The “problem of evil” has been around for a while, as have responses to it. One of the most perennial (appearing in places such as Job) is these days called “skeptical theism”, or else a “mysterian” reply; putting it simply, it questions the question, pointing out that God’s incomprehensibility, the limits of our knowledge, and the fallibility of our moral sensibilities, along with the positive reasons to believe in God’s power and goodness, and argues these should lead us to conclude God has sufficient reason to allow evil, though we cannot necessarily see what it is. It is a conclusion that God is trustworthy, though his ways sometimes seem inscrutable.
Sometimes, when this response has been provided, the natural question will arise: if this response is correct, what does it mean to call God “good”? I want to provide a brief answer to that question here.
Aristotle provides an intuitive definition of good which covers the various uses human beings have for the word beyond and inclusive of the ethical: “the good is that which all things desire.” In light of this definition, the classical conception of God is that God is the most desirable reality. As Thomas puts it:
But all things, each according to its mode, desire to be in act; this is clear from the fact that each thing according to its nature resists corruption. To be in act, therefore, constitutes the nature of the good. Hence it is that evil, which is opposed to the good, follows when potency is deprived of act, as is clear from the Philosopher inMetaphysics IX . But, as we have shown, God is being in act without potency. Therefore, He is truly good.
I’m not here concerned to provide the arguments for the classical view of God, just to explicate what it said about his goodness. If we follow it’s roadmap, we will also say that God’s goodness means God’s desirability. To put it plainly, God is the kind of thing that, when we might see him (whether with the eyes, or in the figurative sense, with the eyes of the mind), we would want him. Or perhaps to say it yet another way, God’s goodness is what leads us to worship him, to be struck with awe and joy at the sense of his presence.
Now we can connect this back to theodicy. Questions of God’s justice focus more specifically on the moral character of God, i.e., his goodness in the more narrowly ethical sense. But the general doctrine of God’s goodness has implications for this more specific sense, too. It means, at minimum, that nothing in God’s character implies God is anything less than the ultimately desirable reality.
Returning to the “mysterian” theodicy, then, we can explain it this way. The character of cruel and evil people is repulsive; people with healthy consciences find such behaviours morally disgusting, not desirable at all. The argument claims that if we knew all the relevant truths about God and the world, which we do not know, we would be able to see both God and all the evil in the world simultaneously, and still see God as the perfectly desirable reality. Nothing in his character provides grounds to react to him as morally sane people do toward evil dispositions.
For those who want to read further on how the classical conception of God relates to the problem evil, you could do worse than to start with Ed Feser’s various posts on the subject.