A Proof of Free Will
One of the first philosophical problems I thought about in college was free will vs. determinism. It was then that I thought of an argument against determinism, which I presented in a term paper. Later, as a professor, I tried to publish the same argument, but it was rejected about fifteen times by different journals. Each time, the referees said to reject it because they could think of some objections to my argument. (Note: Any philosopher can think of objections to any interesting argument.) Each time, I added a reply to the confused objection, then sent it out again to another journal, only to have the next referee make up some other rationalization for rejecting it. I eventually gave up. It seemed that it didn’t matter how many objections I refuted; they’d always just make up something else.
Almost no one has ever liked the argument. Almost everyone thinks that it’s just some cute trick I’m trying to play on them. But it isn’t; it’s just a refutation of determinism.
Eventually, I got a short version of it published in an invited book chapter (“Free Will and Determinism in the World of Minority Report” in Science Fiction and Philosophy, ed. Susan Schneider (Wiley-Blackwell, 2009), pp. 103-112). (See also http://www.owl232.net/papers/fwill.htm.)
Now, you too can read this amazing argument that utterly refutes determinism yet is utterly hated by nearly all philosophers who hear about it.
1. The Intuitive Idea
The intuitive idea goes back to Epicurus (as I discovered long after I’d thought of the argument):
“The man who says that all things come to pass by necessity cannot criticize one who denies that all things come to pass by necessity: for he admits that this too happens of necessity.”
J.R. Lucas argued similarly:
“Determinism … cannot be true, because if it was, we should not take the determinists’ arguments as being really arguments, but as being only conditioned reflexes. Their statements should not be regarded as really claiming to be true, but only as seeking to cause us to respond in some way desired by them.”
The intuitive idea is that determinism is self-defeating when you apply it to beliefs about the subject of free will and determinism itself. Per Epicurus, it implies that you can’t criticize anyone for believing in free will, nor (presumably) can you say that anyone should believe determinism. In its most common (physicalistic) forms, per Lucas, determinism implies that good reasons play no role in explaining why one believes determinism itself. So the determinist couldn’t hold that he himself knows determinism to be true. (My interpretation/modification of Lucas.)
My idea was related to these. It was that in thinking about any issue, one always presupposes certain norms governing belief. E.g., that you should avoid falsehood, or that you should base beliefs on evidence. But any such norm, I think, is incompatible with the truth of determinism. So if you think determinism is true, you’re in an inherently self-defeating position: You’re committed to rejecting norms that you are implicitly presupposing.
2. The Cute Trick
Preliminaries:
By “determinism”, I mean “hard determinism” (I’m not arguing with compatibilists here). Hard determinism, by definition, implies that, at any given time, you only ever have one thing that you can do.
In trying to reason through any issue, I think we are presupposing some kind of truth-seeking norm, roughly that we should believe what is true rather than what is false about that issue.
So here’s how to convert that idea into a cute refutation of determinism.
We should believe only the truth. (premise)
If S should do A, then S can do A. (premise)
If determinism is true, then if S can do A, S does A. (premise)
So if determinism is true, then if S should do A, S does A. (from 2, 3)
So if determinism is true, then we believe only the truth. (from 1, 4)
I believe I have free will. (empirical premise)
So if determinism is true, then it is true that I have free will. (from 5, 6)
So determinism is false. (from 7)
Comments:
Premise 1 is a presupposition of rational thought, as discussed above.
Premise 2 is the famous “‘ought’ implies ‘can’” principle. Most people find this formulation more obvious: if you cannot do A, then it is not true that you should do A. (No one is obliged to do the impossible.)
Premise 3 directly follows from the definition of “determinism” as given above.
Steps 4 and 5 uncontroversially follow.
Step 6 is empirically true. (There is excellent evidence that I, Mike Huemer, believe in free will. I’ve said it many times, said other things that imply it, etc.)
Step 7 obviously follows from 5 and 6.
And 8 follows from 7. In step 7, we see that determinism is self-refuting: Determinism and free will can’t both be true (by stipulation). So, per 7, determinism leads to its own denial. Any view that leads to its own denial is false. So determinism is false.
3. Confused Objections
Confusion #1: “Premise 1 begs the question, because the determinist would just reject all ‘should’ statements. No one ever ‘should’ do anything, because no one ever has any alternatives available!”
Reply:
First, notice what the objection is saying. It appears to be saying (i) that a person who disagrees with the argument’s conclusion would or could reject one of the premises, on the basis of their belief in the denial of the conclusion, and (ii) that this shows a flaw in the argument.
