Yes, in the long term there is an evolutionary pressure toward increased reproduction. However, our ability to affect both our own makeup and the world around us is also increasing at a drastic rate.

It’s totally possible that the system doesn’t have any nice limiting behavior. We might lurch from drastic attacks on reproductive instincts (cutting them out of our jeans) to warfare to periods of reproductive plenty.

Also it seems that as far as aggregate utility goes the amount contributed by some poor descendants will be small compared to the difference that we could make by building happy machines/brains and filling up giant mines with them. Even a small chance of following that plan probably outweighs the other consequences.

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Also here is a quick argument that aggregate utility isn’t a useful measure.

Let’s compare universe A which has reached a steady state with 100 billion people and universe B at a steady state of 200 billion people all having the same level of happiness. If you accept aggregate utility as the desierable end you have to prefer universe B to A (twice the utility!)

But presumably you retain this preference even if you learn that both universe A and B will persist forever in these steady states. Even though we can biject all the people who will live in universe A with those in universe B. Thus it must be the fact that at any particular time B has twice as much utility as A.

However, now suppose that both universe A and B lie inside some larger domain and god decides he is going to slow down the passage of time in universe B so that only one second passes in universe B for every one in universe A. Yet now A and B have the same utility per unit (absolute) time so no discounting of the future (should use absolute time) can give you reason to favor B over A. So what remains to make B better than A? Is it the fact that the B experiences are associated with more physical brains?

I could continue and make the situation even more troublesome but I think you get the argument.

As far as virtual humanity goes, I am also skeptical. It seems to me that a simulation of a human personality is not a person, in the same way that a simulation of an earthquake is not an earthquake.

Lives of continuous torture, where they’d rather be dead, were rare.

That’s the wrong standard of comparison, surely. Instead, shouldn’t you ask how many would prefer that they were never born in the first place, with full knowledge that the average standard of living of their siblings and (to a lesser extent) everyone else would be raised in that case?

(I’m applying my understanding of your ethical system here. This isn’t necessarily the question that I would ask.)