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neopolitan

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Criticism of Plantinga
« on: January 28, 2013, 01:10:50 am »
I'd like to be as polite as possible, so I should point out that I am a fan of neither Doctor Craig, nor Professor Plantinga.  That said, Dr Craig often goes out of his way to discuss his case with people who disagree with him.  I am doing the same sort of thing here and would appreciate being given the same level of courtesy he is offered.  My thanks in advance for your forbearance.

I find Professor Plantinga's arguments to be particularly weak, as I've outlined here in an article about his tiger problem.  His Ontological argument (as portrayed by Dr Craig) is more than weak, it's deceptive in its misuse of logical forms.

What I'd like to ask is, have people here actually sat down and thought these arguments through carefully, after doing so do you still think they are strong and valid arguments and, outside of a debate format, can you provide a convincing case why a) Plantinga isn't mistaken about his tiger and b) why his misuse of logic is acceptable.  The logic question is quite specialised, so if you only feel confident addressing the tiger, I fully understand.

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Geneticist

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Re: Criticism of Plantinga
« Reply #1 on: January 28, 2013, 01:55:37 am »
I didn't get much farther than this:
Quote
Scientists like to use something around 99.9999% certain, while theists (like Craig and Plantinga) like to use something above 50%.

This is an obvious strawman. You claim Craig and Plantinga use >50% as the level at of determining truth. In your previous post, you make this argument citing as evidence the debate between Craig and Krauss. In that debate Krauss accuses Craig of exactly the same thing you have done (I wonder if that is where you got your argument?) but then apparently failed to read Craig's rebuttal where he clearly refutes this accusation:

"
I realized from the start that the question proposed for debate was unusual in that it did not ask whether God exists, but merely whether there is evidence for God. So what does it mean to say that there is evidence for the hypothesis that “God exists”? Probability theory defines this as saying that the probability of God’s existence is greater given certain facts than it would have been without them (Pr (G | E & B) > Pr (G | B)). Far from being “meaningless,” this construal of the question under debate should be non-controversial. Moreover, it does not presuppose a frequency model of probability, as Dr. Krauss seems to assume. Dr. Krauss seems to think that I was arguing on the basis of the above that the probability of God’s existence is greater than 50% (Pr (G | E & B) > 0.5). But I explicitly said in my opening statement that I would not be discussing that probability. For that would involve assessing the so-called prior probability Pr (G | B) of God’s existence given the background information alone, thereby turning the debate into a debate over God’s existence, which was not the topic. Dr. Krauss seems to think that the prior probability of God’s existence is very low. I happen to disagree; but that assessment was irrelevant to our debate topic that evening.
Craig makes it explicitly clear that he is not arguing that >50% is all that one needs to be certain that God exists. In fact he even states he is not arguing that God exists. All he is arguing for is that there is evidence for God's existence and that the criteria that something count as evidence is that it it makes it more probable than not.....in other words raise the probability above 50%. If something increases the probability to 51%, its evidence. You have profoundly misrepresented Craig's argument, presenting instead an obvious strawman which you proceed to attack.

As an aside, there are no absolute levels of certainty in science. I see in your previous post that you used the reporting measures from the those who work on the Higgs Boson from which you make a hasty generalization about the acceptable level of probability used in science. You might pick up some papers from evolution or psychology (seeing as they are the most relevant fields to this topic) because, there, the convention is to use a p-value of less than or equal to 0.05 (95%), which is certainly not 99.9999%. Why 0.05? Well because that is the cutoff Fisher chose back in the day. Its a completely arbitrary cutoff and it is what the vast majority of all published research uses. You will find papers that use even less stringent cutoffs. Its all very arbitrary. The physicists at CERN just happen to be making a Nobel winning announcement that has cost taxpayers billions, so its not surprising they went with higher p-values.

« Last Edit: January 28, 2013, 01:58:52 am by Geneticist »

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Geneticist

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Re: Criticism of Plantinga
« Reply #2 on: January 28, 2013, 02:23:12 am »
I also can't get past the completely irrelevant (not to mention incorrect) jabs you take at Plantinga. For instance this:

"Note here that prehistoric hominids could arguably include humans since there were preliterate humans who were not able to write down history, there is a possibility that there were early humans who did not have a language that was sufficiently rich to convey history and there were certainly early humans who had no real history to convey.  However, if Plantinga meant to imply that Paul is pre-human hominid, then one might wonder why he is worried about tigers at all, tigers never having lived in Africa.  To be as fair as possible, let’s assume that the “tiger” is really a large cat-like thing with a taste for prehistoric hominid flesh."

