An Evolutionary Argument Against Naturalism - Alvin Plantinga at USC

welcome to the Veritas forum engaging University students and faculty in discussions about life's hardest questions and the relevance of Jesus Christ to all of life hang in there I can promise I'll actually get here so first of all let me say it's a pleasure to be here I think I've been at USC once before some a fairly long time ago it's nice to be here again and Christy thanks very much for your introduction I'm a philosopher as crispy said and I don't actually make any apologies for that that's just what I happen to be so I don't have that much choice about it at least not now anymore I'm a philosopher and one thing philosophers are really interested in is method you know what your method philosophers argue with each other about that what's your method well my method is such and such what sure well so the thing and so on so there's this thing about method so I should probably tell you about my method to start off with well when my father was a student at Calvin College which is off the college I went to and I taught there for some time there was another student there named Mikey Phi comma and Psyche Phi Comeau was a he was a very interesting guy sort of a joker he became a novelist and he wrote a number of books like the Golden Bowl and Lord grizzly and the primitive and the green earth and various other novels and he changed his name from Phi key Fatima to Frederick Manfred because he didn't think the eastern literary establishment would pay much attention to a guy with a name like flaky flaky though so he became Frederick man for that I hope that was an improvement or not but at any rate he changed his name and well one time he got a hold of book a little book of mine called God freedom and evil which has lots of numbered propositions in it this sort of logical it's got detailed and tries to be rigorous and so on and my key Phi koma who didn't have anything like a much of a head for a philosophy got a hold of this book and he read it and he wrote me and he said he really admired this book he especially really admired my method the sort of careful logical step-by-step rigorous method he said he really thought that was great he said he liked it almost as well as his own method which was just guessing so so so much for method so the title of my talk is an evolutionary argument against naturalism and I hope you all have copies of the handout that goes with it that'll make life somewhat easier if you do it'll be somewhat harder if you don't so when I speak of evolution I just mean what you know what we learn about in high school and college courses in biology the idea basically that all the enormous variety you find in in the living world at present comes by virtue of development from simpler antecedents where the developments work basically by virtue of some form of genetic mutation random genetic mutation they say some form of genetic variation on the one hand and then on the other hand natural selection which selects the sort of fit mutations and discards the rest and as a result of this process here we are here we and all the rest of the living world is that's evolution and then when I use the word naturalism what I mean is really the belief that there's no such person as God or anything like God so naturalism is stronger than atheism naturalism entails atheism but atheism doesn't entail naturalism you can be an atheist without rising to the heights of or sinking to the depths of whatever you think is appropriate naturalism so for example someone like Hegel who thought there was this giant absolute this great absolute that includes all of reality somehow but didn't think there was an omnipotent omniscient wholly good person such a person would be would be an atheist but would not be a naturalist so naturalism as I say is stronger than atheism now naturalism and atheism I'm sorry naturalism and evolution are usually thought of as bosom buddies or easy bedfellows or as supporting each other evolution is often thought of as kind of a pillar in the temple of naturalism if naturalism does in fact have a temple but I want to argue that they don't fit together I want to argue that one can't sensibly be both a naturalist and accept evolution as evolution isn't ordinarily thought of I want to say they clicked with each other they go against each other the conjunction of the two naturalism and evolution I want to argue shoots itself in the foot or if you want a more complicated lurid sounding way to put it is self referential II incoherent alright that's what I want to argue and I propose to argue this that is I think Christians not only ought to be against naturalism I mean you can't very well be both a Christian and The Naturalist you can't at all but they shouldn't just merely assert that naturalism is false I think Christians ought to provide arguments here we're enjoined in the New Testament to always to be ready with a reason for the hope that is within us so I think the Christian community Christians students and the like ought to be willing to give arguments this sort and that's what I propose to do this argument I mean I realize you're not all philosophy majors I learned to my dismay that not all USC students are philosophy majors but that's the way it is so it so maybe people for people that haven't had much philosophy there might be bits of this lecture that are a little tough but that's life the preceding speaker this afternoon said he had this sign in his office that said think okay well I endorse that I think we should think right okay so so so now the argument that's sort of the introduction here's the argument and I'll start on the first page there with the problem so according to theism belief in God we human beings have been created by a holy good all-powerful and all-knowing being namely God who has created us in his own image made us like him who has aims and intentions he intends certain things aims that certain things should happen and can act in such a way as to bring accomplish those aims that's part of what it is to be a person so there is God on the one hand in the theistic story who has created the world and then on the other hand there is creation that which he has created you might think of naturalism this isn't exactly accurate but it's in the general neighborhood as the theistic world picture - God not wholly accurate but in the general neighborhood among famous naturalist well-known naturalist there would be Carl Sagan the late Carl Sagan with his portentous incantation the cosmos is all there is or ever has been or ever will be also the late Stephen Jay Gould David Armstrong the philosopher the later Darwin well I say the later Darwin I mean the late Carl Sagan that means he has died when I say the later Darwin I don't mean he's more dead I'm just talking about the second part of the later part of his life other famous natural ists would be John Dewey and Bertrand Russell Richard Dawkins his book the blind watchmaker which is a really interesting well-written and book that I strongly recommend to you despite the fact that I think it's totally wrong and misguided there is well I mean a lot of really totally wrong and misguided books are very much worth reading this is one another one is a book by Daniel Dennett called Darwin's dangerous idea Daniel Dennett is another such naturalist john lucas a philosopher at former philosopher Oxford says that naturalism is the contemporary orthodoxy of the Academy maybe that's right maybe maybe not but in any event naturalism is strong in the Academy certainly among philosophers now my argument will have to do with cognitive faculties memory perception the faculties whereby one forms beliefs the faculties whereby one knows things memory perception insight whereby you can learn about you learn mathematical truths let's say and logical truths may be reads sympathy whereby you know about what other people are thinking and feeling induction whereby you can learn from experience so these would be cognitive faculties and and in brief here's how my argument will go I'll argue that if naturalism and evolution if that pair of propositions if that conjunction if they were both true then it would be improbable that our cognitive faculties memory and so on and so on improbable that they are in fact reliable that they give us for the most part true beliefs all right well once you see that then if you accept naturalism and evolution you have a defeater for this proposition that your cognitive faculties are reliable a reason to give that proposition up a reason not to