Why informal logic? Informal logic is a group of proposals meant to contrast with, replace, and reject formal logic, at least for the analysis and evaluation of everyday arguments. Why reject formal logic? Formal logic is criticized and claimed to be inadequate because of its commitment to the soundness doctrine. In this paper I will examine and try to respond to some of these criticisms. It is not my aim to examine every argument ever given against formal logic; I am (...) limiting myself to those that, as a matter of historical fact, were instrumental in the replacement of formal logic by informal logic and initially established informal logic as a separate discipline. If the criticism of the soundness doctrine is defective, then the move from formal logic to informal logic was not theoretically well-motivated. It is this motivation that I wish to bring into question, rather than the adequacy or inadequacy of formal or informal logic as such. While I will tend to the view that formal logic is as adequate as it is reasonable to expect, the real issue is whether it is inadequate for the reasons that, as a matter of historical fact, were used to motivate its rejection. (shrink)

A broad assumption in argumentation theory is that argumentation primarily regards resolving, confronting, or managing disagreement. This assumption is so fundamental that even when there does not appear to be any real disagreement, the disagreement is suggested to be present at some other level. Some have questioned this assumption (most prominently, Perelman and Olbrechts-Tyteca, and Doury), but most are reluctant to give up on the key idea that persuasion, the core of argumentation theory, can only regard disagreements. We argue here (...) that this assumption is false. Argument may be as much about strengthening or maintaining agreement as it is about disagreement. Once we see how argument is possible and manifestly enacted under conditions of agreement, then we have tools to explain otherwise curious fallacies and argumentative phenomena. (shrink)