The Normative Contingency Thesis (NCT) is a compelling objection to Moral Realism.

R3 Theme: Queen, "We Will Rock You". http://www.youtube.com...I want to sincerely thank Con for the best challenge I've gotten on this subject in a long time.I'll be first out of the gate to accept Con's reasoning. I preempted a defense of moral realism, and he chose instead to focus solely on normative contingency. That appears a sound option to me, so we'll be focusing on the nature of the objection--rather than on realism per se--for the remainder of the round.One of Con's central objections is an analogy between the first principles invoked in moral derivations and the first principles upon which I make my case (e.g., the law of identity). He suggests that there is an inconsistency, since I cannot reliably be said to discard first principles when I myself am using them to construct an argument. In reply, I introduceThe Truth/Provability Dichotomy and the Ethics-Epistemology DisanologyRecalling the peculiar Godelian formula I played in R2, we know that all non-trivial axiomatic systems (e.g., logic, realist ethics) must gesture to some kind of exteriority to justify themselves, being unable from within to prove their own completeness and consistency. As I suggested, this exteriority, for ethics, is the discursive fiat of the speakers. People have to posit and agree to certain meta-ethical presuppositions which make moral derivations possible. Recall further that Con has not objected to any of this--not to the idea that realism entails justificationalism, or that justificationalism requires objective meta-ethical content.This is where the difference between truth and provability comes into play. When, in response to infinite regress, the nihilist claims "I know nothing", Con suggests, citing Wittgenstein, that there is nevertheless a certain set of first principles required to make that skepticism expressible. This is entirely true, but it does nothing to help Con's case. Looking at the Godelian structure of justificationalism, one can say that there is always a point at which a proposition may be true, but not provable. Even the notion of identity, which founds logical discourse, falls victim to this constraint--though we may assert and commit to its truth--for good reason--we cannot "prove" that identity is true. In this way, the set of all true propositions shows itself to be larger than the set of all demonstrably true propositions. This is why both moral realism and Con's analogy to epistemology fail. For the nihilist, "I don't know" cannot be countered by questions about how he knows that he knows nothing--the nihilist is not making an argument or attempting to prove that he knows nothing; rather, he is exposing a fatal flaw in the structure of justificationalism which makes certainty impossible. Really, what is being communicated is that the nihilist commits to to the truth of the proposition that he knows nothing while being unable to demonstrate it, since the only condition that would demonstrate nihilism to be true is that it cannot be proven.So, as Con notes, I do accept some first principles in making my arguments. I accept, for instance, that A is A, that you cannot have A and non-A, and that you must either have A or non-A. I can't "prove" them to be true, because the rules of inference which would permit me to do so are grounded in the very thing I'm attempting to prove. So, I assert that they are true, as does my opponent, because neither of us could avoid invoking these principles in argument. To even speak presupposes the law of identity. Perhaps there is some possible world in which these rules do not apply, and to which our own incredulity and epistemic limitations deny us access; however, the parallel that Con attempts to draw with realism doesn't seem to stick.With discourse, we cannot avoid logic--if we attempt to speak, think, reason, communicate, perceive, or even sense, there is an underlying supposition that "things are what they are", i.e., that identity holds. So, it seems like we have a pretty good reason to put our confidence in it, even if we're definitionally prohibited from proving it to be true. So, we default to identity as our way of operating in the world. And, remember the constraints I laid out in R1: predicting that neither side could have a claim to certainty, I worded the debate to concern whether normative contingency is a "compelling objection", defined to mean that, based on what's presented in this debate, supposing you're metaphysically constrained to affirm or reject realism, you would default to rejecting realism based on my arguments. Now, in Con's analogy, we see that things like identity and excluded middle are impossible to avoid in reasoned discourse, so we have to default to those. But there doesn't seem to be a compelling reason to default similarly to realism.As the definition notes, the realist is committed to the idea that there are mind-independent moral facts which validate normative propositions. The problem, though, is twofold:a) unlike the "laws" of logic, meta-ethical propositions are easily interchangeable. There are many different meta-ethical worlds we could construct, and many different normative worlds we could build on top of that, with no real way of determining which one is true; yet, while I cannot avoid assuming logic to be true in discourse, I can avoid assuming meta-ethical propositions to be true in moral discourse Hence, while axiomism might be a semi-useful route in epistemology, the same cannot be said for ethics. So, while both epistemology and ethics are contingent in the manner I've described, the philosophical defaults to which you are in each case lead are quite different. In epistemology, you sort of have to default to logic; in ethics, it seems like contingency leads you to default to a rejection of moral realism (since the justificationalist structure of realism entails certainty claims).b) Con's case is an ipso facto concession. Rather than objecting to the notion of contingency, or trying to defend realism, he opts instead to argue that my case undermines itself. But, one of the criteria for realism being true is that moral propositions are justified by mind-independent features of the world. If his response is that my case is undermined by my own subjectivity with respect to "taking logic for granted", then it's still equally the case that realism is undermined by the subjectivity which posits a meta-ethical claim for others to accept.I mean, look. The whole point of the NCT is that you can get moral realists to backtrack on their moral frameworks to the level of meta-ethical propositions. But, since realism relies on mind-independent features of the world for verification, and the only things which produce the value-axioms (which supposedly come from the world) are the individuals who posit them/the other parties who agree, normative contingency is fundamentally devastating to the realist thesis. Even if you want to cover your basis and exclude the notion that realism is patently false, which is a good move to make, the constraints of this debate only require that I make a compelling case for nihilism, i.e., that I convince you to default against realism, to win.Your turn, Biebs. Thanks again.