Freethought & Rationalism Archive

bd-from-kg · 02-14-2003, 12:27 PM

Diana:

Quote:

True. However, this runs up against the free will problem.

This is certainly a widely held view, but it is mistaken. The best simple exposition of the error involved that I know of is in Norman Swartz�s Lecture Notes on Free Will and Determinism (see esp. page 3).

[Note: To keep this legal I have to mention that this material is �Copyright � Norman Swartz 1997� and can be found at the URL http://www.sfu.ca/philosophy/swartz/freewill1.htm . Also note that I reformatted it somewhat due to the restrictions of vB code.]

Here�s his analysis:

Quote:

In English (and in a great many other natural languages as well), it is common to express the relationship of necessary condition using a strong modal term (underlined in these examples) in the consequent of an if-then sentence.

"If Paul has two sons and a daughter, then he has to have at least two children."
"If you have pneumonia, then you have to have fluid in at least one of your lungs."
"If you have a fever, then your internal body temperature must be greater than normal."

Now, each of the preceding, as ordinarily understood, is true. But they are misleading. They are stated in such a manner as to conceal, and indeed distort, their 'internal logic' (so to speak).

Let's look at the first of these: "If Paul has two sons and a daughter, then he has to have at least two children."

The antecedent of this sentence expresses a true proposition. (Paul is my brother and he does have two sons and a daughter.) Thus according to the valid inference rule (known as "Modus Ponens") which allows us to infer the consequent of any true conditional statement whose antecedent is true, we should be able to infer: "Paul has to have at least two children."

Something is clearly amiss. While it is true that Paul does (in fact) have at least two children (he has three), it is false that he has to have three. He doesn't have to have any. He doesn't have to have one. He doesn't have to have two. He doesn't have to have three. He doesn't have to have four. Etc., etc. Put another way: There is no necessity in Paul's having any children, let alone having three. There is no necessity for Paul (just as there is no necessity for anyone else) to have at least two children.

There is something, then, seriously in error in the following argument (or inference):

If Paul has two sons and a daughter, then he has to have at least two children.
Paul has two sons and a daughter.
So Paul has to have at least two children.

The source of the logical error lies (as suggested above) in placing the strong modal term in the consequent, where it appears to 'modify' that proposition (the 'then-clause').

However, the logical role of the strong modal term is to modify the relationship between the antecedent (the 'if-clause') and the consequent (the 'then-clause'); its role is not to modify the consequent alone.

Although the following sentences are not especially idiomatic (stylish), they do at least reveal, far better than the preceding three sentences, the correct underlying logic of the claims being made.

"It has to be that (if Paul has two sons and a daughter, then he has at least two children)."
"It has to be that (if you have pneumonia, then you have fluid in at least one of your lungs)."
"It must be that (if you have a fever, then your internal body temperature is greater than normal)."

I am not suggesting that we reform our sentences and learn to speak in this latter, stilted, fashion. What I am suggesting is that when we utter sentences of the form "If so-and-so, then it must be that such-and-such", we understand their underlying logic (in most cases) to be: "It must be that (if so-and-so, then it is such-and-such)."

Finally, we can apply these several logical niceties to the problem of Epistemic Determinism. Let's recall the argument that initiated this current discussion:

ORIGINAL Version of the Argument for Epistemic Determinism

Premise 1: If X knows that you are going to do [some action] A, then you must do A.

Premise 2: But if you must do A, then you have no choice in the matter (i.e. you will not be able to do otherwise than A).

Thus: If X knows (beforehand) that you are going to do A, then you have no free choice (i.e. you will not be able to do otherwise than A).

Or, put another way: Foreknowledge is incompatible with free will.

As should now be clear, the first premise - because of the way we ordinarily state necessary conditions - appears to be true. But if taken literally, at face value, as is being done in this argument, the first premise is false.

If, however, we take some care to express the first premise in a non-misleading way, so that it expresses correctly the underlying logic, then the conclusion above does not follow from the (corrected) premises.

