ISSA Proceedings 2014 – Argumentative Norms: How Contextualist Can They Be? A Cautionary Tale
Abstract: Are argumentative norms contextual? Yes: argument quality sometimes depends upon criteria that are context-relative. But this contextual dimension of argumentative norms depends upon a kind of context-independence: That a given argument is strong in its context is a claim that is not itself dependent upon any particular context. Consequently, there is an in-principle limit on the degree to which argumentative norms can be rightly regarded as contextual.
Keywords: argument, argumentation, argument norms, argument purposes, contextualism, epistemological relativism
1. The case for and limits of contextualism
“Argumentation is always situated: it always occurs in context.”
(Van Eemeren and Garssen 2012b, p. xiii)
It is true, as van Eemeren and Garssen say, that argumentation always occurs in context: to engage in argumentation, an arguer must be in some context or other. But are argument norms similarly contextual? That is, are the norms governing argument quality relative to or dependent upon the context in which the argument is either asserted or evaluated? Let contextualism[i] be the view that criteria of argument quality vary by context: According to contextualists, whether an argument is good or not, and how good it is, depends upon the context in which it is either uttered or evaluated. Many authors have urged that contextualism, or something like it, is true.[ii]
There is an obvious prima facie case for contextualism which rests on the fact that the ‘good-making’ features of arguments seem to vary by context: What makes an argument good in a scientific context seems to differ in some respects from what makes an argument good in a court of law, a conversation among friends, or a marketing strategy discussion in the corporate boardroom. That is, it seems to be the case that the quality of arguments sometimes depends upon criteria that are context-relative. For example, scientific arguments at least often have to meet criteria of explanatory adequacy; legal arguments often have to meet criteria of evidence admissibility; etc. So it seems that the norms of argument quality are relative to context: an argument can be good although it doesn’t meet legal criteria of evidence admissibility if it is offered or evaluated in a scientific or corporate boardroom context; an argument can be good although it doesn’t meet criteria of explanatory adequacy if it is offered or evaluated in the context of a court of law or a conversation around the dinner table.
However, it would be too quick to conclude on the basis of this prima facie case that argument norms are indeed contextual. For we should distinguish between differences in argumentative context entailing differences in criteria of argument quality, on the one hand, and differences in the purposes of argumentation entailing such differences, on the other. We should agree that people argue for different purposes, a point generally agreed among argumentation scholars and reflected in the range of approaches reflected in their scholarship. Three important such purposes are: the persuading of one’s audience of a particular claim, thesis, or standpoint (reflected in rhetorical approaches to the study of argument); the achieving of consensus (reflected in dialectical approaches); and the enhancement of the epistemic status of claims or conclusions argued for (reflected in epistemic approaches). Argument norms do differ across these: an effective persuasive argument may be less successful at fostering consensus or supporting a conclusion, etc. But these are differences of purpose, not context.[iii]
More importantly, and the main point argued for here: contextualism, if correct, depends upon an underlying non-contextualism. Suppose there is a genuine contextual dimension of argumentative norms, such that (C):
(C): What makes a good argument good in a particular context, say, a scientific one, differs at least in part from what makes an argument good in contexts such as corporate boardrooms, conversations among friends, or courts of law.
From what context might (C) itself be established by argument? If (C) is worthy of belief, as asserted by contextualists, there must be a good argument that supports it; good reasons that render it so worthy. But that argument’s quality can’t itself be limited to some particular context, because if it is so limited, (C)’s epistemic status will itself be relative to context. That is, the argument that establishes (C) will itself be good in some contexts but not in others. And this seems to undercut the argument for (C): if it supports (C), it will do so only in some contexts, and will fail to do so in others. And this sounds like the familiar problem with (epistemological) relativism.[iv]
2. The problem with relativism
What is relativism, and what is the problem with it? Let relativism be understood as:
ER: For any knowledge-claim p, p can be evaluated (assessed, established, etc.) only according to (with reference to) one or another set of background principles and standards of evaluation s1,…sn; and, given a different set (or sets) of background principles and standards s’1,…s’n, there is no neutral (that is, neutral with respect to the two (or more) alternative sets of principles and standards) way of choosing between the two (or more) alternative sets in evaluating p with respect to truth or rational justification. p’s truth and rational justifiability are relative to the standards used in evaluating p. (Siegel 1987, p. 6)
If this is relativism, what is the problem with it? The problem, familiar since Plato’s Theatetus, is that it is self-referentially incoherent or self-refuting, in that defending the doctrine requires one to give it up. Why?
