Burdens of Proof and the Case for Unevenness


How is the burden of proof to be distributed among individuals who are involved in resolving a particular issue? Under what conditions should the burden of proof be distributed unevenly? We distinguish attitudinal from dialectical burdens and argue that these questions should be answered differently, depending on which is in play. One has an attitudinal burden with respect to some proposition when one is required to possess sufficient evidence for it. One has a dialectical burden with respect to some proposition when one is required to provide supporting arguments for it as part of a deliberative process. We show that the attitudinal burden with respect to certain propositions is unevenly distributed in some deliberative contexts, but in all of these contexts, establishing the degree of support for the proposition is merely a means to some other deliberative end, such as action guidance, or persuasion. By contrast, uneven distributions of the dialectical burden regularly further the aims of deliberation, even in contexts where the quest for truth is the sole deliberative aim, rather than merely a means to some different deliberative end. We argue that our distinction between these two burdens resolves puzzles about unevenness that have been raised in the literature.

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  1. 1.

    To save space, we will sometimes write as though burdens of proof attach to propositions, rather than to their real or imagined supporters.

  2. 2.

    However, in the writings of Whately (and also of Thomas Reid), it is common sense that furnishes us with many presumptions. Hence, arguably, common sense gives us sufficient (rather than no) evidential support according to these authors and this undermines the idea that they are invoking the attitudinal conception when they endorse uneven burdens.

  3. 3.

    We chose “attitudinal” because, as will become clear, the relevant burden is to meet some standard of evidence that is required if one is to hold a particular cognitive attitude towards a proposition to such as believing it, or conjecturing that it is true. We chose “dialectical” because the relevant burdens arise in reasoning and argumentation that involves weighing the evidence for and against a proposition, or the evidence for competing propositions. Such a process is dialectical in a very general sense. Our use of the word is not associated with any more specialised use of it by argumentation theorist such as, for instance, to describe a specific approach to argumentation.

  4. 4.

    In some group deliberation, individual agents assume roles, such as that of an arbiter, or that of a persuader; in others, there is a spirit of joint inquiry. Some groups, such as those you find in protracted trade negotiations, are large or volatile.

  5. 5.

    Grice would include the very formalised or ritualised interactions that constitute legal proceedings, public meetings and parliamentary debates among conversations.

  6. 6.

    We remain neutral on whether deliberation, as characterised here, is always representable as some kind of discourse or dialogue. Note however that unlike some argumentation theorists (e.g. Douglas Walton), we do not use the word “deliberation” to delineate a type of communicative act or exchange.

  7. 7.

    We are not wedded to any particular idea of what makes for evidential support, but here are some very rough terminological constraints. One has evidential support for a proposition to the extent that one has grounds (or reasons) for regarding it as likely. Very roughly, to the extent that such grounds are regarded as credible, the proposition under scrutiny is regarded as credible. The evidential support is sufficient if it satisfies a contextually relevant criterion (a standard of proof) and we mention several examples of such criteria below. We will assume that they are, or correspond to, various inferential and epistemic norms derived from logic, probability theory, accounts of default, or legal reasoning and so on. (Readers who are uncomfortable with this assumption can substitute their own preferred story about norms of reasonableness.)

  8. 8.

    Negative and committed neutral attitudes or stances also attract attitudinal burdens. A negative attitude towards a proposition is a positive one towards its negation. A committed neutral attitude towards it is a positive attitude towards the proposition that it is not appropriate to have a view.

  9. 9.

    Examples from philosophy include: Brown (1970, p. 82), Rescher (1977, pp. 28, 105), Rescorla (2009, p. 86), and Walton (1988, pp. 239, 246). Examples from legal theory include Hay and Spier (1997, pp. 415, 427), Pauwelyn (1998), and Walton (2002, p. 268). Examples from argumentation theory include Bailenson and Rips (1999, pp. 4, 9, 12, 14), Gordon et al. (2007, pp. 876, 878–880, 887, 893), and Prakken et al. (2005, pp. 115–117, 123). There are many more. Of course, “discharging” and “shifting” in these writings might not always be intended to refer to a change. “Discharging the burden of proof” might instead mean: “having sufficient evidential support” and “shifting the burden of proof” might mean something like: “demonstrating that another party, rather than oneself, turns out to have had the heavier burden all along”. So understood, an attitudinal burden can be discharged or shifted, but these are unhappy metaphors.

