Bad bootstrapping: the problem with third-factor replies to the Darwinian Dilemma for moral realism


Street’s (Philos Stud 127:109–166, 2006) “Darwinian Dilemma” is a well-known epistemological objection to moral realism. In this paper, I argue that “third-factor” replies to this argument on behalf of the moral realist, as popularized by Enoch (Philos Stud 148(3):413–438, 2010, Taking morality seriously: a defense of robust realism, Oxford University Press, Oxford, 2011), Skarsaune (Philos Stud 152(2):229–243, 2011) and Wielenberg (Ethics 120(3):441–464, 2010, Robust ethics: the metaphysics and epistemology of godless normative realism, Oxford University Press, Oxford, 2014), cannot succeed. This is because they are instances of the illegitimate form of reasoning known as “bootstrapping.” The phenomenon of bootstrapping has been discussed in detail, most notably by Vogel (J Philos 97(11):602–623, 2000) and Cohen (Philos Phenomenol Res 65(2):309–329, 2002), in a different context as an objection to reliabilism and related theories of knowledge. I introduce four different characterizations of the error of bootstrapping from the epistemic literature in order to argue that the form of reasoning exemplified by third-factor replies would be deemed illegitimate by every one of them. I conclude that the moral realist should abandon third-factor replies, or else suggest a novel diagnosis for what goes wrong in bootstrapping cases that does not apply equally to the realist’s form of argument. However, I am not optimistic about the prospects for this latter strategy.

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  1. 1.

    Enoch ultimately argues that the epistemological challenge for moral realism is not in the end best understood, as it often is, in terms of epistemic “access,” but rather in terms of a demand for an explanation of striking correlations. See pages 415 and 420-1 of his “The epistemological challenge to metanormative realism: how best to understand it, and how to cope with it” in Philosophical Studies.

  2. 2.

    For more on this issue, see e.g. page 11 of Vavova’s (2015) “Evolutionary Debunking of Moral Realism” in Philosophy Compass.

  3. 3.

    Enoch formulates his own version of an epistemological challenge for moral realism, which he suggests is closely related to Street’s (2006) argument. Enoch also compares his argument to Hartry Field’s challenge for mathematical realism as it appears in Field’s (1989) Realism, Mathematics, and Modality. Enoch’s third-factor reply is addressed to Street and to his own formulation of the worry. In addition to Enoch (2010), see Enoch’s (2011) Taking Morality Seriously: A Defense of Robust Realism. Skarsaune’s reply is specifically addressed to Street (2006). See Skarsaune, (2011) “Darwin and moral realism: survival of the iffiest” in Philosophical Studies. Wielenberg includes Street (2006) as well as Joyce (2006), and others, among the intended audience for his third-factor reply. See Wielenberg, (2010) “On the Evolutionary Debunking of Morality,” Ethics. See also Wielenberg’s (2014) Robust Ethics: The Metaphysics and Epistemology of Godless Normative Realism.

  4. 4.

    See Vogel’s (2000) “Reliabilism Leveled” in The Journal of Philosophy, as well as his (2008) “Epistemic Bootstrapping,” The Journal of Philosophy. See Cohen’s (2002) “Basic Knowledge and the Problem of Easy Knowledge,” Philosophy and Phenomenological Research and his (2010) “Bootstrapping, Defeasible Reasoning, and ‘A Priori’ Justification,” Philosophical Perspectives.

  5. 5.

    This “third-factor explanation” is perhaps a bit misleadingly described, because it arguably appeals to more than just one additional factor. It is not the same third factor, C, “Survival is good,” that both (1) bears constitutive relationships to the mind-independent normative truths (A), and (2) is also causally responsible for the normative judgments that we tend to make (B). What is (at least partly) causally responsible for our judgments would be the additional fact that selective pressures favor the evolution of pro-survival attitudes (or as Enoch puts it, that evolution “aims” at survival).

  6. 6.

    Note that Unlike Enoch (2010, 2011), Skarsaune (2011) tends to refer to “evaluative” facts and beliefs rather than “normative” ones. I assume that nothing of significance for our purposes here hangs on this terminological difference. Street (2006) uses both of these terms.

  7. 7.

