What time travelers cannot do

Philosophical Studies

Volumn 81, Issue 2-3, 1996, Pages 315-330

  Vihvelin, Kadri ^a  

^a UNIVERSITY OF SOUTHERN CALIFORNIA   (United States)

Author keywords

[No Author keywords available]

Indexed keywords

EID: 44349086317     PISSN: 00318116     EISSN: 15730883     Source Type: Journal    
DOI: 10.1007/BF00372789     Document Type: Article

References (8)

1. For versions of what I'm calling 'the standard reply', see David Lewis, "The Paradoxes of Time Travel", American Philosophical Quarterly 12 (1976), 145-152
2. (also in Lewis's Philosophical Papers, vol. 2, Oxford University Press, 1986)
3. and Paul Horwich, "Time Travel", Chapter 7 of his Asymmetries in Time (Bradford Books, MIT Press, 1989) .
4. David Lewis is the best-known defender of the view that the closest antecedent-worlds may be worlds with somewhat different laws. But on his view, the laws are only as different as they have to be to accommodate the event which, by the standards of our laws, is a "divergence miracle". See Lewis, "Counterfactual Dependence and Time's Arrow", Nous 13 (1979), 455-76
5. (also in his Philosophical Papers, Volume 2, ibid.).
6. We get the same result if we substitute talk of counterparts for trans-world identity. There are worlds where counterparts of the baby stage and the adult stage are parts of different persons. We might choose to treat either of these persons as the counterpart of our Suzy, but we cannot simultaneously treat both as Suzy counterparts. We can imagine Suzy as one of a pair of identical twins. She might have been the older; she might have been the younger. But she could not have been both twins.
7. But perhaps not that odd. We should all agree that Suzy's duplicate can do some things that Suzy cannot do. For instance, Suzy's duplicate can see Suzy's face without looking at a mirror, but Suzy cannot see Suzy's face without looking at a mirror. Of course, neither Suzy nor her duplicate can see her own face without looking at a mirror. My claim is that the situation with respect to autoinfanticide is exactly the same. Neither Suzy nor her duplicate can kill her younger self. But just as Suzy and her duplicate differ with respect to what particular faces they can see, Suzy and her duplicate differ with respect to what particular babies they can kill. Suzy's duplicate can kill Baby Suzy, but Suzy cannot kill Baby Suzy (though she can kill Baby Suzy's duplicate).
8. I'm grateful to Jonathan Bennett, Bob Bright, Bryson Brown, Curtis Brown, John Fischer, Jeff Foss, Mark Heller, Brian Loar, Ray Martin, George Mavrodes, Adam Morton, Alex Rosenberg, Ted Sider, Paul Teller, and especially Terrance Tomkow for helpful discussion and comments on this paper.