Now I’d like you to notice that that implies that all valid arguments are bad. In a valid argument, the conjunction of the premises, P, entails the conclusion, C. Therefore, it is also true that the denial of the conclusion, ~C, entails the denial of the premises, ~P. That, again, is true of all valid arguments by definition. So if you use your rejection of an argument’s conclusion to evaluate the premises, it would always be true that you would reject at least one of the premises. As far as I can tell, that’s all the objection is pointing to.
Presumably, not all valid arguments are bad. So here is a better account of “begging the question”: you’re begging the question if your justification for one of the premises rests on the conclusion. So if I had said you should accept premise 1 because we have free will, that would be begging the question. But of course I didn’t say that. What I said was that premise 1 is a presupposition of rational thought. So that is nothing like begging the question.
Confusion #2: “The argument has an equivocation: (1) uses the epistemic ‘should’ but (2) uses the moral ‘should’.”
Reply:
I don’t really think there are multiple senses of “should”, but even if there are, there is no reason to think the argument uses different senses in 1 and 2. The “ought implies can” principle should apply to all “should”s. There is no sense of the word “should” on which it’s correct to say that you should do the impossible. So premises 1 and 2 are both true using the epistemic “should”.
Objection #3: “It’s not true that we should believe only the truth. Rather, we should believe only what is overall best justified by our evidence.”
Reply:
Okay. If you put that into premise 1, then the argument proceeds as before, except that step 7 winds up as “If determinism is true, then the belief in free will is overall best justified by our evidence.” I don’t think the determinist could happily accept this.
Objection #4: “(1) is false; no one ever ‘should’ or ‘should not’ believe anything, because (even if we can control our actions) we cannot control our beliefs.”
To show that people cannot control their beliefs, philosophers often say things like this: “Try believing right now that you are a giraffe.” You find that you can’t do it.
Reply:
The example shows at most that a person cannot, at will, believe a proposition that they have conclusive evidence against. However, it does not show that a person cannot refrain from believing falsehoods, or refrain from believing unjustified propositions, which is all that premise 1 requires. As long as you can refrain from believing the unjustified, it makes sense to say that you should do so.
4. What Did this Have to Do with Minority Report?
Minority Report was a fun movie about a society in which people with precognition predict crimes in advance, and the police arrest and punish people before they have committed those crimes.
The free will issue figures prominently. It looks like the system faces a justice-based challenge: (a) If people’s crimes are pre-determined, then it’s unjust to punish people for those crimes, since they lack free will and hence lack moral responsibility. (It’s still right to take actions to prevent those crimes, of course.) (b) If the crimes are not pre-determined because we have free will, then it’s unjust to punish people for crimes they haven’t committed (even if they were likely to commit them), since the people haven’t actually made the blameworthy choice.
The movie suggests (b) because sometimes the people with precognition disagree about what is going to happen. In discussing that, I inserted my proof of free will.
I had this conversation about the argument with Bing chat:
Me: I want you to evaluate an argument for me. This is the argument:
1. With respect to the free-will issue, we should refrain from believing falsehoods. (premise)
2. Whatever should be done can be done. (premise)
3. If determinism is true, then whatever can be done, is done. (premise)
4. I believe in free will. (premise)
5. With respect to the free-will issue, we can refrain from believing falsehoods. (from 1,2)
6. If determinism is true, then with respect to the free will issue, we refrain from believing falsehoods. (from 3,5)
7. If determinism is true, then the belief in free will is true. (from 6,4)
8. Determinism is false. (from 7)
Is that a good argument?
Bing: The argument you presented is known as the “Direct Argument Against Determinism” and it’s a valid argument. However, it’s important to note that the argument is not sound because premise 2 is false. Therefore, the conclusion that determinism is false does not follow from the premises. Here’s a table summarizing the argument:
# Argument
1 With respect to the free-will issue, we should refrain from believing falsehoods. (premise)
2 Whatever should be done can be done. (premise)
3 If determinism is true, then whatever can be done, is done. (premise)
4 I believe in free will. (premise)
5 With respect to the free-will issue, we can refrain from believing falsehoods. (from 1,2)
6 If determinism is true, then with respect to the free will issue, we refrain from believing falsehoods. (from 3,5)
7 If determinism is true, then the belief in free will is true. (from 6,4)
8 Determinism is false. (from 7)
I hope this helps!
Me: Why did you say that premise 2 is false?
Bing: Premise 2 is false because there are things that should be done but cannot be done. For example, it should be done that we prevent natural disasters from happening, but we cannot do so because we don’t have the power to control nature. Therefore, premise 2 is false and the argument is not sound. Is there anything else I can help you with?
