Plantinga's Evolutionary Argument Against Naturalism

[dakoski]

Hadn’t seen Plantinga’s Evolutionary Argument Against Naturalism as a thread (at least for a while) so thought it would be good to discuss.

Here’s the argument:

Premise 1: The probability of reliable cognition and reasoning is low or uncertain if evolution and naturalism are true.

Natural selection acts on hereditary traits that promote survival. Therefore, our cognitive and reasoning systems have not necessarily evolved to generate true inferences, but rather inferences that enhance our survival.

But isn’t the ability to generate true inferences by definition associated with greater probability of survival? Not necessarily, there are several reasons why this may not be the case. For example:

a) Error management theory argues that natural selection may favour avoidance of large risk at the expense of optimal logical inferences. An example atheists might like is that this theory can be used to support the high prevalence of false beliefs regarding theism, on the assumption that naturalism is true.

b) Neuroscience research suggests that higher serotonin is associated with over-optimistic bias. However, given the potential association between serotonin and depression, lower levels of serotonin may be associated with more accurate inferences but less adaptive.

c)For reductive materialists – human behaviour is determined by external factors as we do not have free will. In this context, its irrelevant to survival whether we are able to generate true inferences therefore there is no reason to think natural selection would select for reliable cognition and reasoning.

Premise 2: Anyone who believes that:
- naturalism and evolution are true
- naturalism and evolution are associated with a low or inscrutable probability of reliable cognition and reasoning
Have a defeater for their belief that their cognition and reasoning are reliable.

The obvious objection to this premise is that we know from experience that our cognition and reasoning are reliable. However this objection has a few limitations:

a) The argument is addressing the reliability of our cognition and reasoning – therefore we can’t use the conclusions of our cognition and reasoning to demonstrate the reliability of our cognition and reasoning (i.e. we’re engaging in circular reasoning)

b) The argument isn’t addressing the reliability of our cognition and reasoning given our experience, it’s addressing their reliability given the assumption that naturalism and evolution are true. The objection conflates these - they would first have to demonstrate the truth of naturalism for this objection to be valid.

Premise 3: Anyone who has a defeater for the belief that their cognition and reasoning are reliable – have a defeater for all their beliefs including naturalism. This follows from premise 2.

Premise 4: Anyone who believes both naturalism and evolution acquires a defeater for these beliefs. Therefore believing both naturalism and evolution is self-defeating and can’t be rationally accepted.

Question for debate:
Which premises do you agree or disagree with? Of course providing a rationale for accepting or rejecting the premises.

Some caveats:
1) Plantinga isn’t arguing that our cognition and reasoning are unreliable – that’s the point of the argument to show that naturalism is inconsistent with our experience of relatively reliable cognition and reasoning

2) Plantinga’s argument isn’t trying to refute evolution

[jgh7]

The question to me seems to be whether hereditary traits that promote survival also generally promote truth-discerning ability (is that what is meant by reliable cognition?).

Plantinga seems to jump to conclusions by labelling reliable cognition as low or uncertain if evolution and naturalism are true. He gives arguments based on scientific research that suggest possible areas of less reliable cognition due to evolution. But I would dare say there are many studies which also point to evolution favoring more reliable cognition in order to stay in harmony with survival.

So basically I don't see how it follows that if one believes naturalism and evolution to be true, they should also believe it's associated with low or inscrutable reliable cognition. Inscrutable maybe, but low seems a very far stretch to me.

[2ndRateMind]

Natural selection acts on hereditary traits that promote survival. Therefore, our cognitive and reasoning systems have not necessarily evolved to generate true inferences, but rather inferences that enhance our survival.

It occurs to me, that so far as survival is concerned, there may be a hierarchy of truths according to their relevance to our continued existence. So, for example, it may have been absolutely vital that our fore-fathers could tell the difference between the paw-print of a woolly mammoth, and the paw-print of a sabre-toothed tiger. And, arguably, we may have evolved the senses to spot that kind of difference.

On the other hand, it may not have made that much difference to the survival of our ancestors whether they thought the earth spherical, or flat, and balanced on the back of a turtle. So, we did not evolve the senses to decide between such options.

That is why we need science, and scientific method, to distinguish between what our senses tell us, and what is true. Or, at least, the difference between what our senses tell us, and what is not true.

Best wishes, 2RM.

[dakoski]

[Replying to Divine Insight]

But he did argue that rational reasoning and intellectual understanding were not required for survival. Everything I listed clearly helped humans to survive.

Not only this, but Plantinga actually demonstrated a gross misunderstanding of evolution and natural selection here already. Evolutionary traits aren't chosen because some "consciousness" is evaluating whether something has survived or not. Evolutionary traits are chosen because of "actual" survival. Therefore everything I listed helps humans to actually survive. In fact, it's quite possible that if humans did not acquire these skills they may have very well died off as a species. There were other hominid species that did die off.

