Making Sense - Sam Harris - #34 — The Light of the Mind

00:00:00.000 welcome to the making sense podcast this is sam harris just a note to say that if you're hearing

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00:00:38.840 today i'm speaking with david chalmers david is a philosopher at nyu and also at the australian

00:00:53.300 national university and he's the co-director of the center for mind brain and consciousness at nyu

00:00:59.040 david as you'll hear that we've never met was instrumental in my turning my mind toward

00:01:05.680 philosophy and science ultimately because of the work he began doing on the topic of consciousness

00:01:11.260 in the early 90s and i found it fascinating to talk to david his interests and intuitions

00:01:17.880 in philosophy align with my own to a remarkable degree we spend most of our time talking about

00:01:23.900 consciousness and what it is and why it is so difficult to understand scientifically conceptually

00:01:31.160 we talk about the hard problem of consciousness which is a phrase he introduced into philosophy that

00:01:35.980 has been very useful in shaping the conversation here at least has been useful for those of us who

00:01:43.260 think that there really is a hard problem that resists any kind of easy neurophysiological

00:01:49.020 solution or computational solution we talk about artificial intelligence and the possibility that the

00:01:56.960 universe is a simulation and other fascinating topics some of which can seem so bizarre or abstract

00:02:05.640 as to not have any real tangible importance but i would urge you not to be misled here i think all of

00:02:14.220 these topics will be more and more relevant in the coming years as we build devices which if they're not

00:02:22.660 in fact conscious will seem conscious to us and as we confront the prospect of augmenting our own

00:02:30.080 conscious minds by integrating our brains with machines more and more directly and even copying

00:02:36.780 our minds onto the hard drives of the future all of these arcane philosophical problems will become topics of

00:02:46.140 immediate and pressing personal and ethical importance david is certainly one of the best guides i know

00:02:53.920 to the relevant terrain so now it's with great pleasure that i bring you david chalmers

00:02:59.760 well i'm here with philosopher david chalmers david thanks for coming on the podcast

00:03:09.420 thanks it's a pleasure to be talking with you you know i don't think we've ever met are you aware of

00:03:15.040 whether or not we've met i feel like we've met by email but i don't think so i've had uh emails a couple

00:03:20.560 of emails back and forth over the years and uh with annika your wife as well yeah never in person

00:03:26.700 but i recall yeah you know because i feel the reason why i'm confused about this is because

00:03:30.360 and this is almost certainly something you don't know but you um served a quite an important

00:03:37.080 intellectual role in my life i went to one of those early tucson conferences on consciousness

00:03:42.780 oh i didn't know that i think it was probably 95 was it was 94 the the first one yeah 94 was the first

00:03:49.180 small one with about 300 people then it got really big in 96 with about 2 000 people i think i went to

00:03:55.160 95 and and probably 96 as well and i i had dropped out of school and was i guess you could say looking

00:04:02.920 for some direction in life and i i became very interested in the conversations that were happening

00:04:08.120 in the philosophy of mind i think probably the first thing i saw was some of the sparring between

00:04:12.860 dan dennett and and john searle then i noticed you in the journal of consciousness studies and then i

00:04:18.840 think i just saw an an ad probably in the journal for of consciousness studies for the tucson conference

00:04:25.380 and showed up and and i quite distinctly remember your talk there and your articulation of the hard

00:04:33.320 problem of consciousness really just made me want to do philosophy and which led very directly into my

00:04:41.660 wanting to know more about science and sent me back to the ivory tower and i think a significant

00:04:47.120 percentage of my getting a phd in neuroscience and and continuing to be interested in in this issue

00:04:53.760 was the result of just seeing that the conversation you started in tucson more than 20 years ago okay

00:04:59.440 well i'm really pleased to uh to hear that i had i had no idea yeah um might have been the 96 conference

00:05:05.200 if was dan dennett there you said i you know i don't know if i i don't recall if dan was there i i went

00:05:11.120 to boy i've gone to at least two of them and they were in quick succession and i think i think roger

00:05:16.880 penrose was there i remember stewart hammeroff talking at least about their thesis and it was a

00:05:22.900 fascinating time yeah that's the event that uh people call the woodstock of uh of consciousness

00:05:28.480 getting everyone together for the kind of you know getting the band together for the first time it was

00:05:33.560 really a it was a crazy conference it was a whole lot of fun it was the first time i had met a lot of

00:05:37.320 these people too myself actually oh interesting it was very influential for me i feel like i am a bad

00:05:43.840 judge of how familiar people are with the problem of consciousness because i have been so steeped in

00:05:50.720 it and and fixated on it for now decades so i'm always surprised that people find this a novel problem

00:05:59.120 and difficult to even notice as a problem so let's start at the beginning and let's just talk about

00:06:04.660 what consciousness is what do you mean by consciousness and and how would you distinguish

00:06:09.700 it from the other topics that it's usually conflated with like self-awareness and behavioral

00:06:15.700 report and access and and all the rest i mean it's awfully hard to define consciousness but at least i

00:06:21.840 like to start by saying consciousness is the subjective experience of the mind and the world it's basically

00:06:30.380 what it feels like from the first person point of view to be thinking and perceiving and judging

00:06:37.260 and so on so when i look out at a scene like i'm doing now out my window there are trees

