The big picture shows us that humans have only been around for a millisecond on the cosmological scale and if our limited understanding of the earth's history teaches us anything, it is the likelihood that we will only be here a moment more. Planetary collision, biological viral mutation, or a volcanic eruption that speeds up global warming, given the vastness of time, are not possibilities but probabilities.
Ha! I think intellectualizing my insignificance gives me permission to check-out of this existence without regret.
Then I get an occasional slap of clarity that brings me back to the emotional mess that being human means. Yesterday was Father's Day. SLAP!
While MY "existence" may end with my death, the ripples that my life caused in this pond of humanity will go on. My children confirm to me that I made a positive difference in their lives and they will make a corresponding difference in the lives of others.
With any luck humanity will figure out a way to survive, our collective ripples growing to a tsunami of enlightenment.
As my ability to type has degraded and in the interest of accuracy, I think I will try reading my posts. As you may be able to tell my speech is also wasting away.