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Moral Disagreement and Higher-Order Evidence


This paper sketches a general account of how to respond in an epistemically rational way to moral disagreement. Roughly, the account states that when two parties, A and B, disagree as to whether p, A says p while B says not-p, this is higher-order evidence that A has made a cognitive error on the first-order level of reasoning in coming to believe that p (and likewise for B with respect to not-p). If such higher-order evidence is not defeated, then one rationally ought to reduce one’s confidence with respect to the proposition in question. We term this the higher-order evidence account (the HOE account), and present it as a superior to what we might call standard conciliationism, which holds that when agents A and B disagree about p, and are (known) epistemic peers, they should both suspend judgement about p or adjust their confidence towards the mean of A and B’s prior credences in p. Many have suspected that standard conciliationism is implausible and may have skeptical implications. After presenting the HOE account, we put it to work by applying it to a range of cases of moral disagreement, including those that have feature in recent debates assuming standard conciliationism. We show that the HOE account support reasonable, non-skeptical verdicts in a range of cases. Note that this is a paper on moral disagreement, not on the HOE account, thus the account is merely stated here, while defended more fully elsewhere.

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  1. 1.

    Note that the term ‘conciliationism’ is also used in a somewhat broader sense, denoting views stating that in peer disagreements one should reduce one’s confidence in the disputed belief.

  2. 2.

    Throughout the paper, we will assume that moral intuitions and moral beliefs can be right or wrong/true or false, and that we are epistemically committed (as well as morally committed) to have true moral views. So, in effect we treat moral beliefs and moral intuitions just like ordinary factual beliefs and factual intellectual seemings, or dispositions to judge in certain ways. We also freely assume that rational credences in propositions come in quantitative degrees, i.e. a credence in p can be represented by a number between 0 and 1.

  3. 3.

    This section is based on material first published in (Kappel 2018).

  4. 4.

    This case is adapted from (Christensen 2011, pp. 5–6).

  5. 5.

    Cf. Horowitz’s discussion of epistemic akrasia (2014).

  6. 6.

    Of course, epistemic peers cannot have different evidence, and maybe peers cannot differ with respect to whether they commit a principle error. This leaves performance errors as the only option for explaining peer disagreement, which by itself seems plausible. But ordinary disagreements, of course, often involve different sets of evidence, and a general theory about disagreement should cover such cases.

  7. 7.

    For discussions of Condorcet’s Jury Theorem, and the significance of independent belief formation and consensus, see e.g. (Lackey 2013; List 2001; Goldman 2001).

  8. 8.

    (Christensen 2011, p.1).

  9. 9.

    For discussion, see e.g. (Christensen 2009, 2011; Lord 2014; Moon 2018; Sosa 2010). For Christensen’s most recent defense of a modified version of the Independence Principle, see (Christensen 2019).

  10. 10.

    So, we submit that the HOE account will support restrictions somewhat similar to but not identical to the Independence Principle. We cannot develop the details of this here, but see (Kappel and Andersen unpublished manuscript).

  11. 11.

    Disagreements of a similar sort is discussed by Richard Rowland (2017a) and Kieran Setiya (2012). Setiya writes about moral monsters, i.e. individuals who have horrible moral beliefs. Clearly, on behalf of conciliationism it might be objected that moral monsters are not peers. One problem with this response is whether the judgement that moral monsters are not peers is permitted given that one accepts the Independence Principle. See also our brief mention of the weak and strong evidence requirement below.

  12. 12.

    Discussed by (Christensen 2007, p. 199).

  13. 13.

    When is a moral view bizarre? Often professional philosophers claim to find their colleagues’ views bizarre, but professional philosophers’ judgement that some otherwise widely shared view is hard to make sense of is not quite what we are after. One might also think that if a moral intuition is widely held among otherwise reasonable people this counts against it being bizarre. On the other hand, given that we generally adopt moral beliefs that are entrenched in our culture, we might expect that a moral belief may become widespread even if it is bizarre in some sense, including our sense. Thanks to a reviewer for bringing up this issue.

  14. 14.

    Note that it is not obvious that A’s reasoning needs to cite A’s specific intuition – it may be enough that A reasons from the apparent difficulty of making sense of B’s bizarre intuition.

  15. 15.

    As the cases are described, one may wonder, as a reviewer did, whether local evil and bizarre disagreements provide even prima facie higher-order evidence in the first place. In response, one can modify the cases and add that the individuals in question are generally intelligent and thoughtful, or that we know that they form competent moral beliefs in other cases. It would then be natural to think that the disagreement yields some higher-order evidence, which is then in turn undercut. But of course, there is a general issue about distinguishing between cases in which higher-order evidence is undercut, and cases in which we might prefer to say that there is no such evidence in the first place. Note that the implications for the HOE account would be the same for local evil and local bizarre disagreements even after the suggested modifications. According to the HOE account, if there is no prima facie higher-order evidence to begin with, we should not conciliate.

  16. 16.

    See e.g. (Christensen 2011; Vavova 2014; Rowland 2017a).

  17. 17.

    Here we arbitrarily state the evidence requirements from A’s point of view.

  18. 18.

    We elaborate the epistemic significance of convergence in ethics in (Kappel, Andersen et al. unpublished manuscript).

  19. 19.

    For more on this conception of deep disagreement see (Lynch 2010, 2016; Kappel 2012, 2018).

  20. 20.

    This and the following paragraphs are revised material from (Kappel 2018).

  21. 21.

    (Rowland 2017a, p. 1).

  22. 22.

    Note that a principle T may be foundational in this sense for A, while the negation of T is not foundational for another subject B. We will ignore this complication here.

  23. 23.

    Note that this dialectic impediment is compatible with the disagreement being resolvable in a different sense. Suppose that both A and B accept some version of reflective equilibrium (RE) and suppose A can make clear to B that A’s view is better in terms of RE than B’s, i.e. A’s view instantiates the good-making epistemic features of RE to a higher total degree than B’s view. If we assume that RE is (also) a theory about what theories to choose in ethical theory, then this could be a rationally convincing reason for B to change his view.

  24. 24.

    In our discussion of fundamental disagreement and fully theorized philosophical disagreements we assumed that agents are relying on reflective equilibrium as their method of reasoning. A reviewer questioned this assumption. We make this assumption to make the discussion manageable and more concrete, and it seems a far from problematic assumption as reflective equilibrium is probably the most widely used method of moral reasoning. Moreover, it seems to us that as long as two agents are using (are known to be using) the same methods, then the HOE account will recommend conciliation in both fundamental disagreements and in fully theorized disagreements.


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We have presented this material at workshops in London, Lisbon, and Copenhagen. Thanks to audiences there for helpful comments, in particular Julien Dutant, Alexander Heape and participants in LVU18, Lisbon.

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Correspondence to Klemens Kappel.

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Kappel, K., Andersen, F.J. Moral Disagreement and Higher-Order Evidence. Ethic Theory Moral Prac 22, 1103–1120 (2019).

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  • Moral disagreement
  • Disagreement
  • Higher-order evidence
  • Steadfastness
  • Conciliationism
  • Equal weigh view