Joke Collection Website - Mood Talk - How is "I" defined in philosophy?

How is "I" defined in philosophy?

Disassembling the word "I" means that "hand", "elder brother" and "elder brother" are all weapons, and "hand" means holding a weapon in hand, so I understand that "I" is a person who protects myself, because only "I" will never betray "I" and only "I" will always protect "me".