Friday, December 10, 2010

Reply to David Parker on Bayesianism and Trajectory of Science Arguments

David Parker has noticed my commitment to a subjectivist Bayesian model of belief acceptance. I should add what Monty Python said about Camelot: "It's only a model!" However, I don't see a better one. I believe in openness to evidence, but I don't believe in neutral perspectives. I believe in rationality, but I don't believe in artificial standards of rationality. And I certainly don't believe that people should claim to have achieved objectivity when they really are far from that lofty goal.

Parker wonders if my commitment to a Bayesian model of evidence commits me to the idea that all evidence is physical evidence, and hence will have to support physicalism by definition. I don't see why. Why these constraints? With Richard Swinburne, I see no good reason to suppose that there can't be evidence for theistic hypotheses. If I physically observe someone alive on Thursday, dead on Friday, and alive again on Sunday, that is prima facie evidence for the claim that that person was resurrected supernaturally from the dead. It is what I should expect if there was a resurrection, and what is very puzzling on the assumption that there was no resurrection. Now, I might, on further investigation, decide that indeed there was no resurrection, but the idea that I must rule a supernatural resurrection out from the outset strikes me as absurd. Or, to use my favorite example from atheist philosopher Keith Parsons, if the galaxies in the Virgo Cluster were to spell out the words "Turn or Burn! This means you, Parsons," then I suspect we have evidence that strongly confirms the claim that a deity exists who is threatening my atheist philosopher friend with eternal perdition.

I am unpersuaded of "trajectory of science" arguments which suggest that as we investigate further we will find greater and greater support for reductionism. Two aspects of the materialistic vision of the world as it has been historically understood are the following:

1) The universe had no beginning, and has always existed.

2) The universe is deterministic, and as we do science we will come closer and closer to finding determining causes for everything.

Now, thanks to the development of the Big Bang theory in the first instance, and quantum mechanics in the second instance, confidence in both of these theses has eroded in comparison to what might have been thought in the early days of the 20th Century.

Now, of course, naturalists have revised their conception of what is naturalistically acceptable to accommodate a universe with a temporal beginning, and a universe with quantum level indeterminism. But the point is that science frustrated the expectations of what at the time were the expected results of the naturalistic thrust of science, as it was understood at that time. This gives me some serious doubts about the idea that we can predict that the future of science will confirm physicalism, as we now understand it.

With respect to the analysis of mind, I see a lot of bravado about reductive analyses but no real hard evidence that reductions are going to be successful. In fact, given the fact that "the material" or "the natural" has to be defined in terms of the absence of the mental, it looks to me as if reduction of the mental to the physical is logically impossible, and that the more we study things scientifically the more evident this will become.

26 comments:

Mr Veale said...

Are we back to the "this isn't how I use Bayes in my day job!" objection?

1) We do, typically, have degrees of belief in various propositions. For example, we can consider what we would wager on a proposition

2) "Subjective"* probabilities are used profitably in Bayesian networks for risk analysis, and other expert systems.

3) And apart from observed frequencies, there are other objective data that can be used - simplicity, scope etc.

4) Dr Reppert has drawn attention to the reference class problem. Some degree of subjectivity seems inescapable.

Graham

*I'm using "subjective" very, very loosely. It can mean different things to different Bayesians.

Blue Devil Knight said...

it looks to me as if reduction of the mental to the physical is logically impossible

You really think it is logically impossible? What principle of logic would it violate if consciousness were a brain process? What's your rationale for this extremely strong claim?

Brenda said...

"If I physically observe someone alive on Thursday, dead on Friday, and alive again on Sunday, that is prima facie evidence for the claim that that person was resurrected supernaturally from the dead."

Not really. It's evidence that something went terribly wrong. What is most likely is that you made a mistake along the way. We live in one world. Any new evidence in our world should fit in with what we already know. We know a good deal more than people did 2000 years ago. So if today someone saw someone they knew alive one day, attended their funeral the next, then saw them alive gain later. Their first inclination would be to doubt what they saw. This seems reasonable to me. Believing that your friend was risen from the dead with no further evidence seems unreasonable.

