@Thommo
For Plantinga's appeal to ignorance, see the last paragraph of his original paper
http://mind.ucsd.edu/syllabi/02-03/01w/ ... tinga.html

Note that the statement 'God possibly necessary exists' (in modal logic sense) is much stronger than the empirical statement 'God exists'. So his 'reasonable faith' is nonsense to even Christians.

Shrunk wrote:

byofrcs wrote: We know this though that is why we have the reproducibility of the scientific method. Plantinga is not telling anyone anything new.

Our beliefs about the world around us are always suspect if we have derived these beliefs ourselves. If results can't be reproduced by us or by others then they are suspect. Within an experiment you would repeat tests to see what the margin for error is and between researchers the tests would ideally be duplicated.

Strictly speaking, however, this still does not mean that the conclusions derived from this process are "true." The scientific method simply allows us to generate conclusions that are independent of an individual's subjective impression. And, even though these conclusions have a demonstrated utility in understanding, predicting and influencing the behaviour of entities and processes that we collectively perceive to be real, this still does not mean that they are true. But it also doesn't mean that Plantinga is correct in saying the possibility of their being true is only 50%. In fact, if he is able to assign a probability to it at all, that can only be if he is in fact endowed with the ability to objectively and truthfully perceive reality, an ability that he denies exists!

The real problem with his argument is that he tries to claim that this problem (i.e. of determining whether the conclusions we draw based on our perceptual and cognitive apparatus are true) only arises if one accepts naturalism. I see no reason to justify that claim. In fact, I would go so far and say that if Christianity is true, then we know for a fact that at least some of our perceptions are false. My reasoning: According to Christianity, only God is omniscient and infallible. So if we are created as beings who are lesser than God, we must be wrong in at least some of the things we believe. This should be self-evident to Plantinga, since some of the greatest minds that have ever existed (and which Plantinga believes were created by God) have come to the conclusion that God does not exist.

But I never said they were true - I implied they were just simply the most probable. Plantinga is also applying probability but disingenuously ignores the methods used by science to help us work out what is a more probable view of reality that we can agree on.

Now the magic bit; the materials science that means that you get a better than 50% chance of your car brakes working when you hit them (you probably get a 6-nines i.e. 99.9999% chance of success which means that you can have a belief that is in proportion to that probability) for some reason becomes a worse than 50% chance when the same statistical processes are applied to the subject of the Evolution of species.

That is the incredible bit to me. The cherry-picking of reality to ring-fence the topic of Evolution, which is only a problem with the likes of the more vocal Islamics and American Creationists, so that it suddenly has this special barrier that makes it immune to statistics. He seems to want to couple this one science to humanity so that it is permanently tainted by our subjectivity. He's pulling fast one. Either all science is fundamentally flawed by his magical incantations or none are flawed. He can't just cherry-pick the one his boss says they don't like.

byofrcs wrote: But I never said they were true - I implied they were just simply the most probable. Plantinga is also applying probability but disingenuously ignores the methods used by science to help us work out what is a more probable view of reality that we can agree on.

Now the magic bit; the materials science that means that you get a better than 50% chance of your car brakes working when you hit them (you probably get a 6-nines i.e. 99.9999% chance of success which means that you can have a belief that is in proportion to that probability) for some reason becomes a worse than 50% chance when the same statistical processes are applied to the subject of the Evolution of species.

That is the incredible bit to me. The cherry-picking of reality to ring-fence the topic of Evolution, which is only a problem with the likes of the more vocal Islamics and American Creationists, so that it suddenly has this special barrier that makes it immune to statistics. He seems to want to couple this one science to humanity so that it is permanently tainted by our subjectivity. He's pulling fast one. Either all science is fundamentally flawed by his magical incantations or none are flawed. He can't just cherry-pick the one his boss says they don't like.

He's not trying to argue against evolution. He's trying to argue that, if you accept evolution (which Plantinga does, sort of), then you cannot accept naturalism, because according to evolutionary theory we cannot assume that our minds have evolved to correctly perceive reality. Which is actually true, as far as it goes. Where he trips over his own feet, IIMHO, is in claiming that supernaturalism somehow solves this problem. If our minds were created by God, I don't see why we are any more justified in claiming that they correctly perceive reality.

In any event, I suspect most atheists, myself included, have no interest or investment in defending metaphysical naturalism, which is what I believe he is actually arguing against.

