Mauro Diotallevi wrote: > I shed skin cells all the time, and they are replaced by new cells. > The skin I had 20 years ago is literally not the same skin I have > now. Does that mean my skin doesn't exist, or is only as real in the > same way a whirlpool is real?
I am firmly of the opinion that your skin is real. You may say that it is real in the same way that a whirlpool is real, or the Great Red Spot of Jupiter. If your skin is more real than the whirlpool, simply because its constituent matter is replaced at a slower pace ... assume that the Spot, or something else of similar characteristics, has a replacement cycle longer than that of your skin. Is then that Spot more real than your skin? I find the above not a very interesting discussion. More interesting is the question of identity. Since I have stated that your skin exists, I can also ask if your skin now is the same as your skin 20 years ago. In the case of myself, my intuition tells me that I am the same person occupying the same body that "I" was and occupied twenty years ago. Mostly because this is a useful and intuitive definition of identity. I have changed a lot, but I am the same person. There are cases where the intuitive definition is less obvious. This is the classical problem of identity and the ship of Theseus. Good summary available here: http://faculty.washington.edu/smcohen/320/theseus.html Summary of the summary: - If Theseus has a ship and replaces a plank in the ship, is it still the same ship? - If he subsequently has replaced all the planks and other parts of the ship, is it still the same ship? - If a scavenger took each part as Theseus threw it away and built those into a replica of his ship, which ship is the original? The one Theseus is on, or the one the scavenger built, which consists of all the parts of the original? - If we put Theseus's ship in dry dock, disassembled it and again assembled it, is our intuition as to the identity of the newly assembled ship still the same as in the case of the scavenger? Modern version (and possibly a digression): (1) If a country's government is forced out of the capital and loses control of most of the country, is the area controlled by that government still the original country, only with a drastically diminished territory? (2) If the opposition of a country's government forces the government out of the capital and announces a new constitution, is the entity ruled by the new constitution simply the same country, only with a new constitution? In 1949-1972 the governments of the world seem to have felt that the answer to (1) was "yes" and the answer to (2) was "no". In 1972 the position was reversed. So which is true? I believe that both propositions are true and that people should just get along, decide on some functional-enough terminology on the two countries and move on to find something more useful on which to spend their energy... /c _______________________________________________ http://www.mccmedia.com/mailman/listinfo/brin-l