  10. 10.

    Henceforth, we will not mention that variant in the text, but the way it operates in various contexts of deliberation can be recovered from a consideration of the way that the attitudinal conception operates in those contexts.

  11. 11.

    I may shoulder several dialectical burdens at once, because of the deliberative context in which I find myself. I may be required to provide sufficient evidential support for p, in order to provide sufficient evidential support for q, in order to provide sufficient evidential support for the proposition that my former self was wrong to deny that q.

  12. 12.

    The difference between merely having an attitudinal warrant and also being required to make it available is like the difference between being required to have a visa in a foreign country and being required to display it. I need a visa to be in the USA. I am not required to carry it with me when I walk on frozen Lake Carnegie, but I am sometimes required to display it at Newark airport.

  13. 13.

    The conception of relative weight developed here is intended as a way to make sense of appeals to the burden of proof in argumentation theory; it is not a claim about legal theory.

  14. 14.

    Because of these parallels between conversation and reasoning, we think that the dialectical conception of burden of proof distributions comports well with contemporary research programmes that focus on dialogues or constructions built out of speech acts. We think this conception offers a good account of many references to burdens of proof, explicit or otherwise, in some presentations of pragma-dialectics (see, for instance, van Eemeren and Grootendorst 1984), argumentative discourse analysis (see Schiffrin 1985, p. 40), communicative action theory (see Kopperschmidt 1987) and Walton’s pragmatic approach (see his 1992, p. 383). This does not mean, of course, that all of these theorists would agree with all the remarks we make about how dialectical burdens are distributed in various kinds of deliberative context.

  15. 15.

    We could, of course, adopt a broader definition, according to which there are different sorts of dialectical burden associated with different deliberative aims. The sort that we are calling dialectical burdens might then be called dialectical burdens of evidential support and there would also be dialectical burdens of persuasion, dialectical burdens of negotiation and so on. Certainly, all such burdens exist. We have made a terminological choice in order to draw attention to the issues that seem to have caused puzzlement about unevenness. These have to do with the conditions under which one party is required to establish that a proposition is plausible, to some degree, whereas another party is not. If every deliberative aim directly generates a dialectical burden (and hence, something that might be called a burden of proof), there is no puzzle. Given the more inclusive definition, it is immediately obvious that there are uneven distributions of (broadly construed) dialectical burdens. There will be one, for instance, whenever I aim to persuade you of something and you do not aim to persuade me of anything, or to remain unpersuaded; in deliberative contexts of that sort, I have a (dialectical) burden (of persuasion) and you do not.

  16. 16.

    Since I can do either of these without any personal commitment to the truth of p, not all of these types of context are ones in which I shoulder an attitudinal burden.

  17. 17.

    We have adapted this case from Dare and Kingsbury (2008, pp. 508–509).

  18. 18.

    This does not, of course, mean that he should then regard my ladder as unsafe; he can rationally remain agnostic, or take some more nuanced intermediate position. In a variant of the case, an insurer, building contractor, or other institution stipulates that my brother may only climb my ladder if it passes a specific safety test. In this variant, the default is still that he does not climb the ladder, so there is still an uneven distribution. Notice though that if the test is not performed, or if my ladder fails the test, my brother could still, quite rationally, believe that my ladder is safe, even if he would have had even higher credence in this proposition had the ladder passed the test and even if he should not climb it.

  19. 19.

    Decision-theoretically, the standard of proof, that is, the degree of conviction he would need in order to have a sufficiently “high conviction”, depends, in this context, on the expected utilities of climbing my ladder and of not climbing it.

