ABSTRACT
Thought experiments are widely used in metaphysics (and other areas of philosophy) as a way of testing theories. To give you a flavour of how they work, consider John Locke’s famous case of the cobbler and the prince. We are asked to imagine that, whilst they are asleep, the ‘consciousness’ of a cobbler is switched with that of a prince. In other words, all of the cobbler’s beliefs, desires, personality traits, emotional tendencies and memories are swapped over into the prince’s body, and the prince’s beliefs, desires, and so on, are similarly swapped over into the cobbler’s body. Now comes the crucial question: when the two people wake up, which person is the one who went to sleep in the prince’s bed last night? Is it the one who wakes up in the cobbler’s bed (wondering where all his finery is, where his servants are, and why his bed is so uncomfortable), or is it the one who wakes up in the prince’s bed (wondering why he is wearing fur-trimmed pyjamas and why someone has just brought him a fine breakfast on a golden platter)? Locke thinks the answer is obviously the former. To make things more vivid, we could imagine that yesterday the prince did something terrible – murdered one of his courtiers, say. Who do you think is to blame: the one who now has the body of the cobbler or the one who has the body of the prince? Again, Locke thinks the answer is obviously the former.