00:06:44.740 and there's grass and a pond and so on well there's a whir of information processing where all this stuff

00:06:51.200 you know photons and my retina send a signal of the optic nerve to my brain eventually i might say

00:06:58.000 something about it that's all of a level of functioning and behavior but there's also really

00:07:03.000 crucially something it feels like from the first person point of view i might have an experience of a

00:07:08.020 of the colors a certain greenness of the green a certain reflection on the pond this is a little bit

00:07:15.880 like the inner movie in the uh in the head and the crucial problem of consciousness for me at least

00:07:22.100 is this subjective part what it feels like from the inside this we can distinguish from

00:07:27.480 our questions about say behavior and about functioning people sometimes use the word consciousness

00:07:33.720 just for the fact that for example i'm awake and responsive that's something that can be understood

00:07:39.860 straightforwardly in terms of behavior and there are going to be mechanisms for how i'm responding and

00:07:45.440 so on so i like to call those problems um of consciousness the easy problems the ones about

00:07:51.980 how we behave how we respond how we function what i like to call the hard problem of consciousness is

00:07:58.820 the one about how it feels from the first person point of view yeah there was another very influential

00:08:04.060 articulation of this problem which i would assume influenced you as well which was thomas nagel's

00:08:10.800 essay what is it like to be a bat the formulation he gave there is if it's like something to be a

00:08:18.120 creature or a system processing information whatever it's like even if it's something we can't understand

00:08:23.760 the fact that it is like something the fact that there's an internal subjective qualitative character

00:08:30.660 to the thing the fact that if you could switch places with it it wouldn't be synonymous with the

00:08:36.440 lights going out that fact the fact that it's like something to be a bat is the fact of consciousness

00:08:42.620 in the case of a bat or in any other system i know people who are not sympathetic with that

00:08:49.120 formulation just think it's a kind of tautology or it's it's just a it's a question begging formulation

00:08:55.420 of it but as a rudimentary statement of what consciousness is i've always found that to be

00:09:01.680 an attractive one do you have any any thoughts on that yeah i find it's a uh that's about as good

00:09:07.160 a definition as we're going to get for consciousness the idea is roughly that a system is conscious if

00:09:14.920 there's something it's like to be that system so there's something it's like to be me right now i'm

00:09:20.620 conscious there's nothing it's like presumably to be this glass of water on my desk if there's nothing

00:09:27.480 it's like to be that glass of water on my desk then it's not conscious likewise some of my mental

00:09:34.000 states you know my seeing uh the green leaves right now there's something it's like for me to

00:09:39.220 see the green leaves so that's a conscious state for me but maybe there's some unconscious language

00:09:44.420 processing of syntax going on in my head that doesn't feel like anything to me or some motor

00:09:49.700 processes and the cerebellum and those might be states of me but they're not conscious states of me

00:09:55.800 because there's nothing it's like for me to undergo those states so i find this is a definition that's

00:10:01.280 very vivid and useful for me that said it's just a bunch of words like anything and for some people

00:10:06.400 so for some people this bunch of words i think is very useful in activating the idea of consciousness

00:10:11.740 from the subjective point of view other people hear something different in that set of words like

00:10:17.840 what is it like you're saying what is it similar to well it's like it's kind of similar to my brother

00:10:23.600 but it's different as well you know for those people that set of words doesn't work so what i've

00:10:28.120 found over the years is it this phrase of nagel's is incredibly useful for at least some people

00:10:32.540 in getting them on to the problem although it doesn't work for everybody what do you make of the

00:10:38.120 fact that so many scientists and philosophers find this the the hardness of the hard problem and i think

00:10:45.220 i should probably get you to state why it's so hard or why why you you have distinguished the hard

00:10:51.540 from the easy problems of consciousness but what what do you make of the fact that people

00:10:55.460 find it difficult to concede that there's that there's a problem here because it's i mean this

00:11:02.220 is just a common phenomenon i mean there are people like dan dennett and and the churchlands and other

00:11:07.340 philosophers who just kind of ram their way past the mystery here and declare that it's a pseudo

00:11:16.060 mystery and i you know you and i have both had the experience of witnessing people either seem to

00:11:22.300 pretend that that this problem doesn't exist or they acknowledge it only to change the subject and

00:11:28.360 then pretend that they've addressed it and so let's state what the hard problem is and perhaps you can say

00:11:34.360 why it's why it's not immediately compelling to everyone that it's in fact hard yeah i mean there's

00:11:40.980 obviously a huge amount of disagreement in this area i don't know what your sense is my sense is

00:11:45.520 that most people at least got a reasonable appreciation of the fact that there's a big

00:11:50.340 problem here of course what you do um after that is very different in different cases some people

00:11:57.020 think well it's only a initial problem and we can we ought to kind of see it as an illusion and get

00:12:02.800 past it but yeah this to state the problem i find it useful to first start by distinguishing the

00:12:09.280 easy problems which are problems basically about the performance of functions from the hard problem

00:12:14.740 which is about experience so the easy problems are you know how is it for example we discriminate

00:12:20.660 information in our environment and respond appropriately how does the brain integrate

00:12:27.520 information from different sources and bring it together to make a judgment and control behavior how

00:12:34.320 indeed do we voluntarily control behavior to respond in a controlled way to our environment

