The reliability of moral intuitions: A challenge from neuroscience

Abstract

A recent study of moral intuitions, performed by Joshua Greene and a group of researchers at Princeton University, has recently received a lot of attention. Greene and his collaborators designed a set of experiments in which subjects were undergoing brain scanning as they were asked to respond to various practical dilemmas. They found that contemplation of some of these cases (cases where the subjects had to imagine that they must use some direct form of violence) elicited greater activity in certain areas of the brain associated with emotions compared with the other cases. It has been argued (e.g., by Peter Singer) that these results undermine the reliability of our moral intuitions, and therefore provide an objection to methods of moral reasoning that presuppose that they carry an evidential weight (such as the idea of reflective equilibrium). I distinguish between two ways in which Greene's findings lend support for a sceptical attitude towards intuitions. I argue that, given the first version of the challenge, the method of reflective equilibrium can easily accommodate the findings. As for the second version of the challenge, I argue that it does not so much pose a threat specifically to the method of reflective equilibrium but to the idea that moral claims can be justified through rational argumentation in general.

Notes

1 There is also recent work in social psychology that Singer takes to support his scepticism, such as the research by the psychologist Jonathan Haidt [2001] see also Greene and Haidt [2002].

2 We owe the notion of reflective equilibrium to John Rawls. See in particular [Rawls 1971]. For later developments, see, e.g., Daniels [1979], Brink [1989: chap. 6] and Tersman [1993].

3 The view that intuitions are non-inferential in this sense is congenial with the views Henry Sidgwick expresses when he elaborates his ‘philosophical intuitionism’. See Sidgwick [1907: chap. 13]. For Sidgwick's views on this matter, see also Audi [1996: 109, 131f].

4 For some research about intuitions (in the narrower sense, conceived as ‘gut-feelings’), see Baron [1998] and Klein [1998].

5 So construed, Singer's challenge is simply a version of Harman's well known argument against moral realism [Harman 1977: chap. 1].

6 For a use of the phrase ‘debunking explanation’ similar to mine, see Lillehammer [2003].

7 Since Singer explicitly says that his criticism against intuitions has more general implications for moral methodology (in that it is supposed to undermine the method of reflective equilibrium), I shall ignore the possibility that he merely wants to question certain particular intuitions, namely those that are supposed to cast doubt over his own favourite principle (utilitarianism).

8 However, Daniels stresses that the distinction was implicit already in Rawls [1971], and explicit in Rawls [1975].

9 See, e.g., Ebertz [1993] and Holmgren [1989]. Similar doubts have been expressed by Singer in that he writes that foundationalism is merely the ‘limiting case’ of the method [2005: 347].

10 See, e.g., Brink [1989: 127, 136] and Sinnott-Armstrong [2006: chap. 10]. Sinnott-Armstrong calls coherence between first-order beliefs and beliefs about the reliability of first-order beliefs ‘second-order coherence’.

11 Singer is reluctant to call these beliefs ‘intuitions’. But, given my definition of the term (and given Henry Sidgwick's), they clearly are. In any case, regardless of what we call them, the important question is whether they avoid the criticism he raises against (other) intuitions.

12 Of course, this is a debunking explanation only if we can explain the emergence of Christianity as a cultural force without assuming that any of its basic ethical beliefs are true. But since the explanation merely appeals to the social function of the religion, it satisfies this condition. Moreover, Singer needs to make exactly the same assumption in offering his debunking explanations of people's intuitions about suicide. Also, notice in this connection that Singer thinks that one consideration that helps to explain why humans have evolved a propensity for moral thinking is that it has helped them to solve various Prisoner Dilemma-type coordination cases, and that it therefore has been selected through natural selection [2005: 335f]. Such considerations could also be invoked in explaining the tendency (which is central in Christian ethics) to ignore differences between individuals that Sidgwick's axiom is all about.

13 Nor does it exclude them from being intuitions in the sense defined above. The fact that a preference for simplicity is involved in their formation need not mean that they are inferred from some other principle.

14 See, e.g., Crisp [2002: 57–63] and Audi [2002].

15 I am indebted to two anonymous referees for Australasian Journal of Philosophy for valuable comments that have significantly improved the paper. An earlier version was presented at seminars at Lingnan University, Hong Kong, University of Auckland, New Zealand, and University of Waikato, New Zealand. I also want to thank the participants in those seminars.