It always strikes me as strange when I hear the suggestion that because atheists don’t believe in God, we have no reason to value actions in life. I mean, it’s not like they will last. Why do anything?
This idea that your actions must be remembered in the minds of yourself and others ad infinitum, must be abolished in my opinion. Meaning is not predicated by an actions longevity, but simply by the actions themselves.
If you are dedicated to helping the poor and suffering, and are simultaneously under the impression that you will live forever, would your actions suddenly lose meaning if you suddenly realized this life is all there is? Is the reduction of suffering in that moment any less important?
The recognition that all we have in this life is the present moment, gives more meaning than the idea that this life is only the beginning. Your moment to moment experience is all that you have. The realization of this should give greater meaning to even minute experiences.
Serious arguments suddenly become trivial. Each moment spent grueling in self-pity or loathing, instead of bettering yourself is suddenly amplified when the brevity of life is taken into account. Take advantage of the present moment, of this moment.