3 now you see it, now you don’t: commentary by nicholas humphrey (london)

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Now You See It, Now You Dont: Commentary byNicholas Humphrey (London)Nicholas Humphrey

a

aCentre for Philosophy of Natural and Social Science, London School of Economics,

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Published online: 09 Jan 2014.

To cite this article:Nicholas Humphrey (2000) Now You See It, Now You Dont: Commentary by Nicholas Humphrey(London), Neuropsychoanalysis: An Interdisciplinary Journal for Psychoanalysis and the Neurosciences, 2:1, 14-17, DOI:

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14

Nicholas Humphrey

Now

You See It, Now You Don't: Commentary by Nicholas Humphrey (London)

Those

of

us who have been arguing for some years

for the position that Francis Crick and Christof Koch

arrive at in this paper, namely, that phenomenal con

sciousness occurs only at the level

of

sensation, and

that higher mental processes (including thinking and

perception) have no conscious phenomenology at all,

have made singularly little impact on the current

debate.

In 1992, in A History

of

the Mind (Humphrey,

1992), I summarized my own views

as

follows:

1 To be conscious is essentially to have sensa

tions: that is, to have affect-laden mental representa

tions

of

something happening here and now to me

2

The subject of consciousness,

I,

is an em

bodied self.

n

the absence of bodily sensations

I

would cease.

Sentio ergo sum I

feel therefore I am.

3

All sensations are implicitly located at the

spatial boundary between me and not-me, and at the

temporal boundary between past and future: that is,

in the present.

4

For human beings, most sensations occur in

the province

of

one

of

the five senses (sight, sound,

touch, smell, taste). Hence most human states

of

con

sciousness have one or other

of

these qualities. There

are no nonsensory, amodal conscious states.

5

Mental activities other than those involving

direct sensation enter consciousness only in so far as

they are accompanied by reminders

of

sensation,

such as happens in the case of mental imagery and

dreams.

6 This is no less true

of

conscious thoughts,

ideas, beliefs Conscious thoughts are typically

heard as images of voices in the head-and with

out this sensory component they would drop away

[p.97].

Yet, arguing these points at a conference at Kings

College, London in Spring 1999, I found myself a lone

voice against philosophers John Searle, Ned Block,

David Chalmers, and others who, to a man, continued

to insist that consciousness extends to higher levels of

mentation and in particular that thoughts and percep-

Nicholas Humphrey is a Research Fellow, Centre for Philosophy of

the Natural and Social Sciences, London School of Economics, Houghton

Street, London WC2A 2E.

tions have conscious qualia attached to them in their

own right.

I confess that, on the basis

of

some of Crick and

Koch's own earlier writings (e.g., Crick's The Aston-

ishing Hypothesis 1994), I had assumed that they too

were failing to see how restricted the realm of con

scious qualia really is. And I was hardly reassured to

find them beginning this paper with the advice that

it

is better to avoid a precise definition of conscious

ness, followed not long after by the clueless sugges

tion that self-consciousness is probably a special

case of consciousness. Anyone who has been long

in this field will know the sinking feeling that arises

when yet another author claims, as here,

that'

every

one has a rough idea of what is meant by conscious

ness and proceeds to make a virtue out of having it

all ways.

I was therefore surprised and happy to read

on-and to find Crick and Koch, far from taking their

own advice, instead making a pitch for a very precise

definition of consciousness: a definition of what is

conscious and what is not which turns out to depend

on nothing other than the presence or absence of sen

sory phenomenology. Indeed in the end I found their

paper doubly refreshing-both

as

evidence

of

two ma

jor scientists coming over to a correct, i unfashion

able, point of view, and for its clear discussion of some

of the theoretical and empirical implications.

Crick and Koch are obviously aware that they

are doing something unconventional and possibly the

oretically dangerous. I

t ink

that it is in fact quite

dangerous, and that there is one area in particular

where they need to be careful how they go. This is

when it comes to making the elementary but crucial

distinction between (conscious) sensation and (uncon

scious) perception.