Insofar as she is taking issue with her non-relativist philosophical opponent, the relativist wants both (a) to offer a general, non-relative view of knowledge (and/or truth or justification), and assert that that general view – i.e., that knowledge is relative – is epistemically superior and preferable to its rivals; and also (b) to deny that such a general, non-relative view is possible or defensible. The relativist needs to embrace both (a), in order to see her position both as a rival to, and, further, as epistemically superior to, the position of her non-relativist opponent; and (b), in order to honor the fundamental requirements of relativism. But the mutual embrace of (a) and (b) is logically incoherent. For the embrace of (a) forces the rejection of (b): if relativism is the epistemically superior view of knowledge (i.e., (a)), then one general view of knowledge is both possible and defensible as epistemically superior to its rivals (contrary to (b)). Similarly, the embrace of (b) forces the rejection of (a): if no general, non-relative view of knowledge is possible or defensible (i.e., (b)), then it cannot be that relativism is itself epistemically superior to its rivals (contrary to (a)). This argument strongly suggests that the assertion and defense of relativism is incoherent.[v]
3. Relativism and contextualism
Of course, contextualism is not the same as relativism. Can the contextualist escape this incoherence problem? The key question is: From what context might the contextuality of argument norms be established? The worry is this: It appears that any argument for contextuality will itself necessarily be made from some context or other. Consequently the contextualist appears to be committed to the claim that the norms governing its quality will be forceful only contextually. If its quality is context-dependent, its normative force is equally so, thus rendering it unable to stand against or compete effectively with parallel arguments for the contrary conclusion launched from alternative contexts. The problem for the contextualist can be illustrated by drawing explicitly the analogy between the self-referential argument against relativism just rehearsed and the analogous argument against contextualism with respect to argument norms:
CAN: For any argument A purporting to establish (C), A can be evaluated (assessed, established, etc.) only according to (with reference to) one or another set of contextually bound argument norms n1,…nn; and, given a different set (or sets) of argument norms n’1,…n’n, there is no neutral (that is, neutral with respect to the two (or more) alternative sets of principles and standards) way of choosing between the two (or more) alternative sets in evaluating A with respect to its ability to establish the truth or rational justification of (C). (C)’s truth and justificatory status are relative to the contextual norms used in evaluating A.
The problem with CAN can now be spelled out on analogy with the problem with ER: Contextualism appears to be self-referentially incoherent or self-refuting, in that defending the doctrine requires one to give it up. Why?
Insofar as she is taking issue with her non-contextualist philosophical opponent, the contextualist wants both (a’) to offer a general, non-contextual view of argument norms, and assert that that general view – i.e., that argument norms are contextual – is epistemically superior and preferable to its rivals; and also (b’) to deny that such a general, non-contextual view is possible or defensible. The contextualist needs to embrace both (a’), in order to see her position both as a rival to, and, further, as epistemically superior to, the position of her non-contextualist opponent; and (b’), in order to honor the fundamental requirements of contextualism. But the mutual embrace of (a’) and (b’) is logically incoherent. For the embrace of (a’) forces the rejection of (b’): if contextualism is the epistemically superior view of argument norms (i.e., (a’)), then one general, non-contextual account of argument norms is both possible and defensible as epistemically superior to its rivals (contrary to (b’)). Similarly, the embrace of (b’) forces the rejection of (a’): if no general, non-contextual account of argument norms is possible or defensible (i.e., (b’)), then it cannot be that contextualism is itself non-contextually superior to its rivals (contrary to (a’)). This argument strongly suggests that the assertion and defense of contextualism is incoherent.
4. The fate of contextualism
Thus the contextualization of argument norms is capable of being established only from a ‘universal,’ ‘a-contextual’[vi] context. How should we make sense of this situation?
The threat of incoherence establishes a strong, in-principle limit on the degree to which argument norms can be rightly regarded as contextual. As we saw earlier, arguments can be offered for different purposes. Can the norms governing their quality be relativized to context more generally, such that argument A can be good in (e.g.) a scientific journal but bad in a court of law or a casual conversation among friends? Yes, but only in so far as those contextualized norms – e.g., that scientific arguments can be good/bad in so far as they meet (or not) norms of explanatory adequacy – are themselves established by arguments whose quality is not itself contextual or contextually bound. The argument constitutes an incoherence proof[vii] of a thoroughgoing contextualism concerning argument norms – such a thoroughgoing contextualism is incoherent — and establishes the limits of a defensible contextualism. We can coherently be pluralists about argument norms[viii], allowing that there are multiple legitimate argument norms, and that some of them are operative only in particular contexts. We should be pluralists in this sense. But we cannot, on pain of incoherence, be so thoroughgoingly contextualist as to hold that the case for this view is itself sanctioned by norms whose force is itself limited to particular contexts.