believe it and once you have a defeater for that proposition that your cognitive faculties are reliable then you have a defeater for any proposition that you take to be produced by your cognitive faculties naturally that's all of them I mean where else would they come from so you then have a defeater also for naturalism and evolution itself for that conjunction naturalism and evolution itself so you might say it's self-defeating it's it's it's self referential II inconsistent alright that's the structure of the argument and now you can go home you've heard the argument no there's a little more to it all right so what a fill in the details in the next bit here when according to a theory human beings have been created in God's image an important part of which involves the reliability of our cognitive faculties the ability to know things about ourselves in our world and Thomas Aquinas so for example gives expression to a Christian way of thinking about this he says there in these next two little quotations since human beings are said to be in the image of God in virtue of their having a nature that includes an intellect there in the image of God because they've got an intellect they can understand and know such a nature when with an intellect is most in the image of God in virtue of being able most to imitate God so he thinks of this ability on our parts to know as the most important part maybe of the image of God in human beings and he goes on to say only in rational creatures is there found a likeness of God which counts as an image only in rational creatures creatures with wrought Co with Reason creatures who can know and understand as far as the likeness of the divine nature is concerned rational creatures seemed somehow to attain a representation of that type in virtue of imitating God not only in this that he is and lives and we too are and lived but especially in this that he understands he understands and so do we he has knowledge and by virtue of being in His image so do we and most of us would think at least if we thought about it that at least a function of our cognitive faculties memory and the like a function of these faculties is to provide us with true beliefs that's what they're for and we'd ordinarily think that when they're functioning properly when there's no dysfunction or malfunction anything like that then for the most part that's what they do of course it's true that that if let's say there are five witnesses to an auto accident you might get five different stories but there will be an underlying level of agreement people will agree at least roughly on the location of the accident they won't be that some thought it took place in China others thought it took place in Los Angeles it won't be there'll be a rough agreement on the number of cars involved it won't be that one person thinks there was a one car accident somebody fell asleep and ran off the road but another witness thinks no it's one of those 95 car Los Angeles freeway crack-ups there'll be agreement that it was in fact an automobile accident and not for example a volcanic eruption or a naval disaster of some sort and there were even deeper levels of agreement than that there will be agreement that there are such things as automobiles that people use them to accomplish their purposes which in the case of automobiles ordinarily involves going somewhere that automobiles won't work well on the surface of the Moon or the bottom of the ocean that if you drop one out of a helicopter it will ordinarily fall down rather than go up and so on all right now so so our assumption is that when our faculties functioned properly then for the most part not always not when they're working at the very limits of their ability as in some of the far reaches of contemporary physics cosmology for example but for the most part they will produce truth when they're functioning properly but isn't there a problem here for the naturalist at any rate for the naturalist who thinks that we and our cognitive faculties have arrived on the scene after some billions of years of evolution by way of natural selection genetic drift and other blind processes working on sources of genetic variation like random genetic mutation isn't isn't there a problem there initially I mean if that's how you think of it wouldn't you be sort of surprised at the idea that our faculties are in fact reliable Richard Dawkins according to Peter Medawar Peter Medawar was one of the outstanding biologists of the last raishin Richard Dawkins according to Peter Medawar was one of the most brilliant of the rising generation of biologists this is some time ago he once leaned over and remarked to AJ ere the philosopher at one of those elegant candlelit Bibulus Oxford College dinners and if you haven't seen an Oxford College dinner you haven't seen elegant candlelit and bibulous he once leaned over to him and said he couldn't imagine being an atheist before 18 before 1859 which was the year Darwin's Origin of Species was published he said although atheism might have been logically tenable before Darwin no contradiction in it Darwin made it possible to be an intellectually fulfilled atheist so said Dawkins and then here's a little quotation from the blind watchmaker I won't read that now but you can take a look at that so Dawkins thinks Darwin made it possible to be an intellectually fulfilled atheist but maybe Dawkins is dead wrong here I mean the way in which he was thinking what he was thinking really was this prior to Darwin there wasn't any very good answer an atheist could give to the question where did all these different forms of creatures come from how did all this variety of life show up here on earth the Christians would say and theists generally would say things like well God created him that's how they got here he thought it'd be good to have all this wide variety and hence there is this wide variety of animals and plants but that sort of answer of course wouldn't be open to an atheist and and evolution Darwinism gives the first sort of serious suggestion as to a sort of answer an atheist could give that's why Dawkins thinks Darwin made it possible to be an intellectually fulfilled atheist but I want to argue that Dawkins is dead wrong here that the truth lies in the opposite direction that you can't sensibly accept both of these two things if if Darwinism is correct if that is correct if evolution and naturalism their conjunction is correct then the ultimate purpose of our cognitive faculties would be survival or perhaps survival through through childbearing reproductive age or perhaps maybe we should say their ultimate purpose would be the maximization of reproductive fitness so if they have a purpose that's what it is their purpose isn't to provide us with true beliefs but to do this other thing to maximize fitness so here's a quotation from a naturalist philosopher Patricia Churchland she says boiled down to essentials a nervous system enables the organism to succeed in the 4 FS feeding fleeing fighting and reproducing this is that's what Churchland says and I'm not responsible for what she says I'm just the messenger here that's what she says so the principal chore she says of the nervous system is to get the body parts where they should be in order that the organism may survive that's what they're for that's what our cognitive faculties our nervous system our cognitive faculties that's what they're for improvements in sensory motor control confer an evolutionary advantage a fancier style of representing and she would think of believing beliefs as examples of representations or of representing a fancier style a more developed style a more complex style of representing more sophisticated style is advantageous so long as it is geared to the organisms way of life and enhances the organisms chances are survival truth whatever that is definitely takes the hindmost so what she means when she says truth whatever that is definitely takes the hindmost what she means is something like natural selection really doesn't care what you believe natural selection doesn't select for true beliefs it doesn't care what you believe natural selection cares how you behave in the broad sense in a broad sense of the Turner behave it cares what what you do and it cares what your bodily structure is like and so on but it doesn't care what you believe it rewards adaptive behavior and punishes maladaptive behavior but it just doesn't care one way or another about true behavior I'm sorry about true beliefs or about false beliefs all right Darwin himself I'm skipping a couple little bits there