....this is really quite irrelevant. Plantinga is making an analogy and analogies do not need to be 100% historically accurate, but since you went out of your way to criticize Plantinga on this, I should point out that you are wrong historically. Prehistoric hominids were not isolated to Africa. The Neanderthals lived throughout Europe and parts of Asia. The Denisovans and Homo Erectus both were found in Eastern Asia. The first Homo Sapians out of Africa were pre-literate and they spread throughout all this range and doubtless would have encountered tigers.

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neopolitan

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Re: Criticism of Plantinga
« Reply #3 on: January 28, 2013, 02:58:08 am »
Prehistoric hominid is a sufficiently vague term that I can use it to mean what I like, unless the person using it explains what he means.  And Professor Plantinga didn't.  I chose to use it for humour.

You are correct in saying that pre-literate humans would have met tigers.  Not in particularly good circumstances perhaps.  You are also correct in that some of our non-human hominid cousins would have met tigers.  But, I think that Plantinga is specifically talking about what led us to thinking about evolution, so you have to include Darwin in that chain, and I doubt that his forefathers had travelled via East Asia.

I fully accept that I might wrong on that.

Edit: That all said, you haven't addressed the key point.  Have you sat down and thought through Plantinga's arguments, if so do you still think they are strong and valid and if so, why?

With regard to the tiger, it's not so much that he might have been wrong about the species, or the location in which prehistoric hominids might need to ponder the dining habits of tigers, but that our ancestors might have easily done the right thing to avoid tigers without having any rational thought process or cognition process preceding it.
« Last Edit: January 28, 2013, 03:35:32 am by neopolitan »

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neopolitan

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Re: Criticism of Plantinga
« Reply #4 on: January 28, 2013, 03:44:42 am »
This is an obvious strawman. You claim Craig and Plantinga use >50% as the level at of determining truth. In your previous post, you make this argument citing as evidence the debate between Craig and Krauss. In that debate Krauss accuses Craig of exactly the same thing you have done (I wonder if that is where you got your argument?)

Nope, but I applaud Krauss for picking up Dr Craig on what he does.

I put a lot more effort into Dr Craig's probability arguments in Sweet Probability.  In this article, I show that his use of the equation that he is relying on is poor.

My question was about Professor Plantinga, and I notice that you haven't addressed it.  Could you possibly do so?  Thanks.

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Geneticist

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Re: Criticism of Plantinga
« Reply #5 on: January 28, 2013, 11:04:53 am »
Prehistoric hominid is a sufficiently vague term that I can use it to mean what I like, unless the person using it explains what he means.  And Professor Plantinga didn't.  I chose to use it for humour.

You are correct in saying that pre-literate humans would have met tigers.  Not in particularly good circumstances perhaps.  You are also correct in that some of our non-human hominid cousins would have met tigers.  But, I think that Plantinga is specifically talking about what led us to thinking about evolution, so you have to include Darwin in that chain, and I doubt that his forefathers had travelled via East Asia.

I fully accept that I might wrong on that.

Edit: That all said, you haven't addressed the key point.  Have you sat down and thought through Plantinga's arguments, if so do you still think they are strong and valid and if so, why?

With regard to the tiger, it's not so much that he might have been wrong about the species, or the location in which prehistoric hominids might need to ponder the dining habits of tigers, but that our ancestors might have easily done the right thing to avoid tigers without having any rational thought process or cognition process preceding it.

You missed the real point....that this is an irrelevant criticism. What it is, is an attempt to discredit Plantinga to the readers of your blog, even though the criticisms are not relevant to the validity of his argument. Humour is fine, except when humour is used as a red herring, which is the real point of your humour.

I honestly don't even get what this statement means or why its relevant:

"But, I think that Plantinga is specifically talking about what led us to thinking about evolution, so you have to include Darwin in that chain, and I doubt that his forefathers had travelled via East Asia."
 
