Abstract
In this paper I will defend the controversial thesis that all argumentation in natural language can be reconstructed, for the purposes of assessment, as a deductively valid argument. Evaluation of the argumentation amounts to evaluation of the logical coherence of the premises. I will be taking the pragma-linguistic theory of Bermejo-Luque as an initial starting point.
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Notes
This is why it does not really matter for pragma-dialectics that few real arguments actually conform to the norms of a critical discussion; the rules of critical discussion are still norms for those real arguments, no matter how habitually they may be flouted in real argumentation, or how seriously we take those rule-violations. Even though it may not be the arguers’ aim, we still say that resolution of the disagreement on the merits of the best argument is the aim of the critical discussion as such and hence that its rules can be taken as regulating argumentative behaviour and that arguers are criticizable if they violate those rules.
This does not rule out there being a causal relation between the two—I am inclined to think that the basing relation is actually a causal relation, but not any causal relation can so qualify. The point is this: imagine someone who gets himself to believe things by taking advantage of such causal relations. Does he thereby believe the associated conditional? Now there may be another causal relation that causes belief in the associated conditional, but the question is whether the initial causal relation itself somehow normatively commits the person to the associated conditional. It does not, and generally speaking the person who causes himself to have beliefs this way does not believe this conditional and nor can such belief be attributed to him even dispositionally, the simple reason being that the truth-values are causally irrelevant here.
Another term that often gets used here in place of subjective justification is doxastic justification. I don’t think it matters which is used here. What I want to avoid including are certain kinds of state-given reasons for belief—such as it being useful to have such a belief—that might crawl in when we start to talk about justifying a belief in contrast to justifying what is believed, i.e., the propositional object of the belief. However, we can certainly say that when q is subjectively/doxastically justified by p, this can be glossed as belief that q causally depending on belief that p, without it being the case objectively that the truth of q follows from the truth of p, although the arguer must think that it does, at least as long as he takes his believing that q to be rational. However, his belief that q may be rational (even when he does not think it is) in the objective sense because it is the logical consequence of other beliefs the arguer may have, though not of the proposition that the arguer takes it to follow from, viz., p. We can say in this case that q is propositionally justified. Obviously, q can be propositionally justified irrespective of whether the arguer takes q to be subjectively justified or not (and whether the arguer takes his believing that q to be rational or not), and also the propositions that the arguer takes to subjectively justify q may or may not be propositions that propositionally justify q. There is always when subjective justification is being discussed an implicit reference to the beliefs themselves over and above their propositional objects, but this should not be taken to imply that state-given reasons can doxastically justify a belief, despite the fact that it can make it rational in some sense (in the sense, perhaps, of Pascal’s Wager).
Believing that the reason is good is a constitutive condition of adducing a reason, but I must admit that I am undecided whether being justified (from one’s own point of view) in believing the reason to be good is itself a speech-act condition or a higher-level assertibility condition. If it is the latter, the view I present here is a simplification.
In fact, if an agent’s subjectively justified beliefs lead to contradiction, I think this is evidence that they were not all subjectively justified after all—the agent only thought they were, either by not considering all his beliefs together but only a subset, or by not considering all their consequences. The latter raises the tricky problem of whether justification should be closed under entailment. I think that the dialectical tier addresses precisely that issue, and hence that dialectical closure can, after all, be taken as the operationalisation of an epistemological norm. This must be the subject for another time.
Bermejo-Luque seems to spelling out in greater detail a suggestion made by Grennan (1994) in footnote 7 of that paper.
For instance, in the argument
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Socrates is a man
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Socrates is mortal
the associated conditional is “If Socrates is a man, then Socrates is mortal.” When we fill in the missing premise in the following way
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All men are mortal
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Socrates is a man
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Socrates is mortal
we find that the major premise entails the associated conditional, the latter being a substitution-instance of the former. Grennan (1994) concludes that major premises have a different logical function in arguments, namely as backings for the associated conditional that is already there implicitly. Since you do not have to give the backing of the minor premise in order for the argument to be complete, nor do you need to give the backing of the associated conditional.
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Carroll’s argument thus establishes for deduction something similar to what Hume established for induction. By adding a Principle of Uniformity we can turn inductive arguments into deductively valid arguments, but we have to appeal to induction to establish a Principle of Uniformity, and this is circular. Equally, Carroll might say, even if it was a deductively valid argument, the only way we have of establishing validity is by appealing to deduction, and this is equally circular. Of course, the difference is that the Principle of Uniformity is synthetic and rules of deduction are analytically true, and this is sufficient objectively to justify the conclusion. But subjectively one may still doubt analytic truths, and if one does, then a regress of the kind Carroll illustrates can start. This is a regress of subjective/doxastic justification.
Although Thomson (1960) seems to saying something similar with regard to Carroll’s problem when he says that modus ponens is a comment on the argument, rather than a part of it. I think this is a false dichotomy: it is both (Botting 2015). Thomson’s claim reads rather like Bermejo-Luque’s claim that the inference-claim is just a representation of the inference.
References
Botting, David. 2010. The question of truth. Informal Logic 30(4): 413–434.
Botting, David. 2015. The virtuous tortoise. Philosophical Investigations Early View. http://onlinelibrary.wiley.com/journal/10.1111/(ISSN)1467-9205/earlyview.
Bermejo-Luque, Lilian. 2011a. Exchanging reasons: Responses to critics. Theoria 72: 329–343.
Bermejo-Luque, Lilian. 2011b. Giving reasons: A linguistic-pragmatic approach to argumentation theory. In Argumentation library, vol. 20. Dordrecht: Springer.
Govier, T. 1987. Problems in argument analysis and evaluation. Dordrecht-Holland: Foris.
Grennan, Wayne. 1994. Are “gap-fillers” missing premises? Informal Logic 16(3): 185–196.
Pinto, Robert. 2011. The account of warrants in Bermejo-Luque’s. Giving Reasons 72: 311–320.
Thomson, J.F. 1960. What Achilles should have said to the tortoise. Ratio 3: 95–105.
Toulmin, S.E. 1958. The uses of argument. Cambridge: Cambridge University Press.
Acknowledgments
The author received grant support from “Is moral reasoning essentially dialogical?” (SFRH/BPD/77687/2011) and “Argumentation, Communication and Context” (PTDC/FIL–FIL/110117/2009).
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Botting, D. The Logical Evaluation of Arguments. Argumentation 30, 167–180 (2016). https://doi.org/10.1007/s10503-015-9383-1
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DOI: https://doi.org/10.1007/s10503-015-9383-1