Dear Teed Rockwell,


I have read your paper `On what the mind is identical with'

with interest, though not, as you can imagine with

agreement.  You state that, according to Smart and myself,

"every mental state or event is identical with some

material state or event."  That is not and never has been

my view.  My contention was and is that it is a reasonable

and, when fully spelled out, empirically testable

hypothesis that a particular aspect of the mental life of

the more highly developed of complex free-moving living

organisms (animals) which I refer to as `consciousness' is

a particular process or pattern of activity in the brains

of such creatures.  Consciousness in this sense is

essentially an ongoing process.  It is neither a mental

state, if by that is meant a dispositional state, nor an

event, if by that is meant an instantaneous event, such as

a decision or the occurrence of a thought. 

     Dispositional mental states such as beliefs and

desires, though they may have inward manifestations in the

form of the individual's private thoughts, are no more

inside the brains of their owners than is the magnetic

field of an iron bar inside the bar.  Like all

dispositional properties, mental dispositions depend for

their existence on a state of the structure, usually the

microstructure of the property-bearer.  In the case of

mental dispositions this is invariably a state of the

microstructure of the brain, presumably a pattern of

`weights' at the synapses in the brain.  But these states

of the brain microstructure stand as cause to the

dispositional states as effect.  It follows, in accordance

with Hume's principle, that they are `distinct existences'.

Contrary to the view expressed by Searle, you can't have it

both ways.  If two things are causally connected, they

can't be the same thing.  If they're the same thing, they

can't be causally connected.  Think of the relation between

the cubic capacity of the cylinders of an internal

combustion engine and its horsepower.

     Instantaneous mental events are more difficult.  They

occur at the interface between an antecedent mental process

and a subsequent and consequent dispositional mental state.

The antecedent mental process, according to me, is a

process in the brain; whereas the subsequent and consequent

disposition depends on, but is not, a state of the brain.

Consequently the instantaneous event at the interface

between the two can be thought of either as completing a

process in the brain or as initiating a brain state which

in turn gives the organism whose brain it is a

dispositional property it did not have before, and which is

something over and above the state of the brain on which it

depends.  On balance, since they only initiate dispositonal

mental states by producing the relevant changes in the

brain microstructure, it seems right to view such events as

brain events simpliciter.

     Turning to the phenomenon of consciousness considered

as an ongoing process a part of which (the individual's

private conscious experience) is susceptible to description

by the introspecting human subject and which, according to

me is almost certainly identical with some as yet

unspecified process in the brain.  All the evidence both

from neurology and from brain imaging makes it pretty clear

that in mammals the cerebral cortex is the seat of

consciousness in this sense.  Although there are many

processes and events in the cortex which are not

represented in the subject's introspective reports, if we

take consciousness to consist, as the evidence suggests, in

the process whereby inputs which are identified as

problematic by the subconscious system in the midbrain are

categorized and an appropriate response selected, there

seems to be no activity in the cortex that does not

subserve this basic problem-solving function.  Sub-

conscious centres in the mid- and hind-brain, not to

mention the spinal cord, have important coordinating

functions both in relation to the execution of complex

skilled and habitual behavior, as well as in relation to

the involuntary attraction of attention to problematic

inputs; but when the organism is running on `automatic

pilot' in this way, the brain imaging evidence shows that

cortex is almost completely quiescent.  What becomes of the

the mind in all this?  It's just not a useful concept.


Kind regards,


Ullin Place



I have some reactions to some questions you raise at the end of your

paper where you ask:


>Are you personally willing to give up the idea of sense data as a

>foundation for knowledge?


I gave up that idea fifty years ago when I heard John Austin give

his `Sense and sensibilia' Lectures in Magdalen College, Oxford, in



>What would you loose by doing this?




>If you did give up this idea, would something like the pragmatist

>concept of experience be an effective substitute?


If I understand it which I probably don't, the pragmatist concept

of experience is an attempt to capture the notion of experience in

the phrase `learning from experience'.  This is no substitute in my

view for the notion of sensory or phenomenal experience as that

which we describe when we describe what it is like to be aware of

this or that, of undergoing this or that or of doing this or

that.  The two notions are connected; but nevertheless distinct. We

need both.


>For those of you who are trained in Neuroscience, which concept of

>experience seems more biologically plausible?