00:12:39.900 how does our brain monitor its own states these are all big mysteries and actually neuroscience has not

00:12:46.180 gotten all that far on some of these uh of these problems they're um they're all quite difficult

00:12:52.280 but in those cases we have a pretty clear sense of what the research program is and what it would take

00:12:58.120 to explain them it's basically a matter of finding some mechanism in the brain that for example is

00:13:03.420 responsible for discriminating the information and controlling the behavior and although it's a it's

00:13:10.000 pretty hard work finding the mechanism we're on a path to doing that so a neural mechanism for

00:13:15.940 discriminating information a computational mechanism for the brain to monitor its own states um and and so

00:13:24.020 on so for the easy problems they at least fall within the standard methods of the brain and cognitive

00:13:30.040 sciences where basically we're trying to explain some kind of function then we just find a mechanism

00:13:35.460 the hard problem what makes the hard problem of experience hard is it doesn't really seem to be a

00:13:41.040 problem about behavior or about functions you could explain you can in principle imagine explaining all of

00:13:48.000 my behavioral responses to a given stimulus and how my brain discriminates and integrates and monitors

00:13:56.860 itself and controls you could explain all that with say a neural mechanism and you might not have touched

00:14:03.440 the central question which is why does it feel like something from the first person point of view that just

00:14:10.860 doesn't seem to be a problem about explaining behaviors and explaining functions and as a result

00:14:16.280 the usual methods that work for us so well in the brain and cognitive sciences finding a mechanism that does

00:14:22.840 the job just doesn't obviously apply here we're going to get correlations we're certainly got finding

00:14:29.220 correlations between processes in the brain and bits of consciousness an area of the brain that might light up

00:14:34.900 when you see red or when you uh when you feel pain but nothing there seems yet to be giving us

00:14:41.180 an explanation why does all that processing feel like something from the inside why does it why doesn't it go on

00:14:47.720 just in the dark as if we were giant robots um or zombies without any subjective experience so that's

00:14:55.560 the hard problem and i'm inclined to think that most you know most people at least recognize there is

00:15:00.020 at least the appearance of a big problem here from that point people react in different ways someone

00:15:07.480 like dan dennett says it's all an illusion or a confusion and one that we need to uh to get past and i

00:15:13.920 respect that line i think it's a hard enough problem that we need to be exploring every uh

00:15:19.360 every avenue here and one avenue that's very much worth exploring is the the view that it's an illusion

00:15:25.100 but there is something kind of faintly unbelievable about the whole idea that the data of consciousness

00:15:30.000 here are an illusion to me that the most real thing in the uh universe you know the feeling of pain the

00:15:35.260 experience of vision or of thinking so it's a very um it's a very hard line to take the line that

00:15:41.760 dan dennett takes he took he wrote a book consciousness explained back in the early 90s

00:15:45.780 where he tried to take that line it was very it was a very good and very influential book but i think

00:15:50.080 most people have have found that at the end of the day it just doesn't seem to do justice to the

00:15:56.560 phenomenon to be fair to dan it's been a long time since i've looked at that book i remember that was

00:16:00.780 actually might might have been the first book i read on this topic back when it came out i think in 91

00:16:06.700 does he actually say and this is strange i i i'm very aligned with you and people like thomas

00:16:13.920 nagel on these questions in the philosophy of mind and yet have had this alliance with dan for many

00:16:19.800 years around the issue of religion and and and so it's i've spent a lot of time with dan we've never

00:16:24.680 really gotten into a conversation on consciousness perhaps we've been wary of colliding on this topic

00:16:30.700 and we had we had a somewhat unhappy collision on the topic of free will is it true that he says that

00:16:37.080 consciousness is an illusion or is it is somehow just the the the hardness of the hard problem

00:16:43.860 is illusory that there's a the hard problem is categorically different from the easy problems

00:16:50.760 i i i i completely understand how he would want to push that intuition but as i've said before

00:16:58.460 and i really don't see another way of seeing this it seems to me that consciousness is the one thing

00:17:04.040 in this universe that can't be an illusion i mean even if we are confused about everything even if we

00:17:09.980 are even confused about the the qualitative character of our experience in many important

00:17:16.080 respects so that we're not we're not subjectively incorrigible you can be wrong about what it's like to

00:17:21.520 be you in terms of the details but which is to say you can become a better judge of what it's like

00:17:27.860 to be you in each moment but the fact that it is like something to be you the fact that that

00:17:33.300 something seems to be happening even if this is only a dream or you're a brain in a vat or you're

00:17:38.980 otherwise misled by everything there is something seeming to happen and that seeming is all you need

00:17:47.980 to assert the absolute undeniable reality of consciousness i mean that is that is the fact

00:17:54.980 of consciousness every bit as much as any other case in which you might assert its existence so i

00:18:01.060 just don't see how a claim that consciousness itself is an illusion can ever fly yeah i think um yeah i'm

00:18:10.400 with with you on this i think dan's views have actually evolved a bit over the years on this back

00:18:16.080 in the maybe the 1980s or so he used to say things that sounded much more strongly like consciousness

00:18:22.120 doesn't exist it's an illusion he wrote a paper called on the absence of phenomenology saying there

00:18:27.900 really isn't such a thing as what we call phenomenology which is basically just another

