Wednesday, September 3, 2008

Darwin's Doubt Redux

[Like a fly repeated battering itself against a window, I'm revisiting the topic of the dubious assumption that naturalistic evolution gives us good reason to think our beliefs are true.]


"With me the horrid doubt always arises whether the convictions of man's mind, which has been developed from the mind of the lower animals, are of any value or at all trustworthy. Would any one trust in the convictions of a monkey's mind, if there are any convictions in such a mind?"

- Charles Darwin, in a letter to William Graham (Down, July 3, 1881), in The Life and Letters of Charles Darwin, ed. Francis Darwin (London: John Murray, 1887), Volume 1, pp. 315-16.


Darwin was no intellectual slouch. If this "horrid doubt" could have been resolved simply by testing our convictions (or more generally, our cognitive faculties from whence our convictions spring) to determine their trustworthiness then why should Darwin have this concern? There are at least two reason why Darwin's doubt can't be addressed by testing. First, and most obviously, it begs the question, since it calls on us to assume the soundness of our cognitive faculties so they may adequately serve to judge the soundness of those self-same cognitive faculties. Second, testing our convictions does not address the core issue which is not the trustworthiness of our convictions per se, but rather their trustworthiness given Darwin's hypothesis of naturalism, operating within the confines of his evolutionary theory.

I think our convictions (or beliefs) are indeed trustworthy as a result of our having been created by a rational Mind who endowed us with a share of His own rationality. Given a rational Creator and His bestowing of rationality upon humans, it's expected that our beliefs would be by-and-large trustworthy. Does naturalistic evolution likewise lead to trustworthy beliefs? Darwin doubted it. I doubt it. So does noted philospher Alvin Plantinga. He summarizes his argument in the article, "Evolution vs. Naturalism: Why they are like oil and water" from the July/August 2008 issue of Books & Culture.

The first thing to see is that naturalists are also always or almost always materialists: they think human beings are material objects, with no immaterial or spiritual soul, or self....According to materialists, beliefs, along with the rest of mental life, are caused or determined by neurophysiology, by what goes on in the brain and nervous system. Neurophysiology, furthermore, also causes behavior....[What] evolution tells us is that our behavior (perhaps more exactly the behavior of our ancestors) is adaptive; since the members of our species have survived and reproduced, the behavior of our ancestors was conducive, in their environment, to survival and reproduction. Therefore the neurophysiology that caused that behavior was also adaptive; we can sensibly suppose that it is still adaptive. What evolution tells us, therefore, is that our kind of neurophysiology promotes or causes adaptive behavior, the kind of behavior that [results in our] survival and reproduction.

Now this same neurophysiology, according to the materialist, also causes belief. But while evolution, natural selection, rewards adaptive behavior and penalizes maladaptive behavior, it doesn't, as such, care a fig about true belief. As Francis Crick, the co-discoverer of the genetic code, writes in The Astonishing Hypothesis, "Our highly developed brains, after all, were not evolved under the pressure of discovering scientific truth, but only to enable us to be clever enough to survive and leave descendents."

...

Consider a frog sitting on a lily pad. A fly passes by; the frog flicks out its tongue to capture it. Perhaps the neurophysiology that causes it to do so, also causes beliefs. As far as survival and reproduction is concerned, it won't matter at all what these beliefs are: if that adaptive neurophysiology causes true belief (e.g., those little black things are good to eat), fine. But if it causes false belief (e.g., if I catch the right one, I'll turn into a prince), that's fine too. Indeed, the neurophysiology in question might cause beliefs that have nothing to do with the creature's current circumstances (as in the case of our dreams); that's also fine, as long as the neurophysiology causes adaptive behavior. All that really matters, as far as survival and reproduction is concerned, is that the neurophysiology cause the right kind of behavior; whether it also causes true belief (rather than false belief) is irrelevant.

...

