Making Sense - Sam Harris - #234 — The Divided Mind

00:00:00.000 Welcome to the Making Sense Podcast.

00:00:08.860 This is Sam Harris.

00:00:10.900 Just a note to say that if you're hearing this,

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00:00:52.280 The Master and His Emissary

00:00:58.200 Okay.

00:01:00.800 Well, today I'm speaking with Ian McGilchrist.

00:01:03.900 Ian is a fellow of All Souls College at Oxford,

00:01:07.440 and a fellow of the Royal College of Psychiatrists,

00:01:11.020 also a fellow of the Royal Society of Arts,

00:01:13.420 and he was a research fellow in neuroimaging at Johns Hopkins.

00:01:16.460 And most importantly for our purposes,

00:01:19.480 he's the author of the book

00:01:20.440 The Master and His Emissary,

00:01:22.260 The Divided Brain and the Making of the Western World.

00:01:25.340 And that is the focus of our conversation today.

00:01:27.680 We talk about the differences between the right and left hemispheres of the brain,

00:01:31.600 which are fascinating and consequential,

00:01:34.920 and I think underappreciated.

00:01:37.900 And this gets us into many thorny issues.

00:01:41.280 We discuss the popular misconceptions about these differences,

00:01:44.680 the prospect that consciousness might be partitioned,

00:01:48.360 even in an intact brain,

00:01:50.420 the difference between consciousness and attention,

00:01:53.200 the boundary between the conscious and unconscious mind,

00:01:55.700 how face-to-face encounters differ between the hemispheres,

00:01:59.340 the unique deficits that result from damage to each,

00:02:02.900 the ascendancy of the left hemisphere in modern culture,

00:02:06.400 the possibility that the brain is a mere receiver of mind,

00:02:10.680 people's expectations about surviving death.

00:02:14.580 Anyway, I thought it was a fascinating conversation.

00:02:17.060 We certainly could have gone on for many more hours.

00:02:19.780 And now I bring you Ian McGilchrist.

00:02:25.700 I am here with Ian McGilchrist.

00:02:30.420 Ian, thank you for joining me.

00:02:32.060 It's a great pleasure, Sam. Thank you.

00:02:34.160 So, we're about to speak about what I consider

00:02:38.020 one of the most interesting topics in any field.

00:02:42.440 The focus of our conversation is covered

00:02:44.820 really in exhaustive detail in your book,

00:02:48.020 The Master and His Emissary.

00:02:49.300 And there's also a film based on that,

00:02:51.900 which I discovered online last night,

00:02:54.320 The Divided Brain.

00:02:55.940 But before we jump in,

00:02:57.060 what is your academic and intellectual background?

00:03:00.360 All my life, really,

00:03:01.440 I've been interested in philosophical questions,

00:03:04.280 particularly the end of philosophy

00:03:06.300 that accommodates theology.

00:03:08.300 And so, at 18,

00:03:10.040 I wanted to go to Oxford

00:03:11.140 and study philosophy and theology.

00:03:13.280 But you had to take an entrance exam

00:03:15.260 in some school subject.

00:03:16.400 And almost at random,

00:03:18.220 I chose English literature.

00:03:20.420 And when I went to interview,

00:03:21.560 they said,

00:03:22.020 oh, you can't do theology and philosophy.

00:03:26.160 It's not an honours degree.

00:03:28.060 So, in 1972 in Oxford,

00:03:30.560 theology and philosophy wasn't an honours degree.

00:03:33.560 Each on their own was,

00:03:34.780 but not the combination.

00:03:36.180 I think it is now,

00:03:37.120 but there we are.

00:03:38.140 So, they said,

00:03:38.840 look, you obviously like

00:03:40.120 and are good at English.

00:03:41.320 Come and do that.

00:03:42.080 So, I did.

00:03:43.460 And I was interested, really,

00:03:46.240 in the philosophy of literature

00:03:48.780 and the philosophy of aesthetics, in a way.

00:03:51.240 And something struck me as very odd

00:03:53.120 about what we were doing.

00:03:54.380 I got a fellowship

00:03:55.220 immediately after graduating,

00:03:57.060 which enabled me to have time to reflect.

00:04:00.000 And I thought,

00:04:00.500 there's something that's really troubling me

00:04:02.160 about the way in which we approach literature.

00:04:04.860 Somebody in the past

00:04:06.120 took great pains

00:04:07.500 to create something that is unique,

00:04:10.160 embodied,

00:04:11.200 and largely speaking, implicit.

00:04:13.400 In other words,

00:04:13.800 if you try and unpack it,

00:04:14.960 like explaining a joke

00:04:16.100 or trying to say,

00:04:17.380 well, this is what this poem means,

00:04:19.280 you know,

00:04:19.600 you really are losing

00:04:20.860 a lot of the value and the meaning.

00:04:23.260 And people came along,

00:04:24.240 you know,

00:04:24.440 in seminar rooms

00:04:25.260 and took the disembodied

00:04:26.420 and made it thoroughly,

00:04:28.060 sorry,

00:04:28.400 took the embodied

00:04:29.000 and made it thoroughly disembodied,

00:04:31.100 took the implicit

00:04:32.060 and made it explicit,

00:04:33.700 and in the process

00:04:34.840 rendered this entirely unique thing,

00:04:36.920 this completely unique experience,

00:04:39.500 something that was utterly general

00:04:41.120 in nature.

00:04:42.420 So I thought,

00:04:43.240 there's something wrong with this,

00:04:44.300 and I wrote a book

00:04:45.020 called Against Criticism.

00:04:46.820 And what seemed to me wrong

00:04:48.220 was that we'd become

00:04:50.280 very disembodied

00:04:51.360 in the way that we think

00:04:52.420 about everything.

00:04:53.840 In fact,

00:04:54.240 it's something,

00:04:54.920 you know,

00:04:55.180 I've,

00:04:56.240 since the earliest days,

00:04:57.960 reflected on

00:04:58.640 the way we lead our lives nowadays,

00:05:00.780 that they're over-cerebral

00:05:01.900 in some way.

00:05:03.940 And that the process

00:05:05.500 is somewhat destructive.

00:05:06.920 It has its advantages,

00:05:08.100 but it also has major problems.

00:05:11.120 And I went to the philosophy seminars

00:05:12.800 to discuss the mind-body question,

00:05:16.940 but I found that the philosophers

00:05:18.060 were just altogether

00:05:19.020 too disembodied

00:05:20.300 in their approach.

00:05:21.700 And so I thought,

00:05:23.360 I'd read Oliver Sacks' book,

00:05:25.740 Awakenings.

00:05:26.320 It had just come out

00:05:27.000 around that time.

00:05:27.960 I'm that old.

00:05:29.240 And I thought,

00:05:31.540 this is really fascinating.

00:05:33.040 Here's someone who's attended

00:05:34.380 to the individuality

00:05:35.740 of his patients,

00:05:37.140 but made completely amazing

00:05:38.840 philosophical,

00:05:40.500 drawn philosophical conclusions.

00:05:43.200 They're very important

00:05:44.180 about what happens

00:05:46.060 when something changes

00:05:47.600 your brain or your body

00:05:49.480 and what that does

00:05:50.620 to your personhood,

00:05:52.840 to your mind

00:05:54.160 and to your whole humanity.

00:05:57.120 And I thought,

00:05:57.880 this is what I want to do.

00:05:59.140 So I had to start again,

00:06:01.420 study medicine from scratch.

00:06:03.660 And then as soon as I qualified

00:06:06.000 and done my basic jobs

00:06:08.740 in what you'd call internships,

00:06:11.500 I then did a little bit

00:06:13.680 of psychiatry and,

00:06:16.440 sorry,

00:06:16.800 a bit of neurology

00:06:17.980 in neurosurgery

00:06:18.900 and then went to the Maudsley

00:06:21.100 to study psychiatry.

00:06:23.780 And my interest there

00:06:25.360 has all along

00:06:26.040 been in the overlap

00:06:26.840 between mind and body.

00:06:28.000 So that's how I got into

00:06:29.380 being somebody

00:06:31.080 who writes about

00:06:32.080 the mind-body relationship

00:06:33.440 from an embodied point of view.

00:06:36.180 There's a further question,

00:06:37.280 how did I get into

00:06:38.180 the issue of lateralization?

00:06:40.140 You may be coming on to that

00:06:41.360 so we can

00:06:41.940 take a bit of the time.

00:06:43.840 Yeah.

00:06:44.540 And have you had

00:06:45.680 a psychiatric practice

00:06:47.200 all this time

00:06:48.420 or are you retired in that mode?

00:06:51.300 Oh, I'm retired now.

00:06:52.520 Yeah.

00:06:52.760 But for years,

00:06:54.620 I was a practicing psychiatrist.

00:06:56.560 Yeah.

00:06:57.100 First at the Bethlehem

00:06:58.120 and Maudsley Hospital in London

00:06:59.560 and then privately.

00:07:01.980 Right.

00:07:02.700 So we're going to talk about

00:07:04.020 the divided brain,

00:07:06.040 which is something

00:07:07.460 I've spoken about before,

00:07:09.860 I think,

00:07:10.580 at least in passing

00:07:11.440 on my podcast.

00:07:13.380 and on my app,

00:07:15.720 Waking Up.

00:07:16.900 I've certainly written about it

00:07:18.060 in at least one of my books.

00:07:20.000 But given its strangeness

00:07:22.740 as a phenomenon

00:07:23.600 and its relevance

00:07:25.220 to just how we conceive

00:07:27.240 of ourselves as persons,

00:07:30.160 it really is an underreported

00:07:32.360 finding in science.

00:07:34.240 So I think we should just

00:07:35.400 describe the phenomenon itself,

00:07:38.340 how we've come to know

00:07:39.420 anything about it.

00:07:40.600 I mean, the basic picture

00:07:41.660 is that the human brain

00:07:44.040 and, you know,

00:07:44.840 not just human,

00:07:46.000 this is true of the avian brain

00:07:47.440 and all mammalian brains,

00:07:49.840 but for our purposes

00:07:51.400 and most interestingly,

00:07:53.260 our own brains

00:07:54.160 are divided

00:07:55.320 across the longitudinal fissure

00:07:59.180 into left and right hemispheres.

00:08:01.340 And this could have worked out

00:08:04.140 in various ways.

00:08:05.800 The two hemispheres

00:08:06.620 could have been

00:08:07.300 functionally identical.