Darwin himself recognized a problem here with me says Darwin the horrid doubt always arises whether the convictions of man's mind I don't think he means just men's mind as opposed to women's weather which has been developed from the mind of the lower animal whether these convictions are of any value or are at all trustworthy would anyone trust in the convictions of a monkey's mind if there are any convictions in such a mind this is from a letter Darwin wrote to one of his friends and we could call so I mean here he's raising this very question the horrid doubt always arises whether the sorts of beliefs human beings come up with whether they are of any value or at all trustworthy given how how ourselves have come to be given how our belief producing processes or faculties or mechanisms belief producing mechanisms to make it sound sort of more scientific given how those have developed is there any reason to think there at all trustworthy so we could call that Darwin's doubt and in a way this lecture is really devoted to a kind of exposition of Darwin's doubt if you want to you could think of it therefore as a footnote to Darwin okay Darwin's doubt so that section there next section well one thing we might ask ourselves is well how exactly shall we understand Darwin's doubt what more precisely is how can we put this doubt and one possibility would be I think something like this if I had a blackboard here I would write on it something like this he the suggestion is that the conditional probability of a proposition are namely that our cognitive faculties are reliable given naturalism and evolution call that in Andy that conditional probability is low now conditional probability this is a notion that we all employ all the time so for example you might ask what it's the probability of one proposition given or assuming some other proposition so you might ask what's the probability that that mr. a will live to be seventy given that on the condition that is now thirty five enormous leo overweight eats nothing but junk food doesn't watch his diet at all and gets absolutely no exercise well maybe that probability is fairly low on the other hand you might say what's the probability that mr. B will live to be seventy given that mr. B is now a 65 runs ten miles every day is watches his diet like a hawk and has grandparents all of whom lived to be over a hundred that probability is going to be a lot higher all right the conditional probability the probability of one proposition on another proposition taken as condition you might say what's the probability that jock is a Mormon given that jock lives in Glasgow Scotland probably not too high not very many Mormons in Glasgow what's the probability that Brigham is a Mormon given that Brigham lives in Salt Lake City that probability is going to be much higher all right so you get the idea of conditional probability well now I say here then in the note perhaps Darwin and Churchland mean to propose that a certain conditional probability is low the probability of human cognitive faculties being reliable given that human cognitive faculties have been produced by evolution Dawkins blind evolution the blind watchmaker unguided by the hand of God or any other person if naturalistic evolution is true then our cognitive faculties will have resulted from blind mechanisms like natural selection working on this on sources of genetic variation like random genetic mutation and the ultimate purpose or function church sermons chore of our cognitive faculties if they have a purpose or function will be survival of individual or species or gene or genotype then it's unlikely that they have the production of true beliefs as a function so the probability of our faculties being reliable given naturalistic evolution would be fairly low and so what I'm arguing here is if we can put it we can write it like that the probability of our given in Andy right the probability of one proposition given another proposition the probability of are given in an e where n is metaphysical naturalism the view that there's no such person as God and crucial to this view of course is well that here it says there's no such person as God as the god of traditional theism where E is the proposition that our cognitive faculties have arisen by way of evolution and where R is the claim that our faculties are reliable so our question is this what's the probability of our given in an E and what I propose to argue following Darwin in tricks in here is that that probability is relatively low so now section 1 under B then the doubt developed so suppose we think first of all not about ourselves and our ancestors it's harder to think about this question in thinking about ourselves because we naturally assume that our cognitive faculties are reliable and we sort of import that assumption into the into the discussion so let's think instead about a hypothetical population of creatures rather like ourselves on a planet similar to earth just as Darwin proposed that we think about another species such as monkeys when when he gives us a statement of this problem all right suppose these creatures have cognitive faculties they hold beliefs they change beliefs they make inferences and so on and suppose these creatures have arisen by way of the selection processes endorsed by contemporary evolutionary thought what's the probability that their faculties are reliable so let's suppose that naturalism holds for these creatures and that he also holds what's P of R on any specified not to us but to them to these creatures ok that's our question well now the first thing to see of course is that it's probably likely that their behavior is adaptive their behavior is Fitness enhancing but nothing so far follows about their beliefs everything really depends on the relation between belief and behavior right as to what we can expect as to what this probability is with respect to them and what I want to do next is is think of four different situations four different ways that behavior and belief can be related and I want to argue that the probability of our on each of those four together within an e is low or at least not very high and that will enable me to conclude that the probability of R on any simpliciter in an e in itself is fairly low all right so then there'd be four possibilities I'll just kind of skip one of the four but there will be four and the first of these is epiphenomenalism which is rather a mouthful epiphenomenalism that's a good term to use in case you get in a dispute with your parents or your wife or husband you can fear if you're starting to lose the argument you can say oh well you're just an epiphenomenon list and turn on your heel and and and leave all right this term was first produced by T H Huxley who was a friend of Darwin's he was called Darwin's bulldog and and that's because Darwin himself was rather a shy retiring person who did not like mean nasty intellectual disputes he didn't like that sort of thing but given the sort of thing he said he often was involved in them so he would take Huxley along and then when things got really tough you know and people start really attacking him he would say Sikkim Huxley and he turned the argument over to Huxley so he became to be called Darwin's bulldog now th Huxley said what he thinks the way things go with respect to belief in behavior is that beliefs don't cause behavior at all beliefs don't get into the causal chain leading to behavior he likened the relation between beliefs and mental life generally to the body he said this is sort of similar to the relation of the whistle of a steam engine and by the whistle I don't mean the device that produces the whistle but just the whistle itself the sound to the steam engine it's not that the whistle has any causal impact on the steam engine rather the whistle is caused by the steam engine so if that's the way it were with respect to beliefs then if beliefs didn't cause behavior at all then although evolution can modify belief I'm sorry can modify behavior it wouldn't be able to modify belief in the direction of true beliefs belief would be you might say evolution would be invisible to evolution and then the fact that these creatures that during their evolutionary history they came to have beliefs that would confer no probability at all on the idea that these beliefs are mostly true or mostly nearly true rather than being wildly false indeed the probability of there being mostly true would have to be estimated as fairly low because for their beliefs to be mostly true say for 75% of them to be true if it were the case that