With this as our defition of what is to be Human, there is NEVER a time in our life we should NOT die. It is OKAY to die at anytime in our life because at every moment in our life we are fulfilling our purpose. So if we were to die at any given moment, we will have died in a state of complete life fulfillment.
So why do we fight for life with such vigor? Why are humans such Champions at not giving up?
Well various reasons.
I could go the bitter route and say it is because we are mentally manipulated by our culture to believe we have a high purpose, like curing something, or eating the biggest hamburger ever made, or HAHAHAAHA!!!! finding love, and until we have fulfilled that purpose we must not give up the ghost.
But I think the common route is usually the truest. Most of the time in our communalatative lives as humans, death is just an option being weighed on the scale of everything else in our life. And death when compared to marraige, or having children, or getting high is just not as attractive. Simply because we don't know what death tastes like, while we know what a kiss does. Familiarity is naturally more attractive than obsurity. Of course it is, if it wasn't there would only be a cafe latte, not machiatto/cappuccino/mocha chinchilanga. Humans probably would have gone extinct a long time ago if we were only satisfied with the unknown. So selection deemed it successful for us to choose the common over the uncommon.
So you could say humans are fighters, or you could just say humans stubbornly desire comfort.
This all just looks so funny in the light shown from my first few sentences.
Since there is NO reason for a human to NOT die (according to my definition), It is OK to die at anytime. Yet what keeps us alive? The possibility of a beer on your front porch. A hike in a mountain. A bug in your mouth. A conversation with your Mum. and the list goes on.