00:18:31.940 word for consciousness he wrote another one called quining qualia which said we need to we just need to

00:18:37.720 get rid of this whole idea of qualia which again is a word that philosophers use for the qualitative

00:18:42.420 character of experience the thing that makes you know seeing red different from seeing green this

00:18:48.500 seem to involve different qualities at one point dan was inclined to say oh that's just a mistake

00:18:53.040 there's nothing there over the years i think he's found that people find that line just a bit too strong

00:19:00.520 to be believable it's just it just seems frankly unbelievable from the first person point of view that

00:19:05.280 there are no qualia there is no feeling of red versus the feeling of green or there is no consciousness

00:19:11.220 so he's evolved in the direction of saying that uh yeah there's consciousness but it's really

00:19:18.340 just in the sense of for example there's functioning and behavior and information

00:19:24.080 encoded there's not really consciousness in this strong phenomenological sense that drives the hard

00:19:31.440 problem i mean in a way it's a bit of a verbal relabeling of the old line you know because you must be

00:19:37.960 familiar i know you're familiar with these debates over free will where one person says uh there is

00:19:43.940 no free will and the other person says well there is free will but it's just this much more deflated

00:19:49.420 thing which is compatible with determinism and it's basically two ways of saying the same thing i think

00:19:54.260 dan used to say there is no consciousness now he says well there is consciousness but only in this

00:19:59.420 very deflated sense and i think ultimately it's another way of saying the same thing he doesn't think

00:20:04.420 there is consciousness in that strong subjective sense that poses the hard problem i feel super

00:20:10.960 sensitized to the prospect of people not following the plot here because it's if it's the first time

00:20:18.400 someone is is hearing these concerns it's it's easy to just lose sight of what the actual subject is i

00:20:24.240 just want to retrace a little bit of what you said sketching the hardness of of the hard problem so you

00:20:29.880 have this the distinction between understanding function and understanding the fact that that

00:20:36.260 experience exists and so you see we have functions like you know motor behavior or learning or visual

00:20:42.100 perception and it's very straightforward to think about explaining these in mechanistic terms i mean

00:20:48.760 so you have something like vision we can talk about the the transduction of light energy into

00:20:53.800 neurochemical events and then the mapping of the visual field onto the relevant parts of in our

00:21:00.280 case the visual cortex and this is very complicated but it's not in principle obscure the the fact that

00:21:07.300 it's it's like something to see however remains totally mysterious no matter how much of this mapping

00:21:15.020 you do and if you imagine from the other side if we built a robot that could do all the things we can

00:21:22.080 it seems to me that at no point in refining its mechanism would we have reason to believe that

00:21:28.820 it's now conscious even if it passes the turing test you see so we could i mean this is actually

00:21:33.120 one of the things that concerns me about ai as it seems one of the likely paths we could take

00:21:38.880 is that we could build machines that seem conscious and and and the effect will be so convincing that we

00:21:45.340 will just lose sight of the problem all of our intuitions that lead us to ascribe consciousness to other

00:21:50.280 people and to certain animals will be played upon because we will build the machines so as to do that

00:21:56.020 and it will cease to seem philosophically interesting or even ethically appropriate to wonder whether

00:22:02.440 there's something that it's like to be one of these robots and yet it seems to me that we will we still

00:22:07.760 won't know whether these machines are actually conscious unless we've understood how consciousness arises

00:22:14.280 in the first place which is to say unless we've solved the hard problem yeah and i think we can um

00:22:19.800 maybe we should distinguish the question of whether a system is conscious from how that consciousness is

00:22:25.540 explained i mean even in the case of other people well they're behaving as if they're they're conscious

00:22:29.840 and we tend to be pretty uh confident that other people are conscious so we don't really regard

00:22:36.440 there as a to be a question about whether other people are conscious still i think it's consistent to have

00:22:41.680 that attitude and still find it very mysterious this fact of consciousness and to be utterly puzzled

00:22:49.020 about how we might explain it in terms of the brain so i suspect that with machines we may well end up as

00:22:55.620 you say just finding it undeniable very hard to deny that machine even if there are machines hanging

00:23:02.780 around with us talking in a you know human-like way and reflecting on their consciousness those machines are

00:23:09.540 saying hey i'm really puzzled by this uh this whole consciousness thing because i know i'm just a

00:23:14.800 collection of silicon circuits but it still feels like something from the inside machines are doing

00:23:19.360 that i'm going to be pretty convinced that they are conscious as i am conscious but that won't make it

00:23:25.460 any any less mysterious well maybe it'll just make it all the more mysterious how on earth could this

00:23:31.360 machine be conscious even though it's collection of silicon circuits likewise how on earth could i be

00:23:37.920 conscious just as a result of these processes in my brain it's not that i see anything intrinsically

00:23:42.840 worse about silicon than about brain processes here there just seems to be this kind of mysterious gap in

00:23:49.620 the explanation in both cases and of course we can worry about other people too there's a classic

00:23:54.960 philosophical problem the problem of other minds how do you know that anybody else apart from yourself

00:24:00.640 is conscious you know descartes said well i'm certain of one thing i'm conscious i think therefore

00:24:06.880 i am that only gets you that only gets you one data point it gets me to me being conscious actually it

00:24:11.780 gets me to me being conscious right now who knows if i was ever conscious in the past anything else beyond

