I believe in life after death.
No, I don't think that I will live on as a conscious being after my earthly demise. I'm firmly convinced that death marks the unqualified and irreversible end of our lives.
My belief in life after death is more mundane. What I believe is that other people will continue to live after I, myself, have died. You probably make the same assumption in your own case. Although we know that humanity won't exist forever, most of us take it for granted that the human race will survive, at least for a while, after we ourselves are gone.
Because we take this belief for granted, we don't think much about its significance. Yet I think that this belief plays an extremely important role in our lives, quietly but critically shaping our values, commitments and sense of what is worth doing.
Astonishing though it may seem, there are ways in which the continuing existence of other people after our deaths — even that of complete strangers — matters more to us than does our own survival and that of our loved ones.
Consider a hypothetical scenario. Suppose you knew that although you, yourself, would live a long life and die peacefully in your sleep, the Earth and all its inhabitants would be destroyed 30 days after your death in a collision with a giant asteroid. How would this knowledge affect you?
If you are like me, and like most people with whom I have discussed the question, you would find this doomsday knowledge profoundly disturbing. And it might greatly affect your decisions about how to live. If you were a cancer researcher, you might be less motivated to continue your work. (It would be unlikely, after all, that a cure would be found in your lifetime, and even it were, how much good would it do in the time remaining?)
Likewise, if you were an engineer working to improve the seismic safety of bridges, or an activist trying to reform our political or social institutions or a carpenter who cared about building things to last. What difference would these endeavors make if the destruction of the human race was imminent?