So. On Monday I went out on my bike to clock up some miles. It didn’t go well as there was a regular clunking and thunking from the back wheel. Back home I took the back wheel off and found the rim had split. I took the bike to bike hospital to get it a new wheel and a service. The service resulted in a new wheel, new front chainrings, new rear cassette, new brake blocks, cables and gear cables. There wasn’t really much of the original bike left.
Now, as I have been reading a short introduction to pre-socratic philosophy (a gift from Santa to one of the children, who read it and thought I might be interested) I was thrown back to the old paradox of the Ship of Theseus. Briefly, the ancient Athenians preserved the ship in which Theseus returned to Athens after killing in Minotaur. As its timbers decayed they were replaced until, in the then present, none of the original timbers remained. The question is: is this still Theseus ship? The UK TV audience has also seen the same paradox in Only fools and horses where Trigger’s broom has had 17 new heads and 14 new handles.
I haven’t quite got to that stage yet, but if I rode the bike a bit longer and changed all the other pieces, until there was none of the original left, would it still be the same bike? The philosophers have had plenty of goes at this, but for my money, the answer you give depends on the question. I’m with Trigger, because the question is not, ‘is this the same broom’ but ‘is this Trigger’s broom’ to which the answer is ‘yes’.
And back in ancient Athens, if pirates had carried off the ship, what would they have reported to the (non-existent) police? Obviously: ‘someone has stolen the ship of Theseus’.
[Of course, any passing philosopher is more than welcome to point out the deep and egregious flaws in my reasoning.]