We present a formal, mathematical model of argument structure and evaluation, taking seriously the procedural and dialogical aspects of argumentation. The model applies proof standards to determine the acceptability of statements on an issue-by-issue basis. The model uses different types of premises (ordinary premises, assumptions and exceptions) and information about the dialectical status of statements (stated, questioned, accepted or rejected) to allow the burden of proof to be allocated to the proponent or the respondent, as appropriate, for each premise separately. (...) Our approach allows the burden of proof for a premise to be assigned to a different party than the one who has the burden of proving the conclusion of the argument, and also to change the burden of proof or applicable proof standard as the dialogue progresses from stage to stage. Useful for modeling legal dialogues, the burden of production and burden of persuasion can be handled separately, with a different responsible party and applicable proof standard for each. Carneades enables critical questions of argumentation schemes to be modeled as additional premises, using premise types to capture the varying effect on the burden of proof of different kinds of questions. (shrink)

By far the most detailed surviving examination by any ancient Greek sceptic of epistemology and logic, this work critically reviews the pretensions of non-sceptical philosophers, to have discovered methods for determining the truth, either through direct observation or by inference from the observed to the unobserved. A fine example of the Pyrrhonist sceptical method at work, it also provides extensive information about the ideas of other Greek thinkers, which in many instances, are poorly preserved in other sources.

This book provides a systematic analysis of many common argumentation schemes and a compendium of 96 schemes. The study of these schemes, or forms of argument that capture stereotypical patterns of human reasoning, is at the core of argumentation research. Surveying all aspects of argumentation schemes from the ground up, the book takes the reader from the elementary exposition in the first chapter to the latest state of the art in the research efforts to formalize and classify the schemes, outlined (...) in the last chapter. It provides a systematic and comprehensive account, with notation suitable for computational applications that increasingly make use of argumentation schemes. (shrink)

The purpose of this book is to trace the main developments in Greek philosophy during the period which runs from the death of Alexander the Great in 323 B.c. to the end of the Roman Republic. These three centuries, known to us as the Hellenistic Age, witnessed a vast expansion of Greek civilization eastwards, following Alexander's conquests; and later, Greek civilization penetrated deeply into the western Mediterranean world assisted by the political conquerors of Greece, the Romans. But philosophy throughout this (...) time remained a predominantly Greek activity. The most influential thinkers in the Hellenistic world were Stoics, Epicureans and Sceptics. This book gives a concise critical analysis of their ideas and their methods of thought. The last book in English to cover this ground was written sixty years ago. In the interval the subject has moved on, quite rapidly since the last war, but most of the best work is highly specialized. There is a clear need for a general appraisal of Hellenistic philosophy which can provide those who are not specialists with an up-to-date account of the subject. Hellenistic philosophy is often regarded as a dull product of second-rate thinkers who are unable to stand comparison with Plato and Aristotle. This book will help to remove such misconceptions and arouse wider interest in a field which is fascinating both historically and conceptually. (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.

This book provides a systematic analysis of many common argumentation schemes and a compendium of 96 schemes. The study of these schemes, or forms of argument that capture stereotypical patterns of human reasoning, is at the core of argumentation research. Surveying all aspects of argumentation schemes from the ground up, the book takes the reader from the elementary exposition in the first chapter to the latest state of the art in the research efforts to formalize and classify the schemes, outlined (...) in the last chapter. It provides a systematic and comprehensive account, with notation suitable for computational applications that increasingly make use of argumentation schemes. (shrink)

A detailed treatment regarding the diverse properties and uses of evidence and the judgmental tasks they entail. Examines various processes by which evidence may be developed or discovered. Considers the construction of arguments made in defense of the relevance and credibility of individual items and masses of evidence as well as the task of assessing the inferential force of evidence. Includes over 100 numerical examples to illustrate the workings of diverse probabilistic expressions for the inferential force of evidence and the (...) subtleties they reveal. (shrink)

_Rhetoric_ is the sixth volume in The New Hackett Aristotle series, a series featuring translations, with Introductions and Notes, by C. D. C. Reeve, Delta Kappa Epsilon Distinguished Professor of Philosophy at The University of North Carolina at Chapel Hill. The series will eventually include all of Aristotle's works.

"A sequel to Pollock's How to Build a Person, this volume builds upon that theoretical groundwork for the implementation of rationality through artificial ...

The Rationalist Tradition of evidence scholarship1 The history of the law of evidence is the history of a series of largely isolated responses to particular ...

