Thought experiment: let there be an omniscient being who knows the future and an agent with free will. They are playing a simple game: there is a table with 2 cards and the free agent asks the omniscient being the following question: Which card will I pick up? Since the omniscient being already knows the answer, then the free agent necessarily must do exactly what the omniscient being knows he is going to do (otherwise the omniscient being isn't really omniscient). However, if the omniscient being answers "the left card", then the free agent will pick up the right card, and if the omniscient being answers "the right card", then the free agent will pick up the left card (because he feels like trolling the omniscient being).

Since either option leads to contradiction, doesn't this prove that free will and omnscience are incompatible?

  • That depends on definition of omniscience. Isn't knowing all possible consequences sufficient for omniscience? Actually, omniscient being can say "My words will affect your behaviour, so I won't answer you".
    – rus9384
    Commented May 11, 2018 at 6:39
  • This is giving me a Oracle vibe (The Matrix one). One can assume a person is omniscient, or they can go against what they claim and do what they want. Does an omniscient being know that I would write this comment or is this me being free of choice to say "hey this guy has a point". You have a good point
    – L_Church
    Commented May 11, 2018 at 8:54
  • Omniscience means knowing all there is to know. If free will means creative acting then there is nothing to know about what a free agent will do before he does it just as there is nothing to know about a creation before it is created. See Felt's Impossible Worlds on foreknowledge of free action as "metaphysically inconsistent fictions which cannot form an object of anyone’s knowledge, not even God’s". Alternatively, one can redefine free will as acting without coercion, which does not preclude foreknowledge of the outcomes at all.
    – Conifold
    Commented May 11, 2018 at 21:59
  • @Conifold, but if you define free will as acting without coercion, that definition would not be very useful because your would still be coerced to act by the laws of Physics, wouldn't you?
    – xwb
    Commented May 12, 2018 at 1:35
  • 1
    Coercion is defined as external compulsion, to the extent that laws of physics act through you internally and are part of making you into "you" their operation is not coercion. This position is known as compatibilism.
    – Conifold
    Commented May 12, 2018 at 3:47

2 Answers 2


Given open theism, an omniscient being would not know what a free agent will do since what a free agent will do is not something that is knowable until the free agent does it.

This does not contradict omniscience defined as knowing everything that is knowable. It does challenge one to be precise about what “knowable reality” actually is.

As James Rissler puts it in his article, “Open Theism” (Internet Encyclopedia of Philosophy):

While Open Theists affirm that God knows all the truths that can be known, they claim that there simply are not yet truths about what will occur in the “open,” undetermined future.

Given open theism, there is no paradox.

Regarding the question, Since either option leads to contradiction, doesn't this prove that free will and omnscience are incompatible?, open theists would agree that there is a contradiction between free will and a definition of omniscience that assumes the omniscient being knows more than they claim there is to know.

  • I see, since future actions of free agents are not knowable in advance, there is nothing wrong with an omniscient being not knowing them. However, that would certainly raise problems for religions that claim God knows the future and can make prophecies about it.
    – xwb
    Commented May 12, 2018 at 1:40
  • @xwb It should not cause God any more problems to make prophecies or predictions than a quantum physicist has with quantum indeterminism which can be viewed as the acts of free quantum agents. The two main alternatives to open theism are Molinism which gives God knowledge of counterfactuals or possible worlds and Calvinism which is the theological determinism I think you are referencing in your post. If Calvinism is true, then I do think you have described a real paradox. Commented May 12, 2018 at 3:19
  • But think about it, if God makes a prophecy about the future but free agents end up altering it, that would mean God uttered a false prophecy. Don't you see any problems with that? Doesn't it contradict the assumption that God cannot make mistakes?
    – xwb
    Commented May 12, 2018 at 3:24
  • @xwb Think of God as a quantum physicist making a prediction about the result of a quantum collapse caused by a measurement. God doesn't know any more than the quantum physicist does about what the precise value will be, but both of them can make useful predictions. I don't think God's predictions about our behavior are any more precise that His predictions would be about those quantum events. I am also discussing topics like this in a chat room you might be interested in: chat.stackexchange.com/rooms/76868/… Commented May 12, 2018 at 3:33
  • Since you brought God into this mix, please show me where in the bible there is the term "free will". Not once is it claimed that we are to do as we please, but on the contrary, we are to do what pleases him. All that is created, is by Him, and everything that ever happened or will happen -- is already written. If it is already written, we are already judged, and if already judged, that means there was no "free will" as He knew our life before creating us and He still made that choice for whatever reason. Did you choose to be created ?? Commented May 14, 2018 at 11:43

The thought model has an infinite loop problem

  1. Knowledge of the future, restricts what you can do in the present.
  2. Revelation of the future to the present cannot change the future.

An agent has a choice in front of it. Once that choice is made it is set. Bringing information of whatever type into the situation, may or may not change that future. If the information is locked into the future outcome, ie the actual information of what happens, this information could only be disclosed in a form that does not change the future event.

Now the choice is still free, but knowledge of that choice is not possible if it changes it.

  • An agent as you put it can be placed into an illusion of free will, however if the creator of the agent already knows the outcome before creating the agent, then on creating the agent, is evidence there is no such thing as free will. The agent may believe they are making their own choices, but to the creator, all is going exactly as pre-determined. Commented May 14, 2018 at 11:45

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