ABSTRACT The apparent consistency of Sobel sequences famously motivated David Lewis to defend a variably strict conditional semantics for counterfactuals. If Sophie had gone to the parade, she would have seen Pedro. If Sophie had gone to the parade and had been stuck behind someone tall, she would not have seen Pedro. But if the order of the counterfactuals in a Sobel sequence is reversed—in the example, if is asserted prior to —the second counterfactual asserted no longer rings true. This (...) is the Heim sequence problem. That the order of assertion makes this difference is surprising on the variably strict account. Some argue that this is reason to reject the Lewis-Stalnaker semantics outright. Others argue that the problem motivates a contextualist rendering of counterfactuals. Still others maintain that the explanation for the phenomenon is merely pragmatic. I argue that none of these is right, and I defend a novel way to understand the phenomenon. My proposal avoids the problems faced by the alternative analyses and enjoys independent support. There is, however, a difficulty for my view: it entails that many ordinarily accepted counterfactuals are not true. I argue that this cost is acceptable. (shrink)

1000 time-travelers travel back in time, each with the intention of killing their own infant-self. If there is no branching time, then on pain of bringing about a logical contradiction, all must fail. But this seems inexplicable: what is to ensure that the time-travelers are stopped? For a time, this inexplicability objection was thought to provide evidence that there is something incoherent about the possibility of backwards time travel in a universe without branching time. There is now near-consensus, however, that (...) the objection has no bite: there is nothing inexplicable about the mass failure. Lewis, Sider and Ismael independently argue that since it is built into the description of the class of cases considered that the time-travelers must fail – and so we consider only unsuccessful attempts – there is no mystery. Smith argues that the absence of possible worlds at which auto-infanticide is committed suffices as a complete explanation for the failures. And Baron and Colyvan maintain that available causal and logical explanations jointly account for everything that needs accounting for. I argue that these are wrong. There is remaining, problematic inexplicability. For backwards time travel not to lead to logical contradiction, something would need to do logic’s bidding, after all. (shrink)

Before a fair, indeterministic coin is tossed, Lucky, who is causally isolated from the coin-tossing mechanism, declines to bet on heads. The coin lands heads. The consensus is that the following counterfactual is true: (M:) If Lucky had bet heads, he would have won the bet. It is also widely believed that to rule (M) true, any plausible semantics for counterfactuals must invoke causal independence. But if that’s so, the hope of giving a reductive analysis of causation in terms of (...) counterfactuals is undermined. Here I argue that there is compelling reason to question the assumption that (M) is true. (shrink)