“You” is an incredibly tricky word to define. Is your body you? Is your brain you? Is the set of chemical reactions we call consciousness you? Is only the subset of that set of chemical reactions that’s capable of saying “I am me” you?

I stuck my arm out towards a cat today and it scratched me. What me did it scratch? If my arm gets amputated because that scratch gets infected, have I lost a part of myself, or have I simply lost some thing that belongs to me?