Yes. Evil exists.
Fine, that is a rational conclusion.
And God could have prevented evil.
Fine, that is a rational conclusion as well, so long as God does not consider it evil.
Instead He chose to permit it to exist to demonstrate His power and glory.
Then he must consider its existence good if it exists at his discretion.
The existence of evil demonstrates that choice is real. Evil cannot defeat God.
That would seem to follow, if evil exists at God's discretion
He is proving His ability to overcome evil and transforming evil into good.
To overcome evil? To transform evil into good? Why does god need to prove any of that? Either evil exists at his discretion, or it does not. You seem to claim that it exists entirely at his discretion, in which case it exists because god wants it to exist.
None of that is irrational. What is irrational is your apparent conclusion that: Evil exists entirely at god's discretion although he doesn't want it to exist. That is not a rational statement.
If that is true, that is a capricious or an irrational god, and we cannot reason out the whims of such a god, so he is irrelevant to us from a practical standpoint.
Do you have children?
"Then he must consider its existence good if it exists at his discretion."
Either that or he considers "choice" good, and so He leaves us not with Evil, but with Choice.
You can't take care of a horse without dealing with it's crap.
Again, you are determined to keep everything neatly in a little box.
If we suppose (and this is partially based on Bible references I have already provided, and partially on other Bible passages which I can provide if you wish to examine them) that God created Satan before mankind, and that Satan rebelled (opposing God's will). Satan is essentially arguing that whatever he does is not wrong because God made him the way he is. Satan attempted to trap God with this paradox.
Notice that Satan challenged God as to whether God's "servant", Job, obeyed WILLINGLY or was COERCED or BRIBED.
God created mankind as an object lesson to angelic beings (among other purposes). People can choose to do evil and, through redemption, turn away from evil and choose good. This proves the existence of choice. (God did not offer redemption to fallen angels.) Every possibility and ramification of choice, both good and evil, is being played out on the human stage.
You said it is rational to think God could have prevented evil, "so long as God does not consider it evil".
But what is evil is up to Him. He has the right to command people to do whatever He wants. He calls disobedience evil. He also warns that those who continue to do evil and do not repent will receive divine judgment. Those who do repent and obey His commandments will be rewarded. And He is able to transform all the evil that has ever happened to us (who believe) into good.
These things will be accomplished when Jesus Christ returns.
AntiGuv™, (and the good-versus-evil bunch):
I don’t think it is useful to argue this line. Whether you define ‘good’ and ‘evil’ as something created by the divinity, or whether you say they are the two poles of rational philosophical analysis… the truth is probably more mundane: good is always defined as action-or-investment with a constructive end result (and great good further requires the path-to-the-end to also be constructive, and ‘good’ in its own right). Evil inevitably is associated with destructive ends, unsustainable practices, selfish ideals.
It cannot be clearer: that society in and of itself exists beyond the troop-of-chimps level by the very virtue of equality underlying social enterprise. If we have 5 bananas and 15 very hungry kids, the only equitable solution is to divide the kids into 5 groups and let them share a banana in each group. A good solution. The evil solution would be to peel all the bananas and toss them into the pack of kids, letting them fend for themselves. The weaker, more distant, and less aggressive kids would lose. Some kids might even get 2 or more bananas.
Same goes for murder and theft and usury and covetous adultery. The Bible, along with most every other ancient religious treatise made it clear that these were intrinsically evil. Yet, murder-in-the-name-of-state, theft-in-the-name-of-society, usury-in-the-name-of-business, and adultery-in-the-name-of-freedom are all tolerated, and even possibly lionized in some quarters. The military cannot be seen except evil for a greater good. Same goes for all the other aspects of human existence.
The true evil that is generally recognized as such is that which is wantonly destructive, is barbarous and simply thoughtless, non-empathic, unsustainable, and oppressive. Stalin’s evil, that of starving millions, is so clear that it needs no analysis. But is the lionesses killing of a nearly newborn antelope evil? Is the whole damned animal husbandry thing that leads to hamburger?
And it is in that that “God” did not create either good nor evil. Man recognized that constructive, collective, careful and creative “things” were beneficial in extraordinary ways to society. We also recognized that the opposites were generally anti-civilizational. But whether they are constructive or not is a concept so atheistic, so purely mathematical, that one might as well be talking of the concepts of 1 and 0, of True and False, of integers and operators.
That is why I cannot get into any arguments that pull ‘good/bad’, ‘evil’ and so on into it. Trying to tie one’s-self into a logical knot of great holding strength based on good and evil is like trying to build a good house out of wet newspaper.
GoatGuy