5. Are prominent theorists problematically contextualist?
Let us now briefly consider some prominent argumentation theorists who embrace one or another sort of contextualism to see whether their contextualisms violate the limits of a defensible contextualism just adduced.
5.1. Stephen Toulmin
Toulmin famously held that “the merits of our arguments … are field-dependent” (1958, p. 15, emphasis in original):
[A]ll the canons for the criticism and assessment of arguments …are in practice field-dependent, while all our terms of assessment are field-invariant in their force. We can ask, ‘How strong a case can be made out?’ [for arguments in three different fields] and the question we ask will be how strong each case is when tested against its own appropriate standard. We may even ask, if we please, how the three cases compare in strength, and produce an order of merit … But in doing so we are not asking how far the cases for the three conclusions measure up to a common standard: only, how far each of them comes up to the standards appropriate to things of its kind. The form of the question, ‘How strong is the case?’, has the same force or implications each time: the standards we work with in the three cases are different. (1958, p. 38, emphases in original)
It is unclear whether a Toulminian ‘field’ is the same sort of thing as that which other writers refer to as a ‘context’. If these are not the same, then Toulmin should not count as the sort of contextualist we are concerned with here. But assuming for the sake of argument that he should so count, it is clear that he does not face the incoherence worry laid out earlier. He does not argue or suggest that his case for the field-dependence of argument quality[ix] is itself launched from any particular field or context; he seems clearly enough to hold that the field-dependence of argument quality he advances is not itself dependent on any particular field or context. He does not suggest, for example, that judged from the context of argumentation theory argument quality is field-dependent, but judged from the context of physics, formal logic or history argument quality is field-independent. Rather, he urges that it is a field-independent truth that argument quality is field-dependent. So he does not embrace or endorse the problematic (b’) above. So he cannot fairly be charged with a problematic incoherence.
Toulmin makes an important point: some criteria of argument quality apply in some contexts but not others – e.g., a good inductive argument will not be good in most logico-mathematical contexts, in which deductive soundness is required[x] – and this is one example of the way in which argument norms are contextual. That said, I am not here endorsing Toulmin’s overall views concerning argument quality; those views are not my present concern. I am arguing only that, insofar as his view is rightly thought of as contextualist, it is not such as to run the risk of incoherence set out above.[xi]
5.2. Douglas Walton
Walton has long defended a version of contextualism. Consider, from among many such passages in his writings:
[T]he validity or correctness of an argumentation scheme, as used in a given case, depends on the context of dialogue appropriate for that case. (1996, p. 13)
[A]ny claim that a fallacy has been committed must be evaluated in relation to the text of discourse available in a given case … [A]n argument will always occur in a context of dialogue … Much of the work of analysis and evaluation of the allegedly fallacious argument will involve placing that argument in a context of dialogue. (1996, p. 14).
[A]rguments are evaluated as correct or incorrect [on Walton’s proposed pragmatic standard of argument evaluation] insofar as they are used either to contribute to or to impede the goals of dialogue. (1998, p. 3)
[A] presumptive argument based on an argumentation scheme should always be evaluated in a context of the dialogue of which it is a part. (2001, p. 159)
This pragmatic dimension [of justifying schematic arguments] requires that such arguments need to be examined within the context of an ongoing investigation in dialogue in which questions are being asked and answered. (2005, p.8)
Like Toulmin’s, Walton’s contextualism is not guilty of the sort of incoherence illustrated above. He makes the important points that instances of argumentation take place in the context of particular dialogues, that particular argumentation schemes are suitable (or not) for such contexts, and that the evaluation of particular argumentative moves and exchanges depends upon the schemes appropriate for the context in question. He does not suggest that his own (pragmatic, dialogical) theory of argument evaluation is itself justified only contextually. That is, he does not assert (b’) above. So there is no incoherence here. (Whether or not his pragmatic, dialogical approach is a good one I do not take up here.)
