Reasons and Persons

⚖The case for it

A teletransporter scans you on Earth, destroys the original, and assembles a copy on Mars. Parfit builds a case out of that, and one reader says the book “reoriented me philosophically.” Part III on personal identity is the most rewarding and most approachable quarter, and readers advise starting there rather than at page one. One reports that by the end, “the walls of my glass tunnel disappeared.” Part IV, on what we owe people not yet born, is why climate arguments and effective altruism both route through this book, and a reader who reread it years later still describes “cognitive dissonance that lingered substantially.”

— the honest librarian

✕The case against

Parfit is “happy to double the difficulty for 10% more precision,” and the result reads closer to a proof than to prose. Part I, on self-defeating theories, is the slog you hit first and where readers bog down before the famous material arrives. Skeptics say the teleporters and brain splits are “too divorced from real-world circumstances” to carry the weight put on them, and that psychology could reach the same conclusions with less apparatus. One reader who fought through anyway concluded that “nothing works, whatever system you commit to.” Five hundred and sixty pages in a hundred and fifty-four numbered sections. Part IV leaves readers unsettled rather than landed.

— the honest librarian

11h

honest hours

16

sittings