I am not sure that I can claim to be trained in Neuroscience; but

response of some eminent neuroscientists to what I have been

writing recently on these topics encourages me to think that I can

speak with some authority on this matter.  As soon as I read the

late Donald Broadbent's 1971 book DECISION AND STRESS, it seemed

to me obvious that his concept of a "state of evidence" on the

basis of which the brain categorizes sensory inputs corresponds

rather precisely to the notion of raw uninterpreted sensory

experience.  This notion I take to be implicit both in James'

description of the consciousness of the child as a "big blooming

buzzing confusion" and in Wilhelm Wundt's distinction between

Immediate and Mediate Experience, where Mediate Experience is

experience interpreted as a sensory encounter with external reality

and Immediate Experience is the same experience interpreted as what

it really is, a process taking place within the observer's own

consciousness.  In ordinary language it is implicit in the

distinction we draw between `physical' pleasure and pain which

does not depend on how the stimulus is interpreted and `mental'

pleasure and pain which DOES so depend.












Dear Teed,


I would like to comment on the sensation/perception issue. 

        The traditional view of this matter to which I subscribe

holds that sensation + concept = perception.  This formula implies

that there can be such a thing as a `raw', i.e., uninterpreted,

sensory experience.  As evidence that such a notion is needed, I

would cite the distinction we draw between `physical' pleasure or

pain, where the pleasure or pain reaction is a response simply to

the quality of the sensory experience, and `mental' pleasure or

pain, where it is a response, sometimes to the very same

experience, once it has been conceptualised or interpreted, e.g.,

as a symptom of some fatal illness.

        This notion of `raw' unconceptualised experience is

anathema to the Kantians and the phenomenologists; and there are at

least three sets of considerations which lend support to their

view.  One is the relatively trivial point that you can't say

anything about an experience until it has been conceptualised in

SOME way.  Another is the point that the qualia merchants are in

danger of overlooking, namely, that an unconceptualised experience

is like a unfertilised egg, an entity that has failed to fulfill

its biological function.  But it is the third consideration which,

to my mind, is the most interesting.  It is a point which is

suggested by a lot of recent neurological and neuropsychological

work, particularly the work that has been done on the functions of

the extra-striate visual areas, V2-V5.  Contrary to what is suggested

by the adjective `raw', it is now becoming clear that a great deal of

complex processing has to go on in assembling the experience, BEFORE

it becomes what Broadbent (1971) calls "a state of evidence"

capable of suggesting an interpretation/conceptualisation/

categorization.  What seems to happen in visual areas V1-V5 is that

there are specific neurons in these areas  which are "tuned" to

respond to features of the input which become more and more

abstract and are triggered by retinal stimulation over wider and

wider areas the further removed they are from V1.  These features

are things like an edge, a gradient of texture (interpreted as a

surface at certain angle of slope relative to the horizontal -

Gibson 1950) or a stationary object with a background moving to the

right (interpreted as watching an object moving to the left -

Gibson op.cit.) which are seldom, if ever, conceptualised as such,

but which, when "bound" together with other such features result in

a recognisable "image" of an object of some identifiable kind.

When one way of "binding" a set of features together fails to yield

an identifiable object, another way of "binding" the features may

be tried and, failing that, the standard reaction is to look again,

this time more closely.

        Morover, the phenomenon of simultanagnosia which results

from lesions of this so-called "ventral stream" and which consists

in an inability to perceive the relations between different

objects in a visual array, even though the objects themsleves are

recognised normally, suggests that the interpretation of a complex

visual array proceeds in two stages.  In the first stage the

individual objects are identified.  In the second the

experience/"evidence" is revisited in order to conceptualise the

relations between them.

        The complexity of this process and that of the processes

of response-selection and response execution which ensue, not to

mention the linguistic processes of assigning a name to a concept or

a concept to a name and of organizing and deciphering complex

sentence structures, explains why it is that only PROBLEMATIC

INPUTS (i.e., those that are either unexpected or significant

relative to the organism's motivational concerns) are processed in

this way.  The task of separating the problematic from the

unproblematic, alerting consciousness to the former, while either

ignoring the latter or routeing them automatically and unconsciously

along well-worn channels to output, falls to the automatic-pilot or

"zombie-within" as I call it.