Me: Do you mean that we should prevent all natural disasters, including the ones that we can't prevent, or only that we should prevent the ones that we can prevent?
Bing: I mean that we should prevent the ones that we can prevent. For example, we can prevent some natural disasters like floods by building dams and levees. However, we cannot prevent other natural disasters like earthquakes because they are caused by natural forces that are beyond our control. I hope this clarifies things. Is there anything else I can help you with?
Me: Then I don't see how you're saying that premise 2 is false. You're saying we should prevent the natural disasters that we can prevent. That's not a counter-example to the claim that if we should do X, then we can do X.
Bing: I apologize for the confusion. You are correct that if we should do X, then we can do X. However, premise 2 is still false because there are things that we should do but cannot do. For example, we should prevent all natural disasters from happening, but we cannot do so because some natural disasters are beyond our control. Therefore, premise 2 is false and the argument is not sound. I hope this clarifies things. Is there anything else I can help you with?
Me: Didn't you just contradict yourself?
Bing: I apologize if I was unclear. I did not mean to contradict myself. What I meant to say is that premise 2 is false because there are things that we should do but cannot do. However, I understand that my previous response may have been confusing. Is there anything else I can help you with?
Me: You said I was correct that "if we should do x, then we can do x". But you also said "there are things we should do but cannot do". Do you not see a conflict between those two statements?
Bing: You are correct that there is a conflict between those two statements. I apologize for the confusion. What I meant to say is that if we should do X and we have the power to do X, then we can do X. However, there are things that we should do but cannot do because we don’t have the power to do them. For example, we should prevent all natural disasters from happening, but we cannot do so because some natural disasters are beyond our control. I hope this clarifies things. Is there anything else I can help you with?
I just concluded a conversation with ChatGPT-4 regarding your argument. I thought you might find it amusing. Here is the transcript (I've added the "Q:" and "A:" to distinguish my questions from GPT-4's answers.)
Q: Can you evaluate the validity of reasoning through logical principles like modus ponens?
A: Yes, as an AI language model, I am capable of evaluating the validity of reasoning through logical principles like modus ponens. Modus ponens is a deductive inference rule that states that if a conditional statement of the form “If A, then B” is true and if A is also true, then it logically follows that B must be true as well.
For example, if we have the premise “If it rains, the ground gets wet” and the premise “It is raining”, then we can logically deduce the conclusion “The ground is wet” using modus ponens.
The validity of this reasoning is based on the fact that the logical form of modus ponens is sound. In other words, if the premises of the argument are true, then the conclusion necessarily follows. Thus, as long as the premises of an argument are true and the argument is structured in accordance with the principles of modus ponens, the conclusion can be considered valid.
However, it is important to note that the soundness of an argument depends not only on the logical structure but also on the truth of the premises. If the premises are not true, then the conclusion may not be valid, even if the argument is structured correctly.
Q: Here is a sequence of assertions, structured as a logical argument, concerning the existence of determinism versus free will. 1) Premise: one should only believe the truth. 2) Premise: if a person should do act A, then that person can in fact do act A. 3) Premise: if determinism is true, then if a person can do act A, then that person will do A. 4) We deduce from premise #2 and premise #3 that if determinism is true, then if a person should do act A, then that person will in fact do act A. Please evaluate his sequence of arguments.
A: The sequence of arguments presented is valid and follows the principles of deductive reasoning. Here’s a breakdown of the reasoning:
1. Premise: one should only believe the truth. This premise establishes a standard of truth-seeking and rationality that underlies the subsequent argument.
2. Premise: if a person should do act A, then that person can in fact do act A. This premise is a logical assertion that connects the ideas of moral responsibility and agency. In other words, if a person is morally obligated to do something, then that person must have the ability to do it.
3. Premise: if determinism is true, then if a person can do act A, then that person will do A. This premise is a statement of the deterministic view that all events, including human actions, are ultimately determined by prior causes. It implies that if determinism is true, then any given action is the necessary outcome of prior conditions, and therefore the person must do it.
4. Conclusion: if determinism is true, then if a person should do act A, then that person will in fact do act A. This conclusion follows logically from premises #2 and #3. If a person should do act A (according to some moral standard), and if determinism is true, then the person will inevitably do act A, since determinism holds that all events (including human actions) are determined by prior causes.
Overall, the argument is sound as long as one accepts the premises as true. However, the conclusion of this argument is not universally accepted, as some philosophers and thinkers argue that the existence of moral responsibility and free will are compatible with determinism.