So didn't list these things just to imply that humans are indeed capable of reasoning. I listed them specifically because they are all example where reasoning can indeed contribute to survival. Something Plantinga was attempting to argue against. After all, that's the whole point of his argument. If he can't argue that reasoning doesn't contribute to survival then he doesn't have an argument.

Thanks for clarifying, sorry I misunderstood what you meant.

Couple of responses:

1) The idea that natural selection may result in unreliable cognition has been influential for some time, Darwin was an early proponent:

“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?�

Or Patricia Churchland:
"Boiled down to essentials, a nervous system enables the organism to succeed in the four F's: feeding, fleeing, fighting and reproducing. The principle chore of nervous systems is to get the body parts where they should be in order that the organism may survive…. . Improvements in sensorimotor control confer an evolutionary advantage: a fancier style of representing is advantageous so long as it is geared to the organism's way of life and enhances the organism's chances of survival. Truth, whatever that is, definitely takes the hindmost."

Thomas Nagel:
“If we came to believe that our capacity for objective theory [true beliefs, e.g.] were the product of natural selection, that would warrant serious skepticism about its results"

Btw, these aren’t Christians they are all people who hold naturalistic worldviews so have no incentive to discredit naturalism.

2) It’s also a common view for many decades in cognitive neuroscience and behavioural economics that natural selection can favour sub-optimal and unreliable reasoning. I gave you an example from error-management theory. Similarly, as above I cited some neurotransmitters (serotonin and dopamine) at higher levels can lead us to unreliable inferences but also lead to traits that are adaptive e.g. less likely to have depression and other mental health problems that are associated with less reproductive success, less ability to work (or in our distant past to hunt and gather) and premature mortality.

3) The examples you gave such as tool-making, defeating or hiding from predators, etc don’t necessarily require the high-level cognitive functioning needed to understand quantum physics. One of the challenges of studying behaviour is distinguishing between behaviour that is simply the result of a conditioned or instrumental response and behaviour that is the result of intentional action based on reasoning. It’s a hotly debated topic within both human and other animal behaviour and there’s no sign of it being resolved any time yet. For example, you’ve argued tool-making is the result of high-level intentional reasoning processes whereas actually there’s plenty of evidence that this occurs in birds, fish and many other animals.

4) I completely agree with you, there are plenty of traits that evolve incidently that may not be directly related to survival. One example might be ginger hair or men’s nipples. But the point is that though it is possible for these things to evolve, we know they did because we can observe them, we can’t make that argument about the reliability of our reasoning if the question is about the reliability of our reasoning - as its just begging the question.

I don't see why. Just because things can survive without having achieved reliable cognition it doesn't follow that reliable cognition wouldn't naturally evolve.

I mean think about it. This would be like saying that since an amoeba can survive there is no rational reason to expect that anything should ever evolve with capabilities greater than an amoeba has. After all, what would be the point in evolving to greater capabilities when an amoeba is already surviving quite nicely on its own?

This is basically what Plantingas argument is based on. In other words, he's arguing that anything that isn't "necessary" for survival should be question as to why it would evolve.
But that's really not how natural evolution works at all. Natural evolution works by the simple principle that "anything that can happen will happen". And if whatever happens is capable of surviving then it will survive.

Yeah I agree, its possible that reliable reasoning could evolve even though survival is possible without it, but I don't think that's what he's arguing. It also doesn’t follow that reliable reasoning would just inevitably evolve, so its inscrutable whether reliable cognition would have evolved given naturalism. Hence, agnosticism appearing the most logical response at this point.

I think Plantinga is potentially clinging to a wrong idea of natural evolution, like as if it's only going to do whatever is necessary to survive and no more than this.

But there is nothing in the process of natural evolution that requires that traits and abilities that aren't necessary for survival can't also occur. As long as they don't pose a problem for survival and they "can" occur, then they will occur.

In fact, once this is realized this turns Plantinga's argument on its head.

In other words, Plantinga would need to demonstrate how cognitive reasoning would be detrimental to survival. If he can't demonstrate that, then he has no argument.

1) I don’t think that’s what Plantinga is arguing here.

2) If the grounding of the reliability of our cognitive reasoning for naturalism is in evolution, then all he would need to show is that it’s unclear if reliable cognitive reasoning would have evolved. Given that a) natural selection is driven by reproductive success and survival rather than truth, although it’s not impossible we evolved reliable cognitive reasoning there's no guarantee, b)there is evidence that unreliable reasoning can be adaptive.

A process of natural evolution doesn't give a hoot if things evolve that aren't self-detrimental. Why would it? In fact a process of natural evolution doesn't even "know" anything. It has no clue what's going on. Things that can survive, do survive. Things that can't survive die out.

That's it period.

