Grennan, Wayne

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University of WindsorScholarship at UWindsorOSSA Conference Archive OSSA 4May 17th, 9:00 AM - May 19th, 5:00 PMCommentary on HoaglundWayne GrennanFollow this and additional works at: http://scholar.uwindsor.ca/ossaarchivePart of the Philosophy CommonsThis Commentary is brought to you for free and open access by the Faculty of Arts, Humanities and Social Sciences at Scholarship at UWindsor. It hasbeen accepted for inclusion in OSSA Conference Archive by an authorized conference organizer of Scholarship at UWindsor. For more information,please contact scholarship@uwindsor.ca.Grennan, Wayne, "Commentary on Hoaglund" (2001). OSSA Conference Archive. 60.http://scholar.uwindsor.ca/ossaarchive/OSSA4/papersandcommentaries/60Author: Wayne Grennan In Response to: John Hoaglund’s Implicit Premises © 2001 Wayne Grennan The main conclusion of John Hoaglund’s paper is that the use of the adjective ‘implicit’ in talking about argument premises is undesirable. The issue is important in argument analysis because whatever term we choose has semantic content that conditions our search for such premises. The key to this terminological debate is to make a distinction between arguments conceived as speech act complexes and arguments as propositional complexes. The latter can be regarded as a product of the former. If the premise we are to formulate is a proposition that must be true for the argument to be logically persuasive, then the term ‘implicit’ is much more appropriate in talking about arguments as propositional complexes, since we will identify it by an inference process, which is an act in the realm of semantic content. The terms ‘unstated’ and ‘unexpressed’, on the other hand, are more at home in the realm of speech act talk, and are relatively infelicitous in argument analysis activity since the target of argument evaluation is the argument conceived as a propositional complex. The felicitousness of ‘implicit’ depends on what kind of proposition we think necessary to add to the propositional complex. If the proposition we identify qualifies as a Toulminian warrant, it seems quite appropriate to call it an implicit premise, because in a clear sense we do not have to go outside the argument to identify it. It can be inferred from the content of the argument as stated. For example, given “Jean Chretien is a man, so he is mortal.”, an analyst might identify ‘All men are mortal’ as the premise we need if we are to be persuaded to accept the conclusion. We can formulate this candidate because the inference claim of the argument is entailed by it. (This is what a warrant is.) However, if the identified needed premise is really supplementary evidence for the conclusion, it is inappropriate to call it an implicit premise, simply because it is not to be inferred from the stated propositional complex. Perhaps the expression “supplementary premise” has something to recommend it in such cases.      Now to address some issues raised by the paper that are peripheral to the main point. First, a point about the use of the expression ‘argument analysis’: it is clear from the occurrences of the term ‘analysis’ in the paper that it is being used to cover both the activities of analysis in a descriptive sense, and what I think we should distinguish as argument evaluation, a normative activity. I think we should regard argument analysis as the activity of identifying the conclusions and premises (missing and stated) of arguments. Argument evaluation, on the other hand, is the activity involving standards of logic and/or evidence that leads to a judgment of the logical merit of an argument. Specifically: do the premises give the conclusion a sufficiently high probability to warrant accepting it as true? In any intellectual activity it is always desirable, I think, to distinguish descriptive from normative activities. Secondly, a more important issue. In the very first two sentences of the paper a theory of argument evaluation is presented: “The informal logician ... senses an insufficiency or incompleteness of evidence advanced in support of the conclusion. Unable to proceed without estimating the importance of the lacuna, she scrutinizes the argument in its context ... to identify more precisely what is lacking. Finding this, she may then evaluate the argument as weak ... or strong...”. I do not wish to suggest that this strategy for argument evaluation is mistaken, but I do want to claim that it is difficult to implement in practice. (His comment in the third paragraph 1  A commentary on John Hoaglund  2     shows that Hoaglund is aware of this, since he notes that how to find and formulate implicit premises are “important problems.”)  As I argue in Grennan 1994 and elsewhere, I think we can often avoid the difficulties of the search for implicit premises by simply evaluating the argument as stated. Now this suggestion is incompatible with Hoaglund’s strategy, as reported above, only if he wants to maintain that evaluators always or usually need to identify implicit premises to arrive at an accurate estimate of argument strength. For the purpose of arriving at a private judgment of the logical value of an argument, I just do not think that identifying implicit premises is necessary. Can we not just judge that stated premises are inadequate without stating what else is needed to get our assent? Of course, if there is a need to respond to the arguer by stating our appraisal, it is highly desirable to identify what else we think is needed to persuade us, and if we are engaged in a joint effort to arrive at the truth on the topic, this is even more desirable. On the other hand, much of our everyday argument evaluation is of arguments presented by persons not accessible for confrontation. In these cases, I suggest, it is not necessary to identify implicit premises to arrive at an accurate appraisal. A third, and final, point: pretty clearly, identifying implicit premises even of the supplementary kind involves inferential processes. If we are trying to identify items of evidence that must be added to make the conclusion acceptable, I suggest we actually do something like this: understanding the meaning of the conclusion of the argument is knowing its truth conditions, which, taken jointly, can constitute the evidence for it, or enable us to formulate the evidence. By articulating the truth conditions or the evidence that ensures their presence, and comparing them with the items of evidence given by the arguer, we can identify as supplementary premises the ones  not mentioned in the argument. This strategy applies only for one kind of implicit premise, of course, the kind that represents additional evidence for the conclusion. It does not yield what have been called “gap-fillers.” But I think it is a suggestion worth taking seriously.  

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