributed ...

I describe conventions not of correct reasoning but of giving and taking advice about reasoning. This article is asn anticipation of part of the first chapter of my forthcoming *Bounded Thinking*, OUP 2012.

Introduction This book is about reasoning. It is not a textbook in the conventional sense. Nor does it provide a prescription for how to reason effectively. ...

As the eleventh volume in the New Directions in Cognitive Science series (formerly the Vancouver Studies in Cognitive Science series), this work promises superb scholarship and interdisciplinary appeal. It addresses three areas of current and varied interest: common sense, reasoning, and rationality. While common sense and rationality often have been viewed as two distinct features in a unified cognitive map, this volume offers novel, even paradoxical, views of the relationship. Comprised of outstanding essays from distinguished philosophers, it considers what (...) constitutes human rationality, behavior, and intelligence covering diverse areas of philosophy, psychology, cognitive science, and computer science. Indeed, it is at the forefront of cognitive research and promises to be of unprecedented influence across numerous disciplines. (shrink)

This study argues that Descartes's conception of rationality presupposes that the order of reasoning essentially obeys his metaphysical categories. It takes to the next level the current trend in de-emphasizing his purported epistemology in favor of his unique metaphysics of cognition.

In this essay we argue that reasoning can sometimes generate epistemic justification, rather than merely transmitting justification that the subject already possesses to new beliefs. We also suggest a way to account for it in terms of the relationship between epistemic normative requirements, justification and cognitive capacities.

This book identifies 25 argumentation schemes for presumptive reasoning and matches a set of critical questions to each.

Decision theory explains weakness of will as the result of a conflict of incentives between different transient agents. In this framework, self-control can only be achieved by the I-now altering the incentives or choice-sets of future selves. There is no role for an extended agency over time. However, it is possible to extend game theory to allow multiple levels of agency. At the inter-personal level, theories of team reasoning allow teams to be agents, as well as individuals. I apply (...) team reasoning at the intra-personal level, taking the self as a team of transient agents over time. This allows agents to ask, not just “what should I-now do?’, but also ‘What should I, the person over time do?’, which may enable agents to achieve self-control. The resulting account is Aristotelian in flavour, as it involves reasoning schemata and perception, and it is compatible with some of the psychological findings about self-control. (shrink)

In our commentary we briefly review the work on the neurological differences between the rational ethical analysis used in professional contexts and the reflexive emotional responses of our daily moral reasoning, and discuss the implications for the claim that our normative arguments should not rely on the emotion of repugnance.

Language pragmatics is applied to analyse problem statements and instructions used in a few influential experimental tasks in the psychology of reasoning. This analysis aims to determine the interpretation of the task which the participant is likely to construct. It is applied to studies of deduction (where the interpretation of quantifiers and connectives is crucial) and to studies of inclusion judgment and probabilistic judgment. It is shown that the interpretation of the problem statements or even the representation of the (...) task as a whole often turn out to differ from the experimenter's assumptions. This has serious consequences for the validity of these experimental results and therefore for the claims about human irrationality based on them. (shrink)

It is increasingly argued that there is a single unified constitutive norm of both assertion and practical reasoning. The most common suggestion is that knowledge is this norm. If this is correct, then we would expect that a diagnosis of problematic assertions should manifest as problematic reasons for acting. Jennifer Lackey has recently argued that assertions epistemically grounded in isolated second-hand knowledge (ISHK) are unwarranted. I argue that decisions epistemically grounded in premises based on ISHK also seem inappropriate. I (...) finish by suggesting that this finding has important implications for the debates regarding the norms of assertion and practical reasoning. (shrink)

We survey the meta-ethical tools and institutional processes that traditional Islamic ethicists apply when deliberating on bioethical issues. We present a typology of these methodological elements, giving particular attention to the meta-ethical techniques and devices that traditional Islamic ethicists employ in the absence of decisive or univocal authoritative texts or in the absence of established transmitted cases. In describing how traditional Islamic ethicists work, we demonstrate that these experts possess a variety of discursive tools. We find that the ethical responsa—i.e., (...) the products of the application of the tools that we describe—are generally characterized by internal consistency. We also conclude that Islamic ethical reasoning on bioethical issues, while clearly scripture-based, is also characterized by strong consequentialist elements and possesses clear principles-based characteristics. The paper contributes to the study of bioethics by familiarizing non-specialists in Islamic ethics with the role, scope, and applicability of key Islamic ethical concepts, such as “aims” (maqāṣid), “universals” (kulliyyāt), “interest” (maṣlaḥa), “maxims” (qawā`id), “controls” (ḍawābit), “differentiators” (furūq), “preponderization” (tarjīḥ), and “extension” (tafrī`). (shrink)