  20. 20.

    Supplement the story in whatever way you prefer to rule out other options: going backwards, going nowhere and so on.

  21. 21.

    We do not assume that there is any such threshold (any standard of proof) in this kind of context. Plausibly, one should decide to go in the direction that is clearly supported by more evidence, however much evidence that is. Some writers, including Hahn and Oaksford (2008), would argue that this absence of a standard of proof means that there can be no burden. We will not address this issue. We restrict ourselves to considering when any burden that there might be is uneven.

  22. 22.

    It might help to think of particle physics or mathematics, in order to conceive of it. We will offer more mundane, though controversial, examples of it in Sect. 5 below.

  23. 23.

    Compare Hume in “Of Miracles” (1777, X.I.87; 1975, p. 110).

  24. 24.

    A prosecutor who is convinced, beyond reasonable doubt, that the accused is guilty shoulders a corresponding attitudinal burden. In general, though, questions about related attitudinal burdens shouldered by prosecution and defense counsels have to do with their doxastic attitudes, not with their professional obligations.

  25. 25.

    However, the burden shouldered by a prosecutor is often called “the burden of persuasion”. So another way to think about the situation is to regard the prosecutor’s attempt to establish guilt, beyond reasonable doubt, as a means of persuading the jury, beyond reasonable doubt, that the accused is guilty. Since persuasion is not a solely truth-seeking endeavour, this approach gives us the same picture as the one in the text, via a different route. On both accounts, the jury is required to deliberate appropriately about the verdict. According to yet another account, the prosecutor is not required to (try to) establish anything. The aim is simply to persuade the jury, perhaps by providing sufficient evidential support, perhaps not. On this account, the prosecution has no dialectical burden (in our sense) at all, but does shoulder a dialectical burden (of persuasion) in the broader sense described in footnote 21. Clearly such a burden is unevenly distributed, since nobody in this context is required to persuade the prosecution of anything.

  26. 26.

    What we have argued is that epistemic limitations can explain why the provision of sufficient evidential support for a proposition might redistribute the dialectical burden so that it attaches more heavily to the proposition’s negation than to the proposition itself. This argument seems not to generalise to all contexts where some evidential support is provided for a proposition. Suppose I provided supporting evidence for the proposition that the appointment is to the left that made this proposition just a little more credible, in the context, than its negation. Does this cause a slight redistribution of the dialectical burden? If so, we cannot explain it in terms of the way epistemic limitations call for efficient search strategies, as we did in the contexts where there was adequate evidential support for the proposition. If one view has a slight edge over a competitor, this is not in general a reason for thinking that we should be less sensitive to incoming evidence that offers further support for the view than to incoming evidence that challenges it. We should probably not respond to such a small difference in support by tweaking our evidence-gathering strategy. So can one explain how a small shift in support ratios could usefully be construed as a small dialectical burden redistribution? We suspect not. We suspect that no useful theoretical purpose is served by allowing that a dialectical burden gets redistributed, however subtly, with every change in support ratio. Talk of redistribution plausibly only makes sense when the change in ratio is due to evidential support that meets some standard that determines what we should believe or how we should act.

  27. 27.

    One might doubt that some or all of the deliberative contexts discussed below are solely truth-seeking. However, even if they are not, the uneven distributions in all of them can be traced to the quest for truth, even if that quest is best construed as a means to some other end.

  28. 28.

    It is not hard to think of reasons. A detective, wishing to check details, might ask me exactly how I know it is raining. If my answer disappoints, there will be reason to doubt my reliability and this may undermine the support for the proposition I asserted and perhaps redistribute the dialectical burden. The claim in the text is consistent with the possibility that the asserter does lack evidence. The heavier dialectical burden may fall on the challenger, even when the proposition’s supporters lack sufficient grounds for upholding it. If I, though normally reliable, didn’t look very carefully before reporting to you that it is raining (and even if you suspect this), the dialectical burden is arguably still on you, rather than me, to show that it is not raining. So we are dealing here with contexts in which someone who lacks sufficient grounds for a proposition may nonetheless lack a significant dialectical burden. As we noted in Sect. 5, this is the kind of context that is disallowed by both the attitudinal conception and the “lack of evidence” variant of it that we briefly considered there.

