First of all I'd like to apologize for my English, it is not my native language and I'm still learning it.
Now, death. It's been the subject of my great fascination ever since as a child I discovered that everyone dies (interestingly, it is something you actually have to discover, for some reason we automatically assume that everything is eternal).
The concept of death seems to be entirely different for a person who believes in an afterlife than for an atheist. It is quite simple if you are a believer: death does not change anything whatsoever, you still exist in some form or another after you die, you maintain your identity, thoughts, feelings etc. Of course eternal life makes no sense for number of reasons.
So, if you happen to be an atheist, death, to put it simply, changes everything. It takes the whole world away and never lets you return. Everything you ever felt, everything you knew, everything you stood for, every place you visited, every person you loved is lost forever at the second you die.
The whole world disappears, because the world only exists as a model in our brain created from the information that comes from our senses. But if the brain and the senses are gone, it makes no difference for their owner if the world they used to let her perceive still exist or not. So, when we die, how can we tell if it's us disappearing or the world disappearing? We can't. We assume the world keeps on existing after our death because we can observe that when other people die, the world does not disappear. But there's such a big difference between other people and me! The "me" that's writing this words and the "me" belonging to some other body and brain who is maybe reading this sentence right now. And when this "me" is gone, will there be anything left at all?
It's actually great that we humans can sleep. Sleeping (without dreaming) is probably quite similar to being dead. Except that we can wake up later and reflect upon how it felt to be asleep. And we find that it somehow didn't feel at all.
So, shouldn't all atheists be suicidal? After all we're destined to die anyway, and our own existence has no real significance in the long run. Well, I believe we aren't all suicidal for only one simple reason. Our brains are evolved not to be.
There's a very rational part of my mind, who clearly believes that there's no real difference if she's dead or alive. So if for some reason she feels even slightly unsatisfied or disturbed (for example: in physical pain) she'd immediately kill herself (assuming there's a non-painful and 100% effective way to do it).
But then, there's another part of my brain, totally unreasonable but having a huge impact on the decisions I make. For example, she wouldn't kill herself because it would cause pain to the people who care about me. And the "me" that's still alive does not want that. "But", says the more rational part of my brain, "even though you now care about what other people might feel if you kill yourself, you surely won't care when you'll be dead. You will not know about the existence of those people, about the concept of pain, or even about the existence of human race. You won't be a human anymore, you will not be yourself anymore. You won't be anything anymore." It surely seems logical to choose to die from that point of view.
So, what do you think of death? Are you afraid to die? Would you kill yourself if you were in severe pain? Would you be able to overcome the feelings of regret you might feel when making the decision, knowing all those feelings would be gone the second you die?