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

There are interpretations of quantum mechanics that are fully deterministic.

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

" In fact, given the fact that "the material" or "the natural" has to be defined in terms of the absence of the mental"

Descartes legacy is very pernicious. It is a mistake to divide up the world into two realms, the mental and the physical. This was really a political move, a truce, so that religion and science could live together and investigate their respective spheres without being at war all the time. But there is a real problem with dualism. There seems to be no way for the mental to ever influence the physical and vice versa. So the religious minded tended towards denying the physical. All out experiences are really mental, says Idealism, matter is an illusion. Materialism just reverses that. It says that the mental or subjective reality is all an illusion.

The mistake was to divide up the world in the first place.

We live in one world. A world that is neither wholly material nor mental. A world in which consciousness is a higher level feature of matter. It is entirely the product of the activity of neurons in our brains and yet not reducible to it.

Alex Dalton said...

Brenda: Any new evidence in our world should fit in with what we already know.

Alex: Putting aside the fact that there is great disagreement regarding "what we already know", why *should* new evidence fit in with what we already know?

Brenda said...

"why *should* new evidence fit in with what we already know?"

Because if it did then that would mean that the universe is inconsistent with itself and hence fundamentally irrational.

Victor Reppert said...

Brenda: Because if it did then that would mean that the universe is inconsistent with itself and hence fundamentally irrational.

VR: Assuming the absence of God, the world is irrational, and this should not be the least bit surprising. Only our "animal faith" that the future will resemble the past keeps us from seeing this.

Anonymous said...

Because if it did then that would mean that the universe is inconsistent with itself and hence fundamentally irrational.

And the universe is supposed to be rational because...? I can see why a theist would say this. An atheist, or especially an agnostic?

But the theist wouldn't say it's irrational for a man to rise from the dead either. You may as well say we should reject quantum physics because it goes against Newtonian physics. But Newton went against contact mechanics, and...

Victor Reppert said...

BDK: You really think it is logically impossible? What principle of logic would it violate if consciousness were a brain process? What's your rationale for this extremely strong claim?

VR: This is what I think, in the final analysis, will prove to be true. I think that so long as you are starting with non-mental facts, there will never be an entailment of mental facts, without "the mental" being slipped into the base through the back door. I think that attempts to naturalize intentionality, a la Dretske, are complex and sophisticated attempts to square the circle. It's really transparent in people like Carrier and, actually Dennett, but all you get with everyone else is going to just be better concealment of the fallacy.

But while I think reduction is logically impossible, I don't think it is transparently so. But that is what I think a thorough investigation of the matter will eventually yield.

Walter said...

VR..."If I physically observe someone alive on Thursday, dead on Friday, and alive again on Sunday, that is prima facie evidence for the claim that that person was resurrected supernaturally from the dead."

Brenda...Not really. It's evidence that something went terribly wrong. What is most likely is that you made a mistake along the way.

I gotta go with Brenda on this. If I saw someone walking around a day or two after his funeral, my first thought would be that the guy had a twin brother, or another person who happens to look a whole lot like the truly deceased. I would believe in an unnatural resurrection "event" only if I had personally verified that the person was truly dead for several days, and that this was the same person now found alive. I would not believe second or third-hand stories of this event written decades later. Like the disciple, Thomas, I have to check for myself!

Anonymous said...

Like the disciple, Thomas, I have to check for myself!

Statements about your personal psychology are of interest to who? Brenda at least spoke (incorrectly) of what such reports would be evidence of. PZ Myers your way into saying "I'd never believe! There'd always have to be a natural explanation!" if you wish, but as with PZ, it says little about reason, more about psychology when it's simply "what I'd do".

Walter said...

PZ Myers your way into saying "I'd never believe! There'd always have to be a natural explanation!"

You will note, AnonyMOUSE, that I did not say that I would never believe. Try to read more carefully, or refrain from commenting if my posts are of no interest to you.

Blue Devil Knight said...

Victor that seems different from saying it is logically impossible. If it were logically impossible we should be able to see that a priori, no?

Alex Dalton said...

