You should decide whether you think a merged mind counts as one mind (because it's one set of neurons firing) or several (because this one set of neurons gets 'magnified' as many different entities' subjective experiences) and then do whatever utilitarian calculation falls out the other end. You're starting from the premise set p and not p (utilitarians think a merged mind is one mind, I think it's several), so of course you can prove something stupid about utilitarianism. Argue against a utility function you think isn't dumb!
I don't fully understand, how is there simultaneously "one mind in hell" and yet we have "Everybody going to hell"?
Good question. My claim is more about continuity than identity. It seems that I can say that
Here I'm supposing that
I agree with Robbie Thompson here. It seems the tension is arising because of a flaw in the thought experiment, where there's simultaneously many minds and only one. In my view, merging two minds into one entails the non-existence of one of the minds. It's not clear which one persists, but for the utilitarian calculus that isn't important. The view that two minds
Here’s a thought experiment. As far as I know, no one has written about it yet.
There's a mind fated for hell. Its suffering will last a very long time, and nothing can change that.
You get to decide what happens at the end of everybody else's life. There are two options:
Which do you choose?
I'd choose A. Everybody going to hell is obviously bad, and definitely not worth a dollar to any charity.
And yet standard utilitarianism chooses B. By its count, merging neither adds nor subtracts welfare. There's still one mind in hell, even though it came from a merge of many minds. So, it first says the two options are equal in value. Then, $1 breaks the tie. Now it says you should send everybody to hell.
This is the verdict of any standard utilitarianism that adds up the welfare of experiences - total, average, and even negative - as long as $1 does some good and the merging is considered morally neutral.
The mirror case works too. Offer $1 to charity for letting everybody's lives simply end, instead of merging them into a mind fated for heaven, and standard utilitarianism accepts the dollar, depriving everybody of heaven.
That can't be right. What's going on?
The problem here is that standard utilitarianism doesn't explicitly track what each person goes on to experience. It only adds up experiences as seen from the outside, from a third-person 'view from nowhere'. What you subjectively continue onto is none of its business. That's mostly fine for linear lives, where each experience simply leads to the next, but not for lives that can be copied and merged, and you can construct more counterexamples like this one with those operations.
One could bite the bullet and say only the hell itself matters, but not the fact that multiple people would come to experience it. But then one would have to be indifferent between dying peacefully and waking up in that hell tomorrow, everything else unchanged. I don’t think many people are indifferent.
I think the fix is to care about each perspective’s subjective futures, in addition to its immediate welfare. I’ve proposed that utilitarianism should be based on a Markov reward process over types of experiences. It handles this case, and I think it also fixes problems with identical copies that others have noted.
It feels like we should have started discussing this counterexample a long time ago. Ethics has only handled the extremely special case of linear lives. We may soon be headed for takeoff, yet as a civilization we haven’t even worked out the general case and what it implies.