Life is not meaningless for atheists, it depends on each person how he/she fills it with meaning for the limited time he/she has at disposal. It is arrogant and egocentric to think that our lives should be eternal.
Keith Parsons in his essay ‘Seven misconceptions about atheism’ said ‘Does atheism imply that life is absurd? Prominent philosopher and Christian apologist William Lane Craig thinks that it does. For the atheist, human life is just an infinitesimal moment before the eternal grave:
“If God does not exist, then both man and the universe are inevitably doomed to death. Man, like all biological organisms, must die. With no hope of immortality, man’s life leads only to the grave. His life is but a spark in the infinite blackness, a spark that flickers, and dies forever. Compared to the infinite stretch of time, the span of man’s life is but an infinitesimal moment; and yet this all the life he will ever know …. For though I know now that I exist, that I am alive, I also know that someday I will no longer exist, that I will no longer be, that I will die. This thought is staggering and threatening: to think that the person I call “myself’ will cease to exist, that I will be no more (Craig, 1994, p. 57)!”
One hardly knows where to begin in commenting on this remarkable passage. I guess my first impression is one of monumental egotism. Surely there is something monstrously egocentric in thinking that my life is of such transcendent significance that I should be an exception to cosmic law–that my ego should survive when planets, stars, and galaxies are no more. As for anyone who really worries about the ultimate “death” of the universe, the best advice would be “Get a life!”
More to the point, the implied premise of the above passage is extremely dubious. Why should life have to be everlasting to be meaningful? Why not draw the reverse conclusion and say that, since we know that life is fleeting, we should strive to experience all the meaning we can within that short compass? The message we should draw from our knowledge of our mortality is this: You have a limited number of days, hours, and minutes. Therefore you should strive to fill each of those days, hours, and minutes with meaning. You should strive to fill them with learning and gaining wisdom, – with compassion for the less fortunate, with love for friends and family, with doing a job well, with fighting against evil and obscurantism, and, yes, with enjoying sex, TV, pizza, and ballgames.
What could Dr. Craig say to those of us for whom the above-mentioned sorts of goods–family, friends, learning, compassion–paradigmatically constitute the meaningfulness of life? I guess he could say that we are only fooling ourselves. We think that our lives are meaningful when in fact they are absurd and pointless. I don’t know what to say to someone who insists that my life is meaningless when it seems to me to be rich with meaning. I suspect that he is implicitly defining “meaning” in a question-begging way. More likely, I think that the denial that life is meaningful for atheists is an expression of simple arrogance.’