Comment by perching_aix

> Instead of naming something concrete, it makes more sense to define what the only legitimate basis for morality and the human good is, which is human nature. If you deny that, then there is indeed no possible objective basis for the good.

Quite the opposite - I agree with that, and that's why I think goodness is not an objectively evaluable property. At the risk of making you feel I'm twisting your words, you pretty much said it yourself: what the human good is, is at the very least subject to human nature. Therefore, your evaluation of goodness cannot be objective. You're at best speaking from the subjective perspective of a human being.

But if you now say this doesn't get to the heart of your overall reasoning, I agree.

Consider then if goodness is even more subjective than just being a human value - for example, imagine that individuals might have (if even just slightly but) differing natures and so differing values. This would mean that your evaluation of what's good and what the human nature is like is not going to be durable across people. Worse still, you may even consider scenarios where the nature of a person changes over time, or they may value different things given a specific context. This would mean that your evaluation of what's good and what's bad is no longer durable not just across people, but across contexts, situations, and even time itself.

Notably of course, this is logically indistinguishable from other people simply making a measurement error of the same supposedly objective property. So this all hinges on whether you (can) believe that instead of there being an ontic, fundamental property of goodness, one that you're properly accessing and others disagreeing aren't, your access is the same as anyone else's. And that regardless of whether such a property objectively exists, it may either not hold an observer invariant value, or you may never be able to tell to have learned that value.