Q: Let us continue the argument with the argument. 5) If determinism is true, then premise #1 and conclusion #4 imply that a person can believe only the truth. Is this valid?
A: The argument in premise #5 is not entirely valid, as it makes a leap in logic that is not fully supported by the previous premises.
Premise #1 states that one should only believe the truth, and conclusion #4 states that if determinism is true, then if a person should do act A, then that person will in fact do act A. However, premise #5 attempts to link these two premises by asserting that if determinism is true, then a person can only believe the truth. This conclusion does not necessarily follow from the previous premises, as it is not clear how the truth of determinism leads to this conclusion.
Furthermore, the conclusion of premise #5 seems to be at odds with the idea of moral responsibility, which is a key concept in the argument. If determinism is true and a person can only believe the truth, then it is unclear how that person can be held morally responsible for their actions.
Therefore, while the argument in premise #5 attempts to draw a logical connection between the premises, it ultimately fails to provide a clear and convincing argument for its conclusion.
Q: But argument #4, which you believe to be valid, asserts that if determinism is true, then if a person should do act A (in this case, act A is believing the truth), then that person will in fact do A, which means that the person will in fact believe the truth. That is the conclusion of #5.
A: You are correct that the conclusion of premise #5 does follow logically from premise #4. If determinism is true and if a person should believe the truth, then that person will in fact believe the truth, since determinism holds that all events (including human beliefs) are determined by prior causes.
Therefore, premise #5 can be considered a valid deduction based on the previous premises. However, as I mentioned earlier, the idea that determinism necessarily implies that a person can only believe the truth is still controversial and subject to philosophical debate. Some philosophers and thinkers argue that even if determinism is true, humans still have the capacity for moral responsibility and free will. So while the argument in premise #5 may be logically sound, it may not be universally accepted as a true or compelling argument.
Q: I agree that it may not be accepted.
A: Thank you for the discussion. Is there anything else you would like me to help you with?
Q: Yes, I want to continue the conversation. Suppose you accept premise #6 that I believe that I have free will. Does the following then logically follow: #7 If determinism is true, then it is true that I have free will.
A: No, the conclusion in premise #7 does not logically follow from the premises.
If you accept premise #6, which is the belief that you have free will, then it is not necessarily true that determinism must be true. In fact, one could hold the belief that they have free will and reject the idea of determinism, believing instead that their actions are not fully determined by prior causes.
Even if we assume that determinism is true, the conclusion in premise #7 does not follow logically. Determinism and free will are often seen as incompatible concepts, since determinism suggests that all events (including human actions) are determined by prior causes, while free will suggests that humans have the ability to choose their actions freely and without external constraints.
Therefore, the conclusion in premise #7 is not a valid deduction based on the given premises.
Q: You agree that #5 is a valid deduction. Thus, #5 implies if determinism is true, then I can believe only the truth. Since by #6 I believe that I have free will, does this not imply #7: if determinism is true, then I have free will?
A: I apologize for my mistake earlier. You are correct that if we accept premise #5 and premise #6, then it logically follows that if determinism is true, then you can only believe the truth, and if you believe you have free will, then you have free will even if determinism is true. Therefore, the conclusion in premise #7 does logically follow from the given premises.
So, in summary, if we accept premise #5 that determinism entails that one can only believe the truth, and premise #6 that you believe that you have free will, then it follows logically that if determinism is true, then you still have free will, even if your actions are determined by prior causes. Therefore, the conclusion in premise #7 is valid based on the given premises.
Q: It seems that this line of reasoning leads to the following conclusion: #8 Determinism is false. That is because we agree that #7 follows from the premises. And #7 says that if determinism is true, then it is true that I have free will. But free will and determinism are incompatible. So if I have free will, then determinism must be false. Is this a correct deduction?
A: Yes, you are correct that if we accept the premises and the conclusion in #7, it would follow logically that determinism is false. If we assume that free will and determinism are incompatible, as you have mentioned, then it follows that if you have free will, then determinism cannot be true. Therefore, the conclusion in #8, that determinism is false, logically follows from the given premises.
However, I should note that the relationship between free will and determinism is a complex and controversial philosophical topic, and there are different views and arguments regarding whether they are truly incompatible. Some philosophers argue that free will can coexist with determinism, while others argue that free will is incompatible with any form of determinism. So while the deduction in #8 may be valid based on the premises, it may not necessarily be accepted by everyone as a true or compelling argument.
Q: You are very correct about your final conclusion. Thank you!
A: You’re welcome! It was a pleasure discussing this topic with you. If you have any more questions or if there’s anything else I can help you with, feel free to ask.