    See his (2010), p. 450. Wielenberg’s later (2014) statement of this view describes this first relationship (of a logical connection) more precisely as “D-supervenience” of certain moral rights upon certain cognitive faculties, generating a “necessary connection” between the two (p. 145). See Wielenberg (2014) for more detail.

  8. 8.

    Vogel and Cohen also credit Fumerton (1995) for independently raising a related version of the problem in his Metaepistemology and Skepticism. Cohen (2002) argues that the bootstrapping problem generalizes beyond the initial target of reliabilism to any theory that allows for what he calls “basic knowledge,” that is, knowledge obtained prior to one’s knowing that the source of that knowledge is reliable (pp. 310, 316).

  9. 9.

    This way of characterizing reliabilism about knowledge is an example of “process” reliablism as opposed to “belief” reliabilism. As the names suggest, a reliable process account emphasizes that a belief counts as knowledge when formed via a process that is in general reliable, while a reliable belief account requires that that belief be formed in a way not prone to error in order to count as knowledge. One could also be a reliabilist about justification rather than knowledge. Vogel (2000)’s stated targets are reliable process accounts of knowledge. Yet it is easy to see how the bootstrapping worry he describes would apply equally to reliable process accounts of justification. Vogel’s Roxanne should not be able to gain any justification for the belief that the gas gauge is reliable in the manner she does, any more than she should be said to acquire knowledge.

  10. 10.

    See Vogel (2000), pp. 613–4. Vogel attributes an earlier version of this gas gauge case to Williams’ (1991) Unnatural Doubts.

  11. 11.

    See especially p. 526.

  12. 12.

    For one example of a qualified defense of bootstrapping, see van Cleve (2003), “Is knowledge Easy—or Impossible? Externalism as the Only Alternative to Skepticism” in The Skeptics: Contemporary Essays, pp. 45–59.

  13. 13.

    In fact, Weisberg (2010) argues that this constraint is both too strong and too weak; it bans some intuitively legitimate patterns of reasoning while still failing to prohibit other patterns of intuitively illegitimate reasoning.

  14. 14.

    See also Weisberg’s (2012) “The Bootstrapping Problem,” Philosophy Compass, pp. 597–610.

  15. 15.

    To represent Wielenberg’s third-factor reply, replace “survival is good” with “we have rights” and replace the influence of evolutionary pressure in P2 and C with the role of our cognitive faculties.

  16. 16.

    See Igor Douven and Christoph Kelp, “Proper bootstrapping,” Synthese. The earlier, unpublished (2009) version of Weisberg’s paper cited by Douven and Kelp referred to “possibly other premises” rather than “possibly some of P1-Pm” in what is now Weisberg’s (2010) condition (2). See Douven and Kelp, p. 177 and Weisberg (2010), p. 534. Weisberg’s (2009) paper, “Bootstrapping in General” was made available here as the winner of the 2009 Young Epistemologist Prize before it was published in 2010 with modifications:

  17. 17.

    Douven and Kelp note that Glymour calls his account a “bootstrapping account of confirmation” (Douven and Kelp 2013, p. 180). This mention of “bootstrapping” predates the objection to reliabilism discussed by Vogel and Cohen and is meant to describe a different phenomenon, viz. a legitimate process by which a scientific theory may be confirmed. Douven and Kelp insist that not all bootstrapping in Glymour’s sense is problematic in the way that the reasoning exemplified by Vogel’s Roxanne is problematic, hence their title, “Proper bootstrapping.”

  18. 18.

    See pages 122–4 of Michael G. Titelbaum, “Tell me you love me: bootstrapping, externalism, and no-lose epistemology” in Philosophical Studies.


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For helpful discussion of previous drafts of this paper, I wish to thank Arden Koehler, Jake Nebel, Sharon Street and Michael Zhao. Thank you also to audiences at the University of Oklahoma.

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Dyke, M.M. Bad bootstrapping: the problem with third-factor replies to the Darwinian Dilemma for moral realism. Philos Stud 177, 2115–2128 (2020).

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  • Darwinian Dilemma
  • Moral realism
  • Epistemological objections
  • Third-factor explanation
  • Bootstrapping