This book examines three areas in which abductive reasoning is especially important: medicine, science, and law. The reader is introduced to abduction and shown how it has evolved historically into the framework of conventional wisdom in logic. Discussions draw upon recent techniques used in artificial intelligence, particularly in the areas of multi-agent systems and plan recognition, to develop a dialogue model of explanation. Cases of causal explanations in law are analyzed using abductive reasoning, and all the components are finally brought (...) together to build a new account of abductive reasoning. By clarifying the notion of abduction as a common and significant type of reasoning in everyday argumentation, _Abductive Reasoning_ will be useful to scholars and students in many fields, including argumentation, computing and artificial intelligence, psychology and cognitive science, law, philosophy, linguistics, and speech communication and rhetoric. (shrink)

Argumentation is a dialogical attempt to bring about a desired change in the beliefs of another agent – that is, to trigger a specific belief revision process in the mind of such agent. However, so far formal models of belief revision widely neglected any systematic comparison with argumentation theories, to the point that even the simplest argumentation structures cannot be captured within such models. In this essay, we endeavour to bring together argumentation and belief revision in the same formal framework, (...) and to highlight the important role played by Toulmin’s layout of argument in fostering such integration. (shrink)

Although fallacies have been common since Aristotle, until recently little attention has been devoted to identifying and defining them. Furthermore, the concept of fallacy itself has lacked a sufficiently clear meaning to make it a useful tool for evaluating arguments. Douglas Walton takes a new analytical look at the concept of fallacy and presents an up-to-date analysis of its usefulness for argumentation studies. Walton uses case studies illustrating familiar arguments and tricky deceptions in everyday conversation where the charge of fallaciousness (...) is at issue. The numerous case studies show in concrete terms many practical aspects of how to use textual evidence to identify and analyze fallacies and to evaluate arguments as fallacious. Walton looks at how an argument is used in the context of conversation. He defines a fallacy as a conversational move, or sequence of moves, that is supposed to be an argument that contributes to the purpose of the conversation but in reality interferes with it. The view is a pragmatic one, based on the assumption that when people argue, they do so in a context of dialogue, a conventionalized normative framework that is goal-directed. Such a contextual framework is shown to be crucial in determining whether an argument has been used correctly. Walton also shows how examples of fallacies given in the logic textbooks characteristically turn out to be variants of reasonable, even if defeasible or questionable arguments, based on presumptive reasoning. This is the essence of the evaluation problem. A key thesis of the book, which must not be taken for granted as previous textbooks have so often done, is that you can spot a fallacy from how it was used in a context of dialogue. This is an innovative and even, as Walton notes, "a radical and controversial" theory of fallacy. (shrink)

Searle’s tool for understanding culture, law and society is the opposition between brute reality and institutional reality, or in other words between: observer-independent features of the world, such as force, mass and gravitational attraction, and observer-relative features of the world, such as money, property, marriage and government. The question posed here is: under which of these two headings do moral concepts fall? This is an important question because there are moral facts – for example pertaining to guilt and responsibility – (...) which hover uncomfortably close to the boundary between the observer-relative and the observer-independent. By means of a thought experiment involving an imagined Chinese society in which guilt is determined by the random throwing of sticks, I seek to show that moral concepts threaten the foundations of Searle’s philosophy of social reality. (shrink)

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

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

The study of rationality and practical reason, or rationality in action, has been central to Western intellectual culture. In this invigorating book, John Searle lays out six claims of what he calls the Classical Model of rationality and shows why they are false. He then presents an alternative theory of the role of rationality in thought and action. A central point of Searle's theory is that only irrational actions are directly caused by beliefs and desires—for example, the actions of a (...) person in the grip of an obsession or addiction. In most cases of rational action, there is a gap between the motivating desire and the actual decision making. The traditional name for this gap is "freedom of the will." According to Searle, all rational activity presupposes free will. For rationality is possible only where one has a choice among various rational as well as irrational options. Unlike many philosophical tracts, Rationality in Action invites the reader to apply the author's ideas to everyday life. Searle shows, for example, that contrary to the traditional philosophical view, weakness of will is very common. He also points out the absurdity of the claim that rational decision making always starts from a consistent set of desires. Rational decision making, he argues, is often about choosing between conflicting reasons for action. In fact, humans are distinguished by their ability to be rationally motivated by desire-independent reasons for action. Extending his theory of rationality to the self, Searle shows how rational deliberation presupposes an irreducible notion of the self. He also reveals the idea of free will to be essentially a thesis of how the brain works. (shrink)

This book is an analysis of the distinctive form of reasoning, called practical reasoning by Aristotle (as opposed to theoretical reasoning), that serves to guide behaviour.

The epistemologist John Pollock has implemented computationally an architecture for a rational agent which he calls OSCAR. OSCAR models both practical and theoretical (or epistemic) reasoning. I argue that Pollock's model of practical reasoning, which has seven components, is superior not only to the two-component belief-desire model stemming from Aristotle, but also to the three-component belief-desire-intention model developed especially by Michael Bratman. Despite its advantages, Pollock's model of practical reasoning is incomplete in at least three respects: it is solipsistic, it (...) is egoistic and it is unsocial. (shrink)

what is now the mainstream view as to the best way forward in the dream of engineering reliable software systems out of autonomous agents. The way of using formal logics to specify, implement and verify distributed systems of interacting units using a guiding analogy of beliefs, desires and intentions. The implicit message behind the book is this: Distributed Artificial Intelligence (DAI) can be a respectable engineering science. It says: we use sound formal systems; can cite established philosophical foundations; and will (...) be able to build reliable and flexible software systems. (shrink)

This paper describes an approach to legal logic based on the formal analysis of argumentation schemes. Argumentation schemes a notion borrowed from the .eld of argumentation theory - are a kind of generalized rules of inference, in the sense that they express that given certain premises a particular conclusion can be drawn. However, argumentation schemes need not concern strict, abstract, necessarily valid patterns of reasoning, but can be defeasible, concrete and contingently valid, i.e., valid in certain contexts or under certain (...) circumstances. A method is presented to analyze argumentation schemes and it is shown how argumentation schemes can be embedded in a formal model of dialectical argumentation. (shrink)