Thommo wrote:

Shrunk wrote:Strictly speaking, however, this still does not mean that the conclusions derived from this process are "true." The scientific method simply allows us to generate conclusions that are independent of an individual's subjective impression. And, even though these conclusions have a demonstrated utility in understanding, predicting and influencing the behaviour of entities and processes that we collectively perceive to be real, this still does not mean that they are true. But it also doesn't mean that Plantinga is correct in saying the possibility of their being true is only 50%. In fact, if he is able to assign a probability to it at all, that can only be if he is in fact endowed with the ability to objectively and truthfully perceive reality, an ability that he denies exists!

That isn't really true, he's denying an objective and truthful perception of reality exists if god does not exist since he believes that god exists, he believes he's justified.

Yeah, you're right. Well caught.

The more important question still remains: How can we know that a truthful perception of reality actually exists, even if we assume God does? I don't get that part of his argument, and I suspect it's because he doesn't actually justify that part. But I welcome corrections if I'm wrong.

Shrunk wrote:
He's not trying to argue against evolution. He's trying to argue that, if you accept evolution (which Plantinga does, sort of), then you cannot accept naturalism, because according to evolutionary theory we cannot assume that our minds have evolved to correctly perceive reality.

I've heard some form of this argument a few times before. But I don't understand it; to my mind it's the other way around: If we're created by a God, then we have no idea what that God decided to do with our perception, or with reality for that matter.

But if a materialistic, evolutionary view is correct, then it would follow - as far as I can see - that the evolutionary process would lead to organs and senses that would have to reflect an actual, real, physical reality outside our bodies quite closely, because if not, our ancestors would not have survived (and also, for the simple reason that our sense receptors react to real world forces and effects, like light, because those effects "hit" our ancestors and some reaction to that in cells was likely to happen). For instance, if there was a 'glitch' along the way, where an animal got eyes that severely distorted its view, or if it's brain gave it a severely distorted impression of what the eyes detected, it would most likely not survive for long and/or mate. But if my thoughts on this are wrong, I'd like to hear that counter argument, so that I don't continue thinking and arguing this.

Shrunk wrote:The more important question still remains: How can we know that a truthful perception of reality actually exists, even if we assume God does? I don't get that part of his argument, and I suspect it's because he doesn't actually justify that part. But I welcome corrections if I'm wrong.

I don't know, it looks circular. The argument is sufficiently silly not to bother with beyond a cursory laugh though.

BKSo wrote:@Thommo
For Plantinga's appeal to ignorance, see the last paragraph of his original paper
http://mind.ucsd.edu/syllabi/02-03/01w/ ... tinga.html

Note that the statement 'God possibly necessary exists' (in modal logic sense) is much stronger than the empirical statement 'God exists'. So his 'reasonable faith' is nonsense to even Christians.

Thanks.

Thommo wrote:

Shrunk wrote:The more important question still remains: How can we know that a truthful perception of reality actually exists, even if we assume God does? I don't get that part of his argument, and I suspect it's because he doesn't actually justify that part. But I welcome corrections if I'm wrong.

I don't know, it looks circular. The argument is sufficiently silly not to bother with beyond a cursory laugh though.

Yeah. Like I said, I think he's really trying to refute metaphysical naturalism, which most people consider an indefensible position anyway, and completely irrelevant. If they think about it at all, that is.

Shrunk wrote:Yeah. Like I said, I think he's really trying to refute metaphysical naturalism, which most people consider an indefensible position anyway, and completely irrelevant. If they think about it at all, that is.

I'm not sure what he's trying to do.

If his argument actually were valid it would prove that the system of human belief formation could not have evolved.

OTOH we can apply the nonsense to itself - say I happen to believe naturalism is correct, which therefore has a 50% chance of being correct by his assumptions.

Arcanyn wrote:The problem this argument shares with all ontological arguments is that it can be used to define into existence literally any being. For example:

1. It is proposed that an entity has a maximal destructive tendency in a given possible world W if and only if it has both the power and the will to destroy everything in W; and
2. It is proposed that an entity has maximal destructiveness if it has maximal destructive tendency in every possible world.
3. Maximal destructiveness is possibly exemplified. That is, it is possible that there be a being that has maximal destructiveness. (Premise)
4. Therefore, possibly it is...(Mick says: edit mistake. See his original statement).
5. Therefore (by axiom S5) it is necessarily true that a being with both the power and the will to destroy everything exists.
6. Therefore, a being with both the power and the will to destroy everything exists.
7. Therefore, nothing exists.

Hi.

Plantinga's argument doesn't define god into existence. Definitions of the intensional sort are conditionals rather than existential assertions. Moreover, it'll do you no good to state that it can be used to argue any being into existence but then only 'show' how it can be used to argue a particular sort of being.