00:24:17.560 that has got to be something of an inference or an extrapolation we end up taking for granted most of

00:24:23.580 the time that other people are conscious but you could try to raise questions there if you wanted to

00:24:27.400 and then as you move to questions about ai and robots about animals and so on the questions just

00:24:33.700 become very fuzzy and murky yeah i think the difference with ai or robots is that presumably

00:24:40.100 we will build them or we we may in fact build them along lines that are not at all analogous to the

00:24:48.060 emergence of of our own nervous systems and so if we follow the line we've taken say with like

00:24:54.280 you know chess playing computers where we have something which we don't even have any reason to believe is

00:24:59.980 aware of chess but it is all of a sudden the best chess player on earth and now will always be so

00:25:08.120 if we did that for a thousand different human attributes so that we created a very compelling

00:25:15.440 case for its its superior intelligence it can function in every way we function better than we can

00:25:23.380 and we and we have put this in some format so that it has the memetic facial displays that we find

00:25:32.180 attractive and compelling we get out of the uncanny valley and and these robots no longer seem weird to

00:25:37.800 us in fact they detect our emotions better than we can detect the emotions of other people or than

00:25:43.420 other people can detect ours and so all of a sudden we are played upon by a system that is deeply

00:25:48.980 unanalogous to our own nervous system and and then we will just then i think it'll be somewhat mysterious

00:25:56.680 whether or not this is conscious because we have we have cobbled this thing together whereas in our case

00:26:02.820 the reason why i don't think it's it's parsimonious for me to be a solipsist and to say well maybe i'm the

00:26:09.120 only one who's conscious is because there's this obviously deep analogy between how i came to be conscious

00:26:14.980 and how you came to be conscious so i i have to then do further work of arguing that there's

00:26:20.280 something about your nervous system or your situation in the universe that might not be a

00:26:25.680 sufficient base of consciousness and yet it is clearly in my own case so to worry about other

00:26:31.360 people or even other higher animals seems a stretch at least it's it's unnecessary and it's it's only

00:26:38.780 falsely claimed to be parsimonious i think it's actually it's it's you you have to do extra work

00:26:44.780 to doubt whether other people are conscious rather than just simply not attribute consciousness to

00:26:50.460 them how would you feel if we met martians let's say there are intelligent martians who are behaviorally

00:26:55.820 very sophisticated and we turn out to be able to communicate with them about science and philosophy

00:27:02.020 but at the same time they've evolved through a completely independent evolutionary process from us so

00:27:07.960 they got there in a in a different way would you have the same kind of doubts about whether

00:27:11.760 they might be conscious yeah well i think perhaps i would it would be probably somewhere between our

00:27:19.260 own case and whatever we might build along lines that we have no good reason to think track the

00:27:26.300 emergence of of consciousness in the universe well it's actually a topic i wanted to raise with you this

00:27:31.500 this issue of epiphenomenalism because it is kind of mysterious it's so the the flip side of the hard

00:27:38.840 problem the fact that you can describe all of this functioning and you seem to never need to introduce

00:27:44.800 consciousness in order to describe mere function leaves you at the end of the day with the possible

00:27:52.460 problem which many people find deeply counterintuitive which is that consciousness doesn't do anything

00:27:58.200 that it's just it is an epiphenomenon which is an analogy often given for this it's like the the

00:28:04.100 smoke coming out of the smokestack of an old-fashioned locomotive you know it's it's always associated

00:28:10.220 with the progress of this train down the tracks but it's not actually doing anything it's it's it's a

00:28:16.300 mere byproduct of the actual causes that are propelling the train and so consciousness could be like the

00:28:24.140 smoke rising out of the smokestack it's not doing anything and yet it's always here that a certain

00:28:29.540 level of function if i recall correctly in your first book you seem to be fairly sympathetic with

00:28:36.760 epiphenomenalism talk about that a little bit i mean it's not epiphenomenalism is not a view that

00:28:41.380 anyone feels any initial attraction for the consciousness doesn't do anything it sure seems to do

00:28:46.760 so much but there is this puzzle that pretty well for any bit of behavior you try to explain it looks

00:28:53.040 like there's the potential to explain it without invoking consciousness in this subjective sense

00:28:58.960 there'll be an explanation in terms of neurons or computational mechanisms of our various behavioral

00:29:05.440 responses i mean the one place where um so at least start to at least start to wonder maybe consciousness

00:29:12.240 doesn't have any function maybe it doesn't do anything at all maybe for example consciousness gives

00:29:18.660 value and meaning to our lives which is something we can talk about without actually

00:29:22.820 doing anything but then obviously there are all kinds of questions uh how and why would it have

00:29:29.100 evolved not to mention how is it that we come to be having this extended conversation about consciousness

00:29:34.160 um if consciousness isn't actually playing a role in the uh in the causal loop so in my first book i at

00:29:40.940 least tried on the idea of epiphenomenalism it didn't come out saying this is definitely true but

00:29:46.140 tried to say okay well if we're forced in that direction that's uh that's one way we can go but i mean

00:29:51.860 actually we're in view i mean this is skipping ahead a few steps is that either it's epiphenomenal

00:29:56.380 or it's outside a physical system but somehow playing a role in physics uh that's another

