Post by Josh on Jul 27, 2009 18:15:49 GMT -8
Moritz, and others, I'm curious your thoughts on this "free will proof". I don't know the author's name, I found it on the internet- the link is below.
ABSTRACT: A modest free will thesis, stating that at least sometimes, someone has more than one course of action open to him, can be derived from three premises: first, the proposition that we should believe only what is true; second, the 'ought' implies 'can' principle; and third, the proposition that I believe I have free will. The first of these is the only one that is at all controversial; however, I argue that it is a necessary presupposition of rational thought and discourse. As a result, one cannot rationally accept hard determinism.
The minimal free will thesis (MFT) holds that at least some of the time, someone has more than one course of action that he can perform.(1) This is the least that must be true in order for it to be said that there is free will. It may be disputed whether the truth of MFT is sufficient for us to 'have free will,'(2) but there is no doubt that the main philosophical challenge to the belief in free will has come from the thesis of universal determinism, so understood as to exclude MFT. A proof of MFT is therefore of considerable philosophical interest, whether or not it constitutes a full proof of free will. In any case, it is the minimal free will thesis of which I have a proof to offer.
It will be convenient to have a name for the contradictory of MFT. With apologies to compatibilists, I use the label "determinism." Hereinafter, then, determinism is the thesis that the only thing anyone can ever do is the thing he actually does, where by stipulation, "can" is used in the sense (whatever that is) that is relevant to free will.
My proof requires four premises. First: with respect to the free-will issue, we should believe only what is true; that is, we should refrain from believing false propositions. We should not accept determinism unless it is true; likewise, we should not accept the free-will thesis unless it is true. This is a presupposition of rational discourse on the topic of free will. When we sit down to talk about this issue, or any philosophical issue, there is a tacit assumption that we are all interested in finding out the truth, and we accept this goal as governing the discussion. This does not mean that all of us will always think in the manner that is in fact most truth-conducive, for we may occasionally make mistakes or be unknowingly influenced by biases. What we may not do, consistent with rational discourse, is to accept mistakes or biases as such. That is, we are at least committed in theory to renouncing such mistakes and biases, even if that commitment is sometimes difficult to implement in practice. Thus, if someone announces that he thinks that we should believe what is false, or that having a false belief would be just as good as having a true belief on this matter, then, I think, that person has explicitly disavowed rational discourse on the topic of free will. I will therefore assume that my audience accepts this first premise.
My second premise is the "'ought' implies 'can'" principle: that is, to say that something should be done implies that it can be done. For example, suppose a student explains to me that he could not make it to class because his car broke down. One way I might respond would be by telling him that he could have made it to class some other way. But it would be nonsensical of me to say, "Yes, I understand that you could not have come to class, but you should have come anyway." In general, it is not the case that you should do the impossible. This is equivalent to saying that if you should do something, then you can do that thing.
The third premise states that, if determinism is true, then whatever can be done is actually done. This follows directly from the definition of determinism given above: determinists hold that any person, at any given time, has one and only one course of action open to him. Thus, according to determinists, if a person fails to perform an action, that means he literally was unable to perform it. Which implies that if a person is able to perform an action, then he performs it.
Finally, the fourth premise states that I, personally, believe in free will. This is an empirical fact, which I know on the basis of introspection. Of course, there will be those who dispute my belief, in the sense that they think it is a false belief, but I assume no one will question the mere fact that I have such a belief; I assume, that is, that none will wish to accuse me of lying when I say I believe I have free will. Incidentally, any other example of an individual who believes MFT will do just as well for purposes of my argument.
Given these premises, now, we can deduce the truth of the minimal free-will thesis:
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 MFT. (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 MFT is true. (from 6,4)
8.
MFT is true. (from 7)
The validity of steps 5-8 should be uncontroversial.(3) In step 7, we see that, if determinism is true, then MFT is not a falsehood, since if it were, we would (step 6) refrain from believing it, whereas some in fact believe it (step 4). Thus, we see that determinism is self-refuting, in the sense that, modulo certain true premises, determinism implies its own contradictory (MFT). Any proposition that thus implies its own contradictory is false, so determinism is false, and MFT true.
Despite the unquestionable validity of my proof and its highly plausible premises, in my experience, few people are prepared right away to accept it. Therefore, I shall discuss some of the objections which have been raised against it.
Notes
1. Following Peter van Inwagen's terminology in An Essay on Free Will (Oxford: Clarendon Press, 1983), p. 91.
2. The main problem is that, if some human actions were mere random events, this would seem to be sufficient for MFT to be true, but it would not be sufficient for any actions to be free. A less interesting objection is that "we have free will" would normally be taken to mean that all normal people perform free actions reasonably often.
3. The premises can be symbolized: 1. (x)(Fx → S[~Bx]), 2. (x)(S[x] → C[x]), 3. (Fm → (x)(C[x] → D[x])), 4. Bm; using the following symbolism: Fx = x is false, S[x] = I should do x, C[x] = I can do x, D[x] = I do x, m = the minimal free-will thesis. Premises 1-3 imply (Fm → D[~Bm]), which says that if MFT is false, then I do refrain from believing it ("[~Bm]" denotes the 'action' of not believing MFT). With the tautological premise (suppressed in the text) that (Bm → ~D[~Bm]) (if I believe MFT, then it is not the case that I refrain from believing it), one can infer ~Fm. Given the tautological premise (suppressed in the text) that (~Fm → Tm) (if MFT isn't false, then it's true), one can infer Tm.
