Can ethical statements be understood in terms of some natural qualities or are they non-natural and perceived by some intuition or moral sense?
This problem, raised first by G.E. Moore, suffers from vagueness of the term "natural." What is natural? For Moore, that meant whatever is "the subject matter of the natural sciences and also of psychology." Miller rephrases that as "either causal or detectable by the senses." To me, these attempts at a definition seem arbitrary.
It's far better to recast the problem by considering whether an "ought" can be reduced to an "is." Remember the 4 varieties of good; let's repost them as:
1) X is a physical good = X is loved and X ought to be.
2) X is a metaphysical good = X is and X ought to be loved.
Thus, for 1),
1a) Absence of physical good = X is loved but not chosen.
1b) Indifference = X is neither loved nor hated.
1c) Evil = X is hated (and correspondingly ought not to be).
Let's now define the "is" as any true description of the actual world as it is now or was in the past. The following are part of the is:
- Socrates was a philosopher.
- My cat is asleep as I am writing this.
- I am thinking of a possible world.
Consider the last one of these. That I am thinking of a possible world is part of the is, but the possible world itself of which I am thinking is not part of it.
Now going back to 1), what does it mean that X ought to be? It means that X was chosen out of several alternatives. The essence of a process of choice is precisely contemplating and weighing possible worlds. I think of the world as it is now and try to imagine how it can be changed to my benefit and the costs of each such change. The possibility that seems to yield the highest profit wins, ought to be, and becomes a physical good. All the options set aside are still loved but, since I make them such that they ought not to be (by rejecting them in favor of the thing chosen), are not physical goods.
Since creation of a physical good involves working with possible worlds, and since possible worlds are not part of the is, physical good cannot be described in terms of the is, and so we must be non-naturalists regarding it.
For 2), we have:
2a) Absence of metaphysical good = X is not.
2b) Indifference = X nether ought to be loved nor ought not to be loved.
2c) Evil = X ought to be hated.
It may seems that all things ought to be loved. Well, not when they are in conflict. From my book:
Consider Socrates again, only this time, he is infected with deadly bacteria. Now both Socrates and bacteria have more-or-less objective essences and therefore, a modicum of metaphysical goodness, having a claim on our love (or at least, regard) for them. As St. Thomas would say, everything that exists is good and good to the extent that it exists. Two points, however, make this situation interesting. First, Socrates and the bacteria are natural enemies. Second, Socrates' nature is far more perfect than the nature of the bacteria. ...
In other words, that Socrates is metaphysically better than bacteria is true ad sapientes or self-evidently from "wisdom." But wherein there is a conflict of interest such as postulated here, the more perfect wins over the less perfect, and so, we are permitted to will good to Socrates in desiring him to recover and to will evil to the bacteria in designing for it a speedy death. (SAtK, I, 34)
It may well happen that X may exist and ought to be loved, but is not loved. That's a problem, a sin, if you will. One ought to correct himself and come to love X. As with physical goods we were dealing with possibilities - timeless - thoughts, so with metaphysical goods, we are faced with potentialities - future - feelings. The task is to grow in love for those things that ought to be loved. If you are indeed commanded to "love the Lord your God with all your heart and with all your soul and with all your strength and with all your mind and love your neighbor as yourself," but fall short of this ideal, then God and neighbor are metaphysical goods and demand love from you.
This love must be carefully nurtured and elicited from the is and will come to be, if at all, in the future. An oak tree is an actualized acorn. For charity, God builds a flame from a tiny spark. But as of now, the future does not exist and so again is no part of the is. It seems like for metaphysical goods, too, we must be non-naturalists.
Since moral good
3) X is a moral good = X ought to be and X ought to be loved,
combines possibilities and potentialities, its analysis is straightforward.
There is an irony here. Physical and metaphysical goods are not reducible to the is, but the corresponding evils and wrongs are! The world is chock-full of, saturated with evil. I proved that "murder is wrong" in earlier posts by appealing solely to natural law. Physical evil is any pain or suffering that would "naturally" persist sans human action to alter the course of events and remedy this evil. Moral evil adds to harm an injustice which I cash out as disrespect for the nature of things, especially human nature, also a full aspect of the is.
Thus, "murder is wrong" is a proposition of natural law, but "a sandwich is good" is beyond nature.
We cannot therefore say simply that we are ethical naturalists or non-naturalists. We are naturalists for moral wrongs and evil, and non-naturalists for moral good.