Brenda wrote: Because if it did then that would mean that the universe is inconsistent with itself and hence fundamentally irrational.

Alex: Well, we could ask why the universe must turn out to be "rational" or "consistent" by our standards of thinking (this seems more like a theistic view of the world). But putting that aside, it simply doesn't follow that "new evidence" that doesn't fit in with what we already know, would entail inconsistency or irrationality in any way. Throughout the history of science, "new evidence" has often radically altered our scientific theories about how the world actually operates. Unless we suppose that current theories are absolute, there should be no fear of dis-confirming or anomalous evidence. But such an absolutist assumption about current scientific knowledge is very unscientific. Indeed, the scientific enterprise (in contrast to popular skepticism) is better conceived as an attempt to dis-confirm even and especially that which we think we know.

Brenda said...

Victor Reppert said...
"Assuming the absence of God, the world is irrational, and this should not be the least bit surprising. Only our "animal faith" that the future will resemble the past keeps us from seeing this."

I don't see how in the absence of god the world must be irrational. I don't see the need for a Law Giver and I don't see how animal faith prevents us from seeing that without a god the world must be irrational.

The universe just is what it is and it behaves the way it behaves. We humans come along and then we describe how it behaves but the fact that it behaves the way it does is an objective fact that is independent of us.

DL said...

"Brenda" said: What is most likely is that you made a mistake along the way.

It's true... I originally though "Brenda" was a real person. Of course, good parodies are tricky, and should not be too obvious; you have to be believably outrageous, but without simply lapsing into annoyingness.

"Brenda": Any new evidence in our world should fit in with what we already know.
"Brenda", the immediately following sentence: We know a good deal more than people did 2000 years ago.

At least the pretend-trolls are more amusing than the real ones.

A world that is neither wholly material nor mental. A world in which [everything is] matter.

See what I mean?

Brenda said...

Alex Dalton said...
"Well, we could ask why the universe must turn out to be "rational" or "consistent" by our standards of thinking"

Some people believe that we impose meaning onto the universe and the it is fundamentally chaotic. I think Nietzsche held this view. I believe this is wrong. I believe that the world exists independent of our interests, that there is a way it is that does not depend on our thoughts.

"it simply doesn't follow that "new evidence" that doesn't fit in with what we already know, would entail inconsistency or irrationality in any way."

This is true but it also doesn't mean that we should accept that new evidence without investigation. New evidence that is greatly at odds with what we already know needs to be explained.

Supernatural explanations are not explanations because "supernatural" is a broken concept, it makes no sense. Like "immaterial" it is an eliminative negative term which does not refer to anything. Both are meaningless and incoherent.

Alex Dalton said...

Brenda: Some people believe that we impose meaning onto the universe and the it is fundamentally chaotic. I think Nietzsche held this view. I believe this is wrong. I believe that the world exists independent of our interests, that there is a way it is that does not depend on our thoughts.

Alex: Thanks for sharing your beliefs. None of this, however, supports anything you said. No one is denying the existence of the external world, or that there is a "way it is". Why must the external world conform to your notion of "rational" and "consistent"? To give an example: at present, two of our most rigorous and widely areas of science - Quantum Mechanics and General Relativity - are seen to be inconsistent by some of our greatest living scientists. What justifiable principle (not asking for a belief here) leads you to believe we will eventually have a rational consistent reconciliation of these fields of research?

Brenda: This is true but it also doesn't mean that we should accept that new evidence without investigation. New evidence that is greatly at odds with what we already know needs to be explained.

Alex: No one said it needed to be accepted "without investigation", but I'm glad you conceded that new evidence need not always fit in with what we already know. Indeed, were this the case, scientific progress would be impossible.

Brenda: Supernatural explanations are not explanations because "supernatural" is a broken concept, it makes no sense. Like "immaterial" it is an eliminative negative term which does not refer to anything. Both are meaningless and incoherent.

Alex: This, and most of your other comments, are largely exercises in begging the question. It is great that you've picked up a few philosophical and scientific terms in your reading of skeptical literature, but you don't really seem to have even a basic understanding of either science or philosophy and running around shouting dogmatically that this or that simply does not exist (or is incoherent) isn't really going to get you anywhere on this board. It is the equivalent of a fundamentalist preacher shouting hellfire and brimstone on a street corner.

