If everything has a purpose then evil doesn't exist

[The Grand Nudger]

If everything that happens, both "good" and "bad", has a purpose and ultimately good intention behind it(cancer babies die because god has a purpose for it; a young woman is raped because god wanted to teach both her and her rapist a moving, faithful lesson) then it would stand to reason that evil and sin don't actually exist. Not by the definition of something that goes against the will of god. Because he wills everything to happen and he has allowed things to happen as they do because they're specifically a part of his plan. They could have happened a different way but he had them happen this specific way, including the choices of individual humans, because that was his intent.

It's doesn't seem to me to be purpose, or possessing purpose, but the "ultimately good intention"(ugi) in that formulation which suggests the possibility.  Cognizably evil things or circumstances can also have a demonstrable purpose.  Evil often being that purpose for such.  There are other things you might want to clarify as well.  Does the "ultimately" in ugi refer to a quantitative or qualitative proposition?    

We won't need gods to elaborate - it adds an additional and contentious premise that doesn't help in any way to explore the underlying moral question.  Can apparent evil be modified, and if so, in what manner - by volume of offsetting good (quantitative), by the moral purity of intended outcomes?   

I think so.  The good and the bad must both be weighed in a full moral accounting.  It could be the case that some bad thing x created more good through it's realization.  A surprising amount of medical knowledge was obtained by torture.  The infrastructures of every nation on earth might also fall into this category.  This type of moral accounting...as a plan, an item of intent, is basically a moral iou.  Similarly, it could be the case that even the most horrendous outcome was the product of a maximally good intention.  Alfred Nobel believed that his invention could end all war - and the civil applications were tremendous.  This one, basically, an invocation of specific incompetence.    

In neither of these cases does evil seem to be absent, and there's the question of why we would even require some qualifying process if there were no evil to address - either by saying good and alot of it is on the way or that the fuckup basically meant well.  In both cases, and even in the premises meant to lead to the conclusion that evil does not exist, even though a moral accounting can change to accurately reflect different numbers or sums or circumstances... evil exists. It's not modifying that. It's (maybe) modifying how we judge the moral agent. I'm find myself less permissive of intentional evil that produces circumstantial good - at any ratio- than I am of horrendous outcomes absent effective intent. I feel that the first group should perhaps be overpunished, and the latter underpunished. Bad actors need to be dissuaded no matter how much good might materialize from their actions. Incompetents cannot be held to any moral account.

There's really is no purpose to smacking a turnip over the head, after all. It does turn you into the moral actor promising many, many benefits would eventually flow to the turnip from your having done so, though.