I'm in the midst grading and also reading Richard Muller's
Christ and the Decree, on the interrelationship between Christology and election in early Reformed thought. One of the more interesting point (and one that Muller has brought up before in his published works) is that Calvin has a fundamentally Aristotelian understanding of divine causation. As an interesting illustration of this, I recall that at the beginning of the commentary of Ezekiel, Calvin claims that the wheels and beasts that the Prophets see around the chariot of the divine
kavod are in fact an image of the movement of the casual structure of the universe-bigger things move smaller things until we get to the biggest thing- the unmoved, mover of Aristotle, i.e. the Biblical God.
One interesting thing about this Aristotelian concept of causation is that it distinguishes Calvin's concept of predestination from that of Aquinas (ironically!), Augustine, and most of the other Reformed folks who wrote on the subject in the 16th century (Calvin's lieutenant Theodore De Beza is an exception). For the most part, these folks tend to think of reprobation as something passively permitted by God. In other words, since the human race is a "mass of perdition" (to use Augustine's phrase) left to its own devices it will do itself in. No need for a decree of reprobation. Humans will simply throw themselves off the cliff- no need for God to push them and then jump up and down on their fingers until they finally fall off.
Interestingly enough, this makes for a sort of consensus on the issue of election in the 16th century between the Reformed, Lutherans, and Thomists. The Lutherans would of course also want to say that paradoxically God seriously intends the salvation of the lost (whereas Reformed and Thomists would not), though God's predestination is the sole cause of salvation- whereas the Thomists would like to emphasize the agency of the human will in the process of conversion, although they would agree without divine grace humans could do nothing. At the end of the day, they would probably all agree that God 1. Foresees the fall, he doesn't cause it 2. He saves a certain number by predestination 3. The damned damn themselves by their own choices.
By contrast, Calvin and Beza are much, much more keen on the idea that God is out to get people and that there is no such thing as God's permissive will. According to Calvin, everything actively willed by God and there's no denying this. Muller notes the Aristotelian influence here. That is to say, if God is the mover of all that is moved (Aritotle's "unmoved, mover"), there no permissive will or meaningful secondary causes. God would have to be the active mover of every cause, and there is no permissive or passive willing in God.
Would not Luther agree with this? To an extent. But Luther would likely also endorse the idea (paradoxically) that God cannot be the cause of evil, whereas Calvin and Beza are all too happy to go down the road of Zwingli and think that God is the author of the Fall- though it should be born in mind that for Calvin, although God decree the Fall, he did not some how bring about that decree by the "necessity of compulsion." Also, in all fairness to Beza and Calvin, they are somewhat more guarded about this in their rhetoric than Zwingli. Nevertheless, its hard to see how they aren't endorsing Zwingli's position in "On Divine Providence", where he argues that God is quite literally the author of sin.