00:08:09.080 They could have

00:08:09.940 shared information perfectly.

00:08:12.920 There could be no differences

00:08:14.000 between them

00:08:15.120 and one would sort of think

00:08:17.840 that would be the case.

00:08:19.280 And yet,

00:08:19.820 what we have found

00:08:21.220 is that they're quite different

00:08:22.760 and we're going to go

00:08:25.160 into those differences.

00:08:26.600 And we know this

00:08:27.180 based on the fact

00:08:27.840 that they can be disconnected.

00:08:29.340 So maybe we should,

00:08:30.960 actually,

00:08:31.160 before we dive

00:08:31.700 into the split brain phenomenon

00:08:33.460 and how we know

00:08:34.320 any of this stuff,

00:08:35.900 just explain the title

00:08:36.900 of your book,

00:08:37.600 The Master and His Emissary.

00:08:39.280 What do you mean

00:08:40.360 by that title?

00:08:41.720 Okay.

00:08:42.840 Well,

00:08:43.300 that's essentially

00:08:44.000 a story

00:08:45.600 which illustrates

00:08:46.680 how I see

00:08:48.400 the relationship

00:08:49.100 between the two hemispheres.

00:08:50.460 Here we're kind of

00:08:51.160 jumping ahead a bit,

00:08:52.200 but there's been

00:08:53.820 a general view,

00:08:55.000 the one that I was trained on,

00:08:56.420 that the left hemisphere

00:08:57.400 is the one that does

00:08:59.280 all the heavy lifting

00:09:00.560 and is intelligent

00:09:02.340 and perceptive

00:09:04.080 and that the right hemisphere

00:09:05.140 is a bit of a kind of

00:09:07.180 a no good.

00:09:08.800 We're not really

00:09:09.500 kind of sure what it is.

00:09:10.800 I mean,

00:09:10.960 it might be there

00:09:11.480 for propping up

00:09:12.240 the left hemisphere

00:09:13.260 to make sure

00:09:13.780 it doesn't fall over.

00:09:15.320 I mean,

00:09:15.660 literally people

00:09:16.640 have talked like that.

00:09:18.320 But I see them

00:09:19.740 as having developed

00:09:20.560 two entirely different roles.

00:09:23.300 They've been separate

00:09:24.480 in all the brains we know,

00:09:25.920 going right the way down

00:09:27.220 to reptiles

00:09:28.600 and even the networks

00:09:30.500 of insects,

00:09:31.980 of nematode worms,

00:09:33.820 and even the most

00:09:34.580 ancient sea creature

00:09:35.800 that we know of

00:09:36.820 already shows

00:09:37.940 an asymmetrical

00:09:38.940 neural network,

00:09:40.120 which is very interesting

00:09:41.140 in itself.

00:09:43.200 But what I think

00:09:44.600 has happened in humans

00:09:45.640 is with the evolution

00:09:48.100 of language,

00:09:49.420 we've decided

00:09:50.560 to devote

00:09:51.380 one part of the brain

00:09:53.780 for dealing entirely

00:09:55.540 in theory

00:09:56.660 of the symbols

00:09:59.400 of experience

00:10:00.340 rather than the

00:10:01.300 gathering of experience

00:10:02.820 itself.

00:10:04.500 And in a new book

00:10:05.380 I'm writing,

00:10:06.100 I actually take the pains

00:10:07.260 to go through

00:10:07.860 all the various ways

00:10:09.160 in which we get

00:10:09.880 a hang on the world.

00:10:11.740 And in all cases,

00:10:12.940 the left hemisphere

00:10:13.720 is not as good

00:10:15.300 at this

00:10:15.640 as the right hemisphere.

00:10:17.320 Why is that?

00:10:18.240 Because the left hemisphere

00:10:19.180 needs to be kept

00:10:19.980 away from that

00:10:20.780 because it's busy

00:10:21.660 doing some

00:10:23.100 theoretical processing.

00:10:25.520 Now the thing is

00:10:26.380 that in fact

00:10:27.680 the right hemisphere

00:10:28.560 is actually

00:10:30.200 more intelligent.

00:10:31.880 And I mean

00:10:32.240 in terms of IQ.

00:10:33.900 I can,

00:10:35.420 you know,

00:10:36.020 in the book

00:10:37.540 that I've been writing

00:10:38.500 I've got the information

00:10:39.980 about that,

00:10:41.040 which sounds a bit odd,

00:10:42.480 but it's also

00:10:43.140 the one that attends

00:10:44.300 much more broadly

00:10:45.260 to the world,

00:10:45.980 perceives more,

00:10:47.560 makes better judgments,

00:10:48.920 is less taken in,

00:10:50.080 tends not to jump

00:10:51.280 to conclusions

00:10:52.080 in the way

00:10:52.700 the left hemisphere does,

00:10:54.600 has social

00:10:55.380 and emotional understanding

00:10:56.840 in the way

00:10:57.660 the left hemisphere doesn't.

00:10:59.800 And indeed,

00:11:00.340 it is the one

00:11:00.880 that we rely on

00:11:01.860 to be connected to

00:11:02.800 and make sense

00:11:03.560 of the world.

00:11:04.780 When people have

00:11:05.680 a left hemisphere stroke,

00:11:07.700 they carry on

00:11:08.640 for all intents

00:11:09.900 and purposes

00:11:10.380 being largely in touch

00:11:11.500 with the same world

00:11:12.320 they were in before.

00:11:13.700 But when they have

00:11:14.260 a right hemisphere stroke,

00:11:15.920 they find it hard

00:11:16.900 to understand

00:11:17.600 what's happening,

00:11:18.720 what people mean

00:11:20.080 when they say things.

00:11:21.420 I mean,

00:11:21.560 their language functions

00:11:22.520 are going,

00:11:23.160 but what does this

00:11:23.800 really mean anymore?

00:11:25.640 So patients

00:11:26.580 who are cared for

00:11:28.760 by people

00:11:31.060 and they have

00:11:31.700 a right hemisphere stroke,

00:11:33.280 the main complaint

00:11:34.140 is that these patients

00:11:35.820 lack any human understanding

00:11:37.600 or empathy,

00:11:39.080 whereas the complaint

00:11:40.160 with people

00:11:40.940 who have a left hemisphere stroke

00:11:42.360 is they have difficulty

00:11:43.520 reading and writing.

00:11:45.120 He's really on

00:11:45.820 a very different level.

00:11:46.680 So to come back

00:11:47.700 to the master

00:11:48.260 and his emissary,

00:11:49.820 the right hemisphere

00:11:50.660 is in a way

00:11:52.000 the master.

00:11:53.360 The idea I had here

00:11:54.400 was of a spiritual community

00:11:55.860 in which there was

00:11:57.460 a wise spiritual master

00:11:58.800 who looked after

00:11:59.560 the business of a community

00:12:00.760 so that it flourished

00:12:01.700 and grew.

00:12:03.060 And in a while,

00:12:04.500 it became obvious

00:12:05.420 that the master

00:12:06.360 couldn't look after

00:12:07.100 all the daily business

00:12:08.280 of the community

00:12:09.060 and indeed ought not

00:12:10.120 to get involved with it,

00:12:11.540 in fact,

00:12:12.260 if he was to be able

00:12:13.600 to maintain

00:12:14.300 his all-important overview.

00:12:16.140 And so he delegated

00:12:17.900 his brightest and best

00:12:19.540 sort of second-in-command

00:12:20.860 to go about doing

00:12:22.020 the sort of

00:12:23.660 administrative business.

00:12:25.280 But this administrator,

00:12:27.500 while very bright,

00:12:28.680 wasn't bright enough

00:12:29.540 to know what it was

00:12:30.440 he didn't know.

00:12:32.020 And so he thought,

00:12:33.360 what does the master know?

00:12:34.680 What does he know?

00:12:35.760 He's just sitting back

00:12:36.680 at the palace

00:12:37.840 meditating seraphically.

00:12:39.920 I'm the one

00:12:40.380 that does all the hard work here

00:12:42.100 and I'm the one

00:12:43.380 that knows.

00:12:44.100 And so he took on

00:12:45.720 the mantle of the master

00:12:47.460 and in the process,

00:12:50.460 because he didn't know

00:12:51.340 what the master knew,

00:12:53.020 he was not able

00:12:53.840 to perform his job

00:12:55.100 and the whole community,

00:12:57.020 the master and the emissary,

00:12:58.240 fell to ruin.

00:12:59.320 Now, I see that

00:13:00.220 as a parable,

00:13:01.480 very loosely based

00:13:02.460 on a hint in Nietzsche,

00:13:03.820 to describe the relationship,

00:13:06.240 the advancing relationship

00:13:07.420 between the right

00:13:08.040 and left hemisphere

00:13:08.640 and the way we have ended up

00:13:10.040 in the world today.

00:13:10.920 enthralled to the emissary,

00:13:14.380 to the servant,

00:13:15.660 that doesn't really understand

00:13:16.940 what the master

00:13:17.580 would have known

00:13:18.220 and been able

00:13:18.740 to tell us about.

00:13:19.980 We could move on from there

00:13:21.300 to just a little reflection

00:13:23.220 on this question

00:13:24.900 that you raised

00:13:25.600 of the divided nature

00:13:27.020 of the brain.

00:13:28.280 Yeah.

00:13:28.580 When I was in medical school,

00:13:30.240 I mean, obviously,

00:13:31.140 we saw that it was.

00:13:33.540 There it is on the slab

00:13:35.120 and it's divided.

00:13:36.240 And it was just

00:13:37.040 taken for granted.

00:13:38.840 And nobody really said,

00:13:40.220 why?

00:13:40.840 What on earth

00:13:41.540 is the point

00:13:42.100 of having a mass

00:13:43.220 of neuronal interconnections

00:13:45.520 whose value,

00:13:47.380 we seem to believe,

00:13:49.420 is predicated

00:13:50.160 on the sheer number

00:13:51.360 of interconnections

00:13:52.180 it can make?

00:13:53.380 Why divide it

00:13:54.820 right down the middle

00:13:55.740 in this way?

00:13:56.900 And as I say,

00:13:57.640 this has been the case

00:13:58.580 in all living creatures

00:14:00.460 that we know of.

00:14:01.840 Indeed,

00:14:02.120 the corpus callosum

00:14:03.180 that connects

00:14:04.300 the two hemispheres,

00:14:06.220 a band of fibers

00:14:07.120 at the base of the brain

00:14:08.420 that connects

00:14:09.020 about 2%

00:14:09.840 of the fibers

00:14:11.300 of the brain

00:14:12.060 directly,

00:14:13.340 is a mammalian invention.