Does cognition sometimes literally extend into the extra-organismic environment (Clark, 2003), or is it always “merely” environmentally embedded (Rupert, 2004)? Underlying this current border dispute is the question about how to individuate cognitive processes on principled grounds. Based on recent evidence about the active role of representation selection and construction in learning how to reason (Stenning, 2002), I raise the question: what makes two distinct, modality-specific pen-and-paper manipulations of external representations – diagrams versus sentences – cognitive processes of the same (...) kind, e.g. episodes of syllogistic reasoning? In response, I defend a “division of labor” hypothesis, according to which external representations are dependent on perceptually grounded neural representations and mechanisms to guide our behavior; these internal mechanisms, however, are dependent on external representations to have their syllogistic content fixed. Only their joint contributions qualify the extended computational process as an episode of syllogistic reasoning in good standing. (shrink)

False dilemma is a specific form of reasoning: despite the fact that it is based on a deductively valid argument form, it is rightly depicted as fallacy. A systematic exposition of false dilemma is missing in theoretical approaches to fallacies. This article formulates six criteria for a well-grounded exposition of a fallacy, suggesting also a systematic exposition of false dilemma. These criteria can be used to both explain, and categorise, the various false dilemma fallacies. The article introduces distinction between (...) four types of false dilemma (and the respective subtypes): (1) False quandary , (2) Defeasible sound quandary , (3) False obstruction and (4) Defeasible sound obstruction . The types of criticism appropriate for each variant of false dilemma are suggested. Being able to discover false dilemma in situations when it is important to make good and free choices is a significant dimension of critical thinking. It may liberate us from accepting the consequences that necessarily follow from prearranged alternatives, when these are not the only alternatives possible. It may also liberate us from refraining from actions on the basis of obstructive disjunctive statements. In that respect, the faculty of critical thinking directed at uncovering reasoning based on false dilemma may also initiate the discovery of new alternatives, or discover the ways of unifying seemingly opposing alternatives. Thus, a well-developed ability to understand the tricky argumentative moves of false dilemma may be a good step towards initiating some features of creative thinking. (shrink)

A novel explanation of belief bias in relational reasoning is presented based on the role of working memory and retrieval in deductive reasoning, and the influence of prior knowledge on this process. It is proposed that belief bias is caused by the believability of a conclusion in working memory which influences its activation level, determining its likelihood of retrieval and therefore its effect on the reasoning process. This theory explores two main influences of belief on the activation (...) levels of these conclusions. First, believable conclusions have higher activation levels and so are more likely to be recalled during the evaluation of reasoning problems than unbelievable conclusions, and therefore, they have a greater influence on the reasoning process. Secondly, prior beliefs about the conclusion have a base level of activation and may be retrieved when logically irrelevant, influencing the evaluation of the problem. The theory of activation and memory is derived from the Atomic Components of Thought-Rational (ACT-R) cognitive architecture and so this account is formalized in an ACT-R cognitive model. Two experiments were conducted to test predictions of this model. Experiment 1 tested strength of belief and Experiment 2 tested the impact of a concurrent working memory load. Both of these manipulations increased the main effect of belief overall and in particular raised belief-based responding in indeterminately invalid problems. These effects support the idea that the activation level of conclusions formed during reasoning influences belief bias. This theory adds to current explanations of belief bias by providing a detailed specification of the role of working memory and how it is influenced by prior knowledge. (shrink)

A demanding introduction to logic and critical thinking, this book offers more traditional means of teaching the art of reasoning at a time when the field has become almost mathematical. Francis Dauer has rethought the framework for teaching reasoning in general and formal logic in particular, the desired epistemological context, and the role of the fallacies. The result is a coherent and very readable work, informed by Dauer's extensive experience teaching and writing on the subject.

Qualitative description of the movement of objects can be very important when there are large quantity of data or incomplete information, such as in positioning technologies and movement of robots. We present a first step in the combination of fuzzy qualitative reasoning and quantitative data obtained by human interaction and external devices as GPS, in order to update and correct the qualitative information. We consider a Propositional Dynamic Logic which deals with qualitative velocity and enables us to represent some (...) reasoning tasks about qualitative properties. The use of logic provides a general framework which improves the capacity of reasoning. In this way, we can infer additional information by using axioms and the logic apparatus. In this paper we present sound and complete relational dual tableau that can be used for verification of validity of formulas of the logic in question. (shrink)

Offering an innovative approach to critical thinking, Good Reasoning Matters! identifies the essential structure of good arguments in a variety of contexts and also provides guidelines to help students construct their own effective arguments. In addition to examining the most common features of faulty reasoning--slanting, bias, propaganda, vagueness, ambiguity, and a common failure to consider opposing points of view--the book introduces a variety of argument schemes and rhetorical techniques. This edition adds material on visual arguments and more exercises.