The remarkable fact that human beings-and

presumably many other animals

also-make

use

of

their bodily senses in these two quite different ways,

was first brought to philosophical attention two hun

dred years ago by Thomas Reid, who wrote:

The external senses have a double province-to make

us feel, and to make us perceive. They furnish us with

a variety

of

sensations, some pleasant, others painful,

and others indifferent; at the same time they give us

a conception and an invincible belief

of

the existence

of external obiects


3/5

Commentary on the Unconscious Homunculus

Sensation, taken by itself, implies neither the concep

tion nor belief of any external object.

t

supposes a

sentient being, and a certain manner in which that

being is

affected; but it supposes

no

more. Perception

implies a conviction and belief of something exter

nal-something different bothfrom the mind that per-

ceives, and the act of perception. Things

so

different

in their nature oUght

to be

distinguished

[Reid, 1785,

Vol. 2,

chapters 16

& 17].

For example, Reid said, we smell a rose, and two

separate and parallel things happen: we both feel the

sweet smell

at

our own nostrils and we perceive the

external presence

of

a rose. Or, again, we hear a hooter

blowing from the valley below: we both feel the boom

ing sound

at

our own ears and we perceive the external

presence

of

a ship down in the Firth. In general we

can and usually do use the evidenceof sensory stimu

lation both to provide a subject-centred qualia-rich

representation of

what's

happening to me, and to

provide

an

objective, affectively neutral representa

tion

of

what 's happening out there (Humphrey,

1992).

Now, what Crick and Koch are identifying as the

core phenomenon

of

consciousness is clearly meant

to be the first

of

these: sensation, not perception. Yet,

one reason why

they-and

all

of us-need

to be so

careful is that it is so easy to muddle the two up.

Reid again:

[Yet]

the perception and its corresponding sensation

are produced at the same

time.

In our experience we

never

find

them disjoined. Hence, we are led

to

con

sider them

as

one thing,

to

give them one

name,

and

to

confound their different attributes.

t

becomes very

difficult

to

separate them in thought,

to

attend

to

each

by itself, and t attribute nothing to it which belongs

to the

other. To

do this,

requires a degree of attention

to

what passes in our own minds, and a talent

for

distinguishing

things

that differ,

which is not

to be

expected

in

the vulgar, and

is

even rarely found

in

philosophers [Reid, 1785, Vol.

2,

Chapter 17].

To repeat: sensation has to do with the self, with

bodily stimulation, with feelings about what's happen

ing now to me

and

how I feel about it; perception has

to do with judgments about the objective facts of the

external world. Things so different in their nature

ought to be distinguished. But rarely are they.

Sigmund Freud was surely looking to make just

this crucial distinction when he contrasted his two

principles

of

mental functioning, the pleasure and

15

the real ity principle. But, within the psychoanalytic

tradition, I believe

it

was Ernest Schactel who mapped

out the differences most articulately. In his book,

Metamorphosis Schactel wrote about what he called

the autocentric and allocentric modes

of

experi

encing the world:

n the autocentric

mode

there is little or

no

objectifi

cation; the emphasis is on

how

and what the person

feels; there

is

a close relation, amounting to a fusion,

between sensory quality and pleasure or unpleasure

feelings, and

the

perceiver reacts primarily to some-

thing impinging on him. . . . n the allocentric mode

there

is

objectification; the emphasis

is

on what the

object is like [Schactel,

1963, p. 83].

Psychoanalysts have tended to prioritize sensa

tion over perception, while cognitive psychologists

have done the opposite. But within the cognitive tradi

tion too, some theorists

at

least have recognized the

basic duality

of

sensory experience. In the case

of

vi

sion

in

particular, Irving Rock distinguished

the

vi

sual field and

the

visual world. David Marr

argued that the perceiver does in fact have separate

access to different stages

of

visual processing. And,

as Crick and Koch describe, Ray Jackendoff made

Marr's theory the basis for his own central insight that,

even though we do indeed have cognitive access to

the 3D model

of

the external world, what we are phe

nomenally aware

of

is the

2 hD

sketch that corres

ponds to the subjective sensation

of

the image

at

the

eye.

Even for those who do appreciate the full signifi

cance of this distinction, however, the problems are

not necessarily over. For

it

is one thing to understand

the distinction in principle, another to apply this un

derstanding in the case

of

particular examples. And,

as it turns out, there is plenty

of

room still for confu

sion and objection. Indeed I wonder

if

Crick and Koch

themselves have anticipated how they are going to

cope with some of the uncertain cases.

Let me follow through in one particular direction,

so as to confront, and deal with, a simple example that

might otherwise prove to

be

the Achilles heel

of

the

whole thesis.

