The Possibility of an Afterlife — notes by Justin C. Fisher, SMU Philosophy

Many people believe that after your death on Earth you may go on to have further experiences in some afterlife, either on Earth reincarnated in some new body, or else in some other place like Heaven or Hell. Here we'll consider some of the complexities that would be required for this to be possible. It turns out that some common understandings of the afterlife are logically incoherent—at best they would involve having someone else who is a lot like you live after your death, but it wouldn't be you living on after your own death. Other accounts of how an afterlife might work are logically self-consistent, but also highly complicated with no significant evidence to support all these complexities, so Ockham’s Razor cuts strongly against believing in these. Here are five potential ways in which people have thought an afterlife might work.

a. Dualists like Rene Descartes hold that we are disembodied minds, “ghosts in the machine”, that remote-control bodies, so the death of bodies wouldn’t necessarily kill our minds. However, we have no evidence of remote control signals coming into our brains, and we have strong evidence that different parts of our brains are responsible for different parts of our cognition, so Ockham’s razor weighs against believing in extra ghostly minds that might survive the deaths of our bodies.

b. Dean Zimmerman’s “attack of the clones” holds that a physical duplicate of me made in heaven would be me. However, it instead seems more likely that this would just be someone else who is a lot like me, as becomes especially clear if you imagine me existing alongside one or more clones—they can’t all be me!

c. A literal reading of the bible suggests that “the dead shall rise”, not just clones made out of new material but instead reanimation of the same matter that composed us when we are alive. However, this just seems like a creepier clone, as is illustrated if you imagine gathering the material I’ve shed over the last ten years to make another copy of me—even though this contains material that was me, it’d just be a copy, not actually me. Also the logistics don’t work out, if some matter has been in multiple bodies due to cannibalism or reincorporation into the ecosystem, then that matter would need to go multiple places in the afterlife.

d. Peter Van Inwagen’s “body snatchers” would snatch away a person at the moment of their apparent death and replace them with a lookalike corpse, all too fast for bystanders to detect. This might technically allow for an afterlife, but Ockham’s razor cuts strongly against accepting such a complex story without any evidence.

e. David Lewis holds that in a Everett-style branching worlds interpretation of Quantum Mechanics, random events with multiple possible outcomes actually have both outcomes happen in different branches of reality, e.g., one branch on which Schrodinger’s cat lives and another on which it dies. We should assign high probability to experiencing a dead cat, but the only future an intelligent cat should anticipate experiencing is on a branch where it lives. Similarly, you should expect to have some future branches in which you will luckily not quite be killed, so you should anticipate having future experiences of repeatedly escaping death. Unfortunately the most likely escapes will be narrow escapes that horribly maim you, so you should expect your eternal evasion of death to be “Quantum Hell”.