We must suppose, therefore, that the belief in question is about as likely to be false as to be true; the probability of any particular belief's being true is in the neighborhood of 1/2. But then it is massively unlikely that [one's] cognitive faculties... [would] produce the preponderance of true beliefs over false required by reliability. If I have 1,000 independent beliefs, for example, and the probability of any particular belief's being true is 1/2, then the probability that 3/4 or more of these beliefs are true (certainly a modest enough requirement for reliability) will be less than [10 to the -58th power]. And even if I am running a modest epistemic establishment of only 100 beliefs, the probability that 3/4 of them are true, given that the probability of any one's being true is 1/2, is very low, something like [.000001 to the 7th power].

...

If evolutionary naturalism is true, then the probability that our cognitive faculties are reliable is also very low. And that means that one who accepts evolutionary naturalism has a defeater for the belief that her cognitive faculties are reliable: a reason for giving up that belief, for rejecting it, for no longer holding it. ... No doubt she can't help believing that they are; no doubt she will in fact continue to believe it; but that belief will be irrational. And if she has a defeater for the reliability of her cognitive faculties, she also has a defeater for any belief she takes to be produced by those faculties—which, of course, is all of her beliefs. If she can't trust her cognitive faculties, she has a reason, with respect to each of her beliefs, to give it up. She is therefore enmeshed in a deep and bottomless skepticism. One of her beliefs, however, is her belief in evolutionary naturalism itself; so then she also has a defeater for that belief. Evolutionary naturalism, therefore... [is] self-refuting, self-destructive, shoots itself in the foot. Therefore you can't rationally accept it. For all this argument shows, it may be true; but it is irrational to hold it.

...

The argument isn't an argument for the falsehood of evolutionary naturalism; [or even, may I add, that our cognitive faculties are not, in fact, reliable] it is instead for the conclusion that one cannot rationally believe that proposition. Evolution, therefore, far from supporting naturalism, is incompatible with it, in the sense that you can't rationally believe them both.

16 comments:

CyberKitten said...

LB quoted/said: We must suppose, therefore, that the belief in question is about as likely to be false as to be true; the probability of any particular belief's being true is in the neighborhood of 1/2.

Not so. Whilst true that any proposition must either be true or false this does not mean that there is a 50% probability of any proposition being either true or false. The probability of a proposition being true could be 60% or 90% depending on the proposition itself.

LB quoted/said: If evolutionary naturalism is true, then the probability that our cognitive faculties are reliable is also very low.

That really doesn't make much sense. If our cognitive faculties were inherently unreliable this would seriously reduce our chances of reproduction. It is therefore likely that those who had reliable cognitive functions would out breed those without and therefore produce a species with progressively *more* reliable cognitive functions.

LB quoted/said: Evolution, therefore, far from supporting naturalism, is incompatible with it, in the sense that you can't rationally believe them both.

Nonsense. Evolution and naturalism are most certainly compatible! The whole argument presented (either by yourself or the noted philosopher Alvin Plantinga) is deeply flawed from the probability section onwards.

Laughing Boy said...

CK: ...this does not mean that there is a 50% probability of any proposition being either true or false. The probability of a proposition being true could be 60% or 90% depending on the proposition itself.

Likewise it could be 40% or 10%. Choosing 50% puts the assumption in a neutral position. Let me add some of what I did not quote. See if you think it adequately allows for the 50% assumption...

"But it simply doesn't matter whether the beliefs also caused by that neurophysiology are true. If they are true, excellent; but if they are false, that's fine too, provided the neurophysiology produces adaptive behavior. So consider any particular belief on the part of one of those creatures [from an earlier analogy he makes in which a pre-historic hominid-like creature's false beliefs cause him to flee from a tiger nevertheless]: what is the probability that it is true? Well, what we know is that the belief in question was produced by adaptive neurophysiology, neurophysiology that produces adaptive behavior. But as we've seen, that gives us no reason to think the belief true (and none to think it false). We must suppose, therefore...

