In this action-packed session we began by talking about Pablo the Mule Dog and what he had to tell us about drug trafficking, and went on to the artificial intelligence that will discuss drugs with you (for which Ben mentioned a man named Joseph Weizenbaum, who invented the first of these programs, called ELIZA).
Then we looked at a story about a bicycle which was getting a battering, and gradually being repaired and replaced. In the end, we had enough old spare pieces left over from repairs to make a whole new bicycle from the bits.
Then the question arose: which is the orginal bike?
We discussed this for a long time, and there were two views in the end, which we could not there and then get beyond.
(A) The original bike is the one with the new parts — because replacing a part of something does not mean that that thing becomes an entirely new thing.
(B) The original bike is the one made out of all the old spare parts — because it has all the same parts as the original bike, and the bike is the sum of its parts.
This is the heart of the matter: Can something still be itself if it has changed?
Because we ourselves are changing in tiny, and not so tiny, ways every moment!