I understand the relevance of Plantinga's analogy. I was taking issue with the red herrings you consistently toss in your blogs. Plantinga is right, per Naturalistic Evolution, it is not necessary for man to possess rational thoughts regarding his actions. All that matters is that those actions perpetuate survival of the individuals genetics. Most life forms do exactly this, they react to their environment without rational thought. A plant will move and grow towards the light, though it is incapable of reasoning "I should move towards the light".

Certainly his list of possible explanations are incomplete and sometimes silly, but considering that this is an analogy, that is all that is necessary to clarify the point and that is what Plantinga is doing, using analogy to clarify the issue. A lot of your counter argument gets lost in the red herring of mocking this analogy.

I honestly think Plantinga makes a very valid point. Evolution will not necessarily favor rational thought. It favors reproductive success. Rational thought can contribute to reproductive success, but that does not mean it is the only viable strategy and if incorrect beliefs lead to reproductive success, then they too will perpetuate. Where I differ with Plantinga is that I am uncertain as to what the probability that Evolution would favor this over rational thought would be. I don't discount that he could be right about the probability, I certainly agree with how he describes the relationship between Evolution and correct belief, I just am uncertain about the actual probability and that is the weakness of his argument.

The kicker is, that if we assume Naturalism, then we actually have very strong evidence for Plantinga's argument. If Naturalism is true, then all Religion is false. Assuming Naturalistic Evolution, then religion is a clear example of false beliefs that exist to promote survival in some fashion. So we know with certainty that we have reason to doubt our cognitive abilities given Naturalistic Evolution. But since Religion is not limited to individuals, but is pervasive throughout a group, then this same reason to doubt individual cognitive abilities extends to the group.

Hominid, FYI, is a term that typically includes Neanderthals, Denisovans, Homo Erectus, and even older ancestors.
« Last Edit: January 28, 2013, 11:57:04 am by Geneticist »

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Geneticist

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Re: Criticism of Plantinga
« Reply #6 on: January 28, 2013, 11:19:20 am »
This is an obvious strawman. You claim Craig and Plantinga use >50% as the level at of determining truth. In your previous post, you make this argument citing as evidence the debate between Craig and Krauss. In that debate Krauss accuses Craig of exactly the same thing you have done (I wonder if that is where you got your argument?)

Nope, but I applaud Krauss for picking up Dr Craig on what he does.

I put a lot more effort into Dr Craig's probability arguments in Sweet Probability.  In this article, I show that his use of the equation that he is relying on is poor.

My question was about Professor Plantinga, and I notice that you haven't addressed it.  Could you possibly do so?  Thanks.


I read that post earlier and it is irrelevant to this particular case. The calculation of probability Craig does regarding the resurrection is quite distinct from what he does in his debate with Krauss, where he is merely giving a definition of evidence. Seeing as you reference the Krauss-Craig debate as the source of your "anything above 50%" claim and given that this is a strawman of what Craig said in that debate, this other post is another red herring (specifically poisoning the well) as it relates to your post on Plantinga's argument.

I think your specific arguments in that post are flawed as well. For instance, I disagree that in talking about the resurrection, one is talking about the intersection of background and specific evidence, rather than both background and specific evidence. In this the analogy of the jelly beans is misleading. If we were to consider a murder case, where the suspect is known to be a violent individual, that background evidence sits independent of the specific evidence that his hands are found on the gun. Because if we were to change the background information to the suspect being a kind and loving pacifist, the evidence of his finger prints on the gun still supports that he did the murder, even if it does not intersect with the background. The background and specific evidence add together to make the case more or less likely, but individually they can also make the case more or less likely. So we are talking about a broader inclusion than the mere intersection of the two. The jelly bean analogy, does a very poor job of modeling the background and specific evidence in its calculations, if it does it at all.
« Last Edit: January 28, 2013, 11:56:17 am by Geneticist »

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neopolitan

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Re: Criticism of Plantinga
« Reply #7 on: January 29, 2013, 03:53:20 am »
Hi Geneticist,

You seem to be keen on the straw-man, since your posts have focussed on that accusation almost to the point of totally excluding everything else, for example considerations as to whether Plantinga’s arguments are sound.  So I’ve had a good look to see if either of us has committed that fallacy.