If our cognitive faculties were inherently unreliable this would seriously reduce our chances of reproduction.

Is it necessarily the case that believing falsely would be adverse to survival and reproduction? All that matters is that the belief has the end result of promoting survival and reproduction. Its actual truth or falsity has no bearing. For every true belief, I can think of at least several false beliefs that could result in the same behavior. Naturalistic evolution does not 'see' truth or falsity, only survival-effecting action. That's the point.

The whole argument...is deeply flawed from the probability section onwards

If you say so. I would have guessed that a deeply flawed argument would have been summarily dismissed in short order rather than continuing to generate discussion among professional philosophers more than a decade after it was first published, but I could be wrong. Check out the wikipedia entry on the argument. Cornell University Press published a book of essays in 2002 by critics of the argument along with Plantinga's responses entitled Naturalism Defeated?.

CyberKitten said...

LB said: Choosing 50% puts the assumption in a neutral position.

No it doesn't. Choosing 50% is arbitary & frankly ridiculous.... The probability of my belief that the Sun will raise tomorrow is close to 100%. The probability of my belief that there is a pink unicorn in my garage is close to 0% Assuming that the truth of a belief is on average 50% is both meanigless & misleading.

LB asked: Is it necessarily the case that believing falsely would be adverse to survival and reproduction?

No, of course not. I could believe that an as yet undiscovered moon of Jupiter is made of green cheese. This would have no effect on my reproductive abilities - unless I told the prospective mother of my children first.

LB said: Naturalistic evolution does not 'see' truth or falsity, only survival-effecting action. That's the point.

That's not much of a point. Some beliefs will effect an individuals survival rate, others do not.... and?

LB said: I would have guessed that a deeply flawed argument would have been summarily dismissed in short order

I'm surprised that it hasn't been. The idea that evolution somehow invalidates naturalism is... quite bizarre IMO.

Laughing Boy said...

Say I could put all my beliefs on display to be rated by some ultimate knower as to their truth. Some of my beliefs would be true, some would be false. If you wanted to make a rough guess as to the percentage of my true beliefs as compared to all my beliefs what would you say? If you say over (or under) 50% you'd have to some particular reason to think so. I the absence of a particular reason I think 50% is not an absurd guess.

If you agree that natural selection does not act on a belief's truth, but rather on a behavior's enhancement of reproduction, then it follows that natural selection can't be relied upon to produce true beliefs, since it is blind with them. How would you dispute that?

The idea that evolution somehow invalidates naturalism is...quite bizarre IMO.

Well, you're O is all that matters. :-)

Laughing Boy said...

Challenge: Pose the following question to a few people...

Imagine a random person. What percentage of that person's beliefs would you suppose to be true?

Let me know the results.

CyberKitten said...

LB said: Say I could put all my beliefs on display to be rated by some ultimate knower as to their truth. Some of my beliefs would be true, some would be false.

Agreed.

LB said: If you wanted to make a rough guess as to the percentage of my true beliefs as compared to all my beliefs what would you say?

That such a figure would be impossible to predict & that *any* number I put forward would be highly speculative at best.

LB said: If you say over (or under) 50% you'd have to some particular reason to think so.

*Exactly* right. Firstly I would need to know all of your beliefs in detail. Then I would have to have perfect knowledge to determine which of those beliefs were true and which ones were false. The first hurdle is difficult - the second is impossible to clear.

LB said: In the absence of a particular reason I think 50% is not an absurd guess.

It's *obviously* absurd. There is absolutely no way to tell how many beliefs a random person holds are true (or false) without detailed investigation. You could, theoretically, plot the number of a persons beliefs against a chart and the *average* might be 50% but even that assertion is highly speculative!

LB said: If you agree that natural selection does not act on a belief's truth, but rather on a behavior's enhancement of reproduction, then it follows that natural selection can't be relied upon to produce true beliefs, since it is blind with them. How would you dispute that?