  29. 29.

    We are not claiming, though, that in order to equalise the dialectical burden distribution, the asserters of an outrageous, controversial, or improbable, proposition must establish its truth to the satisfaction of rational disputants. They might need to do this if they want the proposition to be credible. But something less may suffice to make it the case that the potential denier has just as much of a burden as the asserter. (Compare Godden and Walton 2007, p. 315.) Perhaps the asserters only need to explain that they got their information from a government leak, or an expert. Then it seems as though we would have moved to a more even distribution.

  30. 30.

    This is another sort of context in which someone who lacks adequate evidential support for a proposition (perhaps the taxing authority) may nonetheless lack a significant dialectical burden. Tax collecting is plausibly not solely truth-seeking, so factors to do with the aim it serves may also shape dialectical burden considerations. Nevertheless, the factors mentioned here are relevant, whether or not the deliberation is solely truth-seeking. See Hahn and Oaksford (2007, p. 41) for a parallel discussion of product liability.

  31. 31.

    Pragma-dialectical analysis always assumes “that argumentation is part of a critical discussion aimed at resolving a difference of opinion” (Houtlosser 2003, p. 30). So in pragma-dialectics, asserters are always regarded as shouldering a significant burden of proof.

  32. 32.

    A good source for understanding the adoption of these legal notions into the theory of argumentation as a type of situated communication is Ehninger and Brockriede (1962).

  33. 33.

    Our treatment of these issues reminds us that it is wrongheaded to characterise the conditions that make for uneven burdens along lines suggested by “semper necessitas probandi incumbit ei qui agit.” Whatever principles operate in particular legal systems, neither of the burdens we identify is characterised in general by, for instance, the principle that “usually one who makes an assertion must assume the responsibility of defending it.” (Michalos 1969, p. 370) One who believes a proposition should do so for a reason, whether or not one asserts it, because one shoulders an attitudinal burden. Whether one must defend one’s beliefs is another matter. Meanwhile, one who asserts should perhaps defend, if one’s assertion is controversial, because one shoulders a dialectical burden. One need not, however, if one asserts the obvious.

  34. 34.

    The distinction between subjective and objective burdens in German law is similarly a distinction within the class of dialectical burdens. (Likewise, Rescher’s (1977, p. 27) distinction between the probative burden of initiation and the evidential burden and Walton’s (1988, pp. 246–247) related distinction between the external (global) and internal (local) burden.) We suspect that all the burdens discussed in legal theory are primarily dialectical. They apparently constrain the attitudes of deliberators (juries, for instance) only indirectly, if at all. In other words, they may give rise to, but are not themselves, attitudinal burdens.

  35. 35.

    It is open to us, for instance, to agree with Hahn and Oaksford that “the burden of proof is insufficient as an explanatory tool for the fallacy of the argument from ignorance” (2007, p. 58) and that there seems little point in attributing attitudinal burdens except where there is “a threshold degree of conviction above which an action should be adopted, given the particular utilities associated with this action” (p. 57).


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We would like to thank Tim Dare, Justine Kingsbury, Fred Kroon, Immi Patterson, Glen Pettigrove, Chris Tucker, Konni Woods and three anonymous reviewers for detailed comments on various versions of this paper. We would also like to thank the audience at the 2008 meeting of the Australasian Association of Philosophy (New Zealand Division).

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Aijaz, I., McKeown-Green, J. & Webster, A. Burdens of Proof and the Case for Unevenness. Argumentation 27, 259–282 (2013). https://doi.org/10.1007/s10503-012-9285-4

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  • Burden of proof
  • Presumption
  • Argumentation
  • Expected utility