00:14:15.400 Up until mammals,

00:14:16.900 i.e. in birds

00:14:17.740 and reptiles,

00:14:19.560 amphibians,

00:14:20.180 monotremes,

00:14:20.960 there isn't

00:14:21.400 a corpus callosum

00:14:22.360 at all.

00:14:23.520 So that's fascinating.

00:14:25.640 And indeed,

00:14:26.980 a chap called

00:14:27.620 Hughlings Jackson,

00:14:28.700 who's a great,

00:14:29.480 one of the great fathers

00:14:30.540 of modern neurology

00:14:32.020 in the 19th century,

00:14:33.080 said,

00:14:33.300 it's not common enough

00:14:35.400 for us to wonder

00:14:36.500 at this fact

00:14:37.360 that the brain

00:14:38.240 is divided

00:14:38.840 in this way.

00:14:40.460 And when I got

00:14:41.100 to my medical training

00:14:43.080 and so on,

00:14:44.080 this topic of difference

00:14:45.280 between the hemispheres

00:14:46.300 was really

00:14:47.880 a non-subject.

00:14:50.020 It was considered

00:14:50.700 entirely

00:14:51.420 pop psychology.

00:14:54.040 It was tacky.

00:14:55.380 People pled with me,

00:14:56.580 don't allow your career

00:14:58.120 to be tainted.

00:14:58.940 You can do well.

00:14:59.720 Don't do this.

00:15:00.600 Don't get involved

00:15:01.400 in this issue.

00:15:02.120 It's all been 0.96

00:15:03.380 rubbish a long time ago. 0.89

00:15:06.060 But that's actually 0.95

00:15:07.020 to go

00:15:07.720 far too far.

00:15:09.540 First of all,

00:15:10.620 it's very clear

00:15:11.440 and undeniable

00:15:12.340 that the two hemispheres

00:15:13.480 do have

00:15:14.800 quite different

00:15:15.600 functions

00:15:16.220 because,

00:15:17.040 or at least

00:15:17.440 they contribute to,

00:15:19.340 I'd rather put it

00:15:19.960 this way,

00:15:20.320 they contribute to

00:15:21.060 a human being

00:15:21.560 in different ways.

00:15:22.400 You can see that

00:15:22.940 when people have strokes

00:15:24.000 in one hemisphere,

00:15:25.800 or they have a stroke

00:15:26.400 in the exactly same

00:15:27.660 sort of mirror position

00:15:28.940 in the other hemisphere,

00:15:29.880 the outcome

00:15:30.800 is completely different.

00:15:31.980 So it's not good enough

00:15:33.280 to say they're just

00:15:34.360 the same.

00:15:35.000 They aren't.

00:15:36.080 And they wouldn't

00:15:36.620 have evolved in this way

00:15:37.840 if there was really

00:15:38.560 no purpose

00:15:39.180 in their difference.

00:15:40.120 The question simply was,

00:15:41.340 what was that difference?

00:15:43.380 And all the things

00:15:44.260 that people used to say

00:15:45.440 back in the 60s

00:15:46.380 and 70s,

00:15:47.340 after the first

00:15:48.160 split brain operations,

00:15:50.160 which was a procedure

00:15:51.180 invented to

00:15:52.460 aid patients

00:15:54.160 who had

00:15:54.800 constant epileptic seizures,

00:15:57.020 and somebody

00:15:58.260 had the idea

00:15:59.480 that it would be

00:16:00.100 a good idea

00:16:00.660 to divide

00:16:01.480 the connection

00:16:02.820 between the two

00:16:03.500 hemispheres

00:16:04.020 so that if a seizure

00:16:04.920 started in one hemisphere,

00:16:06.680 it wouldn't automatically

00:16:07.600 overwhelm the whole brain.

00:16:09.000 The other half

00:16:09.580 would be able

00:16:10.040 to carry on functioning.

00:16:11.780 And indeed,

00:16:12.140 it was a great success

00:16:13.280 in achieving that.

00:16:15.120 But it gave people

00:16:15.920 a window

00:16:16.520 into the difference

00:16:19.040 between these two worlds

00:16:20.680 because you could actually,

00:16:22.120 by clever experimentation,

00:16:23.920 address problems

00:16:25.360 and questions

00:16:26.260 and test out

00:16:27.360 each hemisphere

00:16:28.100 on its own.

00:16:29.700 And this gave rise

00:16:30.960 to a literature

00:16:31.560 which was,

00:16:33.000 in a way,

00:16:33.880 people jumped

00:16:34.420 to a lot of conclusions

00:16:35.480 rather fast.

00:16:37.140 And the story was,

00:16:39.160 well,

00:16:39.500 the right brain

00:16:40.620 is kind of emotional,

00:16:42.640 but the left brain

00:16:43.960 is rational.

00:16:46.240 And it's dependable.

00:16:47.420 It may be a little bit boring,

00:16:48.900 but at least

00:16:49.400 it's very dependable.

00:16:51.580 It tends to be

00:16:52.380 our contact with reality.

00:16:54.320 Whereas the right hemisphere

00:16:56.100 is all very well

00:16:56.980 if you want to paint pictures.

00:16:58.580 But, you know.

00:16:59.700 And this is just

00:17:00.480 so, so terrible

00:17:02.120 as a way of looking at them.

00:17:03.820 In many ways,

00:17:04.680 it's the inverse

00:17:05.320 of the truth

00:17:06.120 because as I've discovered

00:17:08.040 and explained

00:17:08.740 at length in my works,

00:17:10.580 the left hemisphere

00:17:11.500 is actually less in touch

00:17:12.860 with reality,

00:17:14.040 less reliable,

00:17:15.440 more prone

00:17:16.000 to jump to conclusions,

00:17:17.740 more prone

00:17:18.960 to quick and dirty decisions,

00:17:20.700 and more prone

00:17:21.900 to getting emotional

00:17:23.100 in certain ways.

00:17:24.560 For example,

00:17:25.460 emotions are not all

00:17:26.720 particularly in the

00:17:28.800 right or left hemisphere,

00:17:30.740 but one in particular

00:17:32.260 is especially well represented

00:17:34.680 in the left hemisphere,

00:17:35.680 and that's anger.

00:17:36.380 So, it is a fascinating topic.

00:17:40.040 Hmm.

00:17:40.820 Well, so I want to revisit

00:17:41.920 some of those landmarks

00:17:43.600 that you just sketched

00:17:45.160 because it's,

00:17:46.500 again,

00:17:46.860 this is a topic

00:17:48.580 that it seems to me

00:17:50.040 most of culture

00:17:51.380 and even most of

00:17:52.720 scientific culture

00:17:54.160 and even

00:17:55.680 neuroscientific culture

00:17:57.000 has really only

00:17:59.100 glanced at

00:18:00.560 and it's kept

00:18:02.000 at a distance,

00:18:02.860 I think largely

00:18:04.360 because it is so

00:18:05.560 strange.

00:18:07.380 There's something

00:18:07.720 very disconcerting

00:18:08.660 about what we

00:18:10.380 have come to know

00:18:11.820 about the organization

00:18:13.460 of the brain here

00:18:14.320 and some of its implications.

00:18:16.440 I'm wondering

00:18:16.800 what you think

00:18:17.640 about why

00:18:18.560 this topic

00:18:20.120 has been,

00:18:21.400 it strikes me

00:18:22.060 as it's almost been treated

00:18:22.860 as a kind of

00:18:23.360 intellectual pornography,

00:18:24.860 right?

00:18:25.140 It's been held

00:18:25.980 in disrepute

00:18:26.740 as you describe,

00:18:28.660 but,

00:18:29.400 you know,

00:18:29.680 beyond the fact

00:18:30.820 that there's been

00:18:31.260 some cartoonish

00:18:32.500 portrayals

00:18:33.760 of the differences

00:18:34.540 between left and right

00:18:36.420 and this kind of

00:18:37.660 pop psychological

00:18:38.700 misinformation

00:18:40.060 that has been spread.

00:18:42.040 Is there any other

00:18:42.740 reason why you think

00:18:43.700 this,

00:18:44.640 why you were

00:18:45.360 warned off this

00:18:46.440 as a topic

00:18:46.980 when you were

00:18:47.840 doing your studies?

00:18:49.420 I think there are

00:18:49.840 two main reasons.

00:18:51.600 One is that,

00:18:52.900 as you say,

00:18:53.820 it had got into

00:18:54.480 popular culture

00:18:55.280 in a certain way,

00:18:56.140 so it was an ad,

00:18:57.160 you know,

00:18:57.320 the Volvo,

00:18:58.060 a car for your right brain

00:18:59.300 and this kind of thing.

00:19:00.020 And so people went,

00:19:02.040 oh,

00:19:02.480 please,

00:19:03.340 you know,

00:19:03.580 don't let's go near that.

00:19:06.040 So in order to remain

00:19:08.120 aloof,

00:19:09.060 you know,

00:19:09.540 neuroscience,

00:19:10.140 oh,

00:19:10.300 no,

00:19:10.440 no,

00:19:10.560 no,

00:19:10.700 no,

00:19:10.840 it's not like that,

00:19:11.800 which indeed it isn't.

00:19:13.800 But the other reason

00:19:15.000 is that there were some,

00:19:17.120 as I say,

00:19:17.760 some slightly too

00:19:19.020 quick conclusions

00:19:20.620 drawn

00:19:21.140 in the early days,

00:19:23.060 in the 60s and 70s

00:19:24.620 and on into the 80s.

00:19:25.720 And these were based

00:19:27.180 on,

00:19:28.400 I believe,

00:19:28.940 a misconception,

00:19:30.620 which is that

00:19:31.260 the real difference

00:19:32.580 between the two hemispheres

00:19:33.960 was what they do,

00:19:36.120 which is the right answer

00:19:37.340 or the right way,

00:19:38.680 right question,

00:19:39.520 perhaps,

00:19:39.860 to ask of a machine.

00:19:41.580 What does it do?

00:19:42.860 But it's not necessarily

00:19:43.900 the right question

00:19:45.020 to ask of a person.

00:19:47.020 Of a person,

00:19:47.860 one may be more interested

00:19:48.960 in the how,

00:19:50.020 in what way,

00:19:51.400 in what manner

00:19:52.080 this is done.