Not at all. But so what? You could equally say that the motion of the planets is also blind to the veracity of peoples beliefs.... Evolution and peoples beliefs have, as far as I know, very little (if any) connection and I'm struggling to see where you see one.

LB said: Imagine a random person. What percentage of that person's beliefs would you suppose to be true?

See above.

Laughing Boy said...

Evolution and peoples beliefs have, as far as I know, very little (if any) connection and I'm struggling to see where you see one.

There's the problem we're having! I don't see one, either. Plantinga doesn't see one. The point of the argument is that there is none!

Let's be precise. The argument is not about evolution in isolation but specifically naturalism and evolution (N/E) in combination. That's important because naturalism necessarily adds the following parameter: Beliefs are nothing but the neurophysiological output of a neurophysiological process. (See paragraphs 5-6, "The first thing to see...")

So if our neurophysiology (our belief-producing apparatus) is the entirely the result of N/E, and N/E doesn't 'care' if the beliefs produced are true, then a believer in N/E has no grounds to say that N/E has evolved creatures with cognitive faculties that produce a preponderance of true beliefs. A true belief would be shear coincidence.

"But," one might say, "we can test to see if our beliefs are true." I, ignoring the inherent circularity, would reply that I don't believe N/E is explanation for them, so what would validating our beliefs prove? Only that we indeed can produce true beliefs. Then we must look at how each of us explains why we should believe our system would produce creatures exhibiting a preponderence of true beliefs. As we have just seen, N/E provides us with no reason to think so.

Finally, if under N/E a true belief would occur only by shear coincidence—or in other words the generating of a true belief would be just as likely as not—then the chance that any belief produced by any creature produced by N/E could reasonably, perhaps even generously, be estimated at 50% (just as likely as not).

Please highlight the absurdity.

Laughing Boy said...

Me: The point of the argument is that there is none!

Sorry. That's not the point, that's the initial premise.

CyberKitten said...

LB said: There's the problem we're having! I don't see one, either. Plantinga doesn't see one. The point of the argument is that there is none!

So what are we arguing about? [laughs]

LB said: So if our neurophysiology (our belief-producing apparatus) is the entirely the result of N/E, and N/E doesn't 'care' if the beliefs produced are true, then a believer in N/E has no grounds to say that N/E has evolved creatures with cognitive faculties that produce a preponderance of true beliefs.

I don't see the link. Evolution has over millions of years produced the human brain. This brain has evolved in response to the environment and aids us in our individual survival. If the cognitive functions of the brain were greatly at fault it would have reduced our survival chances - therefore it follows that our cognitive abilities are generally sufficent for our survival and reproduction.

The brain is a natural product and seemingly operates in natural ways (which we are still discovering).

Some of our beliefs will be true - others will be false. However, unless these beliefs have either a positive or negative impact on our survival/reproductive behaviour evolutionary processes will pass them by as irrelevant.

Beliefs are largely cultural in nature. If either of us had been born in a different culture, at a different time or as a different gender then our beliefs would be different too. But I ask again - In the context of evolution/naturalism.... So what? I'm *really* struggling as to what point you're trying to make here.

LB said: A true belief would be shear coincidence.

No it wouldn't. You need to ask yourself where your beliefs come from. Basically from your upbringing & the culture you're born into - plus experience, education etc.... Why do you hold certain beliefs and not others? Because they make sense to you and are internally consistant? Or for no reason whatever? Are the beliefs you hold to be true acquired randomly and held randomly in your head? I'm guessing not!

LB said: Finally, if under N/E a true belief would occur only by shear coincidence—or in other words the generating of a true belief would be just as likely as not—then the chance that any belief produced by any creature produced by N/E could reasonably, perhaps even generously, be estimated at 50% (just as likely as not).

But that's nonsense! Are you saying that it is just as likely that I believe that everyone else is a robot from Mars as it is that I believe that the Sun will come up tomorrow? You must know some *very* strange people!

