I have no problem with Godel-incompleteness, uncomputability, and so on in a system that allows you to state any moral proposition.
However: if a moral realist believes that “moral claims are fact claims possessing truth values”, then what does he belief regarding the proposition (1) “there exists at least one moral claim that can be proven true or false”? (Leaving aside claims that simply induce contradictions, are not well defined, etc.)
If he thinks such a claim exists, that is the same as saying there is a Universally Compelling Argument for or against that claim. And that is a logical impossibility. I can always construct a mind that is immune to any particular argument.
If he thinks no such claims exist, then it seems to be a kind of dualism—postulating a property “truth” of moral claims, which is not causally entangled with the physical world. It also seems pointless—why care about it if no actual mind can ever discover such truths?
ETA: talking about ‘proving’ claims true or false is a simplification. In reality we have degrees of beliefs in the truth-value of claims. But my point is that moral-realistic claims seem to be disengaged from reality; substitute “provide evidence for” in place of “prove” and my argument should still work.
I have no problem with Godel-incompleteness, uncomputability, and so on in a system that allows you to state any moral proposition.
However: if a moral realist believes that “moral claims are fact claims possessing truth values”, then what does he belief regarding the proposition (1) “there exists at least one moral claim that can be proven true or false”? (Leaving aside claims that simply induce contradictions, are not well defined, etc.)
If he thinks such a claim exists, that is the same as saying there is a Universally Compelling Argument for or against that claim. And that is a logical impossibility. I can always construct a mind that is immune to any particular argument.
If he thinks no such claims exist, then it seems to be a kind of dualism—postulating a property “truth” of moral claims, which is not causally entangled with the physical world. It also seems pointless—why care about it if no actual mind can ever discover such truths?
ETA: talking about ‘proving’ claims true or false is a simplification. In reality we have degrees of beliefs in the truth-value of claims. But my point is that moral-realistic claims seem to be disengaged from reality; substitute “provide evidence for” in place of “prove” and my argument should still work.