The first argument that Oppy looks at is the argument from objective values. It usually has something like the following form:
- (P1) The Moral Law, has a real, absolute, objective existence.
- (P2) If the Moral Law has a real, absolute and objective existence, there must be a Mind from which the Moral Law is derived.
- (C1) (Hence) There must be a Mind from which the Moral Law is derived.
Oppy takes this version of the argument from Rashdall (1907),* it is also similar to the argument offered by C.S. Lewis.
1. Terminological Prelude
Before we can even begin to assess this argument, we need to be clear about the meanings of the terms being used. First, "the Moral Law" is obviously some sort of prescriptive law that tells you what you should and should not do ("You should do X"). Another way of putting this is that the moral law gives you reasons-for-action. This makes it distinct from a descriptive law, which simply offers a formal description of the relationship between you and your actions (e.g. "You do X, because of Y").
Next, we must ask what it means to say that the Moral Law has "real existence". I take it that this simply means that the moral law exists, i.e. it is not fictional. Thus, there is something in existence that gives us reasons-for-action.
Of course, it is not enough that there exists something that gives us reasons-for-action. That something must be "absolute". This means it must hold true in all times and places: it is not relative to the needs of particular individual, society or historical moment.
Finally, it must have an objective existence. This seems to mean that it is not observer-dependent; that it is not a matter of subjective opinion; and that it somehow inheres in the fabric of reality.
Now that we have some idea of what the argument means, we can assess its merits. We must question both of its premisses. We begin with P1. It is open to us to reject P1. There are two ways in which we can do this.
First, we can argue that it is impossible to satisfy all three requirements ("reality", "absoluteness" and "objectivity") at the same time. We can say that an objective and absolute law would fail to give us reasons-for-action because what motivates us is (a) subjective and (b) context-dependent. See my post on realism for more.
Second, we can provide an alternative account of our moral beliefs. In other words, we can explain why we might think there is a moral law, even though there really isn't. For example, we might feel bound to particular rules because (a) we are projecting our own emotions onto reality or (b) we are blindly following the morality of our culture.
Let's assume that we accept P1. If we do, we must ask two crucial questions about P2:
- Is there a plausible non-theistic theory that accounts for the reality, absoluteness and objectivity of the Moral Law?
- Does theism actually account for the reality, absoluteness and objectivity of the Moral Law?
In any event, it is not at all clear that God does a better job of accounting for a Moral Law. The problem is that theists want God to make a difference to morality. For them, it cannot be the case that the Moral Law is a necessary truth: it must be contingent upon God's existence. This forces us to imagine that there are many possible worlds in which the Moral Law could have been different. For instance, there must be a possible world in which God could have made the Holocaust morally permissible (or even obligatory). But this destroys the idea of morality: even if such a world was possible, indeed, even if we are now living in that world, we would have no reason to follow this Moral Law.
In short, making morality dependent on the contingent choice of God makes it impossible. If there are genuine moral facts, then these must be necessarily true, or true in all possible worlds.
* "The Moral Argument for the Existence of God" reprinted in Hick (ed) Classic and Contemporary Readings in the Philosophy of Religion (Englewood Cliffs, NJ: Prentice-Hall, 1964).