Beliefs are *not* generated by complete coincidence nor are they randomly arrived at. They are acquired through interacting with the culture you grow up in etc etc ad nausium..

Laughing Boy said...
This comment has been removed by the author.
Laughing Boy said...

P.S. I think I see where the disconnect is. You wonder what the link is between N/E and actual beliefs. But, as you say, we get our beliefs from a variety of sources, not from N/E per se. This is true. N/E does not produce beliefs. A person (or alien hominid) could have a belief handed down from parents, supplied by her culture, set forth in her holy books, or any number of ways. N/E is not generating her beliefs. But N/E is producing the cognitive faculties by which she reasons concerning them, right?

For example: Hominidina might have the belief (from mom) that eating the red berries is an offense against her deity and eating them will result in her eternal damnation. Others of her species believe the red berries incur the diety's favor. The berries are poisonous so the others die off and Hominidina survives and reproduces subsequent generations that don't eat the berries. Her belief is false—her cognitive faculties are not functioning properly, i.e. not producing true beliefs—but N/E doesn't care.

Bottom line: If N/E is responsible for developing our cognitive faculties, we have no reason to think it would have developed cognitive faculties that could determine whether the beliefs it processed are true or false.

CyberKitten said...

LB said: I think I see where the disconnect is. You wonder what the link is between N/E and actual beliefs.

No. I don't see any link - except for the obvious one... that beliefs are held in our minds/brains and that these brains are the product of Evolution and run on Natural principles. But as I've said before - so what. Neither Evolution nor Naturalism has much if anything to say about the *veracity* of those beliefs.

I still think that you are making an obvious (though largely pointless) point.

LB said: N/E is not generating her beliefs. But N/E is producing the cognitive faculties by which she reasons concerning them, right?

Yes. But we can all reason in different ways and come to different conclusions. A case in point is that you have used your reason to arrive at the conclusion that God exists. Whilst I have used my reason to arrive at the opposite conclusion. Does this prove in any way that either Evolution, Naturalism or Reason are at fault? No, it does not. It might indicate that one of us is suffering from a brain malfunction. It might also indicate that one of us - or indeed both of us - are using our perfectly adequate reasoning faculties in an inadequate manner for a who host of reasons, thereby arriving at the wrong conclusion. As they say in the IT world GIGO - Garbage In Garbage Out.

LB said: If N/E is responsible for developing our cognitive faculties, we have no reason to think it would have developed cognitive faculties that could determine whether the beliefs it processed are true or false.

The determination of falsehood or otherwise of beliefs is shown in their interaction with the real world. If my belief sates that eating the red berries is a good thing that God wants me to do - and yet the last three people who ate those berries are now all dead because of poisoning - I would say that either my belief is in error or that my God isn't quite as nice as people make out. I would not eat the berries regardless of my experience with the real world. If I did so I would be incredibly stupid and deserving of being taken out of the gene pool before I could harm other people.

We *can* reason incorrectly. That is also obvious. But what we can do is to check those reasonings against the reasoning of others and against external reality. When there is conflict we need to decide if our beliefs are true or not. How you make that decision is up to you.

Laughing Boy said...

I don't think you read the "berry scenario" attentively since your reply was not based on what I said. Everything else relied on the irrelevant and circular argument that hung us up last time. I've addressed this several times already and unless you can show how your counter-argument is neither irrelevant or circular—and it would be helpful to me if you could—then let's wrap it up. For me, at least, it was not completely futile. Thanks.

I won't be initiating anything here for the next few months, I couldn't be a responsive host, but I'll keep an eye on the usual spots.

Take care, bulldog.

CyberKitten said...

Bulldog?

Anonymous said...

Come on, you know this is all Philosophic crap. You can't mess with Science.

XXX said...

Science is successful because it was founded on theism. That we are created in God's image with ability to know truth. That God put order in the universe.

This is why paganism beliefs have not been very successful at science.