Your counter-argument is puzzling if it is meant to be similar enough to Plantingas. You talk about a tendency which is not found anywhere in Plantingas writing. You also drop the talk about greatness; but this greatness is paramount. Heck, part of the reason why gaunilo's lost island objection fails has to do with the sort of greatness of the greatest conceivable being. A greatness of this sort has a different meaning. Its meaning extends back to anselms time.

Lastly, the conclusion is not strictly a valid inference.


*note* premise 4 is quoted incorrectly. It was an editing error. I can't fix it while I'm on my phone. Please see his original post.

I'm not quite sure what happened there, but your quoting seems a bit off.

Thommo wrote:I'm not quite sure what happened there, but your quoting seems a bit off.

I dunno. Im on my phone. Maybe I messed something up. I'll fix it.

Thanks.

If anyone ends up reading my article on this I want to point out that it needs a rewrite: I went after S5 too harshly, and really should have been clearer that the real issue is thinking that S5 can have any relevance to conventional views of possibility. Plantinga is conflating the two kinds of possibility, by trying to appeal to people's intuitive idea that uncertainty and open mindedness should cause them to accept the possibility of something and then using this as if it were a much stronger statement of modal possibility. The kind of possibility that we may admit to by being open minded is one thing. The kind of possibility we would ever be able to use S5 on is a completely different possibility entirely.

Mick, could you tell me what is wrong with the proof that I will now present, and why whatever is wrong with it isn't also wrong with Plantinga's proof?

I define "pidig" as the sequence of 30 digits that appears one trillion to the power of a trillion to the power of a trillion places after the decimal point in pi (3.141... etc). None of us knows what pidig is, as nobody has computed that many digits in pi. I am going to prove that pidig = 332955209591652908543803809651.

PROOF THAT PIDIG = 332955209591652908543803809651

1. Do you know what the first 30 digits are from the one trillion to the power of a trillion to the power of a trillion places after the decimal point in pi (3.141... etc) are? No? Then you should admit that it is possible that they are 332955209591652908543803809651. Therefore, it is possible that pidig = 332955209591652908543803809651.
(We now have the possibility premise established. Notice that I appealed to nothing more than would be needed to establish Plantinga's possibility that God exists - if you say it is impossible that pidig = 332955209591652908543803809651 I can ask you to prove it - of course you can't, because nobody knows.)

2. There is at least one possible world in which pidig = 332955209591652908543803809651.
(Note that I have taken the rather vague idea that pidig = 332955209591652908543803809651 is possible from 1, and slipped something else in here now - a statement of modal possibility.)

3. But mathematical statements are necessarily true! If something is a mathematical truth in one possible world it must be true in all possible worlds. As pidig = 332955209591652908543803809651 in at least one possible world, this must be the case in all possible worlds. Therefore pidig = 332955209591652908543803809651 in all possible worlds. Putting this another way, it is possibly necessary that pidig = 332955209591652908543803809651, so it is simply necessary that pidig = 332955209591652908543803809651.

4. Therefore, pidig = 332955209591652908543803809651.

and this should be very impressive, because I appear to have just obtained 30 digits of pi, so far downstream of the decimal point that no computer has ever been there or is likely to go there in the foreseeable future without actually doing any calculations.

It should be obvious that what I just did was deeply flawed. So why is it flawed? Furthermore, if you can say why this is flawed (and it shouldn't be too hard - I'll explain if anyone really needs me to), would I then be justified in saying I had established the "rationality" of belief that pidig = 332955209591652908543803809651? Answer: No. I would be talking nonsense. No argument like this can show anything of any interest. It is a hollow game with semantics.

Hi, Paul.

Distinguishing between epistemic and logical possibility is difficult, especially when it matters. as I understand it, something could be logically impossible while epistemically possible. Something else could also be logically impossible and epistemically possible.

Plantinga grants that not everyone who understands and accepts the argument will accept the premise, but that doesn't suggest that it is irrational or contrary to reason for other people to do so. What he aims, therefore, is not that his argument establishes the truth of theism but only its rational acceptability. This is important to keep in mind if not for you than others.

Compare your own argument. You begin by asking if your listener knows that the answer to your particular mathematical question. The listener denies any knowledge of its answer, and then you say that he therefore should accept the possibility of some particular number as the answer.

But wait. Plantinga doesn't proceed in this way. He doesn't ask, even rhetorically, 'do you know whether god exists?' and then also say, 'If not, then you should accept the possibility of His existence.'

