Problems With Divine Omniscience
Christian theists claim that God is omniscient, i.e. all-knowing. The doctrine of divine omniscience, though, faces several philosophical objections; there are a number of arguments in the philosophy of religion that purport to demonstrate that God cannot possibly know everything. These include arguments that the doctrine of divine omniscience is logically incoherent, that it is inconsistent with the further Christian doctrine of divine impeccability (i.e. the doctrine that God cannot sin), and that it is refuted by the fact of human freedom.
If any of these arguments is successful, then the doctrine of divine omniscience as it is usually taught will require at least modification, and possibly abandonment. Further, if being omniscient were thought to be a part of what is involved in being God, then these arguments against the doctrine of divine omniscience might even constitute proofs of atheism, of the non-existence of God. Four problems with divine omniscience are worthy of mention.
The first problemâ€”the paradox of omniscienceâ€”is derived from Cantor’s proof that there is no set of all sets. Omniscience, it is said, entails knowledge of the set of all truths. Cantor’s proof, however, demonstrates that there is no such set. As there is no such set, it is argued, there can be no omniscient being.
The second problem is the problem of experiential knowledge. Here the argument is that there are certain facts knowledge of which can only be acquired through certain experiencesâ€”knowledge of what it is like to sin, for instance, can only be acquired by sinningâ€”and that some of these experiences, and so some of these items of knowledge, are such that they cannot be had by God.
The third problem is that of reconciling freedom and foreknowledge, specifically the existence of divine foreknowledge with the existence of human freedom. If God knows all of our future actions, then the future is fixed, but if the future is fixed, it seems that there is nothing that we can do to change it. The ability to determine our future actions, though, is what constitutes human freedom. Divine foreknowledge, then, seems to preclude the possibility of our being free agents.
The fourth problem is the problem of middle knowledge. Middle knowledge is knowledge of what free agents would have done had the world been other than it is. As the agents are free, their choice of action cannot be determined by the state of the world, and so cannot be calculated on that basis. As middle knowledge concerns counterfactual situations, however, neither can their choice of actions be known by observation of the future. With the two possible sources of knowledge ruled out, it seems that middle knowledge is an impossibility.