Accusation: the “scientists use 99.9999% while Professor Plantinga and Doctor Craig use 50%” argument is a strawman

Response: for the sake of background, if anyone else is reading, I make reference to the certainty that scientists need before they say something is likely to be true, an example being when they announced results for the Higg’s Boson for which the level of certainty was 99.9999% in Planting a Demigod.  In that article, I said “Craig indicates that he is setting out to show that the likelihood of god (given specific evidence and background evidence) is greater than 50%, implying that when any statement is more than 50% probable then it is somehow equivalent to a truth statement”.
Now what Doctor Craig actually said was (from the same transcript that you quoted to me):

Quote from: Doctor Craig's debate with Krauss
Now at one level it seems to me indisputable that there’s evidence for God. To say that there’s evidence for some hypothesis is just to say that that hypothesis is more probable given certain facts than it would have been without them. That is to say, there is evidence for some hypothesis H if the probability of H is greater on the evidence and background information than on the background information alone. That is to say,

Pr (H | E & B) > Pr (H | B).
H = hypothesis
E = evidence
B = background information

Now, in the case of God, if we let G stand for the hypothesis that God exists, it seems to me indisputable that God’s existence is more probable given certain facts—like the origin of the universe, the complex order of the universe, the existence of objective moral values, and so forth—than it would have been without them. That is,

Pr (G | E & B) > Pr (G | B).
G = God exists
E = existence of contingent beings, origin of the universe, fine-tuning of the universe, etc.
B = background information

And I suspect that even most atheists would agree with that statement.
So the question “Is There Evidence for God?” isn’t really very debatable. Rather the really interesting question is whether God’s existence is more probable than not. That is, is

Pr (G | E & B) > 0.5 ?

Now I’ll leave it up to you to assess that probability.

So, sure, Doctor Craig was not explicitly saying >50% = truth, but neither was he saying “for us to accept than anything is true we need to have a high level of certainty, and being cognizant of the fact that any certainty we allocate is going to be arbitrary, I will use the best practice for my field and use X% as being the minimum acceptable certainty”.  If we say that apologetics and theology is as “soft” as psychology, then we could make X=95.  I’d be happy with that (although still not happy with his abuse of probability as discussed in Sweet Probability).

But am I guilty of setting up a straw man?  With respect to Doctor Craig, no.  I wasn’t really talking about Doctor Craig, I was talking about Professor Plantinga.  Professor Plantinga repeatedly uses the “about half” or “about 50%”.  I’ve heard him say it in a number of debates and discussions, he makes an oblique reference to it in an EAAN lecture and he uses it in the video linked here and he uses it a few times in his debate with Daniel Dennett.
If I was guilty of anything, I was guilty of not referencing Professor Plantinga’s repeated use of the 50% argument.

Even if you successfully argue that I inadvertently tarred Doctor Craig with Professor Plantinga’s brush, you still have to prove that Doctor Craig did not intentionally sow the seed of the 50% argument in his debate with Krauss.  I personally think he did, but I can’t prove it, so I don’t make the claim, I merely advise what I think is likely to be the case.

---------------------------------------------------

I did say “almost to the point of excluding everything else”, because you also wanted to focus on the fact that hominids in general might have met tigers.  I grant you that, tigers may well have tried to eat hominids who are related to the sorts of people who may well have come up with a natural selection theory (for example, in a slightly alternative universe in which Darwin didn’t do it).  For someone who also is keen on accusations of red herrings, you like to run off down side alleys a lot.

The major problem with Professor Plantinga, as you aptly point out, is that he uses probabilities that are questionable.

Quote from: Geneticist
Rational thought can contribute to reproductive success, but that does not mean it is the only viable strategy and if incorrect beliefs lead to reproductive success, then they too will perpetuate. Where I differ with Plantinga is that I am uncertain as to what the probability that Evolution would favor this over rational thought would be. I don't discount that he could be right about the probability, I certainly agree with how he describes the relationship between Evolution and correct belief, I just am uncertain about the actual probability and that is the weakness of his argument.

Note that you are questioning his probability calculus, by definition making his probabilities questionable, and I do the same thing.  All we differ on is the extent to which we disagree with him.  You think it is a defect which makes his argument weak, while I think it is a fatal flaw which makes his argument ridiculous.

Something which we all agree on is that humans are more than capable of holding false beliefs, which may be evolutionarily advantageous.  What we differ on is 1) whether all religions are just advantageous false beliefs and 2) whether evolution qualifies as “a belief”.

