To continue playing with our river analogy: consider a man fishing beside the river, who catches a large salmon. The man is ecstatic, for he is poor, and his family is hungry. Just as he draws his knife to gut it, the fish speaks! It says "Please do not kill me. Throw me back into the river, for I am the Fish King, and I will grant you 3 wishes. You can have whatever your heart desires." Astonished, the man agrees, and throws the talking fish back into the water. He speaks his 3 wishes into the air: to be rich, to be respected, and to be young again. Time passes. The man goes home to his hungry wife and child, hands empty. A day passes. A week. Then a year, and youth, wealth and respect remain elusive. A year after that, the man is fishing by the same riverbank - and remember, this is an analogous riverbank - an analogy for our ancestry - and the man catches the same fish! Or is it? It looks the same, but it does not speak. There is no recognition in its fishy eyes. It just lays on the shore, gasping, flopping. The man decides it's just a normal fish after all.

The metaphor appears to have run away with you somewhat.

It is true. It has run away with us all

What are you actually talking about, though? Veiled and gnomic proclamations can be fun, but sooner or later you have to show your hand.

The fish represents the lost dreams of our ancestry, if not the fishy ancestors themselves. The man is us, all of us. The hungry family is our hungry family. Or perhaps our hunger for connection to our past. The story as a whole is meaningless, and in being so, represents the randomness and chaos in which we find ourselves. Is the universe beneficent, malevolent, indifferent? We cannot know for sure. We can only stare into the dying eyes that stare at us in turn, from the mirror, and guess.

I do. This was quite entertaining.

Nobody likes a smartass.

This is true and I approve this comment

To be clear, the river can divide, too. That's speciation, where populations no longer interbreed because their offspring are either unviable or themselves cannot produce offspring.