Full Idea
The Pope's crown is made of crowns. There is no definite answer, when the Pope is wearing his crown, to the question 'how many crowns does he have on his head?'
Gist of Idea
Is the Pope's crown one crown, if it is made of many crowns?
Source
David Wiggins (Sameness and Substance Renewed [2001], 2.7)
Book Reference
Wiggins,David: 'Sameness and Substance Renewed' [CUP 2001], p.75
A Reaction
A very nice example, in which the identity of the item seems clear enough, until you try to apply a sortal to it. I can't get excited about it, though, because calling it one 'crown' creates uncertainty, but calling it the 'Pope's crown' doesn't.