Bananas Enough for Time Travel?

Abstract

This paper argues that the most famous objection to backward time travel can carry no weight. In its classic form, the objection is that backward time travel entails the occurrence of impossible things, such as auto-infanticide-and hence is itself impossible. David Lewis has rebutted the classic version of the objection: auto-infanticide is prevented by coincidences, such as time travellers slipping on banana peels as they attempt to murder their younger selves. I focus on Paul Horwich's more recent version of the objection, according to which backward time travel entails not impossible things, but improbable ones-such as the string of slips on banana peels that would be required to stop a determined auto-infanticidal maniac from murdering her younger self-and hence is itself highly improbable. I argue that backward time travel does not entail unusual numbers of coincidences; and that, even if it did, that would not render its occurrence unlikely.

Time Travel and Time Machines

“…e.g. Smith (1997). 10 Of course, for this imagined response to succeed, it must be clarified what these are frequencies of.…”

Retrocausality in Quantum Phenomena and Chemical Evolution

“…The effect of a non-measurable retrocausal outcome could become perceivable, at most, indirectly only through the succeeding measurable cause. Retrocausality in quantum theory has already been well worked out in the sound conceptual or philosophical contexts [6][7][8][9][10][11]. We shall follow this tradition in the present article.…”

Untitled

“…17 But a neces- Arntzenius (1990), Brown (1992), and Smith (1997). The upshot of these investigations is that it is by no means obvious that a physical theory should be automatically excluded because it allows for the possibility of causal looping.…”