We have investigated the Kalam Cosmological Argument for the existence of God, and likewise the notion that belief in God may not require an argument at all, but might be properly basic. The former does not address God’s goodness, per se; the latter assumes it, for the purpose of demonstrating the model, and deals with objections relating to God’s goodness.
In fact, at the end of the last chapter, the quality of “goodness” figures as a defining attribute of God, one that would not be doubted even in the face of terrible evil. From a certain distance, this might be seen as an incoherence; then again, from a distance, a car might look like a cow. If one keeps the distance, but merely circles, one might constantly confuse whether they are seeing a cow, or a car. But if we drive right up, the view should become clearer.
First, the argument, again from William Lane Craig:
Premise 1: If God does not exist, objective moral values and duties do not exist.
Premise 2: Objective moral values and duties do exist.
Conclusion: Therefore, God exists.
As WLC notes, the argument itself does not say that God, then, is the basis of objective moral values and duties; however, “such a claim tends to be implicit in premise (1) and emerges in the defense of that premise against objections.”
To illustrate the point – wait for it – the analogy of the author seems to serve rather well. Consider: Begin with an author, a composite of body and mind, and nothing else. Take away the body. All that remains is the mind. [This is like God, “in the beginning”].
Now, if anything in this scenario is “good,” what is it? Of course there’s only one thing it could be, and that is the mind. [If anything is good, God is good].
The author begins her story, and the various things she brings into existence are good or bad depending on their cooperation with her [Whatever God wills is good] and their implicit participation in her goodness [We are made in the image of God, and good inasmuch as we reflect that image].
In this way, we can see how God would be the basis of objective moral values and duties. The argument, then, essentially works backwards to this point. That is, do we observe objective moral values and duties?