Zeuglodon, the unit of replication would be either the individual gene or the whole bacterial genome. But the individual gene is expressed as a protein and the genome is expressed as an individual organism. I argue that genomes can make identical copies of themselves. Why would the resulting organism have to be identical atom for atom? As I said before, I'm not exactly the same as one year ago, but I'm still the same individual from an evolutionary point of view.

And that's not the empirical evidence I'm asking for. I'm asking about altruistic behaviour.

If the 1/2, 1/4 and so on only applies when genes or gene variants are not already widespread in the population, then I think I get it.

But if that is the case, I would say this is something that should be pointed out MUCH more. If altruistic gene variants have been successful, they should be widespread in the human population already. And then those 1/2 and 1/4 numbers should be irrelevant for the current human situation. I don't think I'm the only one who gets confused. It seems you are explaining things I'm not asking about.