First written: Sep. 2017. Last update: Dec. 2025.
Are there different possible outcomes given the present state of the universe? One might think that much depends on our answer to this question. For example, if there are no alternative possible futures given the present state of the universe, one might think that ethics and efforts to improve the world would cease to make sense.
An Objection Against the Meaningfulness of Ethics
We can define “global ontological possibilities” as alternative possibilities that could result from the same state of the universe as a whole. Since alternative possibilities in a strong sense seem crucial to ethical deliberation, one might assume that global ontological possibilities are necessary for ethics to get off the ground, and indeed for engagement in ethical decision-making and action to make sense. On this assumption, one could argue that ethics does not make sense due to the non-existence of global ontological possibilities.
To be sure, the assumption that ethics requires global ontological possibilities is highly controversial. For example, one may hold that we can have genuine ontological possibilities at a relative level even if there are no global ontological possibilities, and hold that ethics is meaningful given such relative possibilities. Or one could maintain that purely epistemic or ex-ante possibilities are enough for ethics to make sense.
Yet my goal in this essay is not to question the assumption above. Instead, I will argue that even if one thinks global ontological possibilities are required for ethics to make sense, one cannot reasonably reject the meaningfulness of ethics based on the claim that such possibilities do not exist.
Key Premise: Humility Is Warranted
We do not know whether global ontological possibilities exist. Given our limited understanding of the fundamental nature of reality, it seems reasonable to maintain a degree of humility on this question. Indeed, even if we have reasons to believe that possibilities of this kind most likely do not exist, it still seems overconfident to assign more than, say, a 99.9 percent probability to their non-existence.
Note that the exact probability we assign to the potential existence of global ontological possibilities is not important. The point here is simply that, from our epistemic vantage point, there is a non-zero probability that global ontological possibilities exist.
Why the Objection Fails
The probabilistic premise above implies that it is unwarranted to reject ethics based on the supposed non-existence of global ontological possibilities.
To see why, consider the claim that risks of very bad future outcomes are low. Even if this claim were true, it would not follow that such risks can reasonably be dismissed. After all, when the stakes are sufficiently high, it is not reasonable to dismiss low probabilities. And when we are discussing the meaningfulness of ethics, the stakes could in some sense not be greater, since what is at issue is whether there are any stakes at all. Given such total stakes, even extremely low probabilities are worth taking seriously. Therefore, the mere epistemic possibility that global ontological possibilities are real is sufficient for undermining the above-mentioned objection against the meaningfulness of ethics.
Moreover, when considering the conceivable scenarios before us, an asymmetry emerges in support of the same conclusion. If global ontological possibilities are real, and if ethical action roughly amounts to realizing the best of these possibilities — or at least avoiding the worst — we seem to have good reason to try to realize the better over the worse of these possibilities. On the other hand, if such possibilities are not real, trying to create a better world appears to have no downside in terms of which global ontological possibilities end up getting realized. Thus, when considering these two horns, we seem to have a strong reason in favor of trying to create a better world, and no reason against it.
In sum, even if we grant the controversial premise that ethics requires global ontological possibilities, it does not follow that ethics is meaningless. Given our uncertainty about whether such possibilities exist, and given what is at stake, we have good reason to pursue ethical deliberation and action regardless.
Magnus Vinding 