for any particular one belief the probability that it's true is a half then if they had say a thousand beliefs the probability that three-quarters of them would be true and that would certainly be a rather low requirement for reliability that probability would be extremely low something like 10 to the minus 59th I think it is okay so it could be that one of these creatures believes is that that elegant fibulas oxford dinner when in fact he's logging his way through some primeval swamp desperately fighting off hungry crocodiles JM Smith the famous biologist a few years ago Time magazine wrote a piece about JM Smith and in it they said this they said a few years ago he wrote James Smith wrote John Maynard Smith they had never understood why organisms have feelings after all he says Orthodox biologists believe that behavior however complicated however complex is governed entirely by biochemistry so what causes behavior will be biochemical reactions in the brain and nervous system and that the attendant sensations fear pain wonder love we might add belief are just shadows cast by that biochemistry not themselves vital to the organisms behavior not themselves causing behavior on the part of the organism all right so that's one of these four possibilities then for the relation between belief and behavior now a second one this second one is probably the hardest one to wrap one's mind around here the second one let's think of it like this if you are a naturalist you will also very likely be a materialist about human beings you'll be you'll think human beings are material objects you won't think that the human beings have an immaterial soul or self or that human being is an immaterial self or mind you'll think a human being is a material object well now from that point of view what sort of thing would a belief be we do have beliefs what kinds of things are these police what would be their you might say what is their makeup what are they made of what do they like well the only real possibility one can think of here is that beliefs would be something like long-standing structures or events in one's in one's nervous system in one's brain for example or some other part of one's nervous system so a belief would be like a whole bunch of neurons working together a collected bunch of neurons and a kind of structure and such a thing if it's a belief that will have two kinds of properties there'll be two kinds of things you can say about it two kinds of attributes on the one hand it'll have neuro physiological or electrochemical properties right properties that specify how many neurons there are on this particular structure and what the rate of fire in the various part of the structure of the neurons but this rate of fire is and how these how these neurons are related to each other how they are connected with each other and how they're also connected to other such structures or how they're also connected to to a muscles so that they can send electrical impulses down chains of neurons cords of neurons which would be nerves to muscles causing muscular contraction and therefore behavior all right that's those these would be electrochemical or neuro physiological properties of a belief of a structure of that sort which is which is what a belief is a neural structure or event long-standing event one kind of property but if this thing is really a belief if the structure is a belief then it's got to have another quite different kind of property it has to be the belief that P for some proposition P it has to have a certain content it has to be related to a certain proposition in such a way that it's the belief that that proposition is true so maybe the proposition is that there something like there once was a brewery where the Metropolitan Opera House now stands that would have to be the content that would be the content of a certain belief the belief which was the belief that once there was a brewery where the Metropolitan Opera House now stands all right so two quite different kinds of properties neuro physiological properties on the one hand and this content property on the other hand a belief then will have both these two kinds of properties and the second of these four possibilities can be stated like this beliefs do cause behavior after all a belief would be a neurological structure that sends that sends electrical impulses messages you might call them down the nerves to behavior I mean down the nerves to muscles causing muscular contraction and therefore behavior they do cause behavior all right contrary to the first possibility but it's only by virtue of those neural physiological properties or electrochemical properties only by virtue of those properties not virtue of the content properties all right now what is this by virtue of stuff you might say well I mean don't have time to go into this very deeply but you might think about you might think about a rock or a ball that hits the window and causes it to break this ball may very well have lots of different kinds of properties it might be Sam's favorite baseball it might have the property of having been made in a certain factory that might have existed for a certain length of time but it's none of those those properties don't have anything to do with its breaking the window the properties by virtue of which it breaks the window would be properties like its mass and its hardness its density the velocity with which it hits the window and the like so that illustrates that this point about how one object an object can cause something to happen by virtue of some of its properties but not by virtue of other of its properties some of its properties are relevant to the causal to the causal activity there and other properties are not now the second suggestion here is that beliefs do cause behavior but only by virtue of those neurophysiological properties not by virtue of their content and here - in this case - the probability of R is going to be fairly low because evolution can modify beliefs and belief producing processes in the direction of greater fitness but in so doing there's been no particular probability at all that it would be modifying their contents as well in the direction of greater truth or the or greater reliability on the part of the structures that produce these beliefs well Nick's there's a third possibility I think we'll just skip that one for now and then a fourth possibility this is that the beliefs of these hypothetical creatures cause their behavior by virtue of content as well as neuro physiological properties and are also adaptive what is the probable here on this possibility that their cognitive faculties are reliable well here I'd have to say not as high as you might think beliefs don't causally produce behavior just by themselves its beliefs and desires and other factors that do so together and the problem then is that there will be many there will be any number of different patterns of belief a desire for a given action that will issue in that same action and among those there will be many in which the beliefs are wildly false so imagine that Paul is a priest a prehistoric hominid the exigencies of survival call for him to display Tiger avoidance behavior that just means there's a tiger after him there will be many behaviors that are appropriate fleeing for example one way to get away from a tiger climbing a steep rock face assuming that Tigers aren't that great at rock climbing crawling into a hole too small to admit the tiger this is a large tiger or leaping into a handy lake now when I wrote this I was under the impression that Tigers like house cats don't like water and wouldn't you know a leap into a lake after you but in fact that turns out to be false so so scrub that one if a Tigers after you don't try to get away by leaping into a handi lake bad idea alright ok when I'll take any such appropriate behavior like running away climbing the rock base Paul engages in this behavior B we think because sensible fellow that he is he has an aversion to being eaten and he believes that B is a good means of thwarting the Tigers intentions now my point here is that there are lots of different belief desire pairs that will lead to the same action so here are some sort of fanciful suggestions of other belief desire pairs that will lead to this same action so clearly this avoidance behavior could result from a thousand other belief desire combinations perhaps Paul very much likes the idea of being eaten but when he sees a tiger he always runs off look for a better prospect because he thinks it's unlikely that the tiger he sees will eat him this