I realize that the person I am as I type these letters and the person I am at the end of this sentence is slightly different. Change occurs all the time and infact change within my brain is the reason there is a "me" to begin with.
However from there is a continuity, as I started this question and until I'm done typing it out, there has been a continuous "I" and here starts my question: How much change must occur for a certain being to stop existing and the brain developing a completely new person with zero continuity?
Imagine a person who is driving down the road, he gets a text, checks it and consequentially drives right into a semi-trailer. The guy is instantly braindamaged and launched into a coma. His brain is a complete mess and when "he" wakes up 2 months later, he can no longer speak, move his body or think in any shape way or form like he did before. He is drastically changed, but the memories are still intact. So is he the same person as he was on that fateful night? Or did that person genuinely die and then the new reorganized brain gave rise to a completely new person who has false memories?
Or is there no answer to this really? I mean, everytime I go to sleep the continuity is broken, so is there even such a thing as a continuous identity? What about if I smoke some weed and drink myself to the point where I can no longer stand on my legs or speak coherently? Am I still the same in these situations ?
To put it even to a further extreme, say you stumble into a meatcleaver and your entire brain is turned to mush, but then due to a infinitely unlikely occurence every atom that previously made up your brain becomes the atoms that make up a brand new persons brain ( a kid who is just born ), would this be you? I would say "of course not", but then that requires that there is this boundary where given X amount of change it would no longer be me, is there?