In dealing with the issue of sin its nature and origin, the discussion must include a discussion of God himself. If God is omnipotent (def: infinite in power) as Christianity classically teaches then He is in absolute authority over everything including sin. The Bible says God is not the author of sin.
This appears to be a problem. If we hold to the Bible as our ultimate presupposition then let the Bible answer to this issue. Does the Bible present an infinite or a finite God? Without listing verses, my assessment is the Bible presents a view of God with infinite authority. Are their any philosophical issues with the concept of omnipotence?
Well, I think there are issues otherwise the Bible wouldn’t have to make such a strong case for God not being the author of sin. As a Reformed Christian this is my dilemma. How do I reconcile an omnipotent God with evil in the world?
But what of the other side? If God is not omnipotent then what kind of God do you have? If the future is “open” then God cannot be omnipotent in the traditional sense of the word. If sin happens apart from God’s will then God is not omnipotent. Those who would follow the path of Pelagianism in any measure have to wrestle with the concept of a finite God (if they are consistent, that is).
I (as an Augustinian) will wrestle with the question of why there is sin (etc.), but ascribing all power to God in any case. My opponents must wrestle with proving that limits on God do not take away from His omnipotence (proving a=~a) or they are affirming that God is not infinite and they must reconcile this with the Bible testifying to the contrary.
Summary: Ultimate Presupposition; the Law-Word of God (i.e. Bible) is the foundation for all of Life and Thought. Derivative Presupposition; God is infinite in power, omnipotent.