00:30:02.320 kind of more traditionally dualist possibility or third possibility consciousness is somehow built in

00:30:09.220 at the very basic level of physics so to get consciousness to play a causal role you need to say

00:30:15.980 some fairly radical things i'd like to track through each of those possibilities but to stick

00:30:20.720 with epiphenomenalism for a moment you've touched on it in passing here but remind us of the the zombie

00:30:28.380 argument that i don't know if that originates with you it's not something that i noticed before i heard

00:30:34.800 you making it but the zombie argument really is the thought experiment that describes epiphenomenalism

00:30:41.680 introduce the concept of a zombie and then i have a question about that so yeah the idea of zombies

00:30:46.100 actually i mean it'd been out there for a for a while in philosophy uh before me not to mention

00:30:51.500 out there in the uh in the popular culture but uh the zombies which play a role in philosophy are a bit

00:30:56.960 different from the zombies that play a role in the movies or in the haitian voodoo culture um you know

00:31:02.660 the ones in the movies are all supposed to be all the different kinds of zombies are missing something

00:31:07.360 the zombies in the movie are lacking uh somehow life they're dead but reanimated the zombies in the

00:31:14.220 in the voodoo tradition are lacking some kind of free will well the zombies that play a role in

00:31:19.560 philosophy are lacking consciousness and this is just a thought experiment but the conceit is that

00:31:25.400 we can at least imagine a being at the very least behaviorally identical to a normal human being

00:31:32.600 but without any consciousness on the inside at all just acting and walking and talking in a perfectly

00:31:40.220 human-like way without any consciousness the extreme version of this thought experiment says we

00:31:48.980 can at least imagine a being physically identical to a normal human being but without any subjective

00:31:56.520 consciousness so i talk about my zombie twin you know a hypothetical being in the universe next door

00:32:02.020 who's physically identical to me he's holding a conversation like this with a zombie analog of you

00:32:09.080 right now i'm saying all the uh all the same stuff and responding but without any consciousness now no one

00:32:17.300 thinks anything like this exists in our universe but the idea at least seems imaginable or conceivable

00:32:23.800 there doesn't seem to be any contradiction in the idea and the very fact that you can kind of make

00:32:28.560 sense of the idea immediately raises some questions like why aren't we zombies there's a contrast here

00:32:34.780 um zombies could have existed evolution could have produced zombies why didn't evolution produce

00:32:41.680 zombies it produced conscious beings it looks like for anything behavioral you could point to it starts

00:32:47.660 to look as if a zombie could do all the same things without consciousness so if there was some function we

00:32:53.620 could point to and say that's what you need consciousness for and you could not in principle do that without

00:32:57.720 consciousness then we might have a function for consciousness but right now it seems i mean

00:33:03.020 actually this corresponds to the science for anything that we actually do uh perception learning

00:33:08.960 memory language and so on it sure looks like a whole lot a whole lot of it can be performed even in the

00:33:13.740 actual world unconsciously so the whole problem of what consciousness is doing is just thrown into

00:33:19.060 harsh relief by that thought experiment yeah well yeah as you say that most of what our minds are

00:33:24.940 accomplishing is unconscious or at least it seems to be unconscious from the point of view of the two

00:33:31.680 of us who are having this conversation so the fact that i can follow the rules of english grammar

00:33:36.360 insofar as i manage to do that that is all being implemented in a way that is unconscious and when i make an

00:33:44.280 error i i as the conscious witness of my inner life i'm just surprised at the appearance of the error and i could be

00:33:51.760 surprised for on all those occasions where i make no errors and i get to the end of a sentence in

00:33:57.680 something like grammatically correct form i could be sensitive to the the fundamental mysteriousness of

00:34:03.440 that which is to say that i'm following rules that i am i have no conscious access to in the moment

00:34:10.080 and everything is like that the fact that i perceive that my visual field the fact that i hear your voice

00:34:15.420 the fact that i effortlessly and actually helplessly decode meaning from your words because i am an

00:34:22.260 english speaker and and you're speaking in english but if you were speaking in chinese it would just be

00:34:26.700 noise and i mean this is this is all unconsciously mediated and so they again it is a mystery why

00:34:33.960 there should be something that it's like to be associated with any part of this process because so much of the

00:34:41.340 process can take place in the dark or at least it seems to be in the dark i guess this is something

00:34:47.700 that that is a um the topic i raised in my last book waking up when i was in discussing split brain

00:34:54.140 research but there is some reason to worry or or wonder whether or not there are there are islands of

00:35:02.440 consciousness in our brains that we're not aware of which is to say we have the problem of other minds

00:35:09.520 with respect to our own brains what what do you think about that what do you put the chance of

00:35:13.340 there being something that it's like to be associated with these zombie parts of or seemingly zombie parts

00:35:21.880 of of your own cognitive processing well i don't i don't rule it out you know i mean i think when it

00:35:28.760 comes to the mind body problem there are um you know the puzzles are large enough that we just one of

00:35:34.380 the big puzzles is we don't know which systems are conscious so at least some days i see a lot of

00:35:38.960 attraction to the idea of thinking consciousness is much more widespread than we think so not just

00:35:44.740 i guess most of us think okay humans are conscious and probably a lot of the more sophisticated mammals

