One of the most interesting things I’ve ever read was about this guy who was homeless and living in the forest for a really long time.  He talked about how for certain periods of time, he completely forgot that he existed. Without having anybody to perform his identity to, he had no consistent self or identity.
> “I did examine myself,” he said. “Solitude did increase my perception. But here’s the tricky thing—when I applied my increased perception to myself, I lost my identity. With no audience, no one to perform for, I was just there. There was no need to define myself; I became irrelevant. The moon was the minute hand, the seasons the hour hand. I didn’t even have a name. I never felt lonely. To put it romantically: I was completely free.”
For me personally, this makes me think that the phenomenology of selfhood is very much dependent on perception and others. To be is to be perceived. In the absence of perception, the “I” dissolves.
Perhaps “I think, therefore I am” sorta still makes sense as long as you’re aware of the fact that you’re thinking. But as the Hermit describes– when you’re alone for a long enough period, and you’re not thinking about other people, or what other people will think of you when you return, or what letters you want to write for other people, “I” stops showing up. And therefore “I” does not exist. The entity that is the person is still hanging out in the forest, but he/it has no need for a name or any consistent identity.
– GQ – The Last True Hermit
Also consider Alan Watts’ relevant points