This book traces the development of formal logic from its origins inancient Greece to the present day. The authors first discuss the work oflogicians from Aristotle to Frege, showing how they were influenced by thephilosophical or mathematical ideas of their time. They then examinedevelopments in the present century.

Normal0falsefalsefalseMicrosoftInternetExplorer4 The thesis of this book is that argument is not a kind of logic but a kind of communication—conversation based on disagreement. Claims about the epistemic and political effects of argument get their authority not from logic but from their “fit with the facts” about how communication works. A Theory of Communication thus offers a picture of communication—distilled from elements of symbolic interactionism, personal construct theory, constructivism, and Barbara O’Keefe’s provocative thinking about logics of message design. The picture of (...) argument that emerges from this tapestry is startling, for it forces revisions in thinking about knowledge, rationality, freedom, fallacies, and the structure and content of the argumentation discipline. The burden of this book is to establish a theoretical context for, and to elaborate the implications of, the claim that argument is a form of interaction in which two or more people maintain what they construe to be incompatible positions. (shrink)

I have been supposing that for the theory of reasoning, explicit belief is an all-or-nothing matter, I have assumed that, as far as principles of reasoning are concerned, one either believes something explicitly or one does not; in other words an appropriate "representation" is either in one's "memory" or not. The principles of reasoning are principles for modifying such all-or-nothing representations. This is not to deny that in some ways belief is a matter of degree. For one thing implicit belief (...) is certainly a matter of degree, since it is a matter of how easily and automatically one can infer something from what one believes explicitly. Furthermore, explicit belief is a matter of degree in the sense that one believes some things more strongly than others. Sometimes one is only somewhat inclined to believe something, sometimes one is not sure what to believe, sometimes one is inclined to disbelieve something, sometimes one is quite confident something is not so, and so forth. (shrink)