From a Slashdot thread that started with a question about uses for a software "dead man's switch", and went off on a tangent about the meaning of life. Quoted material is from Slashdot user lukas84.
Whatever these little consequences are, they can't concern me anymore, since i'm already dead...This thinking can, of course, lead to amoral decisions, and that's why we have invented religion :)
The fact that consequences of your death can't concern you when you're dead, in no way means that reasonably foreseeable post-mortem consequences should not concern you now.
That's why even people who don't believe in any sort of "afterlife" still buy life insurance to take care of their kids.
You don't need any sort of supernatural belief to end up with behavior that most people would call "moral", just some compassion and a reasonable ability to foresee the consequences of your actions.
Which takes me off on a bit of a tangent...
Foreseeing the effects of our actions is of obvious use; if you can't do that to at least some degree, you'll quickly end up dead or institutionalized.
But compassion? What's in it for me, you wonder.
Cultivating compassion expands the self. We're pretty darn sure that the human body known as "Lukas Beeler" is eventually going to stop functioning and in some way dissolve (rot in the ground, be burned up, eaten by squirrels, whatever). If you completely identify "yourself" as "Lukas Beeler", well, then, that's it for you. Maybe you can tickle the pleasure centers of that lump of meat a little bit before it dissolves, but that seems an unsatisfactory goal.
But is identifying "yourself" as "Lukas Beeler" the only option? Throughout history, some people - people who seem to derive a great deal more contentment from life than the average Joe - have suggested that transpersonalization provides a more satisfactory experience. This means identifying "yourself" as more than "Lukas Beeler".
By "more than", I do not mean anything supernatural, I am not speaking of a "soul" or anything metaphysical like that. But what if, for example, you were to invest a portion of your own concept of identity into your family? Unless all your relatives are childless, your family will outlast your body, so that "you" might have a larger and longer existence than the body of "Lukas Beeler".
What if you were to invest your identity into your community, your city or your nation? That's an even larger and longer existence. Perhaps we have here a sensible argument for patriotism. But why stop there, when by identifying "yourself" with the whole human race, "you" get even bigger and longer-lived?
Now, hold on there, you ask. How in world am I supposed to accomplish this "investment of identity" that you're going on about? Well, it means to think of yourself as these other people. It's an exercise of imagination, to see things through their eyes, to feel what they feel. With that exercise, eventually it can be seen that the ordinary idea of "self" is just a mental construct, just an idea, not an immutable reality.
In other words, compassion is the tool and the method to get You out of you, the "big You" of consciousness out of the "small you" of flesh.
Indeed, if you get good at it, you may find that you can see "yourself" not just in other humans, but in other animals; in the trees; in the whole biosphere. Expanding "yourself" until not much identity is left connected with the body known as "Lukas Beeler".
And maybe you can keep going. Eventually you might find yourself worrying about the heat death of the observable Universe, billions of years in the future, as your end, instead of the dissolution of "Lukas Beeler" in a few decades. That's a pretty massive trade-up. And if you get that far, it's comforting to consider that cosmology seems more and more to be considering some sort of "multi-verse" scheme in which our observable Universe is only a part; there's still more to become.
"A human being is a part of a whole, called by us 'universe', a part limited in time and space. He experiences himself, his thoughts and feelings as something separated from the rest... a kind of optical delusion of his consciousness. This delusion is a kind of prison for us, restricting us to our personal desires and to affection for a few persons nearest to us. Our task must be to free ourselves from this prison by widening our circle of compassion to embrace all living creatures and the whole of nature in its beauty." -- Albert Einstein
(And darn it, somewhere out there is a great quote from Richard Feynman, shortly before his death, in which he talks about how he felt that he had sort of "spread himself out" to other people and so could be calm about dying. I think it was in that Nova episode, "The Best Mind Since Einstein", but I can't find it.)
I'm a simple person with no special knowledge. No one will remember me. And that's the case with most of the other people in the world (though most of them don't want to acknowledge that fact). Even if they have children, most people are meaningless in the long run.
Must a life have "meaning" in order to be enjoyable and satisfactory? When I noodle around on my guitar, there's no meaning, but it's fun. When children spend the day making sand castles, knowing that they'll be gone when the tide comes in, they still spend hours playing at it. What's the meaning of a snow angel, or of the tune I whistle while waiting for water to boil on the stove?
There's an old Calvin and Hobbes cartoon where Calvin asks, "What if there's no afterlife? Suppose this is all we get?" Hobbes looks around, thinks for a minute, and replies, "Oh, what the heck. I'll take it anyway." (And Calvin continues, "Yeah, but if I'm not going to be eternally rewarded for good behavior, I'd sure like to know NOW.")
The same idea goes for a "meaningless" life: what the heck. I'll take it anyway.
Hindus call the idea "lila" - the universe is the "purposeless play", the "spontaneous game".
If coming at it from that direction doesn't help you, consider the question of just what it means to have a "meaningful" life. Is it just passing on your genes? Then Issac Newton had a meaningless life. Is it being remembered after you die? That makes the whole thing just a popularity contest, like picking the homecoming queen. I'm not willing to leave the "meaning" of my life (if any) in the hands of what other people do.
The question of the meaning of life is not one that is answered by objective science. There's no organelle in a cell that creates meaning the way ribosomes create proteins, no "coefficient of meaning" in quantum electrodynamics.
If "meaning" is anything, is part of our subjective experience. That means that if you really want a meaning for your life, you get to decide what it is, then set about making it happen.