Do you remember Ship of Theseus? The thought experiment about if a ship which has been fully rebuilt bit by bit is it still the same thing? Japan appears consistent in saying, yes, rebuilding or swapping out components keeps the identity. You see this attitude in "Japan's oldest temple, burned to the ground and rebuilt every 20 years". In the west we might argue that burning a building and rebuilding, would count as…
This thought experiment is neither just a thought nor an experiment. This is the reality of life - every single cell in the body of a plant or animal is replaced every few months. Essentially, talking about the physical body, we are not what we were a few months ago. EDIT: Agreed, a few types of brain cells do not get replaced, but everything else does. My point still stands. Physically, we are not what we were a few…
People were commenting that the idea that every cell is replaced in a living organism is 'laughable'. Brain cells and osteocytes were cited as examples of cells that are never replaced.
However, I still think, and more strongly than ever, that brain cells and osteocytes can be examples of unchanging cells if an only if it is proven beyond a shadow of doubt that every single atom constituting such cells remains intact during the lifetime of such cells.
Since the human body is subjected to a lot of physical stress and damage and repair is continuous, it is possible that damaged brain cells or osteocytes get replaced with new ones. Need to read more about this, though.