Necessitation and Moral Concern

Claim 1: Whether or not our actions are necessitated, in itself makes no difference to how we ought to go about moral deliberation. Knowing that you're predetermined to act in a certain way should not foreclose deliberation. Nor should the bare fact of necessitation influence it one way or the other. If you know that you're either going to tell the lie or tell the truth after deliberating, and the laws of physics and the initial state of the universe determine it one way or the other, but you don't know which you're going to do, then you have no reason not to deliberate in the standard way.

Claim 2: Some kinds of necessitation makes moral deliberation pointless. Let action maximalism be the view that for every action you could take in a given circumstance, it is true that there is one person who will take that action. Lewisian modal realism was one version of this The different people exist in different space time regions. If you squint, the many-worlds interpretation of quantum mechanics is another version. (The different people exist in different branches of space-time.)

If action maximalism is true, then you know that no matter which action you take, someone just like you will take the other. If you tell the truth, your counterpart will lie. If you lie, your counterpart will tell the truth.Your counterpart won't act that way because you did what you did, but you can be certain of it even so.


Are these claims in tension? Sometimes I feel that they are. Sometimes, that they are not.

Why should action maximalism make moral deliberation pointless, if necessitation doesn't? It can't be because of the action maximalism makes necessitation true.

If there is a difference, here is a preliminary guess: moral deliberation is worthwhile when you have the power to shape the world, even if you're disposed to use that power in some particular way. When it comes to action maximalism, it seems like your actions are not changing the world so much as revealing (or settling) your location in it. By choosing to lie, you are not choosing to add a lie to the world so much as choosing to be the liar. You know before acting that the world will contain one liar and one truth-teller. Your action decides which one you are. And your location in the world, or your identity, is just not that morally important.

Is this the right way to think about maximalism? It may depend on the metaphysical details. It is true that generally, from an epistemic perspective, your action is self-locating. You don't think, upon taking one action, that the world is any different from how you would have thought it was, if you had taken the other action. However, you may know that had you (albeit impossibly) taken the other action, the world would have turned out differently. By lying, you caused there to be one liar and one truth-teller,  for your counterpart would have told the truth no matter what you did.

This suggests that the value of moral deliberation may turn on which decision theory one accepts. A causal decision theory would say your decision is still significant. You have the power to impact the world, even if you are bound to only do so in one way, so you must deliberate. An evidential decision theorist would disagree. The power to change the world is irrelevant if you can be certain that what would result, conditional on taking either action, is the same.