Argument from free will

From Wikipedia, the free encyclopedia

The argument from free will is an argument against the existence of an omniscient God which contends that omniscience and free will are incompatible, and that any conception of God which incorporates both properties is therefore inherently contradictory. The argument goes as follows:

1. By definition, if someone has free will, then at any point in time they may either choose to do a certain thing or choose not to do it.
2. By definition, an omniscient God knows everything that will happen in the future, including all of the choices he will make at any future point in time.
3. By the definitions of "knowledge" and "choice", if one knows for certain what choice one will make in the future, one will not be able to make the opposite choice.
4. Omniscience and free will are logically contradictory.
5. Either nobody has free will, or nobody is omniscient.

Most monotheistic religions hold both that God is omniscient, and that humans have free will. (For example, they often include a concept of reward and punishment -- e.g., Heaven and Hell -- which logically requires human free will in order to be meaningful.) Many proponents of the argument from free will (AFFW) therefore hold that AFFW is an effective refutation of such religions. AFFW has been used in support of atheism, and as a basis for Deism and various other non-omniscient religious philosophies.

[edit] Criticisms

One criticism of AFFW is that point 3 of the proof (“by the definitions of ‘knowledge’ and ‘choice’, if one knows for certain what choice one will make in the future, one will not be able to make the opposite choice”) simply assumes that knowledge and free will are incompatible. Specifically, point 3 commits the modal fallacy of assuming that because some choice is known to be true, it must be necessarily true (i.e. there is no way it could possibly be false). This fallacy is most easily demonstrated by an example that has nothing to do with omniscience: While it is true that a person has one brother and one sister, it is not necessarily true. For example, it is possible that that person could have had two brothers, or two sisters, or no siblings at all. Logically, the truth value of some proposition can not be used to infer that the same proposition is necessarily true.

Using logical terminology and applying it to AFFW, there is a marked distinction between the statement “It is impossible (for God to know a future action to be true and for that action to not occur)” and the statement “If God knows that a future action is true, then it is impossible for that action to not occur.” While the two statements may seem to say the same thing, they are not logically equivalent. The second sentence is false because it commits the modal fallacy of saying that a certain action is impossible, instead of saying that the two propositions (God knows a future action to be true, and that action does not occur) are jointly impossible. Simply asserting that God knows a future action does not make it impossible for that action not to occur. The confusion comes in mistaking a semantic relation between two events for a causal relation between two events.

With these assumptions more explicitly stated, the proof becomes:

1. Assume that person X has free will (assumption).
2. By the definition of free will, at any point in time, a person can choose to do any action A, where A is the set of all actions they are physically capable of (definition of free will).
3. At time T, person X will choose to do action A (i.e. a person can not logically choose to do both A and not A) (Law of the Excluded Middle).
4. Assume that an omniscient God exists (assumption).
5. By the definition of omniscience, God knows everything that will happen at any point in time (definition of omniscience).
6. From 3. and 5., God knows that at time T, person X will choose to do action A (logical conclusion).
7. Therefore, person X must do action A at time T.

This claims to prove that at time T, person X is unable to do any action other than A. However, you could also remove steps 4–6, and arrive at the same conclusion. This is called logical determinism, and it suffers from the same modal fallacy as AFFW. If a certain proposition is true, that does not imply that the proposition is logically necessary. Once you remove the invalid assertion, then the argument for logical determinism is shown to be false. Similarly, when that same invalid assertion is removed from AFFW (“by the definitions of ‘knowledge’ and ‘choice’, if one knows for certain what choice one will make in the future, one will not be able to make the opposite choice”), the proof is shown to be false.

Another common criticism of AFFW argues that the apparent contradiction arises from an attempt to attribute temporal attributes to an atemporal idea or being. In this view, God exists beyond the constraints of linear time, and the temporal terminology used by AFFW is meaningless when applied to him: God doesn't need to know any event "before" it happens but rather is capable of knowing/experiencing it "while" it happens.

AFFW proponents respond that the above argument does not change the contradiction. They claim that omniscience by definition means that God has knowledge of all human events of all human times, even if God's own relationship to time is entirely different from ours.

A counter-argument to the above argument is that God’s knowledge is a result of the free-will agent's choice, not the cause of it, and therefore no contradiction exists (whether God is temporal or atemporal).

[edit] See also

• Predestination