In “Mercier and Sperber’s Argumentative Theory of Reasoning: From Psychology of Reasoning to Argumentation Studies” (2012) Santibáñez Yañez offers constructive comments and criticisms of the argumentative theory of reasoning. The purpose of this reply is twofold. First, it seeks to clarify two points broached by Yanez: (1) the relation between reasoning (in this specific theory) and dual process accounts in general and (2) the benefits that can be derived from reasoning and argumentation (again, in this (...) specific theory). Second, it suggests one domain—the categorization of arguments—in which argumentation studies and the argumentative theory of reasoning could usefully complement each other to yield a better understanding of the processes of argumentation. (shrink)

In this era of increased polarization of opinion and contentious disagreement, CRITICAL REASONING presents a cooperative approach to critical thinking and formation of beliefs. CRITICAL REASONING emphasizes the importance of developing and applying analytical skills in real life contexts. This book is unique in providing multiple, diverse examples of everyday arguments, both textual and visual, including hard to find long argument passages from real-life sources. The book provides clear, step-by-step procedures to help you decide for yourself what to (...) believe--to be a consumer of information in our contemporary "world of experts.". (shrink)

The Nature of Moral Reasoning is a discussion about the landscape, or environment, in which moral reasoning occurs, and the factors which contribute to it.

Presents the latest research on how reasoning with analogies, metaphors, metonymies, and images can facilitate mathematical understanding. For math education, educational psychology, and cognitive science scholars.

We introduce an Automatic Theorem Prover (ATP) of a dual tableau system for a relational logic for order of magnitude qualitative reasoning, which allows us to deal with relations such as negligibility, non-closeness and distance. Dual tableau systems are validity checkers that can serve as a tool for verification of a variety of tasks in order of magnitude reasoning, such as the use of qualitative sum of some classes of numbers. In the design of our ATP, we have (...) introduced some heuristics, such as the so called phantom variables, which improve the efficiency of the selection of variables used un the proof. (shrink)

Qualitative Reasoning (QR) is an area of research within Artificial Intelligence that automates reasoning and problem solving about the physical world. QR research aims to deal with representation and reasoning about continuous aspects of entities without the kind of precise quantitative information needed by conventional numerical analysis techniques. Order-of-magnitude Reasoning (OMR) is an approach in QR concerned with the analysis of physical systems in terms of relative magnitudes. In this paper we consider the logic OMR_N for (...) order-of-magnitude reasoning with the bidirectional negligibility relation. It is a multi-modal logic given by a Hilbert-style axiomatization that reflects properties and interactions of two basic accessibility relations (strict linear order and bidirectional negligibility). Although the logic was studied in many papers, nothing was known about its decidability. In the paper we prove decidability of OMR N by showing that the logic has the strong finite model property. (shrink)

Presenting the first book-length study in English of Aristotle's Sophistical Refutations, this work takes a fresh look at this seminal text on false reasoning.

Recently a number of variously motivated epistemologists have argued that knowledge is closely tied to practical matters. On the one hand, radical pragmatic encroachment is the view that facts about whether an agent has knowledge depend on practical factors and this is coupled to the view that there is an important connection between knowledge and action. On the other hand, one can argue for the less radical thesis only that there is an important connection between knowledge and practical reasoning. (...) So, defenders of both of these views endorse the view that knowledge is the norm of practical reasoning. This thesis has recently come under heavy fire and a number of weaker proposals have been defended. In this paper counter-examples to the knowledge norm of reasoning will be presented and it will be argued that this viewand a number of related but weaker viewscannot be sustained in the face of these counter-examples. The paper concludes with a novel proposal concerning the norm of practical reasoning that is immune to the counter-examples introduced here. (shrink)

Semantic studies on diagrammatic notations (Barwise & Etchemendy, ; Shimojima, ; Stenning & Lemon, ) have revealed that the “non-deductive,” “emergent,” or “perceptual” effects of diagrams (Chandrasekaran, Kurup, Banerjee, Josephson, & Winkler, ; Kulpa, ; Larkin & Simon, ; Lindsay, ) are all rooted in the exploitation of spatial constraints on graphical structures. Thus, theoretically, this process is a key factor in inference with diagrams, explaining the frequently observed reduction of inferential load. The purpose of this study was to examine (...) the empirical basis for this theoretical suggestion, focusing on the reality of the constraint-exploitation strategy in actual practices of diagrammatic reasoning. Eye movements were recorded while participants used simple position diagrams to solve three- or four-term transitive inference problems. Our experiments revealed that the participants could exploit spatial constraints on graphical structures even when (a) they were not in the position of actually manipulating diagrams, (b) the semantic rule for the provided diagrams did not match their preferences, and (c) the constraint-exploitation strategy invited a partly adverse effect. These findings indicate that the hypothesized process is in fact robust, with the potential to broadly account for the inferential advantage of diagrams. (shrink)

Mercier and Sperber (2011a, 2011b; Mercier, 2011a, 2011b, 2011c, and 2011d) have presented a stimulating and provocative new theory of reasoning: the argumentative theory of reasoning. They maintain that argumentation is a meta-representational module. In their evolutionary view of argumentation, the function of this module would be to regulate the flow of information between interlocutors through persuasiveness on the side of the communicator and epistemic vigilance on the side of the audience. The aim of this paper is to (...) discuss the perspective of the authors in which they conceive this competence as the natural scenario of reflective reasoning. (shrink)