Suppose it is true, as

we

are saying, that people

are conscious only of sensory qualia experienced at

the level

of

sensation and not

of

the content

of

percep

tions or thoughts as such. It must follow presumably

that,

if

and when there is in fact no change in sensa

tion, there will be no change

in

consciousness, even

if

there is a change in what is perceived or thought.


4/5

6

But, then, the obvious test case would seem to be an

ambiguous picture, such as the Necker cube or the

duck/rabbit, where, while the visual image and hence

the raw sensation

of

what's happening to me re

mains constant, the perception

of

what's

happening

out there may radically alter.

At the London conference Searle challenged me

directly about such cases, saying that, for example, it

was perfectly obvious to im that the Necker cube

seen in one way is a consciously different phenome

non from the same cube seen the other way-thus

proving that we can be conscious of what is perceived

as well as of what is sensed.

Well, can we? I admit on the evidence of intro

spective observation the answer must be

Yes

When

the cube reverses in depth there is surely something

that consciously changes. And it is certainly not at the

level of sensation of the visual image (which, qua

represented image, does not even have a depth dimen

sion to reverse).

What is this something, then? When the cube re

verses, is there, as Searle would want to say, a change

in some aspect of nOllsensory perceptual conscious

ness-perhaps the coming and going of cube-qua

lia ? (Just as, with the duck/rabbit, he might want to

postulate the coming or going of duck-qualia or

rabbit-qualia ? I am not joking: some theorists are

really prepared to talk this way. V S Ramachandran

and Hirstein [1997], for example, write of dog qua

lia ). If so, our argument is lost.

Or,

is there perhaps another possibility? When

the cube reverses, is there a change not in nonsensory

qualia nor in visual qualia but

n sensory qualia o

another nonvisual kind

I believe there are in fact two

ways that this could be happening.

One way of understanding it would be to take up

an idea

of

Mark Solms (which he himself attributes

to Freud), and to suggest that conscious experience is

comprised not only of the five basic modalities of sen

sory qualia but also of an additional dimension of af

fect. Affective qualia, Solms writes, (which are

calibrated in degrees

of

pleasure/unpleasure) are

wholly equivalent to the qualia of vision, hearing,

smell, etc., and are irreducible to them (Solms, 1997,

p

773). So, whenever we experience a sight or a sound

or a taste, etc., perhaps the conscious experience is

likely to consist both of the specific sensory qualia

and of whatever affective qualia are being activated.

But, while the sensory qualia are fixed solely by the

sensory stimulus, the affective qualia may be influ

enced not only by the stimulus but also by what is

being perceived. With an ambiguous figure, then, even

Nicholas Humphrey

though the visual sensation remains constant, when

the perception changes the affective qualia may

change too.

I

t ink

this is a nice idea, and in some cases it

might be correct. But I am not sure it will do in gen

eral. Different affective feelings for ducks and rabbits?

Well, why not. But different feelings for the two ver

sions of the Necker cube? Unlikely.

The other way would be to take up an idea of my

own (Humphrey, 1992) and also of Patrick Wall

(Wall, 1999), and to suggest that what is crucial is not

so much affect as action. Suppose that whenever we

perceive anything (and sometimes even when we

merely

t ink

of things) we always implicitly formulate

a plan of action-for example a plan to reach out and

take hold of it. And suppose that such action, even

when implicit, always has a small but noticeable quali

tative feel to

it-either

on its own account via somatic

sensation or through modeling of the sensory feedback

that would be expected.

Let's call this additional dimension the dimen

sion

of

agentic qualia. Then, whenever we experi

ence a sight or a sound or a taste, etc., the conscious

experience can be expected to consist not only of the

sensory qualia appropriate to the particular sensation

but also of whatever agentic qualia are being called

into being.

This solves the problem of the Necker cube. For,

now we can postulate that, even while the visual sen

sation remains constant, there may be a covert change

in action plan when the perception of the cube re

verses, and so a slight change in the overall sensory

qualia.

Unfortunately I suspect that Crick and Koch are

not going to like this last suggestion entirely. For I

have to note that it would complicate and maybe un

dermine one of the main planks of their empirical

approach to looking for the neural correlate of visual

consciousness. The reason is that Crick and Koch be

lieve that one of the best ways to find the neural corre

late of visual consciousness might be to identify

changes in the activity of the visual pathways of the

brain that are correlated with changes in the perception

of just these ambiguous figures; for example, the

Necker cube (e.g., Crick, 1994, p 218).