00:19:52.860 And what I discovered

00:19:54.940 fairly early on

00:19:55.980 was that

00:19:56.740 the old division

00:19:58.540 that reason

00:19:59.520 and language

00:20:00.520 was solely

00:20:01.260 the province

00:20:02.880 of the left hemisphere

00:20:03.840 and emotion

00:20:05.520 and visuospatial things,

00:20:07.800 the province

00:20:08.240 of the right hemisphere,

00:20:09.720 that this was not the case.

00:20:11.100 Each was involved

00:20:12.120 in all of those,

00:20:13.680 indeed in everything

00:20:14.500 that we do.

00:20:15.920 Yeah.

00:20:16.300 So where does that

00:20:17.280 leave my position?

00:20:20.580 Fine.

00:20:21.220 Ready to go

00:20:21.880 on a very interesting adventure

00:20:23.460 because then one says

00:20:25.240 it's not the what,

00:20:27.460 it's the how.

00:20:29.040 And in every case,

00:20:30.540 whatever it is

00:20:31.440 that each hemisphere

00:20:32.600 is dealing with,

00:20:33.620 it deals with it

00:20:34.500 in a reliably,

00:20:36.140 consistently,

00:20:37.020 predictably different way.

00:20:39.540 And what is that?

00:20:40.840 Well,

00:20:41.680 it's to do,

00:20:42.680 I believe,

00:20:43.440 with a problem

00:20:45.140 which is entirely

00:20:46.800 explicable

00:20:47.600 in terms of

00:20:48.420 Darwinian

00:20:49.100 evolutionary advantage.

00:20:50.560 So,

00:20:51.680 yeah,

00:20:51.820 before we jump

00:20:52.500 into that,

00:20:53.500 I want to talk

00:20:54.640 about the

00:20:55.740 evolutionary origins

00:20:57.260 of this

00:20:58.260 insofar as we can

00:20:59.400 speculate about them

00:21:00.700 and just why

00:21:01.640 would it be

00:21:02.660 that brains

00:21:03.600 would be divided

00:21:04.320 and divided

00:21:05.560 in the way

00:21:06.180 that they are.

00:21:07.100 But let's describe

00:21:08.640 how we know

00:21:09.780 that the hemispheres

00:21:11.520 are so different

00:21:13.120 in our own case,

00:21:15.000 you know,

00:21:15.240 based on the,

00:21:15.780 I just want to summarize

00:21:16.760 the split brain research

00:21:17.880 in a little more detail

00:21:19.160 for people

00:21:19.660 who may not be

00:21:20.720 familiar with it.

00:21:21.900 And the interesting

00:21:23.080 thing here is that

00:21:24.080 the claims that

00:21:25.400 you are going to make

00:21:27.060 about the differences

00:21:28.120 between right and left

00:21:29.360 and,

00:21:29.920 you know,

00:21:30.180 you have gone so far

00:21:31.580 as to suggest

00:21:32.180 that the right hemisphere

00:21:33.420 is the more competent,

00:21:35.880 the more fully human,

00:21:37.260 the more,

00:21:37.660 it is the master

00:21:38.840 rather than the emissary.

00:21:40.000 That is quite different

00:21:41.460 from where science started

00:21:44.380 once we started

00:21:46.480 splitting the hemispheres

00:21:48.480 by cutting the corpus callosum

00:21:50.120 in those surgeries

00:21:51.820 you described.

00:21:53.200 And even people

00:21:54.220 who were very close

00:21:55.440 to that research

00:21:56.380 early on

00:21:57.680 felt that

00:21:58.500 they went from thinking

00:21:59.800 that the right hemisphere

00:22:00.900 was in fact unconscious,

00:22:02.980 right,

00:22:03.140 that there was nothing

00:22:03.860 that it was like

00:22:04.520 to be the right hemisphere,

00:22:05.680 that the left hemisphere

00:22:06.880 was entirely the basis

00:22:08.980 for human experience

00:22:10.240 of any kind

00:22:10.880 to thinking that

00:22:12.680 the right hemisphere,

00:22:14.340 while it might be conscious,

00:22:16.240 it is definitely subhuman.

00:22:18.320 And, you know,

00:22:19.120 Michael Kazaniga,

00:22:20.180 who I know

00:22:20.860 and who's very early

00:22:22.820 as a cognitive neuroscientist

00:22:24.720 studying this,

00:22:25.940 you know,

00:22:26.140 worked under Roger Sperry.

00:22:27.780 You know,

00:22:28.080 he at one point,

00:22:29.100 I'm sure he's recanted here,

00:22:31.200 but at one point

00:22:31.900 he suggested

00:22:32.520 that the right hemisphere

00:22:33.420 was essentially

00:22:34.180 beneath a chimpanzee

00:22:36.420 in its cognitive abilities.

00:22:38.020 So we have come a long way

00:22:39.720 in appreciating

00:22:40.980 what the right hemisphere

00:22:42.540 is doing.

00:22:44.580 Ironically,

00:22:45.340 maybe it's our left hemisphere

00:22:47.420 that had to be

00:22:48.420 dragged all this way

00:22:49.580 to appreciate

00:22:50.300 what the right hemisphere

00:22:50.960 is doing.

00:22:52.000 So let's just describe

00:22:53.080 the original

00:22:54.520 Sperry experiments,

00:22:57.300 you know,

00:22:57.580 born of the neurosurgeries

00:22:59.400 done by Joe Bogan

00:23:00.740 and discuss

00:23:02.540 how it is we were able

00:23:03.380 to interrogate

00:23:04.360 the hemispheres separately

00:23:06.460 and know that there

00:23:07.520 really are,

00:23:08.720 in the case of a divided brain,

00:23:11.060 two different points of view

00:23:12.860 on the world

00:23:13.960 and really two different subjects,

00:23:16.020 two different people

00:23:17.020 in a single human head.

00:23:20.220 Absolutely.

00:23:21.080 And it might be worth

00:23:22.620 just saying that

00:23:24.440 already in the 19th century,

00:23:26.660 people saw

00:23:27.440 that the hemispheres

00:23:28.700 were quite different,

00:23:30.380 famously broken.

00:23:31.280 and Dax saw

00:23:32.340 that patients

00:23:33.320 who lost their speech

00:23:34.300 had damage

00:23:35.440 to a certain area

00:23:36.600 only in the left frontal

00:23:38.000 though not in the right

00:23:39.000 and so forth.

00:23:40.400 And people observing

00:23:41.840 people with strokes,

00:23:43.680 massive strokes

00:23:44.340 in one hemisphere

00:23:45.040 or the other

00:23:45.600 over the subsequent decades

00:23:47.920 often noticed

00:23:49.120 that the subjects

00:23:50.380 seemed to live

00:23:51.100 in a quite different

00:23:52.120 kind of a world.

00:23:53.120 So it wasn't just

00:23:54.140 the split brains

00:23:54.900 that told us this.

00:23:56.980 We should also recall

00:23:58.560 that,

00:23:58.920 and this is a point

00:23:59.480 you make in your book,

00:24:01.140 that long before,

00:24:03.760 a full century before

00:24:05.180 anyone thought

00:24:06.200 of doing the split brain work,

00:24:08.000 we already knew

00:24:09.240 or someone already knew

00:24:10.740 that the right hemisphere

00:24:12.900 was sufficient

00:24:14.380 for consciousness

00:24:15.120 because there were

00:24:16.920 neuroanatomists

00:24:18.400 who discovered

00:24:19.040 upon autopsy

00:24:20.020 that people who had lived

00:24:21.680 fully normal lives,

00:24:24.200 you know,

00:24:24.340 which is to say

00:24:24.820 conscious lives,

00:24:26.700 had upon inspection

00:24:28.880 after death

00:24:29.680 only one hemisphere

00:24:31.520 of their brains.

00:24:33.160 It could be the right

00:24:34.100 or it could be the left

00:24:34.920 and this is born

00:24:35.960 of the fact

00:24:36.400 that people,

00:24:37.720 you know,

00:24:37.940 there are people

00:24:38.420 who are born

00:24:38.980 without one hemisphere 0.94

00:24:40.560 or, you know,

00:24:41.240 they suffer some illness

00:24:42.860 or injury

00:24:43.700 very close to birth

00:24:44.780 and manage,

00:24:46.160 you know,

00:24:46.480 developmentally

00:24:47.080 to compensate

00:24:47.720 and this is just

00:24:49.180 not discovered

00:24:49.880 until much later in life.

00:24:51.940 You know,

00:24:52.080 now this kind of thing

00:24:53.200 can be discovered

00:24:53.860 during routine neuroimaging.

00:24:55.900 you can discover

00:24:56.540 that a fully intact person

00:24:58.300 is in fact

00:24:58.980 missing a hemisphere

00:25:00.180 and have been

00:25:01.280 their entire lives.

00:25:02.520 So we already knew

00:25:03.880 that the right hemisphere

00:25:05.480 could be conscious

00:25:06.620 and then we seem

00:25:07.100 to have forgotten that

00:25:08.220 over the course

00:25:08.720 of a hundred years

00:25:09.980 of doing neurology

00:25:11.840 and neuroscience.

00:25:12.540 Yes,

00:25:13.500 I mean,

00:25:13.740 what you're particularly,

00:25:14.780 I think,

00:25:15.420 alluding to there

00:25:16.280 is the work of Wiggin 0.57

00:25:17.260 in the 19th century

00:25:18.300 with an amazing figure

00:25:20.260 who spent a lot of time

00:25:22.060 in the autopsy room.

00:25:24.460 But I would just like

00:25:25.840 to gloss something

00:25:27.080 since you've raised

00:25:28.460 that topic.

00:25:29.960 It's slightly different

00:25:31.260 because if somebody's

00:25:32.420 had only one hemisphere

00:25:34.060 from birth,

00:25:34.780 which can sometimes happen

00:25:36.220 because there may be

00:25:37.420 a space occupying sack

00:25:39.100 or lesion

00:25:39.640 that's in the place

00:25:40.340 where the hemisphere

00:25:40.960 should be,

00:25:41.620 you're dealing with

00:25:43.000 something rather different

00:25:43.940 because from the word go,

00:25:45.480 the central nervous system

00:25:47.940 will have reorganized itself

00:25:49.160 to take into account

00:25:50.180 this element.

00:25:51.440 But still,

00:25:52.100 it is true

00:25:52.700 that people

00:25:53.760 who develop normally

00:25:54.780 can certainly live well

00:25:57.140 with the right hemisphere.

