I own George Washington's hatchet.
You know , the one that chopped down the cherry tree.
It is handed down in the family, awesome and usefull.
The handle has to be replaced every five years or so...
The head has to be replaced every three or four decades.
Don't doubt tho that this is that hatchet!
What is me?
If my leg is titanium and/or my heart is hydralic , I am changed only a bit.
When my body is mostly mechanical I will not be someone elese.
When my memorys are backed up on magnetic media, it will still be me that compiles them.
When my senses are augmented by glasses, then by implanted cameras microphones and feild effect sensors is it not still me looking out the window?
But when each failing part has been replaced by steel and silicon, till not a speck of the origional matter remains, will I be there?
Will the durable entity that I have become need to be me?