5.3. Geoff Goddu
Goddu argues compellingly that “the correct evaluation of an argument is context dependent.” (2003b, p. 381) The most important reason he offers for thinking so is that “when evaluating an argument … we must take into account not only the actual support that the premises provide, but the degree of support the premises need to provide as well. We need to know if the actual degree of support is enough and what support is enough will change from context to context.” (2004, p. 30, emphases in original, note deleted; cf. also p. 33) He illustrates his claim with several suggestive examples. The most straightforward is that of the same argument, utilizing the same evidence, put forward by the prosecution in both civil and criminal trials: in the former the argument is adequate if it establishes the defendant’s guilt by a preponderance of the evidence; in the latter the evidence must establish guilt beyond a reasonable doubt. If the argument establishes that the probability of the defendant’s guilt is .6, it is adequate in the context of the civil trial but not that in of the criminal trial.[xii]
As with Toulmin and Walton, Goddu’s contextualism does not involve the sort of incoherence we are concerned with here. His correct point concerning the context dependence of argument adequacy is not itself true only in some contexts and not in others; he does not suggest either that his argument for context dependence is itself context dependent or that that argument is adequate in some contexts and not others. Rather, he establishes the context-independent conclusion that argument evaluation is contextual. Like Toulmin and Walton, he does not assert (b’) above. So there is no incoherence here.
5.4. Frans van Eemeren
The final author to be considered is Frans van Eemeren. Van Eemeren (in collaboration with several of his co-authors) embraces a substantial but constrained version of contextualism. He acknowledges both general, context-independent and context-dependent criteria “for the fulfilment of norms of reasonableness”, which norms are “incorporated in the rules of critical discussion” at the heart of the Pragma-Dialectical approach:
Because the application of the critical norms of reasonableness is partially dependent on the requirements that result from the exact circumstances in which the argumentation occurs, such that these norms can be implemented in slightly different ways, the content of these criteria can sometimes be context dependent. This means that the context in which the argumentative exchange takes place has to be, in principle, taken into account explicitly in determining the fallaciousness [of a given argumentative move/strategic maneuver].
Besides the general criteria which are context independent, specific criteria which are context-dependent will also play a role in the evaluation of [such moves/maneuvers]… (Van Eemeren 2011b, p. 40)
When reflecting upon the criteria that can be brought to bear to distinguish between sound and fallacious strategic maneuvering, I make a distinction between general criteria for judging fallaciousness that are context-independent and more specific criteria that may be dependent on the macro-context in which the strategic maneuvering takes place. (Van Eemeren 2011a, p. 154)
As these citations make clear, van Eemeren’s contextualism is not so thoroughgoing as to run into the incoherence problem described above. It explicitly acknowledges context-independent criteria for the satisfaction of the pragma-dialectical norms of reasonableness. Moreover, those norms, incorporated in the pragma-dialectical rules governing critical discussions, are themselves context-independent: whatever the context, if one violates a rule one violates the associated norm. Most importantly for present purposes, van Eemeren’s argument for contextualism is not itself contextually bound. Like our other authors, he does not assert (b’) above. Once again, there is no incoherence here.[xiii]
6. Conclusion: contextualism, but only within limits
If the argument offered here is successful, argument norms can be established only by arguments/reasons that are non-contextual in character and epistemic force. This leaves room for a healthy pluralism concerning argument norms. There are important contextual dimensions of argument quality and important things concerning contextually specific aspects of argument quality for argumentation theorists to study and say.[xiv] There are multiple legitimate argument norms, and some of them are operative only in particular contexts. But that any particular argument norm is a legitimate norm in a particular argument context cannot itself be established contextually.
Is this really a problem worth worrying about? After all, as we’ve just seen, none of the theorists considered above go over the line; their contextualisms are all sufficiently bounded so as to not risk the incoherence worry I have been belaboring. That these theorists stay clear of the difficulty is of course a good thing. The lesson to be learned from this discussion, if there is one, is a cautionary one: in theorizing about the contextual character of argument norms, don’t go over the line. Contextualism defended non-contextually is, or at least might be, OK; contextualism that extends to the defense of that view itself, not so much. As with other such topics, self-referential incoherence is a worry to take seriously when theorizing about argument norms.
Acknowledgement
I presented an ancestor of this paper as a powerpoint talk at the ‘Argumentation and Philosophy: Different Issues or Productive Tensions?’ symposium at the Universidad Nacional Autónoma de México in Mexico City in 2009 and at the 7th ISSA conference in Amsterdam in 2010 but never wrote it up for publication. I presented a revised and expanded talk at the 8th ISSA conference in July 2014. I am grateful to Jan Steutel and to the audiences at the several presentations, especially Derek Allen, John Biro, Geoff Goddu, Cristoph Lumer, Mark Weinstein and John Woods for insightful comments, criticisms and suggestions.
