The book was planned and written as a single, sustained argument. But earlier versions of a few parts of it have appeared separately. The object of this book is both to establish the existence of the paradoxes, and also to describe a non-Pascalian concept of probability in terms of which one can analyse the structure of forensic proof without giving rise to such typical signs of theoretical misfit. Neither the complementational principle for negation nor the multiplicative principle for conjunction applies (...) to the central core of any forensic proof in the Anglo-American legal system. There are four parts included in this book. Accordingly, these parts have been written in such a way that they may be read in different orders by different kinds of reader. (shrink)

tational background of dialectic: the structure of formal disputation. Formal disputation Perhaps the clearest, and surely historically the most prominent, ...

When, if ever, is one justified in accepting the premises of an argument? What is the proper criterion of premise acceptability? Can the criterion be theoretically or philosophically justified? This is the first book to provide a comprehensive theory of premise acceptability and it answers the questions above from an epistemological approach that the author calls common sense foundationalism. It will be eagerly sought out not just by specialists in informal logic, critical thinking, and argumentation theory but also by a (...) broader range of philosophers and those teaching rhetoric. (shrink)

Originally published in 1973. This book presents a valid mode of reasoning that is different to mathematical probability. This inductive logic is investigated in terms of scientific investigation. The author presents his criteria of adequacy for analysing inductive support for hypotheses and discusses each of these criteria in depth. The chapters cover philosophical problems and paradoxes about experimental support, probability and justifiability, ending with a system of logical syntax of induction. Each section begins with a summary of its contents and (...) there is a glossary of technical terms to aid the reader. (shrink)

In many actual arguments, the conclusion seems intuitively to follow from the premisses, even though we cannot show that it follows logically. The traditional approach to evaluating such arguments is to suppose that they have an unstated premiss whose explicit addition will produce an argument where the conclusion does follow logically. But there are good reasons for doubting that people so frequently leave the premisses of their arguments unstated. The inclination to suppose that they do stems from the belief that (...) the only way in which an argument's conclusion can follow definitely from its premisses is to follow logically. I argue that this belief is mistaken. I propose a revision of the current generic conception of logical consequence, and its variant specifications, to avoid the paradoxes of strict implication. The revised conception can then be naturally extended to include also what we might call 'enthymematic consequence'. This concept is a kind of consequence, whose properties merit investigation. (shrink)

Our typology is based on two ground adequacy factors, one logical and one epistemic. Logically, the step from premises to conclusion may be conclusive or only ceteris paribus. Epistemically, warrants may be backed a priori or a posteriori. Hence there are four types of arguments: conclusive a priori, defeasible a priori, defeasible a posteriori, and prima facie conclusive a posteriori. We shall give an example of each and compare our scheme with other typologies.

We argue that Cohen’s concept of inductive or ampliative probability facilitates proper explication of sufficient strength for non-demonstrative arguments conforming to the Toulmin model. The data and claims of such arguments are singular statements. We may epistemically classify the warrants of such arguments as empirical (either physical or personal), institutional, or evaluative. Backing evidence and rebutting considerations vary with the epistemic type of warrant, but in each case the notion of ampliative probability for arguments with warrants of that type can (...) be characterized. We may then use ampliative probability to define sufficient strength and related notions for Toulmin arguments. (shrink)