00:25:58.400 They're better off

00:25:59.060 with their right hemisphere

00:26:00.260 if they've only got

00:26:01.140 to have one

00:26:01.820 than with the left.

00:26:03.600 Anyway,

00:26:04.040 to come back

00:26:04.600 to the split brain operation,

00:26:08.460 yes,

00:26:09.380 first of all,

00:26:09.940 people were amazed

00:26:11.600 by a couple of things

00:26:12.600 that they just observed

00:26:13.600 without doing any experiments.

00:26:15.740 People were first of all

00:26:16.820 thinking,

00:26:17.500 what would it be like

00:26:18.340 for somebody

00:26:18.920 to have

00:26:19.820 the two halves

00:26:20.960 of their brain

00:26:21.360 completely separate?

00:26:22.780 When I say

00:26:23.180 completely separate,

00:26:24.700 there are a couple

00:26:25.420 of minor fish,

00:26:26.840 minor...

00:26:27.380 Commesters, yeah.

00:26:28.460 Commesters that connect,

00:26:30.240 that connect the hemispheres,

00:26:32.100 but to all intents

00:26:32.980 and purposes,

00:26:34.200 the very much,

00:26:35.420 the most important

00:26:36.160 had been seven.

00:26:36.920 And the answer

00:26:38.800 to that was

00:26:39.420 that they were

00:26:39.960 remarkably normal.

00:26:42.920 As if the two

00:26:44.040 hemispheres

00:26:44.560 could carry on

00:26:45.260 like that

00:26:45.580 without doing

00:26:46.160 a lot of talking

00:26:46.980 to one another.

00:26:48.200 But they did also notice,

00:26:49.720 at least in the early

00:26:50.640 days after the operation,

00:26:52.420 going on for the first

00:26:53.520 months,

00:26:54.760 that sometimes

00:26:55.540 people would show

00:26:56.500 completely conflicting

00:26:57.760 behavior.

00:26:58.880 So a woman 0.97

00:27:00.260 would go to the wardrobe

00:27:01.420 to take out a dress

00:27:02.680 with her right hand

00:27:03.780 and her left hand

00:27:04.480 would take it

00:27:05.000 and put it back

00:27:05.800 and take out

00:27:06.820 a different one.

00:27:07.880 Or somebody

00:27:08.720 would get out

00:27:09.340 money to pay

00:27:10.160 from the wallet

00:27:10.840 and the other hand

00:27:11.580 would take it away

00:27:12.380 and put it back

00:27:13.100 in his pocket.

00:27:14.080 So this is the kind

00:27:15.240 of thing

00:27:15.660 that you saw.

00:27:17.940 I believe there was

00:27:18.780 a case of a man

00:27:20.480 trying to embrace

00:27:21.420 his wife with one hand 0.89

00:27:22.600 and strangle her 0.99

00:27:23.380 with the other. 0.98

00:27:24.140 Yes.

00:27:25.060 Well, at least

00:27:25.520 push her away 0.74

00:27:26.160 with the other.

00:27:27.500 I think the story

00:27:28.420 has got more...

00:27:29.280 It got better

00:27:30.440 as it got told?

00:27:31.580 But it got better.

00:27:33.100 But, no,

00:27:34.680 that's right.

00:27:36.280 But, you know,

00:27:37.020 very good,

00:27:37.780 very interesting

00:27:39.340 experiments

00:27:40.400 were devised.

00:27:42.720 Very clever

00:27:43.200 and genius

00:27:43.800 experiments

00:27:44.520 were devised

00:27:45.300 whereby,

00:27:46.640 for example,

00:27:47.320 you could give

00:27:47.940 information

00:27:48.500 to just one ear

00:27:50.840 or you could give

00:27:51.700 conflicting information

00:27:52.800 to the two ears

00:27:54.860 at the same time.

00:27:56.700 And normally,

00:27:57.660 of course,

00:27:58.380 information is shared.

00:27:59.960 But in this case,

00:28:00.980 it wouldn't be shared.

00:28:01.960 And so you could

00:28:03.060 actually have

00:28:04.360 a different input

00:28:05.060 to each hemisphere.

00:28:06.280 And you can also

00:28:06.780 do this visually

00:28:07.660 using a technique

00:28:09.600 called tachistoscopy

00:28:10.960 in which a different

00:28:12.760 image is put up

00:28:14.020 in the right visual field

00:28:15.260 which goes to

00:28:15.980 the left hemisphere

00:28:16.740 from the one

00:28:17.600 that's put up

00:28:18.100 in the left visual field

00:28:19.260 which goes to

00:28:20.040 the right hemisphere.

00:28:22.200 And you can then

00:28:23.460 ask questions

00:28:25.160 to the person

00:28:25.740 about what they've seen

00:28:26.720 or what they've done.

00:28:27.640 One of the most interesting...

00:28:28.560 And some of those

00:28:29.180 are rather intricate

00:28:29.900 and would take us

00:28:30.560 a long time

00:28:31.460 to explain,

00:28:33.280 particularly without

00:28:33.860 a diagram.

00:28:35.120 But one of the most

00:28:36.400 interesting findings

00:28:37.480 was that when

00:28:39.060 the left hemisphere

00:28:40.180 knew really nothing

00:28:41.660 at all

00:28:42.280 because the information

00:28:43.660 had all gone

00:28:44.260 to the right hemisphere,

00:28:46.000 it would pretend

00:28:47.220 that it knew

00:28:47.880 all about what was

00:28:48.780 going on.

00:28:49.440 So when it was asked

00:28:50.340 why did you respond

00:28:51.540 in a certain way

00:28:52.660 about which it knew

00:28:54.180 diddly squat

00:28:54.740 because that had been

00:28:55.440 the information

00:28:56.020 the right hemisphere

00:28:56.900 had had

00:28:57.300 and that was why

00:28:58.080 we had responded

00:28:59.360 in that way,

00:29:00.300 it would make something

00:29:01.160 up that was plausible.

00:29:02.780 And it is...

00:29:04.040 One way of looking

00:29:05.180 at it is that

00:29:05.880 the left hemisphere

00:29:06.640 is extraordinarily good

00:29:08.920 at making things up

00:29:10.880 and it's a bullshitter

00:29:12.920 in fact.

00:29:13.900 And this is why

00:29:14.740 Mike Zaniger

00:29:15.580 calls it

00:29:16.320 the interpreter

00:29:17.480 because it can

00:29:18.400 make sense

00:29:19.400 of whatever

00:29:19.880 it sees happening

00:29:20.860 and it actually

00:29:21.760 seems to believe

00:29:22.740 its own propaganda.

00:29:24.200 It seems that

00:29:27.180 the left hemisphere

00:29:27.820 seems to have

00:29:28.460 dominated our politics

00:29:29.760 of late.

00:29:30.700 One thing you can see

00:29:31.600 is the confabulatory

00:29:33.460 nature of the left hemisphere

00:29:35.000 in the news

00:29:36.100 on an hourly basis.

00:29:37.880 You can indeed.

00:29:39.600 And on that,

00:29:41.400 Roger Sperry

00:29:42.120 who as you mentioned

00:29:43.100 was one of the

00:29:43.960 most important

00:29:45.500 neuroscientists

00:29:46.520 of that era

00:29:47.880 investigating

00:29:49.240 this phenomenon

00:29:50.260 for which he was

00:29:51.300 given the Nobel Prize

00:29:52.520 said,

00:29:53.860 and he was no mean

00:29:54.540 philosopher actually

00:29:55.460 as well as being

00:29:56.120 a neuroscientist,

00:29:57.580 he said that

00:29:58.480 the problem with

00:29:59.380 modern Western

00:30:00.620 civilization

00:30:01.160 is that it

00:30:01.980 has relegated,

00:30:05.200 it ignores

00:30:06.060 the right hemisphere.

00:30:07.420 Anyway,

00:30:08.340 Mike Zaniger

00:30:09.000 has changed

00:30:10.660 his views

00:30:11.040 quite a lot

00:30:11.600 since those

00:30:12.240 early pronouncements.

00:30:13.480 I imagine

00:30:14.240 they live on

00:30:15.060 to haunt him

00:30:15.640 slightly.

00:30:16.560 But what

00:30:17.840 pleases me

00:30:18.720 is that some

00:30:19.740 of the things

00:30:20.420 I was saying

00:30:21.000 earlier about

00:30:21.860 the

00:30:22.520 the way

00:30:22.840 in which

00:30:23.160 the left

00:30:24.260 hemisphere

00:30:24.580 is more

00:30:24.940 prone to

00:30:25.420 bias

00:30:25.860 and more

00:30:26.700 prone to

00:30:27.100 jump to

00:30:27.460 conclusions

00:30:27.940 and make

00:30:28.340 poor

00:30:28.620 judgments

00:30:29.040 actually

00:30:29.400 comes

00:30:29.920 from the

00:30:30.740 work of

00:30:31.080 Niki 0.79

00:30:31.280 Marinsek

00:30:31.960 who works

00:30:32.460 in

00:30:32.720 Gazzaniga's

00:30:33.400 lab.

00:30:33.840 So obviously

00:30:34.940 things have

00:30:35.580 changed there.

00:30:36.960 But it's

00:30:37.340 been a process

00:30:38.600 of trying

00:30:39.360 to get

00:30:39.780 people to

00:30:40.340 see

00:30:40.700 that just

00:30:41.820 because

00:30:42.600 all we

00:30:43.640 knew was

00:30:44.300 a rather

00:30:44.700 quick and 0.88

00:30:45.220 dirty

00:30:45.460 formula at

00:30:46.220 a certain

00:30:46.600 stage,

00:30:47.340 it wasn't

00:30:48.120 enough to

00:30:48.540 dismiss

00:30:49.100 hugely

00:30:50.220 important

00:30:50.780 questions.

00:30:51.500 Why is

00:30:52.180 the brain

00:30:52.540 divided?

00:30:53.640 Why is

00:30:54.760 it asymmetrical

00:30:55.580 by the way

00:30:56.180 since the

00:30:56.640 skull that

00:30:57.240 contains it

00:30:57.880 is not?

00:30:58.920 Why is

00:31:00.240 the connection

00:31:00.820 between the

00:31:01.580 hemispheres

00:31:02.180 so much

00:31:03.040 involved with

00:31:03.960 inhibition

00:31:04.780 rather than

00:31:05.960 facilitation?

