I don't know what happens after death, but I'm not alone. In fact, I'm just one of six billion people living in utter ignorance of the afterlife. Many of them may contend otherwise, but their claims are inherently baseless. Simply put, no one has experienced what happens after death and lived to tell about it because, well, they're dead. Furthermore, sacred texts cannot provide enlightenment either as each and every tome contradicts the others while simultaneously claiming to be infallible. Bearing in mind our innate uncertainty about the topic at hand, let us examine one set of beliefs about life and the afterlife. Specifically and paradoxically, let us examine the (possible) beliefs of a nonbeliever.
Some philosophers have professed that all life is an illusion and that nothing is real. And while this may seem radical to some, it is grounded in reasonable observations about our world. For instance, we know that the world went about its business before we were born and that it will continue when we have passed. This theory holds that everyone begins life with nothing, even if many instantly acquire family and shelter. In the beginning, we have no possessions of our own and no knowledge other than what is innate within us like how to breathe. As life progresses, we gain knowledge, build relationships, and acquire possessions. But then when we pass, it follows that we become as we were: nothing, with nothing to show for the life we lived. That's because we no longer exist. And what of the select few who profoundly impact their world? These influential individuals have merely altered the illusion that others temporarily enjoy until they too cease to exist. The idea remains viable.
Elaborating, we can only know what happens in this life. There might be an afterlife of eternal bliss; there might be a heaven and hell, and seventy-two virgins may indeed be awaiting the righteous; the tree outside your window might also start sprouting Federal Reserve Notes, and the sky may start falling, but none of these propositions is all that likely based on knowledge alone. Based on religion, some are practically guaranteed depending on the text you read, but these alone are not reliable sources.
Balance dominates many aspects of the world: what goes up must come down, day and night, every action has an equal and opposite reaction. We came into this world with nothing, so we should leave in the same fashion. I personally find it most reasonable to expect nothing in the way of the afterlife so that balance is preserved: We bring nothing into the world, and we take nothing from it. And since most people don't claim to have had a past life, it's logical to assume there was nothing before this one. Thus, balance dictates that there will be nothing after. This is not evidence in any sense, but I believe this prediction is the most rational speculation we can make given our inability to verify any claims about the afterlife. It takes into account only the things which we intrinsically know about the world and doesn't rely on religious "evidence" that is readily refuted.
Humans tend to require evidence in order to believe things about their world, and thus we can be fully confident in one belief: this life we have is finite. What follows it is highly variable (and we have touched on just some of the possibilities), but most everyone accepts that this life is limited in duration. Upon its inevitable cessation, something else may or may not replace it. Even if the afterlife perfectly mimics our current existence, or if our "souls" stay with us or reincarnation is real, this life, by its contemporary definition, will have ended.
That said, it follows that the realization of one's mortality naturally makes his life devoid of meaning. As far as we know, this life is, in the minimalist view, merely a transitional phase between nothing and nothing once more. I was probably about four years old when I came to terms with my own mortality, and it was easily the worst day of my newly finite existence. It was not a near-death experience, nor the death of a family member which robbed me of my blissful ignorance. Rather, it was my inquisitive spirit that was responsible for ravaging my optimism. I recall crying the whole night after my parents broke the news to me that everyone has to die some time. I was completely inconsolable; it is probably the single hardest concept to accept. I loved life (and still do); why should it have to end?
Sure it's a painful realization, but we go through hardships of various degrees all the time. We still must try to accept what we know to be true. In the extreme cases where the pain is too much, our mind is able to avoid reality and thus avert the pain altogether (or until such time as the issue confronts us again). Psychologically, we call this denial or repression depending on the specifics. Philosophically, this behavior has a different name, faith.
Religion is the means whereby human beings can avoid accepting the most crippling reality. The faithful do not accept the notion that our life is finite because it is simply too terrible. It is no coincidence in my opinion that our notion of the afterlife and creation is exactly as we would prefer it. Thus God shares our image, and good people are rewarded with eternal bliss while bad people suffer for their sins. I like justice too, but this seems entirely too convenient. We can give our own lives personal meaning, but we should not deceive ourselves to do so; our entire purpose should not be based on a theory, for that's all religion will ever be in this world. No one can truly know that accepting Jesus or following Allah will ensure his eternal happiness. And when these ideas are closely examined, the entire notion of rewards after death seems like just so much wishful thinking.