Picking on Irrational Atheists for a Change... Cryonics
Let's think about this rationally for just a second. Suppose for a minute that the technology to reverse brain death will one day exist. This is extraordinarily unlikely because of the way that memories and experiences appear to be stored in the brain, not to mention the insanely complex electrochemical relationships that developed through continuous existence, but let's just give scientists the benefit of the doubt. Maybe they can figure out some kind of way to examine a frozen human brain and figure out the exact relationship between a hundred billion neurons, and then somehow recreate that relationship, resulting in the reanimation of a brain, presumably with the same memories and personality it had at the time of death.
There's a larger question here. What makes anyone think they're so special that the world will need them around again? At the current rate of population growth, we're not too far from ten billion people. What possible benefit could future scientists gain from reviving some rich fuck from the 21st century who thought he was important enough to get to live twice? Are we really going to suggest that there's going to be a time when there isn't enough human DNA around to make new people, or that somebody will think to themselves, "Wow... this problem is so terrible... There's only one person who's ever lived who can solve this. It's Filbert Mackelroy, from the year 2015. He made enough money investing his dad's money that he was able to afford to freeze himself. Surely he's our savior!!"
I'm sorry. Anyone who thinks they're important enough that someone is going to go to the trouble of bringing them back to life in a hundred or a thousand years needs a bit of a humility check, if you ask me. On the outside chance that we do learn how to reverse brain death, we're going to use it on people who just died. We're not going to bring Buck Rogers back. Seriously. Not gonna happen. Science fiction. Save your money.