Dear Teed,

                                        16 July 1998


     If, as seems reasonable, your criterion for the

presence and absence of consciousness is the presence or

absence of conscious/phenomenal experience, we now have

conclusive empirical evidence showing that the function

of conscious/phenomenal experience is to provide what

Broadbent (1971) calls the "evidence" on which the

categorization of problematic inputs (inputs which are

either unexpected or significant relative to the

organism's current or perennial motivational concerns) is

based.  This evidence comes from the work on the effect

of lesions of the striate cortex in man (Weiskrantz 1986)

and in monkeys (Humphrey 1974; Cowey & Stoerig 1995).  We

know from the "blindsight" evidence assembled by

Weiskrantz that the effect of lesions of the striate

cortex in man is to abolish visual conscious experience

in the affected part of the visual field.  Some visual

discriminations are still possible to objects in the

affected part of the field, but are described by the

subject as "pure guesswork".  The Cowey & Stoerig

experiment shows that the principal effect of a near

total ablation of the striate cortex in a monkey is to

deprive the animal of the ability to categorize its

visual inputs.  The work of Broadbent (1958; 1971) on the

so-called "cocktail party effect" in the auditory

modality shows that the function of selective attention,

both involuntary and voluntary, in relation to the

initial processing of sensory input is to protect the

perceptual categorization mechanism from overload by

focusing on the problematic at the expense of the non-

problematic.  Subsequent work by Pashler (1991; 1997) and

Posner (Posner & Petersen, 1990; Posner & Dehaene 1994)

shows that the selective attention which controls the

processing of sensory input (the posterior attentional

system - superior colliculus; pulvinar and posterior

parietal cortex) is to be distinguished from another such

system (the anterior attentional system-anterior

cingulate and basal ganglia) which controls access from

the output of the perceptual categorization system into

another limited capacity channel whose function is to

select a response appropriate to a situation of the type

that has been identified by the categorizer as being

currently present.


     In the light of this evidence I have no hesitation

in concluding that the Rodney Brooks machine is conscious

and that the Minsky machine is not.  Sadly, I have to say

that the argument on which this conclusion is reached

owes virtually everything to empirical neuropsychology

and almost nothing to philosophy.  This, so it seems to

me, is the end of the line as far as the philosopher's

involvement in the mind-body problem is concerned.  Just

as the problem of the origin of the universe has ceased

during our lifetime to be a problem in theology and

become an empirically decideable issue within astronomy;

so, as I foresaw in 1956, the mind-body problem is

ceasing to be a philosophical problem and becoming an

empirically decideable issue in neuroscience.                                                                









Dear Teed,


     A few points in response to your `Beating of an

undead horse'.  The first relates to the difference

between James' "big blooming buzzing confusion" and my

Wundt and "physical" v. "mental" pleasure and pain cases.

What is true is that James identifies what he takes to be

an actual case where experience (as a whole - yes)

remains uninterpreted, because the child hasn't yet

developed the required concepts.  Wundt's two forms of

experience do not involve uninterpreted experience in

this sense.  It's simply that according to him there are

two different ways in which the SAME experience can be

interpreted which implies that the experience and its

interpretation are two different things.  There is no

reason to hold on to this view that any uninterpreted

experience exists, except perhaps momentarily before an

interpretation is arrived at or when switching from one

interpretation to another.


     The pleasure/pain case is slightly different.  Here

the suggestion is that in the case of "physical" pleasure

and pain the emotional response DOES NOT DEPEND ON the

way the experience is interpreted.  Again there is

nothing that requires the actual existence of

uninterpreted experiences.


     My second point relates to Broadbent's use of the

term "evidence".  When I use this term in my own work, I

always put it in quotation marks.  This is because,

according to me, it is not evidence in the ordinary sense

of that word.  It is precisely because the use of the

term `data', together with the phenomenalist theoretical

framework in which it is embedded, treats sense-data as

evidence in the ordinary sense that leads me to say that

sense-data do not exist.  The same incidentally goes for

qualia, if it is taken to be part of the definition of a

quale that it is a functionless epiphenomenon.  But if

you say that sense-data are data only in metaphorical

sense or if you allow that qualia have a vital function

in the process that leads to sense perception, I am happy

to use both expressions and say that a sense datum is a

private sensory experience and that a quale is a property

of such an experience by which we recognise the stimulus

situation confronting us as one of this or that kind.


     What is wrong with treating sensory experience as

evidence for the belief that one is confronted by a

situation of this or that kind in one's external

environment is that we ordinarily use the term `evidence'


(a)  when talking about the relation between two

     statements or sets of statements, the evidence on

     the one hand and the hypothesis it is evidence for

     on the other,


(b)  where the evidence consists in one or more

     observation statements and where the hypothesis for

     which the observation statements provide evidence is

     something that cannot itself be directly observed.


     In the case of the relation between sensory

experience and the categorization of it as an encounter

with a situation of this or that kind, neither of these

conditions apply.  


