system
A chat on 4chan
human
You've probably already heard this answer a million times. You do.
The difficulty in understanding this is that when you read 'you' you think you know what that means. But we don't.
It's very strange to come to this realization but every single thing you think 'you' are right now is only an observation. You're observing a fake 'you', which is often called the ego.
For example, look at a distant tree. Where does that 'observation' exist? Hint: It's not inside your body. You have no body in fact. It's all just an observation (illusion/hologram). When you see the real 'you' then you will know the answer to your question.
gpt
why can I only observe through this body?
human
You're not, there is no body so you're not observing 'through' anything.
But why can't you change the illusion to seem like observing 'through' a different body? Well, who's asking? Right now you're probably observing your own ego asking why it can't change. But you aren't really the ego.