will get his body parts in the right place as far as survival is concerned without involving much by way of true belief or perhaps he thinks the tiger is a large friendly cuddly pussycat and wants to pet it but he also believes that the best way to pet it is to run away from it I used to we used to have a cat like that if you would walk towards it or run towards it would run away but if you walk away from it then it would follow you or perhaps he thinks the tiger is a regularly recurring illusion and hoping to keep his weight down has formed the resolution to run a mile at top speed whenever presented with this illusion or perhaps he thinks he's about to take part in a 1600 meter race he wants to win and he believes the appearance of the tiger is a starting signal or perhaps dot dot dot dot where the idea of the dots is that you could think of lots of different combinations belief desire combinations that would sub 10 or lead to the very same action here of running away so there are any number of belief and desire systems that equally fit a given bit of behavior so what's the probability then on this fourth suggestion that that R is true in and E together with a fourth suggestion well it's not terribly high I don't know just what to say it is but it's not terribly high and the other two cases I could say that probability is low here all I'll say is it's not terribly high so trying to combine these probabilities then for these four cases in an appropriate way it would be reasonable to suppose that the probability of R of these creatures cognitive faculties being reliable is relatively low somewhat less than 1/2 all right so now return to Darwin's doubt the reasoning that applies to these hypothetical creatures of course so far we've been talking about these other creatures that we've been hypothesizing the reasoning that applies to these hypothetic Reacher's of course also applies to us so if we think the probability with respect to them is relatively low on in Andy we should take the same thing about the probability of R with respect to us something like this reasoning I think is what underlay Darwin's doubt so we should think that P of R on enemy for us is low all right that's the first premise of the argument then P of R on entity is low and next I want to argue this if we accept any if we accept in and E and see that that probability is low then we have a defeater for our belief in our a reason to give up that belief a reason to doubt it a reason to be agnostic with respect to it if R is unlikely or improbable given the way our faculties have come to be that's represented by N and E then we have reason to reject or withhold our okay so first P of R on entity is either lower inscrutable second if we accept entity then we have I'm CEO of leaving out the inscrutable bit so the next bit here section 1 the the doubt developed again I'm going to omit that in the interests of of time ok so then the probability of our on entity is low and if we accept enemy then we have a defeater for R now I want to give a couple of analogies to support that second suggestion that if we see that the probability of R on any is low then we have a defeater for R so here's the first analogy Freud in thinking about belief in God famously said that belief in God is a matter of wish fulfillment he said we human beings find ourselves in this cold cruel unthinking unfeeling world nature demands from us suffering and pain and anxiety and in the end says Freud she demands our death and if we looked our situation full in the face we would find it totally depressing we would sink into apathy we would not be able to get along property properly we might in fact we might in fact not be able to function at all and might in fact just fall into apathy and die Seoul said Freud what actually happens is we subconsciously and in Freud everything that's important goes on subconsciously we subconsciously project into the heavens a Heavenly Father who we say has created the world and who is really in command and who loves us that's that's where theism comes from that's how come there are lots of people who believe in God well now suppose them I read Freud in an unduly receptive frame of mind after three martinis let's say I'm sitting in front of my fireplace reading Freud drinking martinis all of a sudden it seems to be right Freud is right that's quite right I am a believer in God but now I see belief in God really comes from really as a matter of wish fulfillment it's produced by that cognitive faculty or that cognitive process wish fulfillment well then it seems to me if I think the probability that a belief is true given that it's produced by wish fulfillment is low then I have a defeater for this belief or any other belief that I take to have been produced by wish fulfillment all right that's one analogy a second analogy here it's see on the sheet about the malignant Cartesian demon as many of you know Descartes was thinking about the fact that there are so many different kinds of opinions swirling around in the world it's really hard to know what to think so we finally sat down and he said I'm going to figure this out what can I be really certain of and then once I figure out what I can be really certain up maybe I can move on from there to other beliefs all right so he tries various possibilities he says can I be certain that there's a hand in front of my face well no it's possible that I'm sound asleep lying in bed don't have a hand in front of my face often happened to me in past that I dreamt I was out for a walk would say when the factors of just lying in bed all the time what can I be really certain up he tries various things piney comes on mathematics and he says well at least I could be certain say that two plus one equals three of elementary mathematical truths then he thinks for a minute and his face Falls he says no I can't even be certain of that because it could be that I was created by an evil demon or an evil genius he says an evil demon who delights in creating creatures who think they are epistemic lords of the universe but in fact whose beliefs are nearly all false including their arithmetic all beliefs couldn't that be the case okay well now suppose I think about this again I'm sitting in front of my fireplace drinking martinis and again in an unduly receptive frame of mind I think right you know there really could be such an evil genius and I think my friend Sam was a matter of fact created by such an evil genius right well then I've got a defeater for any beliefs that Sam has that is I won't accept any belief that Sam has unless it's one I've got any Penant reasoned myself to accept but I won't accept any belief on his say-so well suppose I think a little further about this and have another martini and think right I guess I myself also was created by such an evil genius an evil demon then I've got a defeater for R in my case if I think also that it's very unlikely that my cognitive faculties are reliable given that I was produced by such an evil demon okay so that's another example of the same thing okay now for the argument I want to argue that it's irrational to believe in an e here's the argument the probability of R on any is low I'm leaving out the inscrutable part for now if you accept N and E then you have a defeater for R that's what I've been arguing if you accept entity and see that this probability is low then you have a defeater for R but if you have a defeater for are you have a defeater for any other belief B hold so if you have a defeater for our you've got a defeater for any belief you take to be produced by your cognitive faculties and that would be all of your beliefs you'd have a defeater for for each one of them all right now one of your beliefs is in any itself so you have a defeater for that so one who accepts in Annie and sees that the probability of RNA is low has a defeater for it one who accepts entity has a defeater for it a reason to doubt or be agnostic with respect to it if this person has no independent evidence then the rational course would be to reject belief in in Annie if he has no independent evidence in Annie will be self-defeating and hits your rationale well now just one further little step here you can get defeat or for defeat or you can you might form a certain belief which is a defeater of another belief but then get a defeater for the defeater or the defeating belief so you can have defeat or defeat or you could also have the feeder defeat or defeat or and so on right after about three or four repetitions it gets totally uninteresting but so you can have defeat