[skissane]

> there is an abundance of immanent ethical theories that define the Good (or Right) in terms of basic things in our grasp

The problem with all those theories, is they can be attacked as simply efforts to define "good" – with the ensuing problem that other people will define "good" in contrary ways, and if "good" is just a definition, then how can a mere definition be, in an objective sense, superior to a competing proposed definition?

That's basically G. E. Moore's argument against naturalistic objective ethics. If one agrees with it, then the only options available are to reject objective ethics, or to reject naturalism.

[woodruffw]

Fair enough! I wasn't expecting to have Moore's naturalistic fallacy pulled on me :-)

Neither intersubjective nor Kantian ethics have this problem: intersubjective ethics doesn't admit of an objective Good, and Kantian ethics don't admit of an is-ought distinction (all "ought"s are in fact "is"es that are bound in actions).

[skissane]

> intersubjective ethics doesn't admit of an objective Good

I agree, but intersubjective ethics might not actually work in practice in a world in which people are approaching ethics from wildly different starting points. Consider an issue like abortion – people who support the legal availability of abortion, and people who oppose it, have such widely different ethical views that I think there is no intersubjectivity to be had (on that issue at least)

> Kantian ethics don't admit of an is-ought distinction (all "ought"s are in fact "is"es that are bound in actions).

I wonder, if you could expand on that point?

In my mind, Kant's categorical imperative could be viewed as either a proposed definition of the good (in which case Moore's argument is applicable), or a claim about what actually is good (in which case it escape's Moore's argument)

Kant had a lot to say about normative ethics, but the question of what his metaethical views actually were seems more disputed: https://plato.stanford.edu/entries/kant-moral/#Meta

[woodruffw]

> In my mind, Kant's categorical imperative could be viewed as either a proposed definition of the good (in which case Moore's argument is applicable), or a claim about what actually is good (in which case it escape's Moore's argument)

It’s an academic opinion, but I believe it’s the latter: the very first line in the GMS asserts that the metaethical object itself is the good will: “nothing in the world (or indeed beyond it) can possibly be conceived as good without qualification except for the Good Will.”

The CI is the logical consequence (according to Kant) of what the good is. But that distinction is definitely subtle in the context of his normative ethics.