Michael Huemer on moral objectivism.

Moral objectivism (like objectivism in general) seems to be entailed by the law of excluded middle and the correspondence theory of truth, along with a couple of what seem equally obvious observations about morality:(1) There are moral propositions.(2) So they are each either true or false, (by law of excluded middle). (3) And it's not that they're all false. Surely it is true, rather than false, murdering millions of people for the fun of it is evil. (Although some would disagree, even they would admit some moral judgement e.g., tolerance is good.) (4) So, some moral judgements correspond to reality. (from 2,3, and the correspondence theory of truth). (5) So moral values are part of reality (which is objectivism). We find all many rishonim ראשונים holding that the goal of Torah is to bring up to objective morality. The simplest place to see this is the Sefer HaChinuch, where he lists all the commandments of the Torah along with some of its laws and details and then also explains the reason for teach particular command. The reasons are what Saadia Gaon calls "חוקי בשכל" "laws of reason"---------------------------Objective morality (like objectivism in general) seems to be entailed by the law of excluded middle, and the correspondence theory of truth, along with a couple of what seem equally obvious observations about morality:(1) There are moral propositions. (2) So, they are each either true or false, (by law of excluded middle). (3) And it's not that they're all false. Surely it is true, rather than false, murdering millions of people for the fun of it is evil. (Although some would disagree, even they would admit some moral judgement e.g., tolerance is good.) (4) So, some moral judgements correspond to reality, (from 2,3, and the correspondence theory of truth). (5) So moral values are part of reality (which is objective morality). We find all many ראשונים holding that the goal of תורה is to bring up to objective morality. The simplest place to see this is the ספר החינוך, where he lists all the commandments of the תורה along with some of its laws and details and then also explains the reason for teach particular command. The reasons are what סעדיא גאון calls "חוקי בשכל" "laws of reason"