CORRECTED Version of the Argument for Epistemic Determinism

Premise 1: It must be that (if x knows that you are going to do [some action] A, then you will do A).

Premise 2: But if you must do A, then you have no choice in the matter.

Thus: If x knows (beforehand) that you are going to do A, then you will do A.

The supposed problem - that foreknowledge is incompatible with free will - disappears once the logic of the fallacious argument is corrected.

bd-from-kg · 02-14-2003, 12:59 PM

philechat:

Quote:

Since what men prayed for necessary comes out of the man's own will (which is faulty compare to God's), it follows that every God's actions complying to the man's will must already be deemed good in accordance to God's original will for the man.

Not so. God might deem an action good because someone prays for it. More to the point, it might be that He did deem it good because He foresaw that someone would pray for it.

Quote:

Any "change of will" in God in compliance to the man's prayer implies that the original intention of God (considered by God without the man's prayer) to be "less good" than what is asked for by the man in prayer ...

Why do you think that God�s answering a prayer would necessarily involve a change in His will? My point is that it may have been His intention from �before the beginning of time� to answer the prayer, because He knew that answering it would be good, not because the person making the prayer thought that it would be good.

Also, it�s a misconception to suppose that God�s �answering� a prayer would be an �act� in the usual sense. My idea is that His response (if any) to a prayer could be �built in� to His choice of which possible world to instantiate.

Once again I remind you that I don�t believe any of this. I�m a logician. My interest here is only to point out the logical flaws in these arguments.

Amie · 02-14-2003, 01:57 PM

Quote:

Originally posted by sourdough
if you believe that god already predetermined everything that will happen,
wouldn't you say that your prayers/wishes are meaningless!

not meaningless at all. People do not *only* pray when making requests, there are several forms of prayer sourdough. I wish i had the time to get into this right now...

philechat · 02-14-2003, 02:48 PM

Quote:

Not so. God might deem an action good because someone prays for it. More to the point, it might be that He did deem it good because He foresaw that someone would pray for it.

The question is, would God do differently to the man if the man has not prayed for it? Would it be meaningful even to say God would do "what is best for the men because someone prayed for it" if God is not doing anything differently if someone prayed or not prayed?

Quote:

Why do you think that God�s answering a prayer would necessarily involve a change in His will? My point is that it may have been His intention from �before the beginning of time� to answer the prayer, because He knew that answering it would be good, not because the person making the prayer thought that it would be good.

Again, would it imply that God choose to do differently because someone prayed than the (possible) scenerio that if someone had not prayed? Does God have a set of "other" choices to actualize unless he forsees the person's prayer?

Dr Rick · 02-14-2003, 02:57 PM

What point is there in mortals telling/asking an all-powerful, all-knowing god what you think you or others want, need, deserve and/or are thankful for when he already knows what you think you or others want, need, deserve and/or are thankful for?

Rick

Mageth · 02-14-2003, 03:09 PM

Well, Rick, it's kinda like when you make your dog sit or roll over before giving him a biscuit.

bd-from-kg · 02-14-2003, 06:22 PM

philechat:

Quote:

The question is, would God do differently to the man if the man has not prayed for it?

Please remember that I don�t even believe in God. Questions about what God would do if He existed and if some other couterfactual conditions held are getting ridiculously hypothetical. But there is no logical absurdity (or even implausibility) in supposing that He would.

Quote:

Would it be meaningful even to say God would do "what is best for the men because someone prayed for it" ...

Why wouldn�t it be? If what�s best for the man is different because he prayed from what it would be if he didn�t, what�s the problem?

And we can certainly imagine that God�s only concern is not what�s �best� for each individual, but what�s �best� in some more abstract sense. For instance, God might find a world which is more just �better� overall even if the people in it are �worse off� on the whole. How would I know? I merely point out that these are logical possibilities.

Quote:

Again, would it imply that God choose to do differently because someone prayed than the (possible) scenerio that if someone had not prayed?