Brenda said...

Alex said:
"Thanks for sharing your beliefs. None of this, however, supports anything you said. No one is denying the existence of the external world, or that there is a "way it is"."

Belief in miracles does undermine the belief in a real world because it suggests that there is not a way that the world is in itself.

"Why must the external world conform to your notion of "rational" and "consistent"?"

You have it backwards. Statements about the world should conform to how it actually is, not how we wish it to be.

If QM and relativity cannot be reconciled, if the project of science itself should fail... well, I don't know what to make of that. I guess we'd be back in bed with Nietzsche then. I think that science gives us true objective facts about the world. If that were to turn out not to be the case well, I guess I'd have to start trying to understand Heidegger.

"you've picked up a few philosophical and scientific terms in your reading"

It would be more helpful if you would explain to me how words like supernatural and immaterial are not empty concepts.

GREV said...

December 12th 2010

"Alex: This, and most of your other comments, are largely exercises in begging the question. It is great that you've picked up a few philosophical and scientific terms in your reading of skeptical literature, but you don't really seem to have even a basic understanding of either science or philosophy and running around shouting dogmatically that this or that simply does not exist (or is incoherent) isn't really going to get you anywhere on this board. It is the equivalent of a fundamentalist preacher shouting hellfire and brimstone on a street corner."

Thanks Alex -- my sentiments. I have got to the point where I have little time for fundamentalism of any stripe.

“Brenda said -- Belief in miracles does undermine the belief in a real world because it suggests that there is not a way that the world is in itself.”

I don't know whether to laugh or cry at the amazing claims of such a statement. Hardcore materialism/fundamentalism has a much greater length to go to prove its case then theism does. And if Brenda is not a hardcore materialist, I hope she will be so kind as to explain where she falls on the gradient scale of emergent materialism.

Brenda said...

@ GREV

I'm not a Materialist. I consider that materialism makes the same sort of mistake that Idealism makes. Dualism says there are two world, the mental and the physical. Idealism says there is one world and everything in mental (ideas). Materialism says everything is physical, there is no room for mental events. I think they are all wrong and that consciousness is a real phenomenon that cannot be swept under the rug as most materialists would like to. But I would also say that we live in a world composed entirely of particles moving in lines of force. That's it... and it's enough.

Alex Dalton said...

Brenda:Belief in miracles does undermine the belief in a real world because it suggests that there is not a way that the world is in itself.

Alex: What does this even mean? Believing that God acts in the world means the world isn't "real"? What?!

Alex (previous): "Why must the external world conform to your notion of "rational" and "consistent"?"

Brenda: You have it backwards. Statements about the world should conform to how it actually is, not how we wish it to be.

Alex: Riiiiight, Brenda. But what is at issue is "how it actually is". And since we don't have any absolute unassailable knowledge of existence, we need to be open to whatever way the world turns out to be. What is it, in your worldview, that tells us that the world "should" be fundamentally rational and consistent? As far as I can see, there is nothing.

Brenda:
It would be more helpful if you would explain to me how words like supernatural and immaterial are not empty concepts.

Alex: Right - you make an unsubstantiated/question-begging assertion. Then I need to do the legwork. No thanks. Why don't you just tell us what you meant, and justify it? After all, you're the rational, skeptical, enlightened freethinker. Tell us how you *know* the following:

"Supernatural explanations are not explanations because "supernatural" is a broken concept, it makes no sense. Like "immaterial" it is an eliminative negative term which does not refer to anything. Both are meaningless and incoherent."

Alex Dalton said...

Brenda writes: Materialism says everything is physical, there is no room for mental events. I think they are all wrong and that consciousness is a real phenomenon that cannot be swept under the rug as most materialists would like to.

Alex: Brenda - is consciousness a physical thing or is it not?

Brenda said...

Alex
"Riiiiight, Brenda. But what is at issue is "how it actually is"."

No, miracles are by definition events outside of of the natural order. If an event we call a miracle is really just a part of the natural order, of how the world is, then it was not a miracle.

