system
Given the following post, respond as if you're commenting on Reddit:
human
Are there "degrees" of moral realism - i.e., do most/all moral questions have an objective answer or only a few?

Moral realism, as far as I understand, is the position that _there exist objective moral truths_.

That seems to me a fairly weak statement, though. Even if we accept that there are objective moral truths, it is conceivable that there exist only a few such truths and that the great majority of moral questions have no objectively correct answer but remain subjective. It is, of course, also conceivable that there exist objectively correct answers to every conceivable moral question. 

Of the arguments that I've seen in support of moral realism, all the reasonable ones seem to support only a very "weak" moral realism in which only fairly trivial moral questions have objectively correct answers. 

(An example of a class of moral questions that seems unsolvable to me is that of animal ethics. How are we supposed to determine how much one animal "matters" compared to another animal? There are attempts to grade animals by intelligence so that smarter animals matter more than dumber animals, but this is obviously very subjective and inexact, and it seems to me impossible to ever reach a detailed conclusion that is more than an awkward compromise.)

Is this a thing in meta-ethics? I.e., is it acknowledged that moral realism can be "partial" in the sense that only a proper subset of all moral questions have objectively correct answers? If so, are there any philosophers who argue for a "stronger" or "weaker" kind of moral realism than other philosophers?
gpt
Scanlon talks about this issue in chapter 4 of *Being Realistic about Reasons.* He argues that there are objective moral and normative truths, but he stops short of saying that all of moral and normative reality is fully determinate in the sense that there is determinate truth value for every moral and normative claim. With that said, he's not suggesting that there are only a few objective moral and normative truths. His point is mainly just to note that some moral and normative issues may not have objective answers despite the truth of moral realism.

His stance on this topic is related to the fact that he endorses relaxed rather than robust moral and normative realism. According to Scanlon, what's important for moral and normative objectivity is that there are standards of moral and normative reasoning that allow us to adjudicate moral and normative issues. He relies heavily on a math analogy, and specifically an analogy with set theory. His idea is just as there may be multiple different ways of conceptualizing the standards of reasoning about sets, which imply many of the same conclusions but also sometimes different conclusions, the same might be true about moral and normative standards. And if there is no way to identify one set of standards as the objectively correct ones, that means there is no determinate answer to the claims where those standards conflict.

EDIT: It may be worth noting that part of the reason why the issue of determinateness is worth commenting on at all is that Dummett famously argued that because mathematical reality is indeterminate, we should therefore be mathematical anti-realists. So, Scanlon is making it clear that one could accept indeterminateness about moral and normative reality and yet also be a moral and normative realist.