How to defend the cohabitation theory

The best known defence of the cohabitation theory of personal fission (and fusion) is due to David Lewis. This suffered damaging criticism from Derek Parfit. Though others have developed versions of the cohabitation theory, the theory's advocates, with the exception of Eugene Mills, have been reticent about how to handle Parfit-style objections. I develop a broadly Lewisian cohabitation theory, and show how Parfit's objection can be defused in a way which avoids the costs Mills incurs in his own response to Parfit. The result, I claim, is a plausible new approach to personal survival. © 2007 The Author.