But now this looks like being a mistaken effort.

For if I am right about the role of agentic qualia, or

for that matter if Solms is right about affective qualia,

then when the perception changes, the crucial change

in consciousness is not being generated by activity in

the visual pathways at

all- i t

is almost certainly being

generated much further forward in the region of the

brain that controls action and affect.


5/5

Commentary

on the Unconscious Homunculus

References

Crick, F. 1994), The Astonishing Hypothesis:

he

Scientific

Search

or

the Soul.

New

York: Simon

Schuster.

Humphrey, N. 1992), A History o the Mind. London:

Chatto

Windus.

Ramachandran, V. S.,

Hirstein, W. 1997), Three

laws

of qualia: What

neurology tells

us

about

the biological

functions

of consciousness.

1 Consciousness Studies

4:429-457.

Reid, T. 1785), Essays on the Intellectual Powers

o

Man

ed. D.

Stewart. Charlestown: Samuel

Etheridge,

1813.

17

Schactel,

E. G.

1963),

Metamorphosis.

London:

Routledge Kegan Paul.

Sohns, M.

1997),

What

is consciousness? 1. Amer. Psy

choanal. Assn. 45:681-703.

Wall, P. D.

1999),

Pain: The Science

o

Suffering.

London:

Weidenfeld and Nicolson.

Nicholas Humphrey

Centre

or

Philosophy

o

Natural and Social Science

London School

o Economics

Houghton Street

London WC2A 2AE

Unconscious,

Yes;

Homunculus,???: Commentary by Ray Jackendoff Waltham, MA

In The Unconscious Homunculus and other works,

Francis Crick and Christof Koch make an admirable

case for attempting to discover the neural correlates of

consciousness (NCC). As they observe, their research

complements rather than supplants the sort of work I

have done on what might be called the representa

tional correlates

of consciousness-the

formal organi

zation

of

the computations and data structures that the

NCC instantiates neurally. And I am

of

course grati

fied that my work has played a role in their thinking.

I will offer here four brief reactions to their paper.

Methodology

n their conclusion, Crick and Koch say, It cannot

be overstated that Chalmers's hard problem of con

sciousness is unlikely to yield to a purely logical or

philosophical attack. I can certainly endorse this.

They continue: Rather, it needs to be approached

in a reductionist, scientific manner. This must be

construed with care. f a reductionist, scientific man

ner is meant to exclude every approach but neurosci

ence, I would disagree. I think the problem needs to

be approached from every possible front. There is still

plenty of room in this field for careful introspection,

for philosophical analysis and thought experiments,

for traditional psychological and psychophysical ex

periments, for computational theory and computa-

Ray lackendoff is on the Faculty of Brandeis University and was

a fellow at the Wissenschaffskolleg zu Berlin in 1999-2000 where this

commentary was written.

tional simulation. There is no question that

neuroscience brings new and important tools to the

task, and that these tools may help us reevaluate our

previous thinking; but they do not oblige us to discard

the old tools outright.

I imagine Crick and Koch would concur. But oth

ers have hastened to demean all techniques of cogni

tive science that do not make direct recordings of brain

activity; and therefore I find it vital to reemphasize

the importance of methodological pluralism, with the

goal

of

eventual convergence.

The Valuation o a Percept

Crick and Koch allude to the aspects of consciousness

I have called affects

(1987) or

valuations

(1996,

1997). They speak of them

as

a class

of

conscious

percepts which have a rather different character from

straightforward sensory percepts. Evidently I failed

to make myself entirely clear in my discussions.

Though the valuations are not too important for Crick

and Koch's purposes in this particular article, I think

they eventually have to

playa

crucial role in the theory

of consciousness and its neural correlates.

The notion of a valuation arises from the ques

tion: What in the mind-brain distinguishes a percept

of

something in the world from an image

of

the same

thing? One might first be tempted to say that images

are fuzzier and more fleeting. But compare, for exam

ple, hearing music way off in the distance, which is

indeed fuzzy and fleeting, with hearing in your head

some music you know very well, right down to the

3 now you see it, now you don’t: commentary by nicholas humphrey (london)

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