If we assume that God knows the future, we think that the only possible way He could do that would be if He knew all possible states of the system. He could thus "compute" that future. But this "computation" might imply that no "free will" exists.

A SECOND WAY to get that information is hereby proposed: if God used a time-machine, then God's eyes could move in the future and simply OBSERVE it. By doing so a) the above doubts of lack of "free will" are cancelled and b) God should commit not to modify at least the part of the future that has been observed. Since it has been observed by Him, that future must really take place.

Are there concerns about the logical validity of the proposed "second way"?

  • 2
    Possible duplicate of Is God free to make decisions?
    – Conifold
    Nov 4, 2018 at 23:06
  • There is not even an overlap between the two questions: this question is concerned with the problem of how it is possible to obtain information regarding the future, in the other question "Is God free to make decisions" this problem is not an issue and it is assumed that the future is someway already known. Nov 5, 2018 at 0:01
  • The definition of duplicate is not that there is any relation between questions but rather that the answers answer both. The reasoning in both questions is based on too naive an idea of what omniscience means and how it affects free will, hence they are duplicates. The reading suggestions there also apply here.
    – Conifold
    Nov 5, 2018 at 0:05
  • you don't like my question and I withdraw it but I don't agree that I have a naive idea of the God's "omniscience", the purpose of my questions is to assess what God can do, i.e. what is logical, there is no naivety in that. My first question has been found clear when I posted it. The answers don't answer both, they answer none: my question has been largely answered by "omnibus type" God's theories that didn't address the problem if terms are unclear the right thing to do is ask for clarification rather than provide verbose posts, only with discipline it's possible to make steps forward Nov 5, 2018 at 16:45
  • 2
    The problems are that God's omniscience is not analogous to human eyesight, he does not "observe" anything from "outside", as he is the active source of everything that is, and on many conceptions he is not subject to time either, so there is no future or past for him. There are legitimate concerns about the interaction between omniscience and free will, but your particular presentation is too human-like to get to them. See the SEP article linked at the other thread, it may help you come up with a more elaborate question.
    – Conifold
    Nov 5, 2018 at 21:23

2 Answers 2


For logic to be respected we need to specify all the assumptions to the best of our abilities. Also there is no point in assuming that God's omniscience includes knowing something that is not knowable.

In addition to assuming that God can know future events, we need to agree on a premise that there actually are future events that can be known. We can't use a belief in God's omniscience to guarantee that the propositions that we happen to come up with refer to anything real.

This is nothing against God's omniscience nor even against God's existence.

Michael Dummett made a similar point in presenting arguments about realism and anti-realism: (page 351)

It is a persistent illusion that, from the premiss that God knows everything, it can be deduced that he knows whether any given proposition is true or false - that is, that he either knows that it is true or knows that it is false, and that his omniscience therefore entails that the proposition is either true or false. On the contrary, its being either true or false is required as a further premiss in order to deduce from his omniscience that he knows, in the sense stated, whether it is true or false.

So the assumption that "God knows the future" requires an agreement on another premiss that there is a future that God can know. One cannot argue for this premise by claiming that God's omniscience guarantees such a premise to be true. Omniscience does not require knowing what isn't there to know.

Michael Dummett. The Logical Basis of Metaphysics. 1991. Harvard University Press


We don't need the detour via a deterministic universe to get the issue with "free will" and "knowing the future". Provided that your god can reveal information to people[1], they could tell a person what that person will do tomorrow. The question then becomes whether that person can decide to act differently from what is fortold.

If they cannot, this is a problem for free will.

If they can, you would need something like changing timelines to reconcile. Then you can either have your god being able to observe "future timelines", and repeat the problem; or you can prohibit them from that and get an issue with "omniscience".

[1] Of course you could have a god that observes the entirety of spacetime, but never acts. Since this god is completely irrelevant, it causes no problems for free will or anything else.

  • 1 God WON'T tell people what they will do in the future, this of course would kill their "free will" 2 observing directly the future doesn't mean that God should refrain from interacting with people: God could observe a certain event in the future AND interact with it (those God's actions will be carried out in that future event). Then He could proceed to the following event and so on until the end of time. Nov 8, 2018 at 23:49

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