Natural evolution may well be true (that is some variant of it), irrespective of how poor our individual understanding of it may be.  Individually, we may all be more than 75% wrong in our comprehension of it and that won’t necessarily make evolution a less correct explanation of how we got here than a god hypothesis.  We don’t have to individually hold a true belief with respect to evolution, the understanding that we have is a joint effort.

And one of the revolutionary things about evolution is that, when combined with natural selection, it makes the creator hypothesis unnecessary.  This is why Professor Plantinga is willing to make the sort of wild claims he does, because evolution is a clear threat to his belief.

Edit, I had a quick look to see if I had accused you of presenting a straw man.  I can't see where I did so.  However, even if you did present a straw man, pointing it out would effectively be a straw man in itself, since the thread is about Plantinga's arguments, not your arguments in support of Plantinga nor your arguments against my criticism of Plantinga.  So, I've decided not to get into that.
« Last Edit: January 29, 2013, 04:47:42 pm by neopolitan »

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DavidRandall

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Re: Criticism of Plantinga
« Reply #8 on: April 22, 2014, 10:27:48 pm »
This discussion went stale pretty quickly, but I'll take a shot at some of your questions:

Q: have people here actually sat down and thought these arguments through carefully?
A: Yes
Q: do you still think they are strong and valid arguments?
A: Yes
Q: can you provide a convincing case why Plantinga isn't mistaken about his tiger?
A: Not enough information. Convincing to who? If you mean convincing to you, then probably not.
Q: why his misuse of logic is acceptable?
A: Nice one. I see what you did there.  ;) If I say yes, then I admit that he misuses logic, and that I believe misusing logic is acceptable. If I say no, then I admit that his argument cannot be defended. So I'll just have to say the answer is orange.

I hope my answers were as polite and the questions.
« Last Edit: April 22, 2014, 10:31:33 pm by DavidRandall »

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neopolitan

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Re: Criticism of Plantinga
« Reply #9 on: April 23, 2014, 02:15:17 am »
Hello Mr Randall,

Thanks for your reply.  The tiger is orange.  A coincidence?  I think not.

As to you saying that there is not enough information to comment on Plantinga's tiger, there are links provided with information.

That's the difference between theists like yourself and atheists like me.  I will research my topic before responding, especially if I am going to tell someone that there is insufficient information.

I doubt that there will be profitable debate between us, but again, thanks for your reply.

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Nightvid Cole

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Re: Criticism of Plantinga
« Reply #10 on: July 15, 2014, 06:58:54 pm »
I'd like to be as polite as possible, so I should point out that I am a fan of neither Doctor Craig, nor Professor Plantinga.  That said, Dr Craig often goes out of his way to discuss his case with people who disagree with him.  I am doing the same sort of thing here and would appreciate being given the same level of courtesy he is offered.  My thanks in advance for your forbearance.

I find Professor Plantinga's arguments to be particularly weak, as I've outlined here in an article about his tiger problem.  His Ontological argument (as portrayed by Dr Craig) is more than weak, it's deceptive in its misuse of logical forms.

What I'd like to ask is, have people here actually sat down and thought these arguments through carefully, after doing so do you still think they are strong and valid arguments and, outside of a debate format, can you provide a convincing case why a) Plantinga isn't mistaken about his tiger and b) why his misuse of logic is acceptable.  The logic question is quite specialised, so if you only feel confident addressing the tiger, I fully understand.

Yes, I had a long discussion/debate with Tisthammerw on the evolutionary argument against naturalism here on the old RF forums:

http://rfforum.websitetoolbox.com/post/Evolutionary-Argument-Against-Naturalism-4979750?trail=587

I think s/he never addressed my probabilistic rebuttal and just claimed that I didn't address the argument even though the argument relied on the fact that the mere possibility of what was referred to as "ANPD devices" was supposed to make Pr(RA|N&E) low or inscrutable, and I showed mathematically that possibility isn't good enough, it must be *probable* (that is, Pr(X|N&E) must be high or inscrutable). Thus I did address the argument.

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neopolitan

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Re: Criticism of Plantinga
« Reply #11 on: July 15, 2014, 07:45:12 pm »
It looks like there was a lot of plummeting down rabbit holes in that thread, a technique that apologists seem to be quite fond of.  Drug XX, two types of mad scientist, plus a Matrix reference or two.  Um, what was the topic again?