Paradox

132 A BRIEF HISTORY OF THE PARADOXconstitutes him, then the creditor would be saying that thereare two things in the same place at the same time: the creditorand the collection of particles. This seems like double vision.What stops the collection of particles from being a person inits own right? The “mere collection” looks like a man, walkslike a man, and talks like a man.According to mereological essentialism, each part of anobject is essential to it. The number of objects may grow butnot the objects themselves. What appears to be a singleindividual is a rapid succession of individuals.Epicharmus’s “growing argument” generalizes to a casein which the number of parts stays the same. Recall Heraclitus’sassertion that when one steps into a river twice, one stepsinto different bodies of water. The river stays the same eventhough all of its parts change. Can an artifact survive completereplacement of its parts?The ship wherein Theseus and the youth of Athensreturned had thirty oars, and was preserved by the Atheniansdown even to the time of Demetrus Phalereus, forthey took away the old planks as they decayed, putting innew and stronger timber in their place, insomuch that thisship became a standing example among the philosophers,for the logical question as to things that grow; one sideholding that the ship remained the same, and the othercontending it was not the same.(Plutarch 1880, 7–8)In the seventeenth century, Thomas Hobbes improvedthe riddle of the Ship of Theseus. He supposes that someonehoards the old planks and finally reassembles them into aship. Is the hoarder’s ship the Ship of Theseus?