The immorality of modal realism, or: How I learned to stop worrying and let the children drown

Philosophical Studies

Volumn 114, Issue 1-2, 2003, Pages 1-22

  Heller, Mark ^a  

^a SOUTHERN METHODIST UNIVERSITY   (United States)

Author keywords

[No Author keywords available]

Indexed keywords

EID: 55449112667     PISSN: 00318116     EISSN: 15730883     Source Type: Journal    
DOI: 10.1023/a:1024471800380     Document Type: Article

References (12)

1. Adams, Robert (1979): 'Theories of Actuality', in Michael Loux (ed.), The Possible and the Actual (p. 195), Ithaca: Cornell University Press.
2. Lewis, David (1986): On the Plurality of Worlds (pp. 127-128), Cambridge, MA: Basil Blackwell.
3. Lewis has a little more to say about the moral significance of sharing group membership in 'Illusory Innocence?' (his review of Peter Unger's book Living High and Letting Die) in Papers in Ethics and Social Philosophy (pp. 152-158), Cambridge, England: Cambridge University Press, 2000. There his discussion is explicitly aimed at whether we are permitted to treat those of our group in a privileged way, not whether we are obligated to do so. It is the latter that Lewis would need to defend himself against the Adams worry.
4. Perhaps that is not even quite right. Perhaps the choice is whether to let one child drown or to kill the other. Though I will take no stand on this matter, one might look at the case this way. If Roz saves Righty she will thereby stop Lisa from saving Lefty. To stop someone from saving a drowning child is to actively interfere with a chain of events that would have resulted in the child's continued life, and to do that may plausibly be considered killing and not merely letting die. This way of thinking might have the consequence that Roz is actually obligated, not just permitted, to let Righty drown.
5. I thank Delia Graf for insisting on this point, and many members of the BSPC audience for agreeing with her (including Ted Sider, Daniel Nolan, John Hawthorne, but also others whom I have, alas, forgotten).
6. The point made in the next few sentences is stolen from Hud Hudson's 'A True, Necessary Falsehood', Australasian Journal of Philosophy 77 (1999), 89-91,
7. and especially 'Brute Facts', Australasian Journal of Philosophy 75 (1997), 77-82. I thank Andrew Cortens for bringing these fine papers to my attention.
8. Plurality of Worlds p. 72.
9. The use of epochs within a pluriworld to understand modal claims with subject matters extending across uniworlds evolves out of a question Ned Markosian asked at the BSPC. He called it a "friendly question" at the time, but I did not understand its friendliness until much later. I thank him.
10. 'Island Universes and the Analysis of Modality', in G. Preyer and F. Siebelt (eds.), Reality and Humean Supervenience: Essays on the Philosophy of David Lewis, Rowman and Littlefleld, Jan., 2001.
11. It is a good question why we would be so disinclined to take the radical step. Suppose scientists discovered that Case Two is the way things actually are. That is, suppose they discovered that there are more people in the actual universe than we thought and that, as a matter of nomological necessity, every decision made in our part of the universe is mirrored somewhere else in the universe by someone making the opposite decision. We might disagree about how these discoveries should influence our moral calculations, but if we came to believe that they should influence those calculations, that would in no way lead us to doubt the discoveries. We would instead accept the new calculations. In contrast, no matter what conditionals we come to accept relating modal realism to our moral calculations, we would surrender modal realism before altering our calculations. I take this to indicate something fishy about modal realism. I take that fishiness to have something to do with the challenge that we should not be able to discover the existence of concrete entities by using the sorts of considerations that support the existence of possible worlds.
12. I would like to thank Drew Schroeder, Alyssa Ney, Benjamin Jarvis, Juan Comesana, and James Pryor for a helpful discussion that shaped this paper. I would also like to thank Steve Sverdlik and Alastair Norcross for comments on an earlier draft of this paper. And I'd like to thank my commentator, Delia Graf, and members of the audience at the Bellingham Summer Philosophy Conference. Two members of that audience, John Hawthorne and Liz Harman, raised distinct questions about the role that infinity should play in this discussion, and I thank them, though I have not managed to address those questions here.