If God is All powerful and infinitely good, why is there suffering in the world?
This question was called The Problem of Pain by C.S. Lewis in his book by that name in which he tried to answer it. He did a fairly good job answering some of the more common questions of this form, but unfortunately he also left some both unasked and unanswered. In trying to answer one such question, it occurred to me that the root of all these variants amount to one, simple question: why isn't this the best of all possible worlds?
All of the answers that I've seen amount to proving that this is the best of all possible worlds, given that it's infested with free-willed and sinful creatures. But is this really the best of all possible worlds? If God exists and is infinitely good, would he necessarily create the best of all possible worlds?
There are of course some of the more trite reasons why God might create a merely good world. Some people claim that you can't know good unless you also know evil. While this may sound unlikely, there is some suggestion of this in the book of Genesis: the forbidden tree in the garden is, after all, the tree of the knowledge of good and evil. It's also possible that one can't tell the difference between a good man and a bad man until you've tempted him — it's possible that a free will is not actual until it's in a circumstance that forces it to make a decision. This might be something like quantum mechanics — that a thing isn't in a definite state until it's interacted with. If this were the case, even omniscience couldn't know whether a man was good or not until the man was tempted — even God would have to test people to separate the wheat from the chaff.
It's also possible that there are some forms of goodness which can only exist in a partially evil world. There are soldiers who have been saints — the virtues of a swordsman or marksman seem likely to be only real when there's an imperfect world which makes their talents the lesser of two evils.
On the other hand, to say that God created a world which is not the best of all possible suggests something like the manichean heresy, which I have no desire to tread near. And perhaps the reasons for a mediocre world given above are actually just reasons why this might yet be the best of all possible worlds if one knows how to measure correctly.
And that, really, is the key. What is the right measure of goodness in the world?