He might prefer a scenario in which more prayers were �answered� than one in which fewer were. Or He might simply prefer the results, overall, of answering a particular prayer to those of not answering it (or more precisely, he might prefer to actualize world A in which it is �answered� rather than world B where it is not, whereas had it not been for the prayer He would have preferred to actualize world B).

Quote:

Does God have a set of "other" choices to actualize unless he forsees the person's prayer?

Of course. He would have every logically possible alternative to choose from.

diana · 02-17-2003, 06:27 PM

My apologies for taking so long to get back to this. Been busy elsewhere.

Quote:

Originally posted by bd-from-kg
[B](quote from Norman Swartz): Let's look at the first of these: "If Paul has two sons and a daughter, then he has to have at least two children."

The antecedent of this sentence expresses a true proposition. (Paul is my brother and he does have two sons and a daughter.) Thus according to the valid inference rule (known as "Modus Ponens") which allows us to infer the consequent of any true conditional statement whose antecedent is true, we should be able to infer: "Paul has to have at least two children."

Something is clearly amiss. While it is true that Paul does (in fact) have at least two children (he has three), it is false that he has to have three. He doesn't have to have any. He doesn't have to have one. He doesn't have to have two. He doesn't have to have three. He doesn't have to have four. Etc., etc. Put another way: There is no necessity in Paul's having any children, let alone having three. There is no necessity for Paul (just as there is no necessity for anyone else) to have at least two children.

...

Although the following sentences are not especially idiomatic (stylish), they do at least reveal, far better than the preceding three sentences, the correct underlying logic of the claims being made.

"It has to be that (if Paul has two sons and a daughter, then he has at least two children)."

I read through this carefully, and while the latter makes the meaning unmistakeable, I don't see the difference in the meaning between the first and second wordings. In the first, he argues that saying "Paul has to have at least two children" is false, as he doesn't have to have any. This is equivocation of the term "have," which is a mistake I don't see being made in the free will argument. Hence my request for clarification.

Quote:

CORRECTED Version of the Argument for Epistemic Determinism

Premise 1: It must be that (if x knows that you are going to do [some action] A, then you will do A).

Premise 2: But if you must do A, then you have no choice in the matter.

Thus: If x knows (beforehand) that you are going to do A, then you will do A.

The supposed problem - that foreknowledge is incompatible with free will - disappears once the logic of the fallacious argument is corrected.

I've read through this carefully several times, and don't see how rewording the first premise resolves the free will vs. omniscience problem.

Again, please--from anyone who sees this and would like to take a stab at explaining it to me. I'm not seeing it.

Thanks,

d

Amie · 02-17-2003, 07:53 PM

Quote:

Originally posted by Dr Rick
What point is there in mortals telling/asking an all-powerful, all-knowing god what you think you or others want, need, deserve and/or are thankful for when he already knows what you think you or others want, need, deserve and/or are thankful for?

Hi Rick
emotional comfort and expressions of love...

bd-from-kg · 02-17-2003, 11:01 PM

Diana:

Quote:

I've read through this carefully several times, and don't see how rewording the first premise resolves the free will vs. omniscience problem.

Again, please--from anyone who sees this and would like to take a stab at explaining it to me. I'm not seeing it.

What exactly is unclear to you about Swartz�s explanation? He shows clearly that the argument he analyzes is fallacious. It�s possible, of course, that there is some other, valid, argument showing that omniscience is incompatible with free will, though I can�t imagine what it might look like. But if you have one in mind, by all means let�s hear it.

02-14-2003, 02:57 PM	#15
Dr Rick Veteran Member Join Date: Jul 2000 Location: USA Posts: 5,393	Setting gods straight with prayer... What point is there in mortals telling/asking an all-powerful, all-knowing god what you think you or others want, need, deserve and/or are thankful for when he already knows what you think you or others want, need, deserve and/or are thankful for? Rick

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02-14-2003, 03:09 PM	#16
Mageth Contributor Join Date: Jul 2001 Location: Deep in the heart of mother-lovin' Texas Posts: 29,689	Well, Rick, it's kinda like when you make your dog sit or roll over before giving him a biscuit.

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