Sunday, 8 September 2013

Why Plantinga is wrong about human mental abilities

Alvin Plantinga questions that evolution alone can result in humans having reliable beliefs, and uses this as an argument against naturalism.  As you might expect, I disagree!

Let's take an example that has been mentioned in this context:  why would a human run away from a predator (say, a hungry tiger).  There are a large number of false beliefs that would result in someone escaping from a tiger: the tiger wants to play, and running away will be fun!  Tigers remind me of apples, so I'll go climb that tree and get some.  Tigers have some magic ability to cause floods, so I had better get somewhere high away from the tiger.

It's true - there are plenty of false beliefs that can result in escape, but these are all fragile and isolated.  A belief about a tiger won't be protective against a lion.  A belief that one should seek apples won't work if there are no apple trees.   All of these false beliefs can result in death by tiger if there is a slight change in circumstance.

True beliefs, on the other hand, are both robust and versatile.  A true belief that a tiger is dangerous because of its teeth and claws works with bears, lions, crocodiles, even snakes (just look at those fangs!).  True beliefs can survive the 'Chinese whispers' process of cultural transmission because they are hugely simpler than convoluted false beliefs, and because true beliefs are actually true - they survive continual testing against reality.  The belief that tigers cause floods doesn't survive such tests.

One basic reason why such true beliefs arise and how they persist is because what is going on in both evolution and culture is a form of science: beliefs and mental faculties are being varied randomly and tested against reality with survival as the result of successful experiments.

Another reason why true beliefs are more robust is that they can fit together: true beliefs can combine to form new beliefs which extend our ability to survive.  We know that bears are strong (one truth), and we know that their teeth are dangerous (another truth), so we should definitely avoid angry bears.

Of course, these days there are aspects of reality that are beyond unaided human faculties.  We investigate those aspects of reality using science intentionally, and not just incidentally.  We have computers that can think and reason far faster and more reliably than we can.  We have instruments that can extend the reach of our senses to astronomical degrees.

The key thing here is that evolution tends to result in reliable cognitive faculties about the environment we evolved in because evolution is itself a form of natural science - Nature tested against Nature.


Yorgo said...

Ok – I like this Steve, but first, a few other words.

This all got started when you stated that Plantinga rejects evolution, and that’s just false. He has a good understanding of the TOE and accepts it. It is naturalism that he rejects.

The TOE is completely consistent with the idea that a powerful extra-terrestrial intelligence could have guided evolution over time, protecting certain populations, making the dinosaurs go extinct, causing or introducing certain mutations into the gene pool, and this is just as possible for an agent like God. Nothing about the TOE itself excludes this possibility, but naturalism, when combined with the TOE certainly does. But let’s be clear: it’s naturalism doing that work, not the TOE. Plantinga accepts guided evolution, and nothing about the TOE excludes the possibility of guidance.

You then brought up Plantinga’s EEAN, and you are correct to focus on the first premise, because all turns on it. Plantinga basically asks how evolution, which cares not about truth per se, but about producing behavior that is adaptive (increases reproductive capability), can be relied upon to produce reliable faculties and ultimately, true beliefs. Because he cannot see how this can be the case, he ascribes the probability that a belief may be true at about 0.5, and argues that this is unlikely to create a reliable network of beliefs that are likely to be true.

You are suggesting that true beliefs are more likely to be adaptive than false ones, and if successfully argued, this would certainly sink the first premise. Philosophers are still trying to accomplish this, so please put this into the form of a philosophical argument and get it published. In fact, Stephen Law recently published an attempt to do so within the past year. But more impressively, a collection of essays by 11 prominent philosophers published in 2002 (Naturalism Defeated?) attempted to do that, and apparently wasn’t completely successful, since Plantinga apparently had reasonable rebuttals, and efforts to put the EEAN to rest continue to this day. Apparently Plantinga isn’t the only philosopher who isn’t as familiar with evolutionary biology as you’d like him to be or your rebuttal (or something like it) would have already sunk the EEAN. Note that Plantinga and Dennett went head to head on this topic at the largest event at the 2003 American Philosophical Association Central Division Mtg in Chicago in 2009 – standing room only.

