This collection contains studies on justice, juridical reasoning and argumenta tion which contributed to my ideas on the new rhetoric. My reflections on justice, from 1944 to the present day, have given rise to various studies. The ftrst of these was published in English as The Idea of Justice and the Problem of Argument. The others, of which several are out of print or have never previously been published, are reunited in the present volume. As justice is, for me, the (...) prime example of a "confused notion", of a notion which, like many philosophical concepts, cannot be reduced to clarity without being distorted, one cannot treat it without recourse to the methods of reasoning analyzed by the new rhetoric. In actuality, these methods have long been put into practice by jurists. Legal reasoning is fertile ground for the study of argumentation: it is to the new rhetoric what mathematics is to formal logic and to the theory of demonstrative proof. It is important, then, that philosophers should not limit their methodologi cal studies to mathematics and the natural sciences. They must not neglect law in the search for practical reason. I hope that these essays lead to be a better understanding of how law can enrich philosophical thought. CH. P. (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.

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)

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)

We present a logic-based formalism for modeling ofdialogues between intelligent and autonomous software agents,building on a theory of abstract dialogue games which we present.The formalism enables representation of complex dialogues assequences of moves in a combination of dialogue games, and allowsdialogues to be embedded inside one another. The formalism iscomputational and its modular nature enables different types ofdialogues to be represented.

Reasoning with cases has been a primary focus of those working in AI and law who have attempted to model legal reasoning. In this paper we put forward a formal model of reasoning with cases which captures many of the insights from that previous work. We begin by stating our view of reasoning with cases as a process of constructing, evaluating and applying a theory. Central to our model is a view of the relationship between cases, rules based on cases, (...) and the social values which justify those rules. Having given our view of these relationships, we present our formal model of them, and explain how theories can be constructed, compared and evaluated. We then show how previous work can be described in terms of our model, and discuss extensions to the basic model to accommodate particular features of previous work. We conclude by identifying some directions for future work. (shrink)

The New Rhetoric is founded on the idea that since "argumentation aims at securing the adherence of those to whom it is addressed, it is, in its entirety, relative to the audience to be influenced," says Chaïm Perelman and L. Olbrechts-Tyteca, and they rely, in particular, for their theory of argumentation on the twin concepts of universal and particular audiences: while every argument is directed to a specific individual or group, the orator decides what information and what approaches will achieve (...) the greatest adherence according to an ideal audience. This ideal, Perelman explains, can be embodied, for example, in God, in all reasonable and competent men, in the man deliberating or in an elite." Like particular audiences, then, the universal audience is never fixed or absolute but depends on the orator, the content and goals of the argument, and the particular audience to whom the argument is addressed. These considerations determine what information constitutes facts and reasonableness and thus help to determine the universal audience that, in turn, shapes the orator's approach. The adherence of an audience is also determined by the orator's use of values, a further key concept of the New Rhetoric. Perelman's treatment of value and his view of epideictic rhetoric sets his approach apart from that of the ancients and of Aristotle in particular. Aristotle's division of rhetoric into three genres-forensic, deliberative, and epideictic-is largely motivated by the judgments required for each: forensic or legal arguments require verdicts on past action, deliberative or political rhetoric seeks judgment on future action, and epideictic or ceremonial rhetoric concerns values associated with praise or blame and seeks no specific decisions. For Aristotle, the epideictic genre was of limited importance in the civic realm since it did not concern facts or policies. Perelman, in contrast, believes not only that epideictic rhetoric warrants more attention, but that the values normally limited to that genre are in fact central to all argumentation. Epideictic oratory, Perelman argues, has significant and important argumentation for strengthening the disposition toward action by increasing adherence to the values it lauds." These values are central to the persuasiveness of arguments in all rhetorical genres since the orator always attempts to establish a sense of communion centered around particular values recognized by the audience.". (shrink)

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

Develops a logical analysis of dialogue in which two or more parties attempt to advance their own interests. It includes a classification of the major types of dialogues and a discussion of several important informal fallacies.

Henry Richardson argues that we can determine our ends rationally. He constructs a rich and original theory of how we can reason about our final goals. Richardson defuses the counter-arguments for the limits of rational deliberation, and develops interesting ideas about how his model might be extended to interpersonal deliberation of ends, taking him to the borders of political theory. Along the way Richardson offers illuminating discussions of, inter alia, Aristotle, Aquinas, Sidgwick, and Dewey, as well as the work of (...) several contemporary philosophers. (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)