00:31:07.240 These were

00:31:07.880 questions that

00:31:08.940 haunted me and

00:31:09.760 it took me

00:31:10.460 30 years

00:31:11.780 basically to

00:31:13.080 come up with

00:31:13.860 what I was

00:31:15.100 able to write

00:31:16.300 in The

00:31:16.600 Master and

00:31:17.020 His

00:31:17.160 Hemisphere

00:31:17.500 history and

00:31:18.420 another 10

00:31:19.000 years for

00:31:19.560 what I've

00:31:20.040 just written

00:31:20.980 and I'm

00:31:21.380 hoping will

00:31:21.780 be published

00:31:22.300 in the

00:31:23.180 next 12

00:31:23.620 months.

00:31:24.740 So yes,

00:31:26.440 I mean,

00:31:26.880 it didn't

00:31:27.480 start from a

00:31:28.080 very auspicious

00:31:29.460 place, but I

00:31:30.380 was completely

00:31:31.160 convinced that

00:31:31.920 something of

00:31:32.440 great interest

00:31:33.800 was being

00:31:34.280 neglected.

00:31:35.720 And you

00:31:36.200 asked why

00:31:36.700 you had

00:31:36.960 people not

00:31:37.640 sort of

00:31:38.100 gone further

00:31:39.100 with it.

00:31:39.840 I think the

00:31:40.400 answer is that

00:31:41.300 to make sense

00:31:42.060 of it would

00:31:42.980 have required

00:31:43.440 30 years.

00:31:44.340 And in

00:31:45.300 doing so,

00:31:45.900 they would

00:31:46.200 have basically

00:31:46.760 forfeited their

00:31:47.700 career because

00:31:48.620 when they were

00:31:50.700 juniors, their

00:31:51.400 bosses wouldn't

00:31:51.980 have wanted them

00:31:52.520 to do research

00:31:53.240 on lateralization.

00:31:54.420 They said,

00:31:54.660 no, forget it.

00:31:55.260 That's all

00:31:55.660 passe.

00:31:57.140 And as they

00:31:58.320 got further

00:31:59.740 on, they

00:32:00.120 wouldn't have

00:32:00.500 got grants and

00:32:01.340 they wouldn't

00:32:01.560 have got

00:32:01.740 promotion and

00:32:02.480 so on.

00:32:02.960 So actually,

00:32:03.900 very few people

00:32:04.800 have taken the

00:32:05.680 trouble to

00:32:06.480 really look at

00:32:07.520 this in any

00:32:08.260 great depth.

00:32:10.060 And, you

00:32:10.440 know, if all

00:32:12.040 due modesty, I

00:32:12.700 am one of the

00:32:13.300 people who has

00:32:13.940 spent decades

00:32:15.780 really, really

00:32:16.960 getting acquainted

00:32:17.880 with the

00:32:18.280 literature.

00:32:19.000 And so, you

00:32:20.020 know, I know

00:32:20.780 some things about

00:32:21.740 it that there

00:32:22.780 are people who

00:32:23.400 do know them,

00:32:24.000 but it's not in

00:32:24.760 the general

00:32:25.240 culture.

00:32:26.800 I think there

00:32:27.160 may be an

00:32:28.420 additional reason

00:32:29.680 here, which is

00:32:30.380 that it's, there's

00:32:31.680 something impossible

00:32:33.340 or at least very

00:32:35.120 difficult to

00:32:35.760 assimilate about

00:32:36.980 this finding into

00:32:38.140 one's sense of

00:32:40.120 one's own being

00:32:41.460 in the world.

00:32:42.300 I want to try

00:32:42.860 to make

00:32:43.940 what we're

00:32:44.460 talking about

00:32:45.040 here as

00:32:46.320 subjectively real

00:32:48.220 to people as

00:32:49.060 we can make

00:32:50.200 it.

00:32:50.740 But before, and

00:32:51.480 we'll go further

00:32:52.040 into just the

00:32:52.800 differences between

00:32:53.820 the hemispheres

00:32:55.140 and perhaps what

00:32:56.420 we can start

00:32:57.020 with, with just

00:32:58.240 this basic

00:32:58.840 question which

00:32:59.360 you've raised

00:32:59.720 is, you know,

00:33:00.100 why is the

00:33:00.600 brain divided

00:33:01.160 in the first

00:33:01.580 place and why

00:33:03.060 would it not

00:33:03.580 be functionally

00:33:04.460 symmetrical?

00:33:05.540 But here's

00:33:06.620 what strikes me

00:33:07.160 as most strange

00:33:08.260 about the

00:33:08.840 phenomenon, which

00:33:10.220 you really can

00:33:10.940 just extrapolate

00:33:11.920 from the

00:33:13.620 split-brain

00:33:14.260 finding.

00:33:14.960 So the split-brain

00:33:15.540 finding is that

00:33:16.180 if you divide

00:33:17.140 the brain

00:33:18.300 surgically by

00:33:19.740 cutting the

00:33:20.480 commissures, or

00:33:22.040 at least the

00:33:22.360 corpus callosum,

00:33:23.160 but, you know,

00:33:23.900 the anterior

00:33:24.540 commissure and

00:33:25.280 there are a few

00:33:26.540 others that need

00:33:27.840 not be cut but

00:33:28.540 could be cut,

00:33:29.720 and you have

00:33:31.040 this very stark

00:33:31.740 finding where you

00:33:32.900 have just

00:33:33.840 undeniably two

00:33:35.580 points of view,

00:33:37.200 you know,

00:33:37.380 whatever their

00:33:37.880 differences, as

00:33:39.200 we will yet

00:33:39.860 describe, there

00:33:41.320 are two points

00:33:41.960 of view at

00:33:42.840 that point in

00:33:43.940 the human mind

00:33:45.240 is dual, and

00:33:47.280 the left hand

00:33:48.600 quite literally

00:33:49.580 doesn't know what

00:33:50.320 the right hand

00:33:50.840 is doing.

00:33:52.100 And, you

00:33:52.760 know, reminding

00:33:53.520 people again about

00:33:55.060 the contralateral

00:33:56.220 organization of

00:33:57.440 the nervous

00:33:58.320 system, the, as

00:34:00.120 you said, the

00:34:00.680 right hemisphere in

00:34:02.400 a divided brain

00:34:03.340 sees only the

00:34:05.020 left side of the

00:34:05.820 world, and the

00:34:06.600 left hemisphere

00:34:07.300 sees the right

00:34:07.880 side of the

00:34:08.320 world.

00:34:08.900 It's not divided

00:34:09.600 left and right

00:34:10.780 eye, it's the

00:34:11.560 left hemifield

00:34:13.040 within both eyes

00:34:14.280 and the right

00:34:15.080 hemifield within

00:34:15.860 both eyes.

00:34:16.860 So, you can

00:34:17.980 present an image

00:34:19.000 to the right

00:34:19.540 hemisphere, which

00:34:20.320 the left hemisphere

00:34:21.120 does not see, but

00:34:23.200 because language

00:34:24.160 is so

00:34:26.060 disproportionately

00:34:26.800 subserved by

00:34:28.380 the left

00:34:28.760 hemisphere,

00:34:29.760 certainly, you

00:34:30.480 know, 95%

00:34:31.720 of people, when

00:34:32.960 you're talking to

00:34:33.800 the subject, and

00:34:34.460 you say, well,

00:34:34.720 so what did you

00:34:35.200 see?

00:34:36.080 The answer

00:34:36.640 you're getting,

00:34:37.580 you know, though

00:34:37.920 the right hemisphere

00:34:38.660 hears you, the

00:34:39.440 answer you're

00:34:39.940 getting is coming

00:34:41.280 from the left

00:34:41.860 hemisphere that

00:34:42.620 has control of

00:34:43.560 speech.

00:34:45.120 And so you're

00:34:45.900 talking to a

00:34:46.400 person who says,

00:34:47.020 well, I didn't

00:34:47.560 see anything.

00:34:48.700 And then, in an

00:34:50.540 experiment like this,

00:34:52.060 you could say,

00:34:52.600 well, just, you

00:34:53.260 know, can you take

00:34:54.220 your left hand and

00:34:55.460 reach for the object

00:34:56.260 that you may or may

00:34:57.180 not have seen?

00:34:57.760 And then, at that

00:34:58.660 point, the right

00:34:59.360 hemisphere, which is in

00:35:00.780 full control of the

00:35:01.620 left hand, or near

00:35:02.900 full control of the

00:35:03.700 left hand, can reach

00:35:06.300 and pick up an

00:35:06.980 object, which is, in

00:35:08.700 fact, the object that

00:35:09.480 was presented to it,

00:35:10.540 you know, visually.

00:35:12.100 And then, when asked,

00:35:14.220 well, why did you

00:35:15.060 pick up this key, or

00:35:16.700 egg, or whatever the

00:35:17.820 object was?

00:35:18.960 As you point out, the

00:35:19.860 left hemisphere at that

00:35:20.800 point confabulates and

00:35:23.140 tells a story.

00:35:23.980 It seems to always have

00:35:24.820 a story as to why, in

00:35:27.040 this case, the left

00:35:27.740 hand, over which it has

00:35:28.640 no control, did what it

00:35:29.840 did, and it shows

00:35:32.340 that it has basically

00:35:33.400 no, you know, reality

00:35:35.680 testing mechanism left

00:35:38.460 to it, left to its own

00:35:39.340 devices.

00:35:39.900 It will just publicize

00:35:41.840 some account of the

00:35:43.400 world, and, you know,

00:35:45.220 it's apparently the

00:35:46.280 most credulous person

00:35:48.000 on Earth.

00:35:49.020 The amazing thing

00:35:49.660 about this is, if you

00:35:51.220 extrapolate from this

00:35:52.380 finding that, you

00:35:53.580 know, a divided brain

00:35:54.940 gives you two people,

00:35:58.180 right?

00:35:58.520 Two fairly different

00:36:00.560 people, and, you

00:36:02.420 know, even if they

00:36:02.980 were the same in their

00:36:04.520 emotional tone and

00:36:06.160 their cognitive styles,

00:36:08.180 which they're not,

00:36:09.760 there would still be

00:36:10.340 two of them at this

00:36:11.340 point, two different

00:36:12.880 points of view on the

00:36:14.260 world.

00:36:14.980 If you extrapolate

00:36:16.220 from that and realize

00:36:18.600 that, you know, as you

00:36:19.440 said, an intact corpus

00:36:21.740 colossum only terminates

00:36:23.420 on a mere 2% of

00:36:26.200 cortical neurons,

00:36:27.740 right?

