Our individual lives are irreversibly over once we die. We cannot benefit after our death from anything we do before it. Thus, all rewards must be in this life, and not in an imagined afterlife.
This simple assertion completely disqualifies religions from the competition to provide meaningful explanations.
Do we live to have offspring?
The idea that we live to procreate is at least based on our genetic programming.
But my genes and I are not the same thing. Sure, biologically, my genes use me to replicate themselves. And because each of us is the result of the replication of our genes, and because each of us is the product of genes that were better at reproducing themselves (and thus us) than other genes, the idea that we live to procreate is indeed firmly rooted in our existence.
However, this view of nature is completely shattered by the advent of self-awareness. A major aspect of self-awareness is the awareness of our individual mortality. Self-awareness enables me to recognize that my individual interests can be quite different from, or even the opposite of, the interests of my genes.
My own interest is to be sexually satisfied (because this is the ultimate pleasure) and to die a comfortable death. The interest of my genes is to replicate themselves and, for the purpose of procreation, even endure the worst torture. Suffering is the negation of my interests, but the negation of my genes' interests would be a failure to replicate.
Self-awareness allows us to dissociate ourselves from our genes, and for this reason alone, it quite possibly is a dead-end mutation. We just haven't reached our termination point yet.
Logically, based on our capacity for self-awareness, we do not live to have offspring.
Logically, only ultimate sexual satisfaction, followed by a comfortable death, are values that are in tune with our own interests, not the interests of our genes.