"Right - you make an unsubstantiated/question-begging assertion. Then I need to do the legwork. No thanks. Why don't you just tell us what you meant, and justify it?"

Words like supernatural and immaterial are empty concepts because they don't refer to anything. Take immaterial for instance. How could anything "immaterial" ever exist? If there is such a thing as "spirit stuff" then it must be composed of something. Things are compositions of other things so a spiritual substance must be made out of something and it must operate according to some kind of regular laws. That's materialism so how can how can it be immaterial? It can't, the very concept of immaterial is self contradictory.

The same is true for "supernatural". What is supernatural? Something above or beyond nature, but does this super nature have a nature? That is, does it have a way that it is in itself? Of course it must, therefore it is natural, but that is a plain contradiction to say that what is supernatural is natural. Therefore the term is meaningless.

"Brenda - is consciousness a physical thing or is it not?"

Is a university a physical thing or is it not?

Alex Dalton said...

Brenda: No, miracles are by definition events outside of of the natural order. If an event we call a miracle is really just a part of the natural order, of how the world is, then it was not a miracle.

Alex: LOL - how is that a response to what I said? You seem to just be snipping bits and pieces of our convo, and even responding to the snips with thoughts that are unrelated to them. Please try to follow the flow of the conversation. I'll repeat the question: What is it, in your worldview, that tells us that the world "should" be fundamentally rational and consistent? You have yet to answer this.

Brenda: Words like supernatural and immaterial are empty concepts because they don't refer to anything. Take immaterial for instance. How could anything "immaterial" ever exist? If there is such a thing as "spirit stuff" then it must be composed of something.

Alex: Firstly, you are simply begging the question. Since you assume that all existence is material and can only be material, anything immaterial would lack existence. But really, we can sidestep that (and it looks like sidestepping your question-begging is a prerequisite for having a conversation with you), and show that this is fairly easy to resolve. Immaterial *need* not mean entirely lacking composition. Someone could use the word "immaterial" for instance to denote a substance not composed of matter/energy (your spirit stuff would be an example). Let's suppose there is an alternate universe that popped out of some eternal chaotic inflationary universe-generating mechanism. The laws that govern this universe are so entirely different from our own and substances within this universe, though they possess composite parts, have no resemblance whatsoever to anything we call matter. We could not detect this substance with any of our instruments, nevertheless there it is. One could define immaterial in this manner and avoid your question-begging objection.

Alex Dalton said...

Brenda: Things are compositions of other things so a spiritual substance must be made out of something and it must operate according to some kind of regular laws. That's materialism so how can how can it be immaterial? It can't, the very concept of immaterial is self contradictory.

Alex: Firstly, is the statement "things are compositions of other things" always true? If so, then there are no fundamental things, and don't we have an infinite regress of composition? Secondly, I see no reason why a spiritual substance would have to operate according to regular laws. Please attempt to argue that. Lastly, "immaterial" is only problematic if we assume that, since material things are made of composite parts and covered completely by law (even if probabilistic), immaterial things would also need to be. Try to argue that immaterial things are problematic without making those assumptions (i.e. begging the question).

Alex Dalton said...

Brenda: The same is true for "supernatural". What is supernatural? Something above or beyond nature, but does this super nature have a nature? That is, does it have a way that it is in itself? Of course it must, therefore it is natural....

Alex: Woah...If it has a nature, then it is natural?!!! Is that what natural means to you? To merely *have* a nature? Then supernatural is what? Something that doesn't have a nature? Well, gee...if you define the terms like that, then sure, nothing is supernatural. You might as well say, "Whatever exists is natural. So if the supernatural exists, it is natural. Therefore nothing is actually supernatural!". Can you see the problem with this kind of argument?

Alex (old): "Brenda - is consciousness a physical thing or is it not?"

Brenda: Is a university a physical thing or is it not?

Alex: Let's assume it is for the sake of argument, now can you answer my question? Is there something that makes you uncomfortable about my question? After all, immaterial things don't exist. To be material, is to be physical, right? Consciousness would then have to physical, on your view, would it not?