There's quite a big gap between "some bits have been removed or replaced" and "the brain is the only bit that can't be replaced" without changing who the perso

There's quite a big gap between "some bits have been removed or replaced" and "the brain is the only bit that can't be replaced" without changing who the person is. The nervous system (of which the brain is but a part) is quite a large and complex thing, and there is no guarantee that one's conscious being is tied to that set of neurons in one's head and not, for example, to the extended set below the neck. There's evidence that certain functions are performed mostly or wholly within the brain, but no evidence of consciousness, which is what I think you mean by "changing who the person is". Heart? Liver? Kidneys? Thyroid and appendix and gallbladders? They ain't got nothin' on the nervous system when it comes to me.