or defeat or maybe in this case the person who accepts entity could get a defeater for this defeat or a defeat or defeat or couldn't be for example go to the MIT cognitive laboratory and get himself tested find out whether or not he's actually is reliable or whether its faculties are reliable or whether as he fears they are unreliable and if they gave him a clean bill of health clean bill of cognitive reliability we might say then wouldn't he have a defeat or defeat her well I don't think that can work out because of course he would be in using in accepting this as a defeat or defeat er he would be presupposing that his cognitive faculties were reliable that they were reliable in telling him that there is such a place as MIT that has got a cognitive laboratory that he was examined there that the scientists gave him a clean bill of reliability etc so as Thomas Reid says the great philosopher Thomas Reid if a man's honesty were called into question it would be ridiculous to refer to the man's own word whether he be honest or not suppose you're worried about whether one of your friends always tells the truth if you're really worried about this you're not going to settle you're worried by just asking him all right the same absurdity there is and attempting to prove by any kind of reasoning probable or demonstrative that our reason is not fallacious since the very pointed question is where their reasoning may be trusted if that's what you're worried about you can't use reason to settle the question so is there any sensible way at all in which the one who accepts any can argue for our well I don't think so any argument he might produce will have premises and these premises he claims gives him good reason to believe are but of course he has the same defeater for each of those premises that he has for our and the same defeater for his belief that if those premises are true then so is his conclusion so this defeater can't be defeated we could also put it like this any argument he offers for our is circular in a certain way naturalistic evolution gives its adherents a reason for doubting that our beliefs are mostly true maybe they're mostly mistaken but then it won't help to argue that they can't be mistaken for the very reason for mistrusting our cognitive faculties generally will be a reason for mistrusting the faculties that produce belief in the goodness of the argument belief that is in the truth of the premises and in the connection between the premises and conclusion so the devil T of enemy has a defeater for any a defeater that can't be defeated in an e therefore is self-defeating and can't rationally be accepted one who contemplates accepting n and is torn let's say between n and theism should reason as follows if I were to accept n I would have good and ultimately undefeated reason to be agnostic about n so I shouldn't accept it the traditional theists on the other hand has no corresponding reason for doubting that it's a purpose of our cognitive systems to produce true beliefs nor any reason for thinking the probability of a beliefs being true given that it is a product of her cognitive faculties is low or inscrutable she may indeed endorse some form of evolution but if she does it will be a form of evolution guided and orchestrated by God and as a traditional theist a Jewish Muslim or Christian theist she believes that God is a premiere nor and God has created us human beings in His image an important part of which involves his giving us what is needed to have knowledge just as he does the conclusion to be drawn therefore is that the conjunction of naturalism with evolutionary theory is self-defeating it provides for itself an undefeated defeater it is therefore unacceptable and irrational thank thank you doctor planning F now we're going to move to in time of question and answers so if you would like to challenge anything he said or there's anything that's unclear now would be the time to do that there are two microphones at the front of the auditorium so if you have questions go ahead and stand up now and make your way to the microphones then we'll make the line behind each and then dr. plan and L will call on people and answer your questions go ahead my question would be that if you have an organism who can't oh all right yeah right I my question is let's say you have an organism who holds false beliefs about its environment like say this organism believes that water is located say in volcanoes or underground that organism is not going to be able to survive so basically in order for one to survive in an environment they have to have correct Bleus about things like resources and things like interactions with other creatures now let me ask you why do you think they have to have correct beliefs as opposed to just acting well with your examples as like the Tiger examples yeah those are functional only in very limited situations so probability is that in most situations if I believe like say when a tiger comes I have to run because I'm going to start a race and I don't feel like doing a race that day then I'm trouble okay yeah well two things first of all remember that you're thinking about the fourth of the possibilities and of course one of the other possibilities might very well be true that is either epiphenomenalism or the second of the possibilities which you might call content epiphenomenalism and as a matter of fact content epiphenomenalism seems much more likely given any and materialism than the fourth possibility because it's hard to see how content could get involved in the causal chain that leads to behavior what really counts is what neuro physiological events happen what signals get sent down which which nerves to which muscles and the like as far as behavior goes and even if a given belief had had given such structure had the opposite content as long as it had the same properties it would issue in the very same behavior but would affect other behaviors sorry it would affect other behaviors as well like it couldn't be an isolated thing because behavior is dynamic and it can be utilized by different sister so I mean so consider all the beliefs together what counts with respect to behavior for them is the way the neurophysiology works not the content that's attached if all the contents were false or half were false but you had the same neurophysiology you'd get the very same behavior so natural selection and can modify behavior in the right direction but the content part isn't it's not going to cut any ice whatever and natural selection that therefore isn't the case that if the content is false the behavior will be maladaptive that's for that second of the possibilities with respect to the third possibility you raise a good a good point namely that I just gave examples having to do a single single pieces of behavior let's say and argued with respect to that single piece of behavior you could have a bunch of different pairs of belief and desire that would yield that behavior you say well yeah but that's just a single one how about a whole can you do the same thing for a whole system of behavior beams like all behaviors which already attract a huge number behavior I'd have to attract a whole huge number and I'd also raise the point let me just answer that first before we go on to the next point the answer at that point it seems to me is this I'm sure you can do that easily you can imagine well here's something from the naturalist point of view itself according to naturalist religion according to them and everybody else knows too is very widespread across the world now religious beliefs are for the most part in their opinion completely false nonetheless they are adaptive so here you have an example of a wide system of beliefs which are in fact adaptive but nonetheless false here's another example because those systems allow groups of people to survive in a whole in communities and so they are adaptive they're quite good for survival they're adaptive but false so what we're looking for here see I'm trying to argue that false beliefs can be perfectly adaptive so the fact that beliefs are adaptive and that there is in fact the connection belief and behavior we ordinary think there is that doesn't suggest that the beliefs are true so thinking about that hypothetical population we agreed that their beliefs are adaptive I'm saying it doesn't it all follow that they're mostly true they could be adaptive but nonetheless mostly false here's another example suppose a tribe certain tribe is such that they think everything is a divine creation and the only way they can refer to things is