exist, cease, persist

This short article by Brian Greene was really interesting to me.

I think about death and dying a lot. That sounds morbid I guess, but I don't think I'm morbid. I have encountered something that changed me profoundly; I consider it often because I need to understand it as best I can, or risk running mad, shattered by my lack of... well. Shattered by my lack.

People rarely seem to want to talk about it, which makes me appreciate candid opinions and theories like this one all the more. It's only a way of thinking, of course; but what else do we have?