Instead, he reflects on that premise alone. He sees it as neither irrational nor contrary to reason to accept. Not only this but it also seems true. He thus accepts it on that basis as a reasonable belief.

This sort of reasoning is absent in your own example.

Moreover, mathematical questions like these are fortunate enough to be determined by methods far more reliable than our modal intuitions and the like. Even if we were to grant that fellow reasonable acceptance of the conclusion, we could then turn to our trusty calculators or do a proof to help ensure ourselves. In contrast, our modal judgements are rarely so privileged. Despite this poverty, we need to rely on them; and so perhaps we should rely on them with a commitment which doesn't exceed rational acceptability. In his case, that's exactly what Plantinga does.

Mick wrote:Hi, Paul.

Distinguishing between epistemic and logical possibility is difficult, especially when it matters. as I understand it, something could be logically impossible while epistemically possible. Something else could also be logically impossible and epistemically possible.

Plantinga grants that not everyone who understands and accepts the argument will accept the premise, but that doesn't suggest that it is irrational or contrary to reason for other people to do so. What he aims, therefore, is not that his argument establishes the truth of theism but only its rational acceptability. This is important to keep in mind if not for you than others.

So who should give a fuck, then? All that obscure and inscrutable verbiage, just to demonstrate that an idea as plastic and vaguely defined as "god" is not rationally unacceptable? Who cares? Why doesn't he just say up front "I make no claims that what I'm about to say demonstrates that god exists. It only demonstrates that god might exist." Then the vast majority of readers could just skip over the whole thing, knowing that they haven't missed anything of the remotest significance.

I mean, does this happen in any discipline other than philosophy? Are there historians who have become known as major figures in their field for showing that it's not impossible that Julius Caesar was from Venus? Do they give out the Nobel Prize in medicine to someone who shows that it can't be said that cranberry juice isn't a cure for AIDS?

When someone doesn't admit defeat at logical impossibility, it's time to walk away. That means that you have quite literally proved their assertion false by the strictest possible rules and they still refuse to admit defeat. There's nothing that you can't say by those rules.

It's time to just walk away. Let the philososaurs roam their corridors, they'll go extinct in the end.

Mick wrote:Hi, Paul.
Distinguishing between epistemic and logical possibility is difficult, especially when it matters. as I understand it, something could be logically impossible while epistemically possible. Something else could also be logically impossible and epistemically possible.

A proposition is epistemically possible iff its truth is consistent with our body of knowledge. Propositions representing a logically impossible state of affairs are known to be necessarily false, and therefore aren't epistemically possible. That is, given our logical knowledge, the truth of such propositions is ruled out.

Teuton wrote:
A proposition is epistemically possible iff its truth is consistent with our body of knowledge. Propositions representing a logically impossible state of affairs are known to be necessarily false, and therefore aren't epistemically possible. That is, given our logical knowledge, the truth of such propositions is ruled out.

Hi, Teuton.

Consider your first sentence. What group of persons does the word our refer to? Is there some sort of social matrix of knowledge for which we are all tapped into or....? Please explain. Furthermore, I'm a bit puzzled with the role you attribute to consistency. Neglecting the point that there are inconsistent interpretations of consistency, you offer no conditional of awareness. It's far from obvious that we need to be aware of a proposition's inconsistency with "our" body of knowledge. This being so, if p's truth were inconsistent with our body of knowledge and we did not know it (we are not logic machines), I'm puzzled as to why it'd be called an epistemic possibility.

So far as my education goes, I've been taught something similar to this:

Φ is epistemically possible for a subject S if and only if Φ is not ruled out by what S knows.
Example: Given everything James knows, it is possible that Frank is out of town.

http://plato.stanford.edu/entries/modal ... stemology/

Here we have the use of a particular person, S. But, like you, this whole "ruled out by what S knows" is vague. It seems to assume internalism.

Consider your second sentence:

Propositions representing a logically impossible state of affairs are known to be necessarily false,

This is puzzling. I think it relies on some sort of antirealism. If we are realists, or at least if we use so-called common sense, we should grant that there are logically impossible states of affairs which we do not know about.

This is puzzling. I think it relies on some sort of antirealism. If we are realists, or at least if we use so-called common sense, we should grant that there are logically impossible states of affairs which we do not know about.

Wait .....what ? common sense =/= logical possibility .
And maybe you get teuton backward ,he simply state that the logically impossible state of affair can be known since it doesn't exist at all , you know it's called "to fail". it's not because you believe it's true that we are going to rank your belief to knowledge even if you say so .