An Omniscient Being Is Impossible

The caption should probably read "I've omniscience," but ignore that.

I need to reformat this entire thing because I've changed my mind on same of these arguments. I'm going to drop the "I have free will" part from my argument and progress without it. My belief in free will has waned and this is quite a big assumption in the argument that is not needed. I will leave everything else up, though, for you to read it. Not too much will change, but a point of the argument will.

My current thoughts on free will can be found here. Feel free to read this post, but it's not what I currently think.

I had to write a paper dealing with something from Augustine's works for my Ancient and Medieval Philosophy class. Instead of writing about the problem of evil again, I decided to tackle something different and more difficult: divine foreknowledge and human freedom. If you'd like to think more about this topic and listen to a three-part podcast about this, feel free to listen to the following episodes: one, two, and three. Enjoy the podcast and my paper. Feel free to point out errors and raise objections.


In The City of God, Augustine argues that human free will (the ability to make choices and be able to exercise such choices) and divine omniscience (the ability of God to know everything including future events) are compatible. I will argue that human free will and divine omniscience are incompatible; human free will entails that there can be no omniscient beings. To defend my conclusion, I will argue that knowing the future is a contingent property of omniscience; omniscient beings can only hold true beliefs and are incapable of making errors in reasoning; God has known the future of humans well before humans existed, so the future is “set;” and respond to various objections.

Laying Out The Foundations Via Augustine

An omniscient being must know the future. Augustine makes it very clear in several different ways that God must know the future because he is omniscient: “God […] is most rightly and most truly believed to know all things before they come to pass.” (p. 188-189) “For, to confess that God exists, and at the same time to deny that He has foreknowledge of future things, is the most manifest folly.” (p. 190) “For one who is not prescient of all future things is not God.” (p. 194)

Despite the idea that God knows the future, Augustine maintains that humans still have freedom to make choices and execute those choices: “But we embrace both [omniscience and human free will]. We faithfully and sincerely confess both.” (p. 196) “But the religious mind chooses both, confesses both, and maintains both by the faith of piety.” (p. 191) Some may argue that human free will and omniscience are incompatible, but Christian ideas say otherwise, as noted above.

Building on the Foundations

An omniscient being can only possess true beliefs; a false belief would negate the quality of omniscience. Omniscient beings are incapable of making an error in reasoning, thus if God knows the future today, the future cannot change because a true belief that was held cannot turn out to be false in the future. If God knew today that you were going to eat pizza at 9:19PM tomorrow, you would have to eat pizza for lunch tomorrow, otherwise God's belief would be false – and that is impossible because an omniscient being could only hold true beliefs. If God had this belief today about what will happen tomorrow at 9:19PM, this entails that there is only one possible future that can happen: you may only eat pizza at 9:19PM.

Right now, as I am sitting in a chair typing this essay, I am pondering a multitude of options: I can change the music I am listening to, leave the room, go to sleep, drink green tea, continue to type this essay, read a book, etc. It is obvious that I can act upon any of these choices and choose one of at least six possible futures. If God knew what was going to happen yesterday, only one of these futures would be possible, but this is clearly not the case because I can easily choose what is going to happen from the above list. If an omniscient being exists and knows the future, this entails that only one future is possible, thus I have no freedom to choose my own future. If God knew that I was going to take a break and read a book yesterday, this means that I could take no other action even if I really wanted to drink green tea or change my music.

In order to have the freedom to make choices, I must be able to either partake or not partake in any option I cogitate. In order to have freedom, if I were to think about drinking green tea, I must have the choice to either drink green tea or not drink green tea. If God envisioned a future in which I am drinking green tea, I have no choice but to drink the green tea because his belief about the future must be true. I do not have the choice to refrain from drinking green tea if God envisioned a future of me drinking green tea. God's beliefs simply can't be false.

Theists including Augustine assert that God has always existed and was always omniscient, thus his envisioned future was determined a very long time ago (or always has been envisioned?). Since this is the case, God must have known every event in every person's life and every minute detail of the creation that he would set in place such as the date of my birth and who my parents would be. If God exists and is omniscient, my parents had no choice in the matter of being in a relationship and were simply unable to cease seeing each other because God knew that I would be born at a specific time. It was impossible for my mother to move to Canada if she desired because God knew that she would become impregnated in Pennsylvania. God's knowledge of this specific future also binds many other countless events and limits the freedom of many people who may have wanted to assassinate my mother and father, kidnap them at an early age, etc.

The Argument

It is impossible to reconcile the freedom of humans to make choices with an omniscient being; If an omniscient being exists, humans have no freedom to make choices. Since humans have the freedom to make choices, an omniscient being does not exist.

  1. Freedom entails that humans can choose either to partake or not partake in any given option.

  2. If an omniscient being, God, exists, such a being knows exactly what is going to happen in the future and cannot be mistaken.

  3. If God, knows my future (such that I must partake in event x at time y) it is not possible for me to refrain from partaking in event x at time y. Since I cannot refrain from partaking in event x at time y, I have no freedom.

  4. If God exists, I am not freely performing any action because God knows what is going to happen in the future. My actions cannot invalidate God's foreknowledge, thus only one future is possible (the future that he knows is going to happen).

  5. I am able to freely perform actions and can, at any given moment when I am cognizant and able to act, choose a multitude of actions.