So there's nothing in natural evolution that would prevent cognitive reasoning from emerging. And as I had already pointed out, cognitive reasoning actually does contribute to survival anyway contrary to Plantinga's claim that it wouldn't.

I think all you can show is that reliable cognitive reasoning potentially could contribute to survival, but these traits/behaviours can also be explained by conditioning processes rather than intentional mental states. Plus, there is also data pointing the other way that unreliable reasoning can be adaptive.

Cognitive reasoning most likely evolved in humans for the same reason that Lions evolved from amoebas. In other words, once there were amoebas, according to Plantinga's arguments there would be no need to evolve any higher than that just to "survive" as an amoeba. Why bother evolving in to higher animals at all?

I just don't see where Plantinga's arguments make any sense.

Perhaps I'm missing something

But the bottom line for me is that cognitive reasoning in humans would be no different from a lion evolving to have fangs, claws and a coat of hair, or that birds would evolve wings to fly. Why bother with any of that when amoebas already had "survival knocked"?

There would be no reason to evolve any higher than mere survival according to Plantinga's arguments.

It seems to me that Plantinga just has a very wrong idea of what natural evolution is actually all about. We don't need to make an argument that everything that evolved was "necessary" for survival. All it needs to be it "not" detrimental to survival.

The difference is that these traits are directly and immediately related to our survival in terms of either defeating/fleeing from predators or preventing us from dying of exposure. For example, its undebatable that conditioned responses of the amygdala signalling threat in the presence of cues associated with danger is adaptive. But the reliability of our reasoning, particularly of the level that allows us to solve highly abstract mathematical problems or philosophical riddles, is less unequivocal.

[dakoski]

The point as above is looking at the consistency of naturalism with the reliability of our cognition and reasoning. Its not addressing the consistency of our experience with the reliability of our cognition and reasoning - that's not a topic addressed in his argument. In fact, he argues given our experience he does think our cognition and reasoning are reliable.

And yet sometimes we're wrong. Which, according to his theory, means his god messed up, right?

In my view, Christians are wrong; in Plantinga's view, atheists are wrong. Why, if there is a god, would anybody be wrong?

Since error does happen, we know that there are no gods.

-

That's not a good argument, of course, but it is every bit as good as Plantinga's argument.

I don't think Plantinga is claiming our reasoning is infallible - there's an important distinction between reliability and infallibility.

[dakoski]

[Replying to post 9 by wiploc]

You having him saying that "The probability of reliable cognition and reasoning is low or uncertain if evolution and naturalism are true." That is only significant to his argument if that reliability would be higher on theism. So the fact that reliability has not been shown to be higher on theism is a full refutation of his argument.

Suppose I point out that, on naturalism, there was essentially zero chance that evolution would produce you. If my point is that I must know black magic, because how else can we account for the fact that evolution produced you against all odds, then you are entitled to point out that I haven't shown how the odds would be better if I knew black magic.

You would be entitled to argue that. It would be on point. You would be entitled to ignore any suggestion that we ought to delay that discussion until later because right now we are discussing the odds of naturalism producing exactly you. Because your point would not be an aside or a distraction, it would be a full refutation of my argument. The essence of Plantinga's argument--even if it remains implicit--is that our mental state is more likely on theism than on atheism. Since he hasn't yet made that case, his argument fails.

You've misunderstood, the point of his argument is to attempt to show that naturalism is internally incoherent. So the internal coherence of theism, although interesting, is outside the scope of that argument.

You have him saying, "Therefore believing both naturalism and evolution is self-defeating and can’t be rationally accepted." He wants us, like Pascal, to assume a dichotomy: Either naturalism is true, or Plantinga's god exists.

He implicitly argues that our minds are more likely if his god exists. He says our minds are much more likely to have resulted from his god than from natural causes. So much more likely that it is irrational to believe in naturalism.

To reach that conclusion, he would have to show that our minds would be likely to result from the existence of his god. He hasn't shown that. He doesn't have a case.

I showed the conclusion that he could have drawn, that a logical person would have drawn. I showed that in order to contrast it to the conclusion that Plantinga drew.

Again, the point of the argument is to attempt to show that naturalism is internally incoherent. But yes you are right that of course Plantinga does think that theism is more internally coherent - but the comparison of the two worldviews is a different argument altogether all be it related.

[dakoski]

[Replying to post 1 by dakoski]

Alternatively, one can affirm Plantinga’s argument and acknowledge the inherent unreliability of our senses as well as our minds. That's why optical illusions are a thing, that's why logical fallacies are a thing, that's why religions are a thing. We have to be extra careful not to fall into those traps. As such his arguments are not defeaters for naturalism/evolution, given we are indeed careful with our thinking on those topics.