00:35:50.200 at least are conscious apes monkeys dogs cats around the point of mice maybe some people start to flies

00:36:00.440 some people start to wobble but you know i'm attracted by the idea that for you know many at least

00:36:07.660 reasonably sophisticated information processing devices there's some kind of uh some kind of

00:36:13.020 consciousness and maybe this goes down very deep and you know one at some point maybe we can talk

00:36:17.200 about the idea that consciousness is is everywhere but before even getting to that point if you're

00:36:22.360 prepared to say that say a fly is uh is conscious or a worm with its 300 neurons and so on then you do

00:36:29.040 start to have to worry about uh bits of the uh bits of the brain that are enormously more sophisticated

00:36:34.780 than that but that are also part of another conscious system there's a uh there's a guy

00:36:40.520 giulio tononi who's put forward a well-known recent theory of consciousness called the information

00:36:45.220 integration theory and he's got a mathematical measure called phi of the amount of information

00:36:50.520 that a system integrates and thinks but roughly whenever that's high enough

00:36:54.080 you get uh you get consciousness so then yeah you'd look at these different bits of the brain the uh

00:36:59.820 the uh the hemisphere different things like the cerebellum and something well okay the phi there

00:37:04.540 is not as high as it is for the brain but it's still pretty high high enough that in an animal he

00:37:09.760 would say it's conscious so why isn't it and he ends up having to throw in an arbitrary an extra

00:37:14.560 axiom that he calls the exclusion axiom saying if you're part of a system that has a higher phi than you

00:37:19.600 then you're not conscious so if the you know if the hemisphere has a high phi but the brain as a whole

00:37:25.460 has a higher phi then the brain gets to be conscious but the hemisphere doesn't but to many

00:37:30.340 people that axiom looks kind of arbitrary and you know if it wasn't for that being in there then

00:37:35.220 you'd be left with a whole lot of conscious subsystems all over i agree it's who knows what

00:37:40.280 it's like to be a subsystem you know what it's like to be my cerebellum or what it's like to be a

00:37:44.660 hemisphere but yeah at least makes you uh you know makes you uh makes you uh makes you worry and wonder

00:37:49.420 on the other hand you know there are these experiments where you know one half of the brain is basic

00:37:53.820 these situations where one half of the brain basically gets destroyed and the other half keeps going

00:37:57.640 fine yeah yeah well so i wanted to ask you about tenoni's notion of consciousness as integrated

00:38:03.340 information and it to my eye it seems yet another case of someone just trying to ram past the hard

00:38:10.280 problem and i actually i noticed max tegmark wrote a paper that actually took tenoni as a starting

00:38:16.980 point and max has been on this podcast where i don't think we touched on consciousness but he also

00:38:22.240 did a version of this he just basically said you know let's start here we know that there are certain

00:38:27.380 arrangements of matter that just are conscious we know this there there is no problem we just this

00:38:33.200 is this is a starting point and now we just have to talk about the plausible explanation for what

00:38:39.240 makes them conscious and then he sort of went on to embrace tenoni and then and then then did a lot

00:38:44.720 of physics but what do you i mean is there anything in tenoni's discussion here that pries up the lid on

00:38:52.260 the hard problem more than the earlier work he did with edelman or or anyone else's attempt to give some

00:39:00.680 information processing control or a a synchronicity of neural firing control of consciousness yeah to be

00:39:08.720 fair to uh to julio uh tenoni yeah i mean i think it's true that in some of the presentations of his

00:39:14.300 work and the popular press and so on you can get this idea all information integration is all there

00:39:19.260 is let's explain that we've explained everything he's actually very sensitive to the uh to the problem

00:39:25.820 of consciousness and and if you're and when pressed on this and even in some of the stuff he's written

00:39:31.240 he says i'm not trying to solve the hard problem in the sense of showing how you can get

00:39:37.120 consciousness from matter he's not trying to cross the explanatory gap from physical processes to

00:39:44.220 consciousness rather he says i'm starting with the fact of consciousness i'm just taking that as a

00:39:49.200 given that we are conscious and i'm trying to map its properties and he actually starts

00:39:53.980 with some phenomenological axioms of consciousness it's consists of information that's differentiated in

00:40:02.860 certain ways but integrated and unified in other ways and then what he tries to do is take those

00:40:09.420 phenomenological axioms and turn them into mathematics turn them into mathematics of

00:40:14.400 information and say what are the informational properties that consciousness has and then he comes

00:40:19.980 up with this mathematical measure then at a certain point it somehow turns into the theory that

00:40:25.640 all consciousness is is this what consciousness is is a certain kind of integration of information

00:40:31.120 the way i would hear the theory i don't know if he puts it this way is basically there's a correlation

00:40:36.400 between different states of consciousness and different kinds of integration of information

00:40:43.300 in the brain there's still a hard problem here because we still have no idea why all that

00:40:49.460 integration of information in the brain should give you consciousness in the first place but even

00:40:54.660 someone who believes there's a hard problem can believe there are still really systematic correlations

00:40:59.520 between brain processes and consciousness that we ought to be able to give a rigorous mathematical

00:41:04.960 theory of you know just which physical states go with which kind of states of consciousness

00:41:09.440 and i see julio's theory is basically as at least a stab in that direction of trying to give a rigorous

