I figured it's one of those things you should never take literally, more like Serial Experiments Lain than NGE. I thought of it as a comparison of imagination and reality; the fact that what Ophelia imagined actually became real when she died could be an argument that the imagination, even though it's insubstantial, is the only way that we can each perceive reality. That reality is impossible without the imagination, and that because of the imagination everyone's reality is truly different instead of their being any one cohesive proof of what is real and what isn't. Come to think of it this would be an excellent topic for an essay.