||The death process is virtually never instantaneous, on a cellular level. Execpt perhaps in a nuclear explosion, all of the bodies cells do not die at once. It is actually possible that some cells may live on for hours or even days after "death", by whatever definition you are using.
It begins with some event which may be labled the "cause of death", such as the destruction or failure of some organ like the heart or liver. Maybe the lungs become choked with searing gasses or ravaged by an acid, say. Can you imagine the pain? Anyway, the brain no longer gets oxygen delivered in the blood, and so it ceases functioning. Again, not an instant process. Some brain cells die, others try to soldier on. Probably they panic, trying to function in some way. Picture desperate signals flying across synapses, thence to other synapes but something is wrong... no response there. What about over here...? No response there either... and now that one is down too! And that one just went? What is happening?
So then the brain finally goes from sending alarms across the nervous system to sending garbage, and finally sending nothing at all. "Death." But, still, you can have all sorts of cells still alive. The heart has quit, no more circulatory system, but then lots of cells don't need constant attention, right?
But sooner or later, they die. How can they survive, in the long run? They need oxygen, sugars, waste removal. They are prey to bacteria, but no antibodies are circulating any more.
Most people don't think too much about the exact details of the dying process because it doesn't really matter, does it? After the writing is on the wall, who cares about this particular cell that might hang on a few more minutes? The end is coming, with total certainty.
But then, why wait for the moment of "death" to realize this? Even now, the end is just as certain. And the end is certain for each of us, and for our species as a whole. We are like the individual cells of a dying body in that respect. We might go on, but that means nothing in the long run. Eventually, the oxygen will not be there any more. There will be no more food or light. Maybe a cell will die, and that cell's descendents will be there for the final death of the body. What difference there, eh? Death one way, or death another.
So maybe after we die, our descendents will see the Earth fail them. Or the sun will, by expanding to swallow the planet, vaporizing it all. Maybe their descendents will expand to other planets or stars. And what will happen to them once there? They will die there, of course. If not sooner, then later. What difference does it make?
So when some fool wants to say, "Well, forget about all that. I'm just going to enjoy my life", it's the same as looking at a decapitated person and ignoring the immediate death of the body and getting all wrapped up in the moment's life of some insignificant cell in the big toe or somewhere. Heh. Like it matters.
Didn't Peter Murphy have a song about this? I think so.
I do, I do, I do