00:41:15.340 mathematical theory of the correlations yeah yeah well i should say that i certainly agree that

00:41:20.660 one can more or less throw up one's hands with respect to the hard problem and then just go on to do the

00:41:27.240 work of trying to map the neural correlates of consciousness and understand what consciousness

00:41:33.760 seems to be in our case as a matter of its its instantiation in the brain and never pretend that

00:41:41.340 the mystery has been reduced thereby so that you know if if it just if it turned out that i think i

00:41:48.460 said this once in response to the work he did with edelman so they they put a one of the criteria

00:41:53.780 they they i don't know if he still does this but one of his

00:41:57.240 criterion for for information integration was that there had to be within a window of

00:42:01.980 something like 500 milliseconds right and i just by analogy extrapolated that out to you know

00:42:09.460 geological processes in the earth and what if it was just the fact that integrated processes in the

00:42:16.040 earth over the over a time course of a few hundred years was a sufficient basis of consciousness if we

00:42:23.600 just stipulate that that's true that's still just a statement of a miracle from my point of view from

00:42:29.340 the point of view of being sympathetic with the hard problem that would be an incredibly strange

00:42:34.580 thing to believe and yet that is the sort of thing we are are being forced to believe about our own

00:42:41.080 brains just uh you know under a slightly different description i do think there's something intermediate

00:42:46.500 that you can go for here even if you do believe and you're very convinced there's a serious hard

00:42:51.600 problem of consciousness that allows the possibility of a at least a broadly scientific approach to

00:42:57.180 something in the neighborhood of the hard problem it's not where it's not just oh let's look at the

00:43:02.020 neural correlates and see what's going on in the human case but it's something like try to find

00:43:07.500 the simplest most fundamental principles that connect physical processes to consciousness as a

00:43:15.060 kind of basic general and universal principle so we might start with some correlations we find in the

00:43:22.400 familiar human case between say certain neural systems and certain kinds of consciousness but then

00:43:27.660 try and generalize those based on as much evidence as possible of course the evidence is limited which is

00:43:33.480 another which is another limitation here but then try and find principles which might apply to other

00:43:39.800 systems ultimately look for really simple bridging principles that cross the gap from physical

00:43:46.740 systems to consciousness and that would in principle predict what kind of consciousness you'd find in

00:43:51.780 what kind of physical system so i would say something like to know these information integration

00:43:56.480 principle with this mathematical quantity phi as a proposal maybe a very early proposal about a

00:44:01.800 fundamental principle that might connect physical processes to consciousness now it does it doesn't try it

00:44:09.360 doesn't exactly remove the hard problem because at some point you've got to take that principle

00:44:13.140 as a basic axiom yeah when there's information integration there's consciousness but then you can at

00:44:18.840 least go on to do science with that principle and it may well be that you know my take on this is that

00:44:24.440 we know that elsewhere in science you have to take some laws and some principles as fundamental

00:44:33.020 fundamental laws of physics the law of gravity or the unified unified field theory of the laws of

00:44:39.820 quantum mechanics some things are just basic principles that we don't try and explain any

00:44:44.880 further but it may well be that when it comes to consciousness we're going to have to take something

00:44:49.540 like that for granted as well so we don't try to explain space or at least we didn't try to explain

00:44:53.720 space in terms of something more basic some things get taken as primitive and we look at the fundamental

00:44:58.580 laws that involve them likewise the same could be true for consciousness and we ended up you know

00:45:04.120 maybe it's we ended up pretty satisfied about what goes on in the case of space space is one of the

00:45:07.980 primitives but we've got a great scientific theory of how it works we could end up in that position

00:45:13.060 for consciousness too yes we have to take something here as as as basic but we'll get this really

00:45:19.080 fundamental principle say like the information integration principle that crosses the gap and yet

00:45:23.940 won't remove the hard problem because that'll be taken as basic but that will at least be reduced

00:45:27.500 to a situation we're familiar with elsewhere in science yeah yeah and actually i'm quite sympathetic

00:45:33.080 with that line as you say there there are primitives or brute facts that we accept throughout science and

00:45:42.740 they're really they are no insult to our thinking about the rest of reality and so i want to get

00:45:49.860 there but i i realize now i i forgot to ask a question that annika wanted me to ask my wife annika

00:45:54.740 wanted me to ask on the zombie argument and she was wondering why i mean whether it was actually

00:46:01.560 conceivable that a zombie would or could talk about consciousness itself i mean how is it that you take a

00:46:09.160 zombie you know my zombie twin that has no experience there's nothing that it's like to be that thing but it

00:46:16.020 is talking just as i am and is is functioning just as i am what could possibly motivate a zombie that is

00:46:24.500 devoid of phenomenal experience to say things like i have experiences but other creatures don't or or to worry

00:46:32.660 about the possibility of zombies there would seem to be no basis to make this distinction because

00:46:39.320 everything he's doing he can easily ascribe to others that have no experience so there's there's no

00:46:46.600 there seems to be no basis for him to distinguish experience from non-experience so so i just want

00:46:52.720 to get your reaction to that on on her behalf i mean this is a big puzzle and it's probably one of

00:46:58.020 the biggest puzzles when it comes to thinking through this idea of a zombie if you'd like to

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Making Sense - Sam Harris - April 18, 2016

#34 — The Light of the Mind

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