By Medieval logic, the world we live in is necessary. All that is in the world necessarily exists. God created our world and therefore everything that God created is necessary.

I guess purposeful or not doesn't matter. You can throw it in the argument to obfuscate things a bit but if you stick with necessity you don't need to bring in value judgements, good, evil, all that stuff. It's just necessary therefore it's justified.

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You don't need a weatherman to know which way the wind blows - Robert A. Zimmerman