I've heard it said there are as many souls as grains of sand on a beach.
The constant movement of waves crashing on the beach grinds rock from large chunks, to pebbles and eventually grains of sand. Each grain nestles amongst other pieces and moves with the flow—sometimes shifting to another part of the coast, sometimes carted away by humans or blown on the wind as part of a desert. As far as we know, the grains don't think or feel.
On the other hand, the desire to survive and multiply governs humanity. With their different characteristics, some want to dominate others or kill them while others seek peace and harmony. Humans want to entertain, teach, heal, or occupy their mind, or work for their family. We're not satisfied to allow outside forces to toss us about amongst our fellows. Most of us strive to conquer some part of our personality. Some aim for perfection and to reach a higher goal than simple existence.
One thing is certain, humankind dies. Maybe their bones become grains of sand. Does our inner soul live on?