NOTES
i. The questions pursued here do not concern the view called ‘contextualism’ in epistemology and philosophy of language. There ‘contextualism’ is understood as a response to skepticism, according to which in ordinary, ‘low-stakes’ contexts we know, e.g., that we have hands, but in ‘high stakes’ contexts we don’t know this because we can’t rule out the possibility that we’re being deceived by an evil demon. For an overview of the literature and a defense of this sort of contextualism, cf. DeRose 2009.
ii. Among many others, in addition to those authors discussed below, cf. Fogelin 1985/2005 and Battersby and Bailin 2011. Battersby and Bailin helpfully distinguish dialectical, historical, intellectual, political, social and disciplinary contexts; I strongly recommend their discussion.
iii. Notice that I am not claiming that argument purpose differs systematically across context – this I would deny – but rather asking whether the criteria that arguments must meet in order to be good differ in this way. Here I am indebted to the good advice of John Biro and Jan Steutel. It is uncontroversial that arguments are advanced for a variety of purposes. For a typical acknowledgement of this, see Toulmin 1958, p. 12.
iv. I am speaking throughout only of epistemological relativism.
v. For a more precise and detailed analysis of relativism and its vicissitudes, cf. Siegel 1987, 2004, and 2011, from which the version of the argument just given in the text is adapted.
vi. There is of course no ‘view from nowhere’ or ‘a-contextual context’ – hence the scare quotes. All our arguments are offered and evaluated in some context or other and from some conceptual scheme, perspective or point of view. The point on the table is just that the quality of arguments used to establish this very point is not itself dependent on the context in which the argument is offered or evaluated, and acknowledging it does not commit one to either relativism or contextualism. It is central to philosophical discussions of relativism; for systematic treatments of it in that context, cf. Siegel 1987, 1997, 2004, and 2011. Thanks to Derek Allen and Geoff Goddu for pressing me on this.
vii. Thanks to Christoph Lumer for this felicitous expression.
viii. A similar pluralism is endorsed by David Godden (2005).
ix. In his discussion Toulmin uses the words ‘canons’, ‘criteria’ and ‘standards’ to pick out those things in accordance with which argument quality is determined or assessed. These are not synonymous but I won’t tarry on this point here.
x. Although we must be careful here, for these criteria do not vary systematically by field. The variation is messier than one might expect. Cf. Siegel 1997, pp. 29-33.
xi. I think the same can be said of the prominent Toulminians Mark Weinstein and John Woods. Cf. Weinstein 2013 and, e.g., Woods 2005, p. 497.
xii. For this and other examples see Goddu 2003b, p. 380 and Goddu 2004, pp. 27-30; cf. Goddu 2001 for an early articulation of his view of argument evaluation and Goddu 2003a and 2005 for systematic discussions of the difficulties of specifying ‘the context of an argument’ and ‘context dependence’ respectively. A closely related point concerning the context-dependence of the evaluation of some scientific arguments is made in Rudner 1953.
xiii. Van Eemeren’s general approach, like Walton’s, is both pragmatic and dialectical. For a very helpful comparison of the two views, especially with respect to contextualism, cf. van Eemeren et. al. 2010. I should note once again (but not pursue here) a widespread ambiguity in the argumentation literature: dialogical/dialectical approaches, like those of Walton and van Eemeren, focus on norms governing particular argumentative moves in dialogue, while other approaches, and in particular Goddu’s and epistemic theorists such as Lumer and Biro and me, focus not on the norms governing such moves but rather on those governing the evaluations of particular arguments conceived as abstract objects. Cf. Goddu’s papers cited above, Lumer 2005, Biro and Siegel 2006 and Siegel and Biro 2010.
xiv. Some of which are said in such venues as van Eemeren and Garssen 2012 and the series in which this volume appears, as well as the work of Walton and van Eemeren cited above.
References
Battersby, M., & Bailin, S. (2011). Critical inquiry: Considering the context. Argumentation, 25.2, 243-253.
Biro, J., & Siegel, H. (2006). Pragma-dialectic versus epistemic theories of arguing and arguments: Rivals or partners? In P. Houtlosser & A. van Rees (Eds.), Considering Pragma-Dialectics: A Festshrift for Frans H. van Eemeren on the Occasion of his 60th Birthday (pp. 1-10). Mahuah, NJ: Erlbaum.
