Below I reproduce an email I sent to Maverick Philosopher the other day after having seen his recent posting related to the topic.
To what's below I want to now add a summary/clarificatory note: I think that the metaphysical and epistemological issues hadn't been so clearly distinguished not just for the reasons I note below, but also because what both issues or aspects come down to is this: any grounding for moral knowledge must come from reason(s), meaning that any moral command, to be authoritative (not authoritarian), must be grounded in reason. In the theistic tradition, God is (the ontological principle of sufficient) reason or logos, and must rule or command accordingly. This is why the 'naturalism' vs. 'voluntarism' debate among (late) medieval ethical theorists as discussed in the Irwin (The Development of Ethics, vol. 1 [Socrates to the Reformation]) comes down so decisively in the naturalists' favor. Which is to say, that whatever the ultimate source of morality's authority, the only means we have for discovering any such grounds is via our unaided reason (drawing on the evidence of the senses) - which is why moral philosophers have been at work without any substantive resources (that I can see) being provided by Divine Command theory qua such. And isn't this a vindication of what many take to be Plato's original point - that "what's favored by the gods" doesn't give a useful answer, and that it is the task specifically of philosophy/reason to discover what merits the gods' favor?
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[To Maverick Philosopher]
I made a blog post last month in which I indicate that one could approach the Dilemma in at least two ways, which I term the metaphysical and the epistemological.
The metaphysical: The question of the origin of morality and its authority. Does morality('s authority) require the existence of God? Does this authority depend on God's mere willing as in voluntarist interpretations, or is this authority constrained by the nature of what God created as in naturalist interpretations? (I find this dispute covered at length in the 'medieval' section of T.H. Irwin's magisterial historical survey 'The Development of Ethics', and the debate seems to come down decidedly in favor of the naturalist view.)
The epistemological: how do we come to discover (the content of) moral truths, whether or not they are brought into existence by God? Or: How do we come to know what a perfectly benevolent being would command, or what conscientiously virtuous agents would do?
It's not hard to see how these distinct ways of coming at the Dilemma could be conflated throughout the history of addressing it, since they both end up raising the question of the basis for moral authority or goodness.
And the epistemological question seems like the one that we're actually most interested in, since we need to know how any putative truths have authority for us, and that leads us to inquire in the ways that moral philosophers have inquired (in meta-ethics and normative ethics).
And if the question is how we come to know moral truths via reason, then the metaphysical question drops out of the picture for all practical purposes, since whether or not we have good grounds for thinking there are moral truths (and for what those truths would be) doesn't seem to be settled by the metaphysical issues. I don't see thinkers such as Aristotle and Kant directing their ethical inquiries in the metaphysical direction (except inasmuch as Kant treats God, freedom and immortality as postulates of practical reason, but these are matters ultimately of faith rather than knowledge; and it's not like he doesn't present some pretty good reasons for behaving morally regardless of these postulates; his argument for the possibility of libertarian freedom is seriously undercut by his phenomenal determinism in any case, when he could have quite readily, sensibly, and plausibly denied that all of nature has to be deterministic in order to be lawful, i.e., the laws applying to human actions would be of a special sort based on our unique organizationally complex makeup, a point about causation that I think Aristotle and Aquinas would accept).
(The Dilemma raises tougher challenges to those who appeal to Scripture as the source of authority, since Scripture appears to contain a lot of genuinely erroneous things that are putatively God's will[*], and at the same time does not to contain moral truths, or ones stated unambiguously, that have come to be widely acknowledged since Scripture appeared (e.g., Lockean natural rights). I think that perhaps a work like Summa Theologica is better suited for philosophical purposes.) [* - I had this in mind when writing this sentence.]
Anyway, I will look again/closer at your recent Euthyphro post to see if it covers these points.
