I hope I'm not making a fool of myself by taking issue with Douglas Walton, but his brief comment, while thought-provoking, seems to me off the mark.

(1) The proposal before us is that an argument be defined as an attempt to justify a claim. (Actually, the term used was 'conclusion', but the use of that word seems to me to make the definition circular: 'conclusion' will have to be defined in terms of 'argument', will it not?) Professor Walton says in reply that an argument "can be used" to justify a proposition. Now if an argument simply is an attempt to justify a claim, as the proposed definition says, then to speak of using one to justify a claim is to speak loosely at best. So I take Professor Walton to mean that justifying a claim is not what an argument essentially is or does but is merely something that we (sometimes) do with arguments. This claim seems to me unpersuasive in the absence of a competing and at least equally plausible definition of an argument. (The definition common in logic textbooks, according to which an argument is a set of propositions or sentences, one of which is designated as the conclusion, seems to me implausible and useless outside of formal logic.)

(2) To say that "an argument can be used . . . to support or attack another argument" seems to me to have no bearing on the proposed definition. An argument still has to have a conclusion. That conclusion may be a claim about some other argument. I don't see how this is supposed to count against the proposed definition. (Perhaps the remark was not so intended, and I have misinterpreted it; but then I don't see what its point is.)

Miles Rind

Douglas Walton wrote: