That’s a good and deep question, for which I don’t have an answer. My intuition about the answer would be no, though, i.e., we have different values/preferences with a complicated history and a degree of inconsistency forming some n-dimensional vector space that cannot be reduced to a simple scalar. But even granting that they could be reduced to a vague ‘desire for the good’ terminal value, it would seem you can develop this in wildly different and opposite ways. The fact that minds desire a common x would, if proven (like, sampling aliens for example) update me towards the existence of some shared, emergent subjective belief that arises in sentient and intelligent creatures, but I don’t see how it would update me towards believing this belief is ‘true’ in the naturalist, correspondence-to-an-external-reality kind of sense. I think I’d agree with your second interpretation, ‘that makes goodness real for minds, but not objectively’. Objectivity is a term whose use I always find extremely confusing. It makes sense to talk about natural phenomena with the lens of “based on real facts, evidence, and logic without letting personal feelings, likes, or unfair biases change your view”, because we’re assuming they are mind-independent and follow laws that are orthogonal to our subjective feelings, likes and biases. When you talk about what minds believe, it becomes messier (because a lot of facts are socially constructed, like money or laws, and not independent of feelings, likes and biases; in fact, they are intrinsic to what it is like to be a human, part of a human community with its intellectual and material limitations. What does ‘real’ mean when we say ‘this piece of paper is worth 100 dollars’ except something like “well, this is some kind of useful and enforced belief/practice which is contingent on the existence and interactions of a particular type of being with properties x, y, z”). There’s like three tiers here: stuff that’s mind-independent (it doesn’t matter what any mind or group of minds believe and think with respect to the underlying truth), stuff that’s intersubjective (which is mind-dependent but not amenable to change by an individual) and purely subjective stuff (which is completely dependent on the subject’s subjective beliefs, feelings, whatever). Morality is for me something that belongs to somewhere between the second and third tier (the ‘agreed social norms’ is 2nd tier, the personal belief that x is wrong independently of what anyone thinks, to 3rd tier).
So on moral realism: I just feel there’s nothing you can really use for updating on the view that there are “stance-independent moral truths whose truth does not depend on what any mind happens to value or desire.” (Theology is more updatable here; like, you just need to have God(s) appear, interact with you and do supernatural stuff repeatedly and measurably). If you view of moral realism is something like “Given creatures with volition, reason, different interests, etc..., who would want to engage in positive-sum social games, there might exist an optimal configuration of the latter that would be reachable by different creatures without any contact with each other”, then while I am still somewhat skeptic, this is something I can imagine to be true, and I can think of ways in which it can be updated.
That’s a good and deep question, for which I don’t have an answer. My intuition about the answer would be no, though, i.e., we have different values/preferences with a complicated history and a degree of inconsistency forming some n-dimensional vector space that cannot be reduced to a simple scalar. But even granting that they could be reduced to a vague ‘desire for the good’ terminal value, it would seem you can develop this in wildly different and opposite ways. The fact that minds desire a common x would, if proven (like, sampling aliens for example) update me towards the existence of some shared, emergent subjective belief that arises in sentient and intelligent creatures, but I don’t see how it would update me towards believing this belief is ‘true’ in the naturalist, correspondence-to-an-external-reality kind of sense. I think I’d agree with your second interpretation, ‘that makes goodness real for minds, but not objectively’. Objectivity is a term whose use I always find extremely confusing. It makes sense to talk about natural phenomena with the lens of “based on real facts, evidence, and logic without letting personal feelings, likes, or unfair biases change your view”, because we’re assuming they are mind-independent and follow laws that are orthogonal to our subjective feelings, likes and biases. When you talk about what minds believe, it becomes messier (because a lot of facts are socially constructed, like money or laws, and not independent of feelings, likes and biases; in fact, they are intrinsic to what it is like to be a human, part of a human community with its intellectual and material limitations. What does ‘real’ mean when we say ‘this piece of paper is worth 100 dollars’ except something like “well, this is some kind of useful and enforced belief/practice which is contingent on the existence and interactions of a particular type of being with properties x, y, z”). There’s like three tiers here: stuff that’s mind-independent (it doesn’t matter what any mind or group of minds believe and think with respect to the underlying truth), stuff that’s intersubjective (which is mind-dependent but not amenable to change by an individual) and purely subjective stuff (which is completely dependent on the subject’s subjective beliefs, feelings, whatever). Morality is for me something that belongs to somewhere between the second and third tier (the ‘agreed social norms’ is 2nd tier, the personal belief that x is wrong independently of what anyone thinks, to 3rd tier).
So on moral realism: I just feel there’s nothing you can really use for updating on the view that there are “stance-independent moral truths whose truth does not depend on what any mind happens to value or desire.” (Theology is more updatable here; like, you just need to have God(s) appear, interact with you and do supernatural stuff repeatedly and measurably). If you view of moral realism is something like “Given creatures with volition, reason, different interests, etc..., who would want to engage in positive-sum social games, there might exist an optimal configuration of the latter that would be reachable by different creatures without any contact with each other”, then while I am still somewhat skeptic, this is something I can imagine to be true, and I can think of ways in which it can be updated.