Theological compatibilism

The basic challenge is ancient. If God knows today that I will choose X tomorrow, then at the moment of my choice I cannot actually choose otherwise — because if I did, God's prior knowledge would be false, which is impossible. The conclusion seems to be that my choice is not free in any meaningful sense. Theological compatibilism is the family of positions that try to defuse this argument and preserve both divine foreknowledge and creaturely freedom.

Several strategies have been tried. Boethius and Aquinas argued that God is outside time entirely, so God's knowledge of my future choice is not temporally prior to it — it is eternally present, all at once, in a way that does not reach back and constrain my deliberation. Molinism (Luis de Molina) adds the doctrine of middle knowledge: God knows what I would freely choose in any possible circumstance and creates the world by selecting circumstances that produce the outcomes God wants, without overriding my freedom at any point. Ockhamists distinguish "hard" facts about the past (which I cannot change) from "soft" facts about the past that depend on what I will do in the future (which are in a weaker sense still up to me).

Some theological compatibilists are also philosophical compatibilists — they hold that free will is compatible with causal determinism in general, so adding divine causation on top of natural causation does not create a new problem. Jonathan Edwards, the eighteenth-century Calvinist, took this approach: freedom consists in doing what you want, and God's ultimate determination of what you want does not compromise that. This move is widely considered to trade "free will" for a weaker notion that many philosophers and most ordinary speakers would reject as the real thing.

The contrary position is theological incompatibilism, which holds that divine foreknowledge and libertarian free will cannot coexist. Theological incompatibilists usually resolve the tension by giving up one of the two. Open theists give up exhaustive foreknowledge (see the open theism entry). Hard Calvinists give up libertarian freedom and embrace theological determinism. Molinists and eternalist Thomists insist both can be held together but do it through elaborate technical machinery.

For a secular reader, theological compatibilism matters because it is where the most sophisticated Christian philosophy does its hardest work. The simpler picture — "God knows what you'll do but you're still free" — is not an answer, it is a restatement of the problem. Every serious theist has to pick a position on the compatibility question, and the positions available are few and each has real costs. Knowing the landscape lets you engage the discussion at the level actual philosophers engage it.