Abstract

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