mind & identity · new to this edition
the ship of theseus
replace every plank, one by one. is it the same ship? now rebuild it from the old planks.
Plutarch recorded the puzzle two thousand years ago; Hobbes sharpened it into a trap. It is the oldest question about identity over time, and it is really a question about <em>you</em>: for your body, too, replaces nearly all of its matter across a lifetime. Take the ship one step at a time.
the ship has had every plank replaced. is it the same ship?
The ship of the hero Theseus is preserved in harbour. As each plank rots, the keepers replace it with a new one of identical shape. Over the years, plank by plank, every original timber is removed, until not one piece of the original wood remains.
The keepers never stopped calling it Theseus’ ship; it never left the water; it looks and sails exactly as before.
further reading
- identity over time stanford encyclopedia of philosophy
- ship of theseus wikipedia