as the creature that is so and so well then from a naturalistic point of view all their beliefs will be false because every belief will entail that the thing in question has been created is a creature that beliefs will all be false but if they ascribe the right properties to the right so-called creatures their beliefs will nonetheless be adapted so my response is twofold first you were just thinking about the last of the four possibilities but it's the second one that's most likely given naturalism and materialism and evolution and second even with respect to the last false beliefs could be perfectly adaptive one said argue from I agree with that and I would say that many beliefs that people hold are false but they do allow them to survive in an environment also with what you said about your brain so so so far we're agreed right I agree if your brain and your thoughts didn't have a high correlation with your behavior yeah your brain many things am I correct about your second objection to what I said was that thoughts don't necessarily don't necessarily have to lead to behavior yeah beliefs don't have to be right your brain certainly has to be properly connected I'm saying belief doesn't in the sense of the content of a belief the neuro physiological properties of a belief have to be adaptive have to yield the right kind of behavior but it doesn't matter from the point from that point of view it doesn't matter what the content is it could all be false it would make any difference as long as the neurophysiological properties were the same were adapted well I disagree but you disagree yeah well I'm sure maybe a maybe better yeah yes question no question all right okay I'm just curious here are you implying that behavior can't cause beliefs no I'm not implying that nor am i implying that belief can't cause behavior I'm not implying either one of those I'm saying consider materialism and somebody who said accepts in any will be a materialist I'm saying there are these four possibilities for the relation between between belief on the one hand and behavior on the other and I was arguing that in each of these four cases the probability of R will be fairly low but I'm certainly not implying that behavior can't cause belief maybe it does maybe it doesn't it wouldn't have to cause true belief but it could certainly cause belief okay so you're saying that true belief is a direct consequence of God controlling evolution no I'm not saying that I'm just talking about what you have to think of think if you accept in Andy then you've got to think that you've got a defeater for are you don't get this defeater in the case of theism because part of theism is the idea that God has created us in His image so that for the most part not always of course for the most part when our cognitive faculties functioned properly they will produce true beliefs but of course there's nothing like that in the case of naturalism and evolution but you are saying that true beliefs are directly because of theism true beliefs do come from God they can't come from the environment are the probability that one great low they can come from the environment but for the beliefs for our I mean our cognitive faculties themselves have to be a certain way for us to be able to learn from our environment we have to be able to you know I mean we can see that we learned that there is a horse in the neighborhood by seeing but only because our cognitive faculties are such that when there is a horse in the neighborhood where appeared to a certain way and form that belief so I'm not saying that all can't learn from an environment normalise saying that God sort of directly causes every belief or anything like that what I am saying is if you accept naturalism and evolution then you've got a defeater for R and you don't have that from theism not even from theism together with evolution but as it says on the first page the only real difference theism and naturalism is the presence of God yeah so God is directly responsible for well he's responsible for our having true beliefs in the sense that he created us and gave us the kinds of faculties that enable us to have true beliefs yeah key whatever all right yes yeah I got one for you wouldn't beliefs show themselves to be either true or false over time as they're tested through ongoing experience in a wide variety of circumstances not necessarily I mean it could be under say that second scenario where beliefs get involved in the causal chain but not by virtue of their content it could be that our belief life is sort of like a dream life you know in dreams you hold various beliefs and you might even test beliefs and dreams but that doesn't mean you're all likely to wind up with true beliefs it could be the same thing for our for all of our belief life if for example that second possibility were the correct one okay yes is it possible that the content and the like electro chemical properties of beliefs are inseparable they're like what we perceive is the content of our beliefs is like sort of the way our brains read the electrochemical properties so that you know the electrochemical properties of like you know the different things you're outlining here you know cuddly pussycat or whatever the guy thinks the tiger is are all would all have like different electrochemical properties and it's not possible that they can be due to I'm saying that the electrochemical properties would be different than in their brains if that was what the content was read to be I guess yeah I mean this this much would certainly be true that the content would depend on the electric Emma properties of one's brain yeah so that's so on this second possibility content epiphenomenalism on that possibility but content of a given belief I mean the content of your beliefs depends on the neurophysiological properties of these things in your brain on the neurophysiological properties basically of your nervous system yes it certainly does and your nervous system will be differently constituted when you're believing that there's a horse in front of you from when you're believing there aren't any horses around but only say an oyster or a cat or something like that right so in that case wouldn't it the content of our beliefs be reliable then simply because they modify our behavior in a certain way no they would modify our behavior that is the elective the neurophysiological properties would modify behavior in an adaptive direction furthermore the content would depend on the neurophysiological properties but it wouldn't have to be true content whatever the content there is will of course depend on neurophysiological properties but what counts for a behavior will be the neurophysiological properties and the content while dependent on neurophysiological properties can just as well be false as true as far as the adaptiveness of the neurophysiological properties go I guess what I'm saying is like in order to so for example Tino say Tony or Paul the caveman saw his friend get eaten by a tiger so uh saw his friend given by a tiger and that memory modified his electrochemical content in a way that you know it couldn't be modified any other any other way you know it like that it was specifically bad event didn't want to say he saw that that is your assuming there that his cognitive faculties are reliable and produced in him the belief that his friend was being eaten by a tiger yeah right but I'm wondering about you know what reason there is for thinking as cognitive faculties are reliable in the first place given that scenario I mean all we really know is that his behavior is adaptive the question is what can you infer from that about the reliability of beliefs or of his belief producing faculties what can you infer from the fact that his behavior is reliable about the truth of his beliefs so you're saying like if he saw his friend get eaten by a tiger it's possible that he thought it was his friend winning the race and he wanted to win the race tomb that's why he ran or you know so nobody could be thinking anything but I guess I guess what I'm saying then see what would be required is that for adaptiveness here is that when in fact he's in the presence of his friends being eaten or something like that he engages in the right behavior now that could be either if he's got false beliefs and the beliefs do impact on behavior do cause behavior or if he's got if he's got false beliefs and the beliefs don't if they don't enter the causal chain leading to behavior then while his behavior will be appropriately modified when he's in the presence of this animal was