A conclusion follows from given premisses if and only if an acceptable counterfactual-supporting covering generalization of the argument rules out, either definitively or with some modal qualification, simultaneous acceptability of the premisses and non-accepta-bility of the conclusion, even though it does not rule out acceptability of the premisses and does not require acceptability of the conclusion independently of the premisses. Hence the reiterative associated conditional of an argument is true if and only it has such a covering generalization, and a (...) supposed unexpressed premiss supplied to make an argument formally valid should be a covering generalization. (shrink)

Premissary relevance is a property of arguments understood as speech act complexes. It is explicable in terms of the idea of a premise's lending support to a conclusion. Premissary relevance is a function of premises belonging to a set which authoritatively warrants an inference to a conclusion. An authoritative inference warrant will have associated with it a conditional proposition which is true— that is to say, which can be justified. The study of the Aristotelian doctrine of topoi or argument schemes (...) may contribute to the task of identifying authoritative warrants. (shrink)

Relevance is a triadic relation between an item, an outcome or goal, and a situation. Causal relevance consists in an item's ability to help produce an outcome in a situation. Epistemic relevance, a distinct concept, consists in the ability of a piece of information (or a speech act communicating or requesting a piece of information) to help achieve an epistemic goal in a situation. It has this ability when it can be ineliminably combined with other at least potentially accurate information (...) to achieve the goal. The relevance of a conversational contribution, premiss relevance and conclusion relevance are species of epistemic relevance thus defined. The conception of premiss relevance which results provides a basis for determining when the various ‘arguments ad’ called fallacies of relevance are indeed irrelevant. In particular, an ad verecundiam appeal is irrelevant if the authority cited lacks expertise in a cognitive domain to which the conclusion belongs, the authority does not exercise its expertise in coming to endorse the conclusion, or the conclusion does not belong to a cognitive domain; otherwise the ad verecundiam is relevant. (shrink)

Traditionally, logicians construed fallacies as mistakes in inference, as things that looked like good (i.e., deductively valid) arguments but were not. Two fallacies stood out like a sore thumb on this view of fallacies: the fallacy of many questions (because it does not even look like a good argument, or any kind of argument) and the fallacy of petitio principii (because it looks like and is a good argument). The latter is the concern of this paper. One possible response is (...) to say that the tradition is right about the concept of fallacy but wrong about its extension: petitio principii is not a fallacy. If the only proper ways to criticize an argument are to say that it is invalid or that it is unsound, and petitio principii is not criticisable on either of these counts, then calling it a fallacy is tantamount to saying we should prefer invalid or unsound arguments Robinson (Analysis, 31(4): 114 ,1971). I will present a third way to logically criticize arguments and show that fallacious instances of petitio principii are so criticisable while other instances of petitio principii are non-fallacious; hence, this fallacy is not a reductio of the Standard Treatment. It is not my intention in this paper to come out on the side of any of the competing theories—the Standard Treatment, the dialectical theories, and the epistemic theories—as general theories of fallacy. I show only that petitio principii can be handled by something closely resembling the Standard Treatment in so far as that, on entirely logistical principles, there can be made a distinction such that circular arguments form at best a degenerate kind of argument. Circular arguments look like good arguments but are not, not because they are deductively invalid (which they are not) but because they do not deserve to be called arguments at all. (shrink)

In their book, Relevance, Sperber and Wilson make an important contribution towards constructing a credible theory of this unforthcoming notion. All is not clear sailing, however. If it is accepted as a condition on the adequacy of any account of relevance that it not be derivable either that nothing is relevant to anything or that everything is relevant to everything, it can be shown that Sperber and Wilson come close to violating the condition.