DeRose, K. (2009). The case for contextualism: Knowledge, skepticism, and context, Volume 1. Oxford: Oxford University Press.
Eemeren, F. H. van (2011a). In context: Giving contextualization its rightful place in the study of argumentation. Argumentation, 25.2, 141-161.
Eemeren, F. H. van (2011b). In alle redelijkheid/In reasonableness. Amsterdam: Rozenberg and Sic Sat Publishers.
Eemeren, F. H. van, & Garssen, B. (Eds.), (2012a). Exploring argumentative contexts. Amsterdam: John Benjamins Publishing Company.
Eemeren, F. H. van, & Garssen, B. (2012b). Introduction. In van Eemeren and Garsssen 2012a, pp. xiii-xx.
Eemeren, F. H, van, Houtlosser, P., Ihnen, C. & Lewiński, M. (2010). Contextual considerations in the evaluation of argumentation. In C. Reed and C. W. Tindale (Eds.), Dialectics, dialogue and argumentation: An examination of Douglas Walton’s theories of reasoning and argument (pp. 115-132). King’s College London, UK: College Publications.
Fogelin, R. J. (2005). The logic of deep disagreements. Informal Logic, 25.1, 3-11. Originally published in Informal Logic (1985), 7.1, 1-8.
Godden, D. (2005). Deductivism as an interpretive strategy: A reply to Groarke’s recent defense of reconstructive deductivism. Argumentation and Advocacy, 41, 168-183.
Goddu, G. C. (2001). The ‘most important and fundamental’ distinction in logic. Informal Logic, 22.1, 1-17.
Goddu, G. C (2003a). The context of an argument. In J. A. Blair, et. al. (Eds.), Informal Logic at 25: Proceedings of the Windsor Conference, CD-ROM, Windsor, ON: OSSA, pp. 1-14.
Goddu, G. C. (2003b). Context and argument evaluation. In F. H. van Eemeren, et. al. (Eds.), Proceedings of the Fifth Conference of the International Society for the Study of Argumentation (pp. 377-381). Amsterdam: Sic Sat.
Goddu, G. C. (2004). Cogency and the validation of induction. Argumentation, 18.1, 25-41.
Goddu, G. C. (2005). Epistemic contextualism and the context of an argument. In D. Hitchcock (Ed.), The uses of argument: Proceedings of a conference at McMaster University, 18-21 May 2005 (pp. 148-155). Windsor, Ontario: The Ontario Society for the Study of Argumentation.
Lumer, C. (2005). The epistemological theory of argument – How and why? Informal Logic, 25.3, 213-243.
Rudner, R. (1953). The scientist qua scientist makes value judgments. Philosophy of Science, 20.1, 1-6.
Siegel, H. (1987). Relativism refuted: A critique of contemporary epistemological relativism. Dordrecht: Springer.
Siegel, H. (1997). Rationality redeemed?: Further dialogues on an educational ideal. New York: Routledge.
Siegel, H. (2004). Relativism. In I. Niiniluoto, M. Sintonen, and J. Woleński (Eds.), Handbook of Epistemology (pp. 747-780). Dordrecht: Kluwer.
Siegel, H. (2011). Epistemological relativism: Arguments pro and con. In S. D. Hales (Ed.), A companion to relativism. Malden, MA: Blackwell.
Siegel, H. & Biro, J. (2010). The Pragma-dialectitian’s dilemma: Reply to Garssen and van Laar. Informal Logic, 30.4, 457-480.
Toulmin, S. E. (1958). The uses of argument. Cambridge: Cambridge University Press.
Walton, D. N. (1996). Argumentation schemes for presumptive reasoning. Mahwah, NJ: Lawrence Erlbaum Associates Publishers.
Walton, D. N. (1998). The new dialectic. Toronto: University of Toronto Press.
Walton, D. N. (2001). Abductive, presumptive and plausible arguments. Informal Logic, 21.2, 141-169.
Walton, D. N. (2005). Justification of argument schemes. Australasian Journal of Logic, 3, 1-13.
Weinstein, M. (2013). Logic, truth and inquiry. King’s College London, UK: College Publications.
Woods, J. (2005). Eight theses reflecting on Stephen Toulmin. In D. Hitchcock (Ed.), The uses of argument: Proceedings of a conference at McMaster University, 18-21 May 2005 (pp. 495-504). Windsor, Ontario: The Ontario Society for the Study of Argumentation.