00:36:28.380 I mean, it's not

00:36:29.180 that every neuron is

00:36:31.340 connected with every

00:36:32.320 other like neuron across

00:36:34.040 the hemispheres, right?

00:36:35.000 So we have to be

00:36:36.300 imperfectly connected,

00:36:38.100 even in the healthiest,

00:36:39.560 most intact brain,

00:36:40.960 which is to say there

00:36:41.960 isn't perfect information

00:36:43.160 sharing across the

00:36:44.140 hemispheres.

00:36:45.280 And so it opens the

00:36:46.560 question, to what degree

00:36:48.720 are we dual even now?

00:36:51.520 To what degree is there,

00:36:53.700 could there be islands of

00:36:55.560 consciousness in an intact

00:36:57.700 brain?

00:36:58.160 We're shifting,

00:36:59.980 overlapping, non-shared

00:37:02.080 spaces of consciousness,

00:37:04.380 whereas it is something

00:37:05.680 that it's like to be part

00:37:07.220 of the right hemisphere,

00:37:08.940 and there's something that

00:37:10.400 it's like to be part of the

00:37:12.300 left hemisphere.

00:37:13.660 And in any given moment,

00:37:16.080 these points of view may not

00:37:17.560 be unified.

00:37:18.280 They may be, I'm agnostic as

00:37:20.160 to whether or not this is a

00:37:21.280 totally fluid situation and

00:37:23.480 they can come to be unified

00:37:25.240 and separate again.

00:37:27.480 But it gives a kind of

00:37:29.700 Freudian spooky picture of

00:37:32.880 the mind that the

00:37:34.400 unconscious, from the point

00:37:36.440 of view of the conscious you

00:37:38.600 in this moment, may in fact

00:37:40.640 be conscious, you know, and

00:37:42.340 looking over your shoulder in

00:37:43.960 a sense.

00:37:44.940 The phenomenology with which

00:37:46.400 any person is identified

00:37:48.240 subjectively may not be the

00:37:50.920 totality of the subjectivity,

00:37:53.440 the conscious subjectivity

00:37:54.780 in their own brain.

00:37:56.260 And I think there's something

00:37:57.060 about that picture that is

00:38:00.720 so weird that people just

00:38:03.900 don't want to think about it.

00:38:06.160 I think it, yes, you pointed

00:38:08.140 to something definitely that I

00:38:09.660 don't think can be dismissed.

00:38:12.260 But I think I'd like to sort

00:38:15.140 of moderate that picture a

00:38:16.440 little.

00:38:17.000 Sure.

00:38:17.520 And the first is that we all

00:38:19.980 grow up with information

00:38:22.700 coming to us from both

00:38:23.940 halves of the world and it

00:38:26.100 is communicated through the

00:38:28.080 body and into the brain

00:38:30.400 using both endocrine

00:38:34.020 transmitters as well as the

00:38:36.940 neurological system that we

00:38:38.980 are describing.

00:38:40.060 Right.

00:38:40.660 And the normal person is

00:38:43.480 receiving a picture all

00:38:44.960 round of the world and this

00:38:46.720 information is being taken as

00:38:49.540 a whole.

00:38:50.400 So on the whole, we don't

00:38:52.120 find ourselves noticing

00:38:53.960 this.

00:38:54.500 In fact, if we noticed it, it

00:38:55.880 would be very damaging for us

00:38:57.980 because we would find

00:38:58.780 ourselves constantly torn like

00:39:00.340 the person who's trying to pay

00:39:02.040 and putting the money back in

00:39:04.060 the pocket.

00:39:04.960 And it's also worth saying that

00:39:06.760 after usually about the first

00:39:09.040 five or six months, most split

00:39:10.820 brain subjects started to lose

00:39:13.280 this intermanual conflict, as

00:39:15.680 it's called.

00:39:16.180 So it's something that the

00:39:18.380 person sort of accommodated

00:39:20.320 to.

00:39:21.880 But it's also not just true of,

00:39:24.620 I mean, on the other hand, it's

00:39:26.180 also not just split brain

00:39:28.140 patients that must be thinking

00:39:29.720 very differently and seeing the

00:39:31.860 world very differently because

00:39:33.340 you can produce this effect

00:39:35.360 experimentally in normal

00:39:39.020 subjects using transcranial

00:39:41.480 magnetic stimulation, which is a

00:39:43.860 technique whereby you can

00:39:45.660 painlessly stimulate or

00:39:47.820 suppress, depending on the

00:39:50.000 frequency of the pulses,

00:39:52.200 areas of the brain.

00:39:53.620 And I don't know, but you've

00:39:54.740 probably talked about that in

00:39:56.120 another podcast.

00:39:57.520 But in any case, the point is

00:39:59.240 this.

00:39:59.980 When you do that, something

00:40:02.140 full-fledged and ready to go is

00:40:04.640 released.

00:40:05.900 So it's not like it was there.

00:40:09.080 You know, when you knock out the

00:40:10.480 left hemisphere and knock out the 1.00

00:40:11.780 right hemisphere, you find

00:40:13.120 instantaneously decisions being

00:40:15.720 made which are characteristic of

00:40:17.920 what we know to be the way of the

00:40:19.700 right or the left hemisphere.

00:40:21.680 And this can actually be

00:40:22.920 advantageous in certain

00:40:24.100 circumstances.

00:40:24.880 So the problem solving of a

00:40:26.520 certain kind, Alan Snyder in

00:40:29.160 Sydney has experimented on this,

00:40:32.180 can be facilitated by suppressing

00:40:34.880 the left frontal cortex and

00:40:36.520 enhancing the right frontal cortex.

00:40:38.500 So complex problems, including

00:40:41.120 mathematical problems, can be more

00:40:43.500 easily solved.

00:40:45.100 In any case, all I'm really saying

00:40:46.920 there is that, yes, there is

00:40:51.360 something spooky.

00:40:52.840 And it's not just in split brain

00:40:54.640 patients.

00:40:55.160 I acknowledge that because, as I say,

00:40:57.000 it's there and ready to go.

00:40:58.300 And when people have a stroke and

00:40:59.960 they suddenly start experiencing the

00:41:01.580 world differently, you know, how did

00:41:03.480 that happen just like that unless it 0.61

00:41:05.320 was there and ready to go in the

00:41:07.180 intact individual?

00:41:08.100 So we know that is the case, but I

00:41:11.880 suppose I'm less troubled by the

00:41:13.900 idea that there might be two people

00:41:15.800 here.

00:41:16.540 It looks like that, but then it would

00:41:18.820 only be like that if, as it were, we

00:41:23.700 were sure that whatever it is that is

00:41:26.800 my left hemisphere's consciousness and

00:41:28.740 my right hemisphere's consciousness were

00:41:31.100 generated straight out of those

00:41:33.760 hemispheres.

00:41:34.300 Now, I suspect that this may be a point

00:41:36.440 on which we might differ, but I'm not

00:41:39.720 convinced that the brain is merely a

00:41:42.300 producer or secretor of consciousness.

00:41:44.860 So it becomes possible to think of

00:41:46.500 consciousness that is a flow and that

00:41:49.300 is transmitted, transduced by the brain.

00:41:55.000 So you can see the brain as something

00:41:56.620 that is receiving a stream of information

00:42:00.360 to both hemispheres simultaneously and

00:42:02.460 together and that that is producing the

00:42:05.600 whole personal experience.

00:42:07.640 But what happens when you artificially

00:42:10.560 divide the brain is that it's rather

00:42:13.600 like an island in a stream where the

00:42:15.880 stream has to go either side of the

00:42:18.820 island and then reconvene again.

00:42:20.840 And the stories I've been telling about

00:42:22.700 the coming together and the coming

00:42:25.180 separately of the two hemispheres might

00:42:28.760 be better thought of in terms of such a

00:42:31.700 metaphor.

00:42:32.700 That's all really I'm suggesting.

00:42:35.100 I think it's too extreme to say that

00:42:36.860 there are two persons that are, you know,

00:42:39.120 there's Sam Harris left and Sam Harris

00:42:41.920 right.

00:42:42.360 I don't think that's a, I think that's

00:42:45.140 too simple.

00:42:46.280 Yeah, no, I wasn't suggesting that.

00:42:48.200 I guess what I was suggesting, though, is

00:42:50.300 that in any picture other than perfect

00:42:54.600 information sharing, then you have to ask

00:42:57.760 yourself what is left out and what are the

00:43:00.700 consequences of its being left out for

00:43:03.120 subjectivity in any given moment.

00:43:05.620 And however fluid you want to make it,

00:43:07.860 anything less than perfect access across

00:43:10.840 the commissures gives you this Venn diagram

00:43:14.820 where of conscious experience where in the

00:43:18.520 two circles don't completely overlap and

00:43:21.240 become one.

00:43:21.940 And so then you have to ask yourself, well,

00:43:24.640 what is the penumbra like where the left

00:43:28.600 doesn't share what the right is in fact

00:43:32.000 experiencing and vice versa?

00:43:34.620 And again, this could be completely fluid so

00:43:36.780 that, you know, you could have more global

00:43:39.780 states of the hemispheres where there is a

00:43:41.560 kind of synchrony and synchrony may in fact be

00:43:44.600 what is mediating the sharing of, you know, a

00:43:49.100 conscious percept or thought in any given

00:43:51.740 moment.

00:43:52.700 But again, the spooky part for me is not so

00:43:56.920 much that much of what the brain is doing is

00:44:00.720 unconscious, you know, or outside the

00:44:03.040 experience of the conscious subject in any

00:44:06.000 moment.

00:44:06.820 It's the idea that some of what's outside

00:44:09.900 your experience as a conscious subject in

00:44:13.060 this moment may itself be conscious, right?

00:44:16.520 That's the thing that just makes the hair 0.56

00:44:19.640 stand up on the back of one's neck.

00:44:22.700 And yeah, go ahead.

00:44:24.900 Well, yeah, just so much that you're

00:44:27.980 commenting on there that's so important.

00:44:31.520 I mean, something we might come to later

00:44:34.020 because it comes back to the question why

00:44:36.560 the two hemispheres are separate in the way

00:44:38.840 that they are, is that much of the traffic as

00:44:41.900 you describe it, bringing information together

00:44:44.860 across the corpus callosum, is inhibitory.

