"The skull is the primary organ responsible for producing dreams," she explained. "As any neurologist can tell you, it contains far more complex marrow than any other bone in the human body.”

"Really? Given how thin the bone is, I wouldn't think that there would be any- oh." Is that seriously what she meant? "But surely, that's a different organ altogether, right? It would seem rather absurd to classify it in this manner."

“Oh. You’re close, but I’m not talking about the brain. I'm talking about what's missing from it, all those curls and folds and shadowy spaces. That's the marrow of the skull, where all the interesting stuff happens.”

”Hang on. You’re saying that, somehow, the empty space of the brain is an organ to itself?”

"No- like I said, the skull is an organ that contains that ‘empty space.’ The brain cannot contain what’s missing from it by definition; only something that encompasses it from outside can do this. Once you’ve grasped this much, I can get into the difference between thoughts and dreams, but that’s no simple matter to discern, especially while awake.”

“So, what happens when there is no brain? After we die, and the skull is all that’s left?”

“Well, that missing stuff doesn’t go away. In fact, there’s even more of it at that point, especially when there aren’t any eyes to hold it in. I can’t even imagine what those dreams are like.”