  6. Thus, an omniscient being does not exist.

Responding to Objections

A theist may object and say “The knowledge of a future event does not mean that the future event must happen.” This objection fails for several reasons. If an omniscient being has a belief about the future, the event must happen because the omniscient being could not hold a false belief. If God has a belief today that something will happen tomorrow, the event must happen and the agent has no choice in the matter because the event is “set in stone.” Once God has a belief, the belief simply can't change because this would entail that his past belief was false. If God knows that event y happens at time x, only event y could happen at time x because his belief would be false if anything other than event y took place.

Another objection might exist in the form of “Omniscience only means the being with this quality knows what will happen, but does not force it to happen.” This objection also fails. While God might not have to come down and literally force the events to happen, the events still must happen. Suppose God knows that I'm going to eat pizza at 6:19PM. Since the belief of the omniscient being cannot be false, I am forced to eat the pizza. God need not move pizza into my mouth or deliver a pizza to my residence, but the pizza eating will still occur without God acting. Regardless of whether or not God would force an event to happen, the event must still happen because God's belief cannot be false. The person who poses this objection also misunderstands the argument because the argument has nothing to do with being forced by God to take a specific action. Responding with this objection does not solve the problem or attack any of the premises.

An unconventional response to the argument may exist in the form of “Our future actions that we would have taken before we existed cause God's beliefs.” Even if God were to know that I, for example, were to attend King's College and major in philosophy and psychology if I had the chance to exist and make free actions, I still could never change my mind about this decision when I would later exist, thus I am not free.

A popular response to this problem of free choice and omniscience is as follows, “God knows all possible futures and all possible actions by all possible beings. He doesn't just have one vision of the future! People can still freely act and arrive at their freely chosen actions.” Even if this is the case, we're still constrained to one specific future and do not have freedom to choose another possible future. Only one possible future can exist. An all-knowing being must know precisely what will happen at any specific given time and cannot hold two or more beliefs about what will happen. An all-knowing being would know exactly what action I would take and what thought processes would exist in my mind that would lead me to that action. If an interview with an omniscient being would be possible and the omniscient being agreed to answer any question, the questioner could simply ask “What is Jim going to do at 4:00PM tomorrow?” The being would answer with a very precise answer such as “He will be watching television” and could not possibly say something like, “Well, if he is thinking of drinking water, he'll drink water, but if he's not thirsty, he'll watch television.” The interviewer would ask, “I'm not asking you what-if questions, I'm asking specific questions. What will happen?” The omniscient being would know exactly what will happen and will be able to answer the question.

This objection to the problem is also a misunderstanding of the argument because this objection is only positing how God knows the future, but is not objecting to any of my premises. It matters not how God knows the future; the mechanism of knowing is not at question and is not important. God, if he exists, knows specifically what will happen in the future and humans do not have the freedom to choose an action if God knows what will happen because they could not do anything that is contrary to God's envisioned future. If God knows of all “possible” futures, this means that God holds false beliefs because only one future can happen, but God can't hold any false beliefs.

Another possible objection to my argument is, “Omniscience entails that a being knows all possible outcomes, but not the particular outcome that will be chosen.” This objection is similar to the one previously discussed with a caveat. An omniscient being must know the outcome in the future. If the omniscient being did not know the outcome that would happen in the future, the being would not be considered omniscient. If omniscience entails knowing possible outcomes, but not a particular outcome, all humans would be considered omniscient when events containing a limited number of outcomes are concerned such as rolling a die, a horse race, an outcome of a sports contest, or flipping a coin. My definition of omniscience as far as God is concerned as previously mentioned is contained in (2): knowing exactly what will happen in the future and the ability to never be mistaken. Other properties of God are omnipotence, omnipresence, and omni-benevolence. Specific qualities may differ from believer to believer, but for the sake of this argument, we only need to be concerned with the foreknowledge and infallibility properties of omniscience.

Other Problems

Suppose our ability to make choices is just an illusion and someone attacks (5) in my argument above. Perhaps although I can sit typing this essay and really think about leaving my room and see a movie, I don't really have the choice to do this. Perhaps my actions are the result of my brain interacting with my environment and no matter how hard I think about leaving my room, I'm going to continue my essay because my neuronal activity leads me to the conclusion to stay in my room. Even if this were the case that I couldn't really make choices, my freedom would still be restricted by events outside of my control. Suppose God envisioned that I would be blindsided and killed by a church van at the age of 23. This is not the result of my choices, but is someone else acting to restrict my freedom.

Suppose that God had the ability to choose what the future would be. If this were the case, it obviously would not defeat the argument I presented, but would raise several moral objections. Many versions of theism include belief in a place of eternal punishment set forth for humans who wronged God in some manner. If God were able to decide a future, how can he be morally justified in punishing people for the actions that he knew that would take after either “designing” the people to take the actions or setting the future in a specific manner [it matters not how he goes about making certain events happen]? Why should people be punished for eternity for actions that they had no choice in partaking in? If God knows that Jim is going to be a murderer and chooses this future for Jim, God sends him to Hell for something that God declared. Any God who behaves in this manner is grossly unjust.


Despite Augustine's well-thought out belief in an omniscient god who knows the future and human free will, his belief has been shown to be false. Attempts to redefine omniscience do not work because an omniscient being must know the future and could not hold any false beliefs. What part of this definition could possibly change to salvage the concept of God's omniscience? If God doesn't know the future, as Augustine says, “one who is not prescient of all future things is not God.” (p. 194) If God can hold false beliefs, he is fallible, which can't be the case. Divine foreknowledge and the ability of humans to freely choose actions is incompatible. Since humans are able to freely choose which actions they will take, an omniscient being does not exist.

Works Cited

Dods, Marcus. The City of God by Saint Augustine. New York: Hafner Publishing Company, 1948. Print.