Harald Thorsrud - Cicero on his Academic Predecessors: the Fallibilism of Arcesilaus and Carneades - Journal of the History of Philosophy 40:1 Journal of the History of Philosophy 40.1 1-18 Cicero on his Academic Predecessors: the Fallibilism of Arcesilaus and Carneades Harald Thorsrud IN AN IMPORTANT PAPER, Couissin argued for what has come to be called the dialectical interpretation of Academic skepticism. On this interpretation, Arcesilaus and Carneades practiced the same, purely dialectical method -- they would elicit assent to premises (...) characteristic of their interlocutor's position and then derive unacceptable consequences exclusively on the basis of those premises. This method allowed them to remain uncommitted to the premises as well as the conclusions of their arguments. They would simply draw logical consequences from their opponents' own premises for the sake of refutation. This is in keeping with the current consensus that an ancient skeptic is one who has no beliefs, or at least no beliefs of a problematically dogmatic sort. Consequently, the methods of ancient skeptics, including Academic skeptics, are thought to be strictly negative, seeking only the elimination of belief. So when we come to Cicero's Philonian version of Academic methodology and find that it explicitly includes provisions for the acquisition of fallible beliefs, it is no surprise that commentators who are sympathetic to the dialectical interpretation tend to view.. (shrink)

Ancient sceptics, unlike their modern counterparts, claim to live their scepticism. Nowadays scepticism, whether epistemological, moral, or of any other variety, is seen as a purely theoretical position, with no direct bearing on the actual living of one’s life; this is because philosophical theories and everyday attitudes are taken to be in some way “insulated” from one another. Serious questions may be raised about the character of this alleged “insulation,” but these are not my present concern; the fact is that (...) no such split between “the philosophical” and “the ordinary” was entertained in the ancient world. It follows that the viability of scepticism as a way of life is a crucial issue for ancient sceptics. It is no accident that one of the most enduring objections to ancient scepticism is to the effect that the sceptical attitude—that is, the posture of universal suspension of judgement—is incompatible with any kind of normal human action; this was known in antiquity as the charge of apraxia, “inaction.” The sceptics for their part, were just as persistent in arguing that suspension of judgement had no such damaging consequences. In as much as the assessment of actual or imaginable types of human life is the province of ethics, I take this debate between ancient sceptics and their detractors to be, in a broad sense, an ethical debate. (shrink)

The idea that Western philosophy is a footnote to Plato is simplistic and inaccurate. Much of modern and contemporary epistemology owes a debt not so much to Platonism or Aristotelianism as to their antithesis: scepticism. Recent discussions in the history of philosophy have sparked a great deal of interest in the ancient sceptics, but until now they have been misunderstood and the significance of their philosophy not fully appreciated.

Recent work in artificial intelligence has increasingly turned to argumentation as a rich, interdisciplinary area of research that can provide new methods related to evidence and reasoning in the area of law. Douglas Walton provides an introduction to basic concepts, tools and methods in argumentation theory and artificial intelligence as applied to the analysis and evaluation of witness testimony. He shows how witness testimony is by its nature inherently fallible and sometimes subject to disastrous failures. At the same time such (...) testimony can provide evidence that is not only necessary but inherently reasonable for logically guiding legal experts to accept or reject a claim. Walton shows how to overcome the traditional disdain for witness testimony as a type of evidence shown by logical positivists, and the views of trial sceptics who doubt that trial rules deal with witness testimony in a way that yields a rational decision-making process. (shrink)

with Thomas F. Gordon and Henry Prakken. Artificial Intelligence, forthcoming. [Preprint posted.].

Carneades is an open source argument mapping application and a programming library for building argumentation support tools. In this paper, Carneades’ support for argument reconstruction, evaluation and visualization is illustrated by modeling most of the factual and legal arguments in Popov v Hayashi.

Developments in the Academy from the time of Arcesilaus to that of Carneades and his successors tend to be classified under two heads: scepticism and probabilism. Carneades was principally responsible for the Academy's view of the latter subject, and our sources credit him with an elaborate discussion of it. The evidence furnished by those sources is, however, frequently confusing and sometimes self-contradictory. My aim in this paper is to extract a coherent account of Carneades' theory of probability from the testimony (...) with a further end in view, namely to understand better the uses to which that theory was put by the Academy in its debate with the Stoa. Though it is not its principal object, the investigation should also help make clear how the Academy's scepticism and its probabilism were related to each other as parts of a single consistent practice of philosophy. (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.