In The Problem of Pain, C.S. Lewis said, " . . . the very strength and facility of the pessimists' case at once poses us a problem. If the universe is so bad, or even half so bad, how on earth did human beings ever come to attribute it the activity of a wise and good Creator?"
Evil covers this planet like a smelly blanket. But, despite all that, God is still good. The idea of theodicy is still legitimate because as long as we're living on this side of eternity, we're faced with questions about God's goodness. Seekers want to know. Atheists want to know. Heck, Christians want to know: How do you know God is good?
In the same work, Lewis expounds on the idea of the Numinous:
Suppose you were told there was a tiger in the next room: you would know that you were in danger and would probably feel fear. But if you were told ?There is a ghost in the next room,? and believed it, you would feel, indeed, what is often called fear, but of a different kind. It would not be based on the knowledge of danger, for no one is primarily afraid of what a ghost may do to him, but of the mere fact that it is a ghost. It is ?uncanny? rather than dangerous, and the special kind of fear it excites may be called Dread. With the Uncanny one has reached the fringes of the Numinous.
Lewis later ties the idea of the Numinous to religious development:
The third stage in religious development arises when men identify them [gods] ? when the Numinous Power of which they feel awe, is made the guardian of the morality to which they feel obligation.
Of course, as Lewis later points out, Christianity is unique in that this Numinous Power -- the source of any real idea of morality and righteousness -- came down to our level; he ate with us; he cried with us; he saved us. Thus begins the true Problem of Pain:
Christianity is not the conclusion of a philosophical debate on the origins of the universe: it is a catastrophic historical event following on the long spiritual preparation of humanity which I have described. It is not a system into which we have to fit the awkward fact of pain: it is itself one of the awkward facts which have to be fitted into any system we make. In a sense, it creates, rather than solves, the problem of pain . . .
I would postulate that Christianity, as a faith or belief system, is completely logical given the intricacies of human suffering, sin, redemption and salvation. Yes, Christianity creates the Problem of Pain, but it also solves that problem too.
So, how do you know God is good?
Dude, that's deep.