This weekend I read Jonathan Edwards's Freedom of the Will. It's a bit . . . dense. As far as I can tell, his argument goes thusly:

1. Every action we take is based on a Motive - what we consider will bring us the greatest good.
2. One cannot Will a change in Motive - for what would be the motive for that will?
3. At the end, one finally comes down to Motive as Nature or Personality.
4. Arminians assert that Free Will demands that Will be able to choose good or evil from an unbiased and indifferent position.
5. But God is praised for His goodness, which He is infinitely biased towards.
6. Ergo, one Wills good only because one is good; an evil person does not will to be good; it does not please him.
7. God decides sovereignly to regenerate an evil person so that he can will good (by making him good).
8. For a Calvinist, "Free Will" means "free to act in accordance with our natures - free to choose what we believe will please us most."

All of which, of course, makes perfectly logical sense, but can in no wise explain how unfallen angels and Adam & Eve could will to do evil.