Connecting Social and Individual Goodness
About halfway between Von Neumanna and Rawls, John Harsanyi mathematically proved that if we add some more assumptions, then the right thing to do within a particular set of people is equivalent to maximizing a weighted sum of their individual utilities "author": "J C Harsanyi".
To do this, Harsanyi assumed
- Goodness is a number. We will refer to "utility" as "social welfare".
- Individual wellbeing is a number.
- If everyone has utility 0, then social welfare is 0.
- If everyone is indifferent between two universes, both universes have equal social welfare
We've talked about (1) and (2) being true in previous posts. (3) is just an assumption that simplifies the proof by allowing us to say "sum of individual utilities" rather than "sum of individual utilities plust a constant". That leaves (4).
(4) basically represents the idea that if you aren't actually helping someone, you aren't doing good, and if you aren't actually hurting someone, you aren't doing evil. While I find this intuitively true, some people like Kant disagree "title": "Categorical imperative".
I don't have a convincing argument here except this: it takes a special kind of privilege to think that something can be right/wrong if it doesn't actually help/hurt someone.
If you accept all this, you still aren't quite a utilitarianism - at least not a traditional one. That's because nothing we've said has implied anything about consequentialism. Everything we've talked about is consistent with consequentialism, but it's also consistent with rule-based ethics, virtue ethics, etc, because we haven't defined well-being. Is it happiness or the satisfaction of preferences? Freedom or the guarantee of human rights? That's why I refer to this idea by a new name: Summatarianism.