There is no doubt that some people find meaning and purpose in their lives through religion. I have even met people who don't believe in their religion, but chose to follow it anyway for this very reason. Beyond the obvious social benefits and support that religion gives, the "big questions" which religion attempts to answer (i.e. "Why are we here?" "Where are we going?" etc.) can also give people purpose. For example, believing that your actions in this life will affect the type of life you get in the next can be a motivational factor for doing good. Although, I would argue there are better reasons.
This is one of the main principles for many of the Eastern religions which employ reincarnation and Nirvana. Many of these religions claim some kind of hierarchy within the animal kingdom, yet I never see them proselytizing to goats, field mice, wombats, fish or spider monkeys. It makes you wonder why humans are so special that we are the only animals with knowledge of the effect our actions might have on reincarnation. As PETA says, "Rats are people, too."
Besides, how exactly does an animal like a badger do something bad? They are instinctually ill tempered. Is that their lot? Does being a good badger simply mean being a prick? If so, can the same be applied to people who are justifiably upset and assault some one? Would this make aggravated assault permissible under some circumstances? Who decides? Fate? God? A jury of peers so stupid they couldn't come up with an excuse to get out of jury duty? I digress.
The point is, many people have a hard time seeing the point of living if their religion isn't true. For some, discovering their religion is false means suicide, but for most they just see life as being pointless, and anything becomes permissible (i.e. Nihilism). Of course, religion is not the only reason to do good things, let alone the only reason to live. But still, the prospect of life without god can be bleak for some, and people often ask atheists why they continue living if life is meaningless.
Well, for starters, even if life is essentially without purpose or meaning, that is not the same thing as saying life is not worth living. Family, friends, movies, fly-fishing and reveling in the misery of others can all be reasons to stick around. Naturally, those would apply to me as well (except for the fly-fishing, of course). But ultimately the reason I "stick around" is simply curiosity.
Growing up I believed in Mormonism implicitly. It had to be true--all of it. I couldn't see a way for it not to be. I knew what my life had in store for me; I knew Christ would come again; I knew the apocalypse was inevitable. Now that I don't "know" those things, I see the world as much more interesting and mysterious. At one point I even used the argument that god will not allow global warming to destroy us because of his promise after the Great Flood, and that the Second Coming of Christ would happen before such an event, anyway. Similar to this gentleman here:
While I am still skeptical of mankind's effect on global warming (which is not to say we shouldn't do anything about it), I am certainly open to the possibility of mankind destroying itself by accident or neglect. Without the certitude that god will stop Iranian terrorists from starting a nuclear war and killing everyone on earth before Christ returns, humanity has become better than television. We really don't know if North Korea will finally create a missile capable of reaching US soil. We don't know if Muslims will take over Europe, as they have tried several times, and as some are trying now. We don't know if American Democracy will fail, and if Obama really is trying to convert us to a Socialist Regime (OK, that's a bit of a stretch). But still, in a hundred years, who knows? A thousand years?
In 50 years, will Christ return? Will the Jewish Messiah finally come? Will everyone on earth convert to Islam or die by the hands of terrorists? Or, is religion merely our first attempt at science and philosophy? Will atheists outnumber Christians in America?
What about scientific advances? Will we ever cure cancer? Is stem cell research the key to fighting HIV/AIDS? Is there life outside of our solar system? What about space travel? Will Utahns ever be able to buy alcohol on Sunday? Will the government stop funding "abstinence only" education? Will the Boy Scouts break free from the Mormon Church and finally allow gays and atheists in their ranks, like the Girl Scouts? Will my gay friends ever get married? Will the Seahawks ever win the Super Bowl?
The human drama is infinitely more interesting and compelling when we acknowledge our solitude, and, hopefully, our solidarity. Uncertainty coupled with a finite existence makes life infinitely more worthwhile. How much worse would the first Act of Hamlet be if you already knew the end of Act III. What if some one told you that Bruce Willis was a ghost before you saw the Sixth Sense? Or that Darth Vader was Luke's Father? The uncertainty of life adds suspense unmatched by any TV drama or cliffhanger commercial break. This includes Heroes and 24.
I don't know what will happen in the next 50 years, but I'm dying to find out.
Here is the Atheist Experience discussing life's meaning:
And one on Nihilism: