Joscha Bach says the self is experienced as real through perceptual validation, and that derealization can make the self seem like only an idea while the conscious observer's subject and object disappear.

“And your own experience of yourself is also something that is validated in this perceptual way, so you experience it as real. And now you should be able to test this by getting into a state where your-yourself become derealized, and you suddenly experience yourself only as an idea, and the object of the conscious observer and the subject of the conscious observer disappear.”