In the last post, I tried to give an overview basic and broad enough to cover the spectrum of anti-realisms. And one that does a bit more justice than usual to why Barth's dogmatic ethics are an anti-realism as a plausible ethics of divine command by analogy with ethics of human command. (This is an essential part of the differentiation in the Church Dogmatics II.2, as to the nature of the command of this Commander in difference from every other command and authority.)
But it could also be said that I played fast and loose with how divine command theory fits into moral anti-realism, so let's back up a step. Any "divine command theory" (DCT)—also known as "theological voluntarism" for its reliance on the will (voluntas) of a god (theos) (and yes, I know, that's quite bad because one's Latin and the other's Greek; I didn't invent it)—is at rock bottom a claim that moral truth is dependent on the divine will. In Philip Quinn's formulation of the basic idea, what God commands is obligatory, what God forbids is prohibited, and what God does not forbid is permissible. Good is what God wants, bad is what God doesn't want, and there's a plausible gray area depending on the particular theory, but God (or a god, or multiple gods; any god will do) is the decisive moral subject.
Since I'm basically going to be filling out the rest of this series with divine command theory, and there's quite a bit of material, it's going to be broken into manageable chunks. So today is a basic overview of the nature of DCTs, tomorrow is going to handle Euthyphro as the first hurdle to any DCT, and we'll move on from there into specific relevant versions to get closer to Barth.
So, last time, I glossed the anti-realisms as subjectivist moral theories, making the basic differentiation between divine command and human command theories be about the nature of the subject as moral exemplar. But that just covers the nature of the source of the moral norm, not what kind it is. In the process, I glossed over the differences between cognitivist and non-cognitivist anti-realisms.
Put briefly: there are no non-cognitivist realisms, because what "cognitive" means in this sense is that we cognize actual external truth values, or at least make statements that attempt to deal in actual moral truth or falsehood. Some anti-realisms are cognitivist, but the location of truth values is subjective rather than objective. Other anti-realisms are non-cognitivist, which means that their moral judgments don't deal in truth or falsehood. They deal, instead, in emotive values ("X is good" means I like or feel good about X; "Y is bad" means I don't like Y, or feel bad about Y—equivalent to "Yay, X!" or "Booo, Y!"), or prescriptive/proscriptive statements ("X is right" means "do X," and "Y is wrong" means "don't do Y"), or personal judgment about normative systems ("X is good" means "I accept the value of X" or "I reject the negative valuation of X," and "Y is bad" means "I reject the value of Y," or "I accept the negative valuation of Y").
All of which is simply to say that the non-cognitivist believes that moral judgments, while subjective, express no factual value. This is the kind of thing I was pointing toward when I suggested that modern non-natural realism tended toward mental states rather than actual non-natural reals. Which is also to say that you can be a non-cognitivist naturalist. (Counter-intuitive, I know—the non-cognitivist believes in the strictly mental or psychological value of a moral judgment. Your moral opinion may be formed on the basis of the world as you understand it, without ever issuing in genuine factual statements of moral value. "Factual" statements are simply the absolute expression of your moral opinion on the matter.)
How is this relevant for theological voluntarisms? Well, if a DCT is defined by the deity as a moral subject making moral judgments, any given DCT will differ according to what kind of statements the deity is understood to be making. Are they declarations of binding moral fact, divine distaste, or simple prescription or proscription of actions? (We'll see in Euthyphro the problem with suggesting that God approves or disapproves of normative moral theories or categories.)
Now, a strong cognitivist DCT will attempt to state that what God judges right and wrong, and good and bad, is absolutely right or wrong, good or bad, in a universal sense. This works quite well in a strict monotheism (such as Christianity generally represents) in which there is, as the Scots Confession puts it, "ane onely God," un seul Dieu, creator of all things. And Barth certainly represents such a Christianity, but it remains to be seen if his embodies this sort of strong cognitivism.
A weaker cognitivist DCT will not state that its deity is the only possible source of subjective moral truth. And yet it will do so without appeal to any external objective moral truth. Deities provide relevant moral truth for their followers, but there are a plurality of such systems of moral truth. Truth values in moral statements have to do with the divine subjectivity of your particular deity. These systems may compete, but this competition is ultimately not decidable, because we're dealing in multiple subjectivities. Normativity is based on allegiance.
Weak cognitivist DCTs say something that I have said before about the classical world in which Christianity developed: pistis, the quality of your allegiance to a deity, determines your nomos, or set of normative customs and moral rules. Nomos has everything to do with piety. Different deity, different piety—which means different lifestyle and different ethics.
It might further be said (though not by Barth, who thinks that Judaism has been superseded in its knowledge of God by the revelation in Christ, whom they rejected) that your moral obligations depend on the nature of your relationship to the deity. This is something like Paul's solution, in which Moses and Christ are equally valid ways before the same God of Abraham. It is a solution by which, today, we might say that Judaisms, Christianities, and Islams all pursue just ways of life before God by the nature of their own relationships with this same God. In this case, however, moral truth has more to do with the particular divine-human relationship, rather than just the particular deity.
So we've just briefly covered the range from absolute through a couple of relativist forms of cognitivist theological voluntarism. Looking at the non-cognitivist side, I find it harder to make bright lines between them and relativist cognitivisms. If there is only one deity, period, and we're out of the realm of correspondence to objective truth because we have a true DCT here, the difference becomes one of formulation. Because, really, what's the difference between the creator's opinion, the creator's emotive valuation, the creator's demand or countermand, and subjective moral truth?
In an absolute system, whether or not there are other deities, the difference is strictly in the character of the deity being considered. If we have an eternally faithful deity, who keeps promises forever, whose judgment is eternal, and who always makes good on declarations, and whose word is absolute and universal, then whether God says "I hate that" or "don't do that" or "that's bad," it amounts to a factual moral value. If we have a deity who changes, then there's a difference between moral fact (to which God considers Godself bound) and moral opinion, emotive valuation, or simple demand (all of which may change, and are only temporarily binding).
The character difference holds through grades of moral relativism. If we have an eternally faithful deity, who keeps promises forever, whose judgment is eternal, and who always makes good on declarations, and whose word is absolute but not universal, then whether God says "I hate that" or "don't do that" or "that's bad," it amounts to a factual moral value to whomever it is said. If the same character belongs to a deity whose word is truly relative, then the factual moral value depends on both the audience to whom it is spoken and the context in which (or for which) it is spoken. Such a deity remains a valid moral exemplar as a source of truth, but at finer and finer granularity of judgments.
And, obviously, a mutable and pathetic deity makes judgments that are just as arbitrary, in terms of reliance on the divine will, but might really feel arbitrary in the common sense, and so it's relevant to distinguish between subjective fact (according to its persistence in the mind of the deity) and the vagaries of emotion or opinion or momentary demand. It gets harder to call such a deity a valid moral exemplar—at least, by appeal to its divinity. It gets easier to argue the conflicts of divine and human obligations under such a god.
And now we're ready for Euthyphro.