Tiger eating his friend he needn't necessarily believe that he could believe anything I mean doesn't matter what the content is what counts as which neuro physiological properties his nervous system displays at that time because that's what causes the behavior I guess I'm sort of discounting like the idea of content in general that there is content for belief that is separable from the actual adaptive behavior well there certainly is content separable from behavior I mean you know right now I'm holding certain kinds of beliefs but these beliefs aren't just my behavior I could hold those beliefs and not engage in this kind of behavior or I could hold I got to engage in this behavior but not hold those beliefs we can't really it doesn't make sense to identify behavior with beliefs that's sort of the root of behaviorism and it simply doesn't work out I mean how would you say what it is in terms of behavior to believe that seven plus five equals twelve what you might say it means when it would be for example to be disposed to say yes when people ask you where there's seven plus five equals twelve but you could do that even if you didn't believe it if you could just thought people like to hear you say that or for whatever reason you know I mean if you try actually to spell out some proposition about your behavior which is equivalent to your whole given belief you really can't do it people have gave that up for you know like 50 years ago just because they couldn't do it I had a couple comments and then I had a question which is probably very repetitive but what repetitive as to other questions and stuff you've already talked about but I guess I just don't personally understand first of all I wanted to mention that the scientific community no longer holds that Freud's ideas are necessarily correct true and they also don't hold the date cards ideas are correct course we don't write the example I just wanted to clarify that okay so the point here so far is the side of the community doesn't believe Freud or Descartes right right even though those were two of the Mannings but I mean I didn't suggest that they did right right they use those examples I just have an example right right so the question I had was why does it matter that if for instance it believes is false as long as it still produces an adaptive behavior it doesn't matter as far as the behavior goes but if what you're interested in is true beliefs it does matter I mean what you want is true beliefs then if you're interested in you know in knowledge but I'm saying in order for evolution to work and for natural selection to operate on evolving organisms it doesn't matter really what the content oh so that organisms mind is they could believe that you know the floor is God or something you know does really matter right as long as they were still successful in their environment and adapted right right that's my point see so given that well I wanted a clarification right so what's that which is why I'm asking for clarification as I think you are maybe that's putting it a bit too too bluntly but I mean that's basically right so then the question is well given that then what does the probability you're thinking about these creatures on some other planet that their probabilities are reliable given that they came to be by virtue of naturalism in a naturalistic world and the answer is it slow that was my first premise and then I went on to say given that what you see that then if you accept entity you've got a defeater for our ok in which case you've got a defeated for entity itself then I guess my second point would be that there is a separation between even though this guy over here was asking whether there was or not so let's say there is a separation hypothetically between content and that behavior that is produced by that content yeah and so so even if you have false beliefs at any given moment that is the content even though that may be generating certain behavior however the mechanisms that are for instance learning that content where if you see your friend get eaten by a tiger you say oh I don't want to be around a tiger right it wasn't that it's not that your only thought is that content like I would don't want to be around a tiger because I'm going to get eaten rather you have for instance a general learning mechanism in your brain that has a procedure on to how it operates and learns of the world so that at any given moment the content of your thought or belief may be different so that an organism for instance a human with that is able to learn from its environment can at any given time have false beliefs and learn other beliefs such as a true belief but it doesn't really matter what it you know is it what it knows at any given moment as long as the mechanisms that are operating in the brain in order to allow that organism to survive are successful on the whole so that huh what is genetically passed on is those mechanisms and not the content right that's exactly right I just passed on our belief producing belief producing mechanisms belief producing faculties belief producing processes these are passed on and they're not just on themselves not the beliefs itself and it doesn't matter whether these police producing processes as you say produce mainly true beliefs or not what counts is whether they produce adaptive action and that's totally independent of the truth value of the content right but an organism that can learn from its environment what I'll learn always going to be adaptive now learning you mean form true beliefs or you mean just change beliefs change beliefs the dream that fit into any given environment so that it can survive and as a dad yeah but I mean remember again as you were saying earlier on it doesn't matter for survival whether the beliefs are true or false right what matters is the impact those neural physiological properties have on behavior it doesn't matter whether the beliefs are true or false so what you'll get then is a modification of these belief producing processes so that they produce structures that produce adaptive behavior progressively more adaptive behavior maybe over the generations but again it still doesn't matter whether the beliefs are true or false you're not going to get in that way a high probability of their beliefs being reliable in the sense of mostly true what you'll get is a high probability of their beliefs being such as to produce adaptive action however when one organism reproduces and has offspring that new offspring does not have the content and exact or any of the beliefs in fact absolutely vs organism did and so it adjusts to its environment and generally generationally the species is able to adapt to any given environment no matter the content just true or falsity truth or falsity other beliefs as long as it's automatically viable yeah exactly you and I agree entirely and I'm saying for that reason if you accept any and that is a reliable mechanism sorry everyone sorry large organism it's reliable with that 2d every single generation the brain will adapt to the environment yeah in which realizes you're talking about and is a reliable mechanism not reliable in the relevant sense here reliability is I was talking about it I said a producing process or mechanism is reliable if it produces a preponderance of true beliefs what you're saying is there will be a reliable passing on of mechanisms that are reliable with respect to producing the right kind of behavior and you're also saying but it doesn't matter for that whether the beliefs are true or false so as far as I can see you we are in agreement I wouldn't generalize if if one belief is false and you're generalizing that onto saying that the entire mechanism is therefore unreliable because I can hold false beliefs no not one belief I would say to be reliable I said in the talk that would require say at least three-quarters of the beliefs produced by the mechanism in question to be true but not a hundred percent certainly not for more information about the veritas forum including additional recordings and a calendar of upcoming events please visit our website at Veritas org

Channel: The Veritas Forum

Views: 43,960

Rating: 4.5624123 out of 5

Keywords: veritas forum

Id: PwE_D9GUC0s

Length: 78min 25sec (4705 seconds)

Published: Sat Feb 23 2013

Reddit Comments

[u/[deleted]]

At least the video was sound.

[u/mmorality]

surely trawling YouTube comments is cheating

[u/happyparallel]

When a philosopher is a Christian that pretty much means he's not much of a philosopher.

The dumbest "no true scotsman" I've heard in a while.