I’m on your side. I want to see the EEAN defeated. But something tells me that your little blog post may not be as powerful as you suggest it is in washing the EEAN away. Why not formalize it and get it published? Enlist the help of a philosopher like Stephen Law, or an evolutionary biologist if you like. Become one of the stars of the atheist movement and accomplish what no philosopher has so far been able to do.

Steve Zara said...

My blog post is only going to express my ideas, I agree. The problem I see with this subject is that, to be blunt, I can't see many people being that interested in refuting Plantinga's work. I view it only as a philosophical curiosity, not as a serious challenge to either evolution or naturalism or both.

I haven't encountered anyone who has been dissuaded from belief in evolution by Plantinga's ideas - although there might be such people!

djs56 said...

"Let's take an example that has been mentioned in this context: why would a human run away from a predator"

Ok, so why would a human run away from a "ghost" ? I suspect plenty do.... and some don't, but then again, not everyone runs from a tiger?

Yorgo said...


Check it:

Yorgo said...

And another:

Yorgo Veenhuyzen said...

“True beliefs are both robust and versatile”

I think that Plantinga would respond as follows:

“No, beliefs that are both robust and versatile are more adaptive at reproducing here on Earth, but what in the world makes you think that they are actually true?”

The idea that animals that are strong and have sharp teeth are to be avoided is going to be adaptive against a wide variety of animals and in a wide variety of situations but what makes you think that it’s actually true that they are strong, that they have sharp teeth, and that they are to be avoided? Surely those beliefs are adaptive and lead to adaptive behavior (which evolution will select for), but what makes it true of reality?

Perhaps such animals are actually weak and have no teeth, nor any interest in consuming us. Perhaps they really do want to play with us and by doing so, we go on a one way trip to a new dimension where all we do is enjoy blissful play with animals. When we enter into the new dimension, it appears to us as though we are being eaten. In that new dimension, we are obviously less able to pass on our genes and/or care for the vessels of our genes (our offspring) in this dimension. By avoiding them with the false belief that they are dangerous, we increase our adaptiveness here on Earth while remaining clueless about the true nature of reality. Here on Earth, evolution selects for whatever produces behavior that adapts us to life on Earth, but why think that what evolution selects for leads to beliefs that are true about the actual nature of reality?

Plantinga has written: “It's as likely, given unguided evolution, that we live in a sort of dream world as that we actually know something about ourselves and our world.”

If, as Plantinga argues, our beliefs are invisible to evolution, then we really have no reason to think that they are true. We certainly do have good reason to think that they are likely to be adaptive, though.

Until the EAAN, these kinds of skeptical challenges could be swept under the rug by claiming that countless things are possible, but until we have a reason to believe that they are true, we needn’t entertain them because without reason, they aren’t likely. However, the EAAN leads us, by virtue of reason, to believe that these crazy scenarios are as likely to be true as the scenarios that we think we have reasons to believe are true. The key there is “as likely”. This provides us with an internal rationality defeater for our beliefs.

If we have reason to believe that the orange is as likely to be blue as it is orange, we can’t really go on believing that it’s orange, can we?

I’m beginning to think that the naturalist may have to accept that truth reduces to adaptiveness, and that’s all. I think I may be ok with that.

Yorgo Veenhuyzen said...

Plantinga's response to your post might look something like this:

Steve Zara said...

Where Plantinga's response fails is that we all live together in reality, both animals with teeth and those who are chased by animals with teeth. If we are in some sort of dream state, then unless we share the dream state with other species, that dream state will be maladaptive. Dream states involve a distancing from reality, and that distancing takes brain power, and excess brain power is very expensive biologically, and so is selected against by evolution. The only stable condition is for us to be all in contact with the same reality, because when it comes to predators and prey there is a continuous 'arms race' to see who can get closest to truth.