Why? How is that not a violation of agency?
Land and natural resources are just there and not a product of your agency. If many people want to make use of them neither can as they will be at odds, so the natural state is that nobody can act using natural resources. If we prohibit their use we're not limiting agency as there is none to begin with, but if all but one person agree to not use these resources that one person's agency is being increased as he has now more options. The land tax would be a compensation for the other people's claim they'd have to give up, which is a perfectly fine trade.
I think to make that argument sufficiently detailed would require a new top-level post or at least its own comment thread.
what about children?
Children don't have full agency which is why we need to raise them. I think the right of the parent to decide for their children diminishes as the child's agency increases, and that government has a right to take children away from parents that don't raise them to agency.
either your ethics can be formulated as maximizing a utility function, [...]
I have a utility function because I value morality, but using that utility function to explain the morality that I value would be circular reasoning.
I don't get it. Are you saying not killing the one person is the right decision even if millions of lives are at stake?
It would be the moral decision, not necessarily the right decision. I'm using morality to inform my utility function but I can still make a utility tradeoff. The whole point of agency ethics vs. value ethics is to separate the morality consideration from the utility consideration. Killing the one would as I put it make me a both bad and good person and people could still think that the good in this instance outweighs the bad. My point is that when we mash the two together into a single utility consideration we get wrong results like killing the organ donor because we neglect the underlying agency consideration.
How is it "more realistic" if it neglects to take asymmetry into account?
I meant 'more realistic' than the simple prisoners' dilemma but it's not realistic enough to show how defecting against a defector might not always be the best strategy with asymmetrical payoff.
OK, but are there stakes high enough for you to cooperate?
I don't know what you mean.
The land tax would be a compensation for the other people's claim they'd have to give up, which is a perfectly fine trade.
OK, let's do a thought experiment. On planet K, labor is required to keep the air temperature around 25C: let's say, in the form of operating special machines. The process cannot be automated and if an insufficient number of machines is manned, the temperature starts to rise towards 200C. The phenomenon is global and it is not possible to use the machines to cool a specific area of the surface. Now, 10% of the population are mutants ...
Preface
I have trouble expressing myself in such a way that my ideas come out even remotely like they sound in my head. So please apply the principle of charity and try to read how you think I thought of it.
Tit for Tat
Tit for Tat is usually presented in a game between two players where each chooses to either cooperate or defect. The real world game however differs in two important ways.
First, it's not a two player game. We make choices not only on our single instance of interaction but also on observed interactions between other players. Thus the Advanced Tit For Tat not only defects if the other player defected against itself but also if it could observe the other player defecting against any other player that employs a similar enough algorithm.
Second, there is a middle ground between cooperating and defecting, you could stay neutral. Thus you can harm your opponent, help him or do neither. The question of the best strategy in this real life prisoners dilemma is probably still unanswered. If I see my opponent defecting against some of my peers and cooperating with others, what do I choose?
Agency
The reason why there even is a game is because we can deliberate on our action and can take abstract thoughts into account that do not directly pertain to the current situation, which I think is the distinguishing factor of higher animals from lower. This ability is called agency. In order to be an agent a subject must be able to perceive the situation, have a set of possible actions, model the outcomes of these actions, value the outcomes, and then act accordingly.
We could act in such a way that infringes on these abilities in others. If we limit their ability to perceive or model the situation we call this fraud, if we limit their set of possible actions or their ability to choose between them, we call it coercion, if we infringe on their ability to value an outcome, we call it advertising.
Ethics
I propose that the purpose of our moral or ethical intuitions (I use the two words interchangeably, if there is a distinction please let me know) is to tell us whether some player defected, cooperated or stayed neutral, and to tell us who we should consider as having a close enough decision algorithm to ourselves to 'punish' third players for defecting against them. And I further propose that infringing on someones agency is what we consider as defecting.
Value Ethics
Utilitarians tend to see defecting or cooperating as pertaining to creation or destruction of values. (Edit:) Three things bother me about value ethics:
1. Valuations between different people can't really be compared. If we shut up and multiply, we value the lives of everybody exactly the same no matter how they themselves value their own life. If there are chores to be done and one person claims to "not mind too much" while the other claims to "hate it with a passion" we can't tell if the emotional effect on them is really any different or maybe even the other way round.
2. It makes you torture someone to avoid an insanely huge number of dust specs.
3. It makes you push a fat man to his death.
Agency ethics
Instead I propose that defecting in the real world game is all about infringing on someone's agency. Thus we intuit bankers who destroy an insane amount of wealth while not as good people still as neutral because they do not infringe on agency. At least that is my moral intuition.
So infringing on agency would make you a bad person, while not infringing on agency doesn't make you a good person. What makes you a good person is increasing value. Maybe agency is more fundamental and you cannot be a good person if you are a bad person, but maybe you can be both. That would create cognitive dissonance in people who consider ethics to be a singular thing and don't see the distinction, and that might be at the root of some ethics discussions.
Evil
In my version of ethics it counts as evil to push the fat man or to switch the tracks, as that would mean deliberately causing a death of someone who doesn't want to die. I would let the five die and not feel guilty about it, because I am not the cause of their deaths. I make a fundamental distinction between acting and not acting. If I hadn't been there the five would still die, so how could I be responsible for their deaths? I am aware that this view makes me evil in the eye of utilitarians. But I see less people acting consistent with utilitarianism than I see people arguing that way. Then again, this perception is probably heavily biased.
Conclusion
I don't really have a conclusion except of noticing that there exists a disagreement in fundamental morality and to inform you that there exists at least one person who considers infringing on someone's agency as defecting in a prisoner's dilemma.