If one was to argue that being extra careful doesn't help as even our best attempts at rationality is in itself unreliable, then the argument can be rejected out of hand for pragmatic reason, as we reject strict solipsism out of hand. The somewhat reliable capability of our senses and reasoning prowess, are taken for granted.

That would work if we had an objective method to evaluate and correct our unreliable senses and cognition. Does such a method exist that can lead to objectively valid conclusions?

I think we both agree that the scientific method can provide that function, an objective method of identifying logical fallacies and faulty reasoning. But what is the scientific method? Its the use of our minds and our senses. If, given naturalism, our senses and reasoning are questionable, why would we take for granted the conclusions of our senses and reasoning that our senses and reasoning are somewhat reliable?

I get that's the pragmatic response - and you have no choice if naturalism is true - but though avoiding sollipism how do you avoid the abandonment of the objectivity of truth and the scientific method.

[dakoski]

The question to me seems to be whether hereditary traits that promote survival also generally promote truth-discerning ability (is that what is meant by reliable cognition?).

Plantinga seems to jump to conclusions by labelling reliable cognition as low or uncertain if evolution and naturalism are true. He gives arguments based on scientific research that suggest possible areas of less reliable cognition due to evolution. But I would dare say there are many studies which also point to evolution favoring more reliable cognition in order to stay in harmony with survival.

So basically I don't see how it follows that if one believes naturalism and evolution to be true, they should also believe it's associated with low or inscrutable reliable cognition. Inscrutable maybe, but low seems a very far stretch to me.

Yeah that's correct, Plantinga is questioning whether selecting on hereditary traits on the basis of survival and reproductive success necessarily lead to truth-discerning ability.

Yeah, I'm with you that inscrutable is more persuasive. His argument for low is based on using Bayesian conditional probabilities and assessing the impact on the estimate for reliability when varying the probabilities - his base estimate is 0.41 probability of our cognitive faculties being reliable and I think his most optimistic probabilities go up to around 0.6. I can take you through the scenarios if you want as it only makes sense when you go through what probabilities are going in and how they impact the estimate- but I assumed people wouldn't be interested so left it out. The other option is just to say all these probabilities are inscrutable.

[dakoski]

It occurs to me, that so far as survival is concerned, there may be a hierarchy of truths according to their relevance to our continued existence. So, for example, it may have been absolutely vital that our fore-fathers could tell the difference between the paw-print of a woolly mammoth, and the paw-print of a sabre-toothed tiger. And, arguably, we may have evolved the senses to spot that kind of difference.

On the other hand, it may not have made that much difference to the survival of our ancestors whether they thought the earth spherical, or flat, and balanced on the back of a turtle. So, we did not evolve the senses to decide between such options.

Yeah I think that's approximately what Plantinga is arguing, on the assumption that naturalism is true.

That is why we need science, and scientific method, to distinguish between what our senses tell us, and what is true. Or, at least, the difference between what our senses tell us, and what is not true.

The problem would be that the scientific method relies on the objective validity of our reasoning to infer conclusions about the world from the data of our sensation and perception. But if our minds aren't capable of generating reliable inferences then the scientific method can't help us.

[William]

[Replying to post 4 by Divine Insight]

Is Plantinga aware that we are a member of the Great Apes family of primates? Had we not evolved to a high level of tool usage we would be no different from all the other Great Apes.

Apparently 2% difference in DNA is the Margin of Difference. Without it our forms would not have evolved as they did. The difference is not a mere thing but an extraordinary one. An anomaly of nature - humans are far more different than any other biological critter on the planet. We actually should be no different than the rest of the 'Great Apes' and pointing out the 98% similarity does not change this fact.

It is the 2% which enabled us to evolve to a high level of tool usage, but what isn't suggested in that statement is that not only do we USE tools, we CREATE them as well. We actually take the raw materials available from the planet and we create intricate and versatile devices from them.

Show me the Great Ape which is 'basically human' while you show me the human that is 'basically Ape' and I will show you how ridiculous the comparison is in terms of reality.

An anomaly of natural process definitely occurred, as is evident in humankind.

[2ndRateMind]

The problem would be that the scientific method relies on the objective validity of our reasoning to infer conclusions about the world from the data of our sensation and perception. But if our minds aren't capable of generating reliable inferences then the scientific method can't help us.

Indeed. But this would be a self defeating argument. If our minds can't depend on our reasoning, they cannot depend on any reasoning that supports the conjecture that our reasoning is undependable. (I make allowances for individual errors, on the grounds that free, open debate allows for human progress on the whole).

And, it has to be said, since the invention of scientific method, humanity has made much progress with the understanding of the universe, and what it contains, both on the macro (galaxy scale and beyond) and the micro (sub-atomic scale and smaller) levels. Where our theoretical findings are consistent with our experimental findings, we have cause to be, to some extent, confident in the mind's capacity to reason, and the practical relationship between that reasoning and the way reality is.

Best wishes, 2RM.