Dem Bones: I'll bite

People naturally make stuff up to explain the unknown. The fact that no two groups of people, primitive or "advanced", have discreetly founded the exact same religion is proof that the explanations are indeed "made up", and not an epiphany from above.

Then you must take into account science. Scientific research finds explanations based on logic to replace "made up" beliefs.

Scientific research isn't always right either. We may have no perfectly accurate scientific explanations, but they are closer to the truth than the ideas they replaced. It provides enough foundation to continue further research, which will eventually replace its own foundation with even more accurate observations.

The problem is that few humans are willing to reform their beliefs. They're indoctrinated with "made up" religion from youth, and spend their lives executing Galileo and Copernicus because their supportable discoveries disagree with dogma.

That, my friend, is why everyone is mortal. With every generation the latest scientific observations take root, further displacing the last generation's "made up" crap.

While we have yet to stand on a firmly "logical" base, I think this trend will continue forever, with each new generation treating the last generation's "made up" crap as being based more on beliefs than logic, whether that last generation was profusing what we now refer to as religion or to science that has since been disproved.

This is a good thing. I know I will become stagnant in my old age. My death will be necessary to allow new ideas to flourish.
I am yet young and able to smile about my own mortality.