" When you walked through a park, the immersive world that surrounded you was something that existed inside your own brain as a pattern of neurons firing. The sensation of a bright blue sky wasn't something high above you, it was something in your visual cortex, and your visual cortex was in the back of your brain. All the sensations of that bright world were really happening in that quiet cave of bone you called your skull, the place where you lived and never, ever left. If you really wanted to say hello to someone, to the actual person, you wouldn't shake their hand, you'd knock gently on their skull and say "How are you doing in there?" That was what people were, that was where they really lived. And the picture of the park that you thought you were walking through was something that was visualized inside your brain as it processed the signals sent down from your eyes and retina.

It wasn't a lie like the Buddhists thought, there wasn't something terribly mystical and unexpected behind the veil of Maya, what lay beyond the illusion of the park was just the actual park, but it was all still illusion. "

― Eliezer Yudkowsky , Harry Potter and the Methods of Rationality