Full text/ internet source: home.sprynet.com/~owl1/fwill.htm
ABSTRACT: A modest free will thesis, stating that at least sometimes, someone has more than one course of action open to him, can be derived from three premises: first, the proposition that we should believe only what is true; second, the 'ought' implies 'can' principle; and third, the proposition that I believe I have free will. The first of these is the only one that is at all controversial; however, I argue that it is a necessary presupposition of rational thought and discourse. As a result, one cannot rationally accept hard determinism.
The minimal free will thesis (MFT) holds that at least some of the time, someone has more than one course of action that he can perform.(1) This is the least that must be true in order for it to be said that there is free will. It may be disputed whether the truth of MFT is sufficient for us to 'have free will,'(2) but there is no doubt that the main philosophical challenge to the belief in free will has come from the thesis of universal determinism, so understood as to exclude MFT. A proof of MFT is therefore of considerable philosophical interest, whether or not it constitutes a full proof of free will. In any case, it is the minimal free will thesis of which I have a proof to offer.
It will be convenient to have a name for the contradictory of MFT. With apologies to compatibilists, I use the label "determinism." Hereinafter, then, determinism is the thesis that the only thing anyone can ever do is the thing he actually does, where by stipulation, "can" is used in the sense (whatever that is) that is relevant to free will.
My proof requires four premises. First: with respect to the free-will issue, we should believe only what is true; that is, we should refrain from believing false propositions. We should not accept determinism unless it is true; likewise, we should not accept the free-will thesis unless it is true. This is a presupposition of rational discourse on the topic of free will. When we sit down to talk about this issue, or any philosophical issue, there is a tacit assumption that we are all interested in finding out the truth, and we accept this goal as governing the discussion. This does not mean that all of us will always think in the manner that is in fact most truth-conducive, for we may occasionally make mistakes or be unknowingly influenced by biases. What we may not do, consistent with rational discourse, is to accept mistakes or biases as such. That is, we are at least committed in theory to renouncing such mistakes and biases, even if that commitment is sometimes difficult to implement in practice. Thus, if someone announces that he thinks that we should believe what is false, or that having a false belief would be just as good as having a true belief on this matter, then, I think, that person has explicitly disavowed rational discourse on the topic of free will. I will therefore assume that my audience accepts this first premise.
My second premise is the "'ought' implies 'can'" principle: that is, to say that something should be done implies that it can be done. For example, suppose a student explains to me that he could not make it to class because his car broke down. One way I might respond would be by telling him that he could have made it to class some other way. But it would be nonsensical of me to say, "Yes, I understand that you could not have come to class, but you should have come anyway." In general, it is not the case that you should do the impossible. This is equivalent to saying that if you should do something, then you can do that thing.
The third premise states that, if determinism is true, then whatever can be done is actually done. This follows directly from the definition of determinism given above: determinists hold that any person, at any given time, has one and only one course of action open to him. Thus, according to determinists, if a person fails to perform an action, that means he literally was unable to perform it. Which implies that if a person is able to perform an action, then he performs it.
Finally, the fourth premise states that I, personally, believe in free will. This is an empirical fact, which I know on the basis of introspection. Of course, there will be those who dispute my belief, in the sense that they think it is a false belief, but I assume no one will question the mere fact that I have such a belief; I assume, that is, that none will wish to accuse me of lying when I say I believe I have free will. Incidentally, any other example of an individual who believes MFT will do just as well for purposes of my argument.
Given these premises, now, we can deduce the truth of the minimal free-will thesis:
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 MFT. (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 MFT is true. (from 6,4)
8.
MFT is true. (from 7)
The validity of steps 5-8 should be uncontroversial.(3) In step 7, we see that, if determinism is true, then MFT is not a falsehood, since if it were, we would (step 6) refrain from believing it, whereas some in fact believe it (step 4). Thus, we see that determinism is self-refuting, in the sense that, modulo certain true premises, determinism implies its own contradictory (MFT). Any proposition that thus implies its own contradictory is false, so determinism is false, and MFT true.
Despite the unquestionable validity of my proof and its highly plausible premises, in my experience, few people are prepared right away to accept it. Therefore, I shall discuss some of the objections which have been raised against it.
Notes
1. Following Peter van Inwagen's terminology in An Essay on Free Will (Oxford: Clarendon Press, 1983), p. 91.
2. The main problem is that, if some human actions were mere random events, this would seem to be sufficient for MFT to be true, but it would not be sufficient for any actions to be free. A less interesting objection is that "we have free will" would normally be taken to mean that all normal people perform free actions reasonably often.
3. The premises can be symbolized: 1. (x)(Fx → S[~Bx]), 2. (x)(S[x] → C[x]), 3. (Fm → (x)(C[x] → D[x])), 4. Bm; using the following symbolism: Fx = x is false, S[x] = I should do x, C[x] = I can do x, D[x] = I do x, m = the minimal free-will thesis. Premises 1-3 imply (Fm → D[~Bm]), which says that if MFT is false, then I do refrain from believing it ("[~Bm]" denotes the 'action' of not believing MFT). With the tautological premise (suppressed in the text) that (Bm → ~D[~Bm]) (if I believe MFT, then it is not the case that I refrain from believing it), one can infer ~Fm. Given the tautological premise (suppressed in the text) that (~Fm → Tm) (if MFT isn't false, then it's true), one can infer Tm.
Full text/ internet source: home.sprynet.com/~owl1/fwill.htm