There are two different ways that I sometimes think about population ethics, and I think it’s useful to keep these situations distinct.
First, suppose you are altruistic, and given the chance to make decisions affecting only people other than yourself. From this perspective, the mere addition paradox would involve redistributing utility among a population that I am not a member of, and I accept the repugnant conclusion without much reservation. I would even accept killing off the current population (that I am not a member of) if that allowed me to replace it with a population whose lives are barely worth living, if the size of the potential new population were sufficiently high. My response to your other modifications is that I am not altruistic towards paperclippers, nonsentients, etc, so I would not harm a human population for their benefit. This may seem unobjective, but that is necessary. There is no objective way to compare utilities between different agents, to say that gaining a dollar is 10 times as valuable to Alice as it is to Bob. The closest I can do is say that I care about Alice gaining a dollar 10 times as much as I care about Bob gaining a dollar.
The other perspective that I look at population ethics problems from is that of a typical member of the original population being affected. Here, creating an additional population whose lives are barely worth living, while not changing the utilities of the original population, is neutral. Creating an additional population whose lives are barely worth living while increasing the utilities of the original population (such an increase could happen due to altruism towards the newly created people) is good. And creating an additional population while decreasing the utilities of the original population (e.g. through resource redistribution) is a bad thing. Let’s suppose the original population is given the opportunity to create a new population, whose lives are barely worth living, and gain some utility themselves. Suppose they take this opportunity, and afterwards, the new, larger population, has the option to redistribute resources, increasing average utility, but decreasing the utilities of the original population below where they were originally. Locally, this looks like a good idea. But if redistribution occurs, then it would not have been a good idea for the original population to create the additional population in the first place, so by TDT, redistribution is a bad idea in that scenario, and the repugnant conclusion is averted.
There are two different ways that I sometimes think about population ethics, and I think it’s useful to keep these situations distinct.
First, suppose you are altruistic, and given the chance to make decisions affecting only people other than yourself. From this perspective, the mere addition paradox would involve redistributing utility among a population that I am not a member of, and I accept the repugnant conclusion without much reservation. I would even accept killing off the current population (that I am not a member of) if that allowed me to replace it with a population whose lives are barely worth living, if the size of the potential new population were sufficiently high. My response to your other modifications is that I am not altruistic towards paperclippers, nonsentients, etc, so I would not harm a human population for their benefit. This may seem unobjective, but that is necessary. There is no objective way to compare utilities between different agents, to say that gaining a dollar is 10 times as valuable to Alice as it is to Bob. The closest I can do is say that I care about Alice gaining a dollar 10 times as much as I care about Bob gaining a dollar.
The other perspective that I look at population ethics problems from is that of a typical member of the original population being affected. Here, creating an additional population whose lives are barely worth living, while not changing the utilities of the original population, is neutral. Creating an additional population whose lives are barely worth living while increasing the utilities of the original population (such an increase could happen due to altruism towards the newly created people) is good. And creating an additional population while decreasing the utilities of the original population (e.g. through resource redistribution) is a bad thing. Let’s suppose the original population is given the opportunity to create a new population, whose lives are barely worth living, and gain some utility themselves. Suppose they take this opportunity, and afterwards, the new, larger population, has the option to redistribute resources, increasing average utility, but decreasing the utilities of the original population below where they were originally. Locally, this looks like a good idea. But if redistribution occurs, then it would not have been a good idea for the original population to create the additional population in the first place, so by TDT, redistribution is a bad idea in that scenario, and the repugnant conclusion is averted.