00:44:48.840 And much of the effect of the corpus callosum

00:44:51.540 is for one hemisphere to say, I'm dealing

00:44:54.080 with this.

00:44:55.440 You keep out of it because that's just going

00:44:57.520 to make the matter confused and I'll work

00:44:59.820 slower.

00:45:00.840 So even in a perfectly functioning brain where,

00:45:04.780 as it were, at one level the communication

00:45:06.880 is good, some of the functional effect of the

00:45:10.020 communication is not positive but negative.

00:45:12.780 It's not facilitation, it's inhibition.

00:45:15.640 But even more so, I wanted to comment on the

00:45:18.160 question about consciousness because, of course,

00:45:21.900 consciousness means many different things.

00:45:25.140 And in one sense, we think that consciousness

00:45:28.560 is what is in my mind that I'm aware of right

00:45:32.400 now and I'm focusing on.

00:45:34.060 But that is variously estimated to be between

00:45:38.380 half a percent and five percent of what's going

00:45:42.460 on in one's brain.

00:45:43.960 In fact, I read a paper in which the authors said

00:45:48.120 that 99.44% of brain activity was not within the field

00:45:54.000 of consciousness, which is alarmingly precise.

00:45:56.960 But in any way, it makes the point.

00:45:58.240 But the way I would see that is that there is also

00:46:02.180 material that can quite quickly become conscious.

00:46:05.120 It's just that it's not conscious now for reasons

00:46:07.620 of expediency.

00:46:09.540 If we are to function, we simply can't be conscious

00:46:12.360 of many things of which we have consciousness

00:46:16.460 at a different level.

00:46:18.540 And that can be brought into effect like that

00:46:20.720 if it's necessary.

00:46:22.080 So the way I see it is that one distinction between

00:46:24.980 the left and the right hemisphere, which we must

00:46:27.920 come on to at some point, is that the left hemisphere

00:46:30.400 has very narrow beam attention that is highly

00:46:34.320 clarified and precise.

00:46:37.100 But it's only to like three degrees of the 360 degree

00:46:41.780 attentional arc, whereas the right hemisphere

00:46:45.240 sees a very broad picture.

00:46:48.700 And that is quite different.

00:46:50.000 It's on the lookout.

00:46:51.400 It's vigilant all the time.

00:46:53.060 So if you think of the field of consciousness

00:46:57.100 as being a stage on which life is going on,

00:47:03.180 the bit that is within the spotlight is the bit

00:47:07.260 the left hemisphere sees.

00:47:08.520 And that's the bit we say, oh, I'm conscious of that.

00:47:11.440 But when the spotlight moves, five minutes later,

00:47:14.440 you're no longer conscious of what you were conscious

00:47:16.480 of even a few seconds ago.

00:47:19.760 But it's still within your consciousness.

00:47:21.900 It's still possible for you to summon it.

00:47:23.780 And it's still there.

00:47:25.200 It's like the part of the stage that's not illuminated.

00:47:27.620 It hasn't gone away.

00:47:28.840 It's just the bit we're not any longer attending to

00:47:30.960 in this very particular, highly self-conscious consciousness.

00:47:37.320 What would you say about that?

00:47:39.640 That's interesting.

00:47:40.220 I think I would bound the concept of consciousness

00:47:44.220 a little differently there.

00:47:46.300 Because for me, again, I think consciousness as a concept

00:47:50.980 is actually irreducible, which is to say we define it

00:47:55.800 in circular terms.

00:47:58.240 It's synonymous with experience.

00:48:00.180 It's agreed, yeah.

00:48:00.920 You know, I like Thomas Nagel's framing that it's something

00:48:04.660 that it's like to be a system.

00:48:07.240 So if a bat is conscious, that's simply saying that there's 0.87

00:48:10.620 something that it's like to be a bat.

00:48:12.080 If you could trade places with a bat, you'd have some qualitative character 1.00

00:48:16.480 to your being in the world.

00:48:19.820 It wouldn't be synonymous with just having the lights go out.

00:48:22.460 And so when talking about one's own conscious experience,

00:48:28.260 I would differentiate consciousness from attention, say.

00:48:32.060 So I can be paying attention to one thing,

00:48:34.480 but also dimly aware of the things that I'm trying to exclude

00:48:38.580 from my experience by focusing on the one thing.

00:48:41.500 There's a kind of a center and periphery,

00:48:44.220 you know, very much analogous to what we experience in vision.

00:48:47.520 You know, you have your foveal, you know, in-focus vision,

00:48:50.360 and then you have all the stuff you can see in the corner of your eye.

00:48:55.260 And so there's a spotlight of attention,

00:48:58.060 but then there's this wider field of illuminated experience

00:49:03.000 that has a qualitative character.

00:49:05.000 And at the margins of this, it's always possible to have, as you say,

00:49:09.900 new percepts and ideas and phenomenons surface

00:49:14.240 and be brought into direct awareness.

00:49:17.940 And there, you know, as William James quite brilliantly pointed out,

00:49:23.060 I mean, now over a hundred years ago,

00:49:25.100 our experience of this, the kind of liminal boundary

00:49:29.040 between consciousness and unconsciousness

00:49:31.720 has a kind of structure that can be interrogated if you're clever.

00:49:37.660 And we've learned to do that scientifically in all kinds of ways.

00:49:41.800 But even just introspectively, you can notice things that,

00:49:45.420 one example that James gave is that if you think about

00:49:49.860 what it's like to suffer the tip-of-the-tongue phenomenon,

00:49:55.240 you're trying to remember a word, you're trying to remember somebody's name,

00:49:58.640 and you just can't get anything.

00:50:00.500 So on the one hand, we're talking about what is absent from consciousness.

00:50:05.920 Like, the word is not there.

00:50:07.720 The name is not there.

00:50:08.880 There is a vacancy, which you're struggling to fill.

00:50:12.940 But this vacancy has structure because someone can say to you,

00:50:18.300 is the name Jim?

00:50:20.480 And you instantly know, no, it's not Jim.

00:50:23.520 You can exclude Jim because Jim is not the name you're trying to think of,

00:50:27.920 and yet you don't know what the name is that you're trying to think of.

00:50:31.740 You know, there are fascinating aspects to this where,

00:50:33.960 take a phenomenon like hemi-neglect, which, you know,

00:50:37.860 we're in our leisurely way getting to is one of these issues where,

00:50:43.240 you know, where you have a, in this case, a right hemisphere lesion,

00:50:47.020 you know, usually in the parietal lobe,

00:50:49.740 which causes this phenomenon of people neglecting the left half of the world

00:50:56.640 and being unaware of their deficit, right?

00:51:00.520 So if you tell them to draw a clock face, they'll draw a circle,

00:51:05.220 but then they'll put all the numbers on the right side of the clock.

00:51:08.400 If you ask them to start writing on a piece of paper,

00:51:11.840 they'll start writing down just the right half of the piece of paper.

00:51:15.580 But this raises a kind of Jamesian conundrum,

00:51:19.680 which is in order to systematically neglect the left half of the world,

00:51:24.980 you need to know where the middle is, right?

00:51:27.780 And to know where the middle is, you do need to know where the left half of the world is.

00:51:31.860 I mean, in order to reliably start writing on the right half of a piece of paper,

00:51:35.700 part of you needs to have found the middle

00:51:37.560 in order to jump over to the right side of things.

00:51:40.560 So the question is, again, the very strange question from my point of view

00:51:45.360 is not that some or most of this processing

00:51:48.460 is happening subliminally, you know, in the dark,

00:51:53.000 you know, beneath the light of consciousness.

00:51:54.820 It's that some of it could be associated with consciousness,

00:52:00.040 that there could be something that it's like

00:52:01.740 to see the left half of the world

00:52:04.120 and then get the rest of the person to ignore it.

00:52:08.300 There's something that it's like to know the word

00:52:11.140 that the rest of you is trying to think of

00:52:13.900 and yet not provide it or not be able to provide it.

00:52:17.820 And this just opens the door,

00:52:19.260 and I'm not suggesting that in an intact brain

00:52:21.980 we have two separate people in there,

00:52:23.720 but insofar as the real estate of consciousness itself

00:52:27.280 might not be fully integrated,

00:52:29.700 it does force a very spooky picture,

00:52:33.900 and again, a quasi-Freudian picture,

00:52:35.960 of a conscious part of you

00:52:39.120 that you, the so-called conscious subject,

00:52:43.380 isn't aware of in any given moment.

00:52:46.620 There's something that it's like to be part of your mind

00:52:50.120 that you, the conscious person in this moment,

00:52:54.180 doesn't directly experience.

00:52:56.940 And that's, again,

00:52:58.200 even if you're convinced that that is a possibility,

00:53:02.240 and even if you see some indication of that in your life

00:53:05.960 in moments of self-deception

00:53:08.140 or in moments of, you know, dream,

00:53:11.380 you might experience a dream

00:53:12.800 where it really seems like there's an author of the dream

00:53:16.420 that has anticipated you as the protagonist of the dream

00:53:20.520 not knowing what's going on.

00:53:22.080 I mean, like, having a dream

00:53:23.620 where a dream character is telling you a joke

00:53:28.280 that has a punchline that surprises you,

00:53:31.640 I mean, like, that's just an incredible experience.

00:53:33.980 They say, just, you're the protagonist in your dream,

00:53:36.080 you meet a person who doesn't exist,

00:53:38.280 and you're obviously not aware of that

00:53:39.840 because it's a dream,

00:53:41.440 it's not a lucid dream,

00:53:42.320 and this person tells you a joke

00:53:45.080 and you're waiting to hear the punchline,

00:53:47.260 and then when the punchline is delivered,

00:53:49.420 it's actually funny.

00:53:51.420 And so how is it possible for part of your mind

00:53:54.220 to have written on demand

00:53:56.820 something that the other part of your mind will find funny?

00:53:59.880 All of these moments, again,

00:54:02.400 suggest something very weird,

00:54:04.980 and I think it's just very hard for people

00:54:07.780 to keep this in focus.

00:54:09.860 You raised so many things.

00:54:11.860 A few issues, yeah.

00:54:13.420 If you could be patient.

00:54:14.780 Sure.

00:54:16.200 I think the first thing I think is...

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00:54:47.800 Thank you.

00:54:48.740 Thank you.

00:54:49.420 Thank you.

00:54:50.300 Thank you.

00:54:52.620 Thank you.

00:54:54.300 Thank you.

Making Sense - Sam Harris - February 05, 2021

#234 — The Divided Mind

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