(a)  In the categorization of sensory input there are no statements

     involved. Sensory experience and the categorization for which it

     provides the evidence are neural processes which

     occur in the brains of animals just as much as in

     the brains of humans.  Even in the human brain

     identifying the kind of object or situation with

     which one is confronted is a distinct process both

     from that of naming the object or situation and

     putting what is observed into words in the form of a



(b)  Contrary to the opinion of the phenomenalists, in

     the ordinary sense that word we DO directly perceive

     the objects and situations in our stimulus

     environment for whose presence sensory experience

     and its qualia provides "evidence". 


     Contrary to the view expressed by Ryle in THE

CONCEPT OF MIND, there are cases where we can quite

properly be said to observe our sensations and other

private experiences.  After filling a particularly deep

cavity in one of my teeth recently, my dentist asked me

to check any pain I might subsequently have to see

whether it was caused equally by hot and cold stimuli

(good) or only by hot (bad, particulary if throbbing).

This, however, is a rather sophisticated form of

observation which we learn only AFTER we have already

learned to observe what is going on in the world around

us.  When I say I rejected the doctrine of sense-data

more than fifty years ago, what I rejected was the idea

that in observing what is going on around us, we begin by

observing our sensory experience, formulate those

observations in the form of a sentence in a private sense

datum language and then use those private observation

sentences as evidence for the existence and nature of

what we NEVER observe, namely the objects and situations

in the world around us. 


     That, of course, means that I rejected - here

following Wittgenstein - the notion that the observation

sentences which provide the foundation of empirical

knowledge are sentences in a sense-datum language

describing the private sensations of a single individual.

What it did not mean is that I denied either the

possibility of describing private experience or the idea

that empirical knowledge has to be anchored to

observation statements.  With regard to the former, I

have been insisting for more than forty years that our

ability to describe our private experience is parasitical

on a prior ability to describe what is going on in the

public world.  With regard to the latter, I have long

assumed, but rather more recently begun to insist, that the

observation statements which anchor our language to the reality it

enables us to depict are statements describing a publicly observable

state of affairs (events disappear too quickly) on whose correct

description any competent speaker of the natural language or

technical code in current use will agree.  It is because I take

this principle as axiomatic that I describe myself as a

behaviorist.  See `A my radical behaviorist methodology

for the empirical investigation of private events'



     One final point in this connection.  The relation

between a sensory experience and the categorization of

the current state of the stimulus environment for which

it provides the "evidence" is a straightforward causal

relation;  whereas the relation between evidence in the

ordinary sense and the hypothesis for which it provides

evidence is a logical relation.  Logical relations such

as this can, of course, act as causes in persuading an

individual to accept (or sometimes reject) the hypothesis

for which it is evidence.  But that does not alter the

fact that logical relations, as such, are not causal

relations.  The analogy between the two cases is that in

both, it is important for the individual to GET IT RIGHT.

The difference is that in the experience-categorization

case what the individual has to get right is what it is

he or she is currently observing; whereas in the

evidence-hypothesis case what the individual has to get

right is a verbal description of something that is NOT

currently available for direct inspection. 


        Another difference is that all the might of

natural selection is mobilised to ensure the conformity of

our perceptual categorization to the way things are;

whereas, except in a handful of cases where getting it

right is a matter of life or death, there are only a few

relatively weak social sanctions to ensure that our

hypotheses are and remain consistent with the available



     Sergio Chaigneau's mention of J.J.Gibson reminds me

of my own excitement when, as a very inexperienced

psychology teacher at the University of Adelaide, I read


when it appeared in (?) 1951.  Here for the first time

was a psychologist doing experimental work within a

conceptual framework entirely consistent with what I had

learned from Austin's `Sense and Sensibilia' lectures -

so different from the ghastly conceptual confusion of the

Gestalt Psychologists, whose work had been endlessly

thrust down my throat during my psychology course at

Oxford in 1947-9 and which was the principle target of

my critique of the phenomenological fallacy in `Is

consciousness a brain process?'. 


        During the winter of 1955 after I had returned to

Oxford from my four years at Adelaide and while I was

waiting for `Is consciousness a brain process?' to appear

in print, I had the privilege of getting to know Gibson

personally.  He had a visiting appointment at the

Institute of Experimental Psychology where I was registered

as a candidate for the D.Phil., a degree which I never

managed to obtain.  I tried to persuade him, unsuccessfully

as it turned out, that his position would be more consistent

if he dropped the phenomenological veneer and stated it in a

straightforward behaviorist way.  Interestingly, I was

supported in this by his wife, Eleanor Gibson, who not only

worked on perception in animals, but had been a student of

Clark Hull at Yale.  I have a copy of my correspondence with

J.J.G. during this period on file on my computer and could

e-mail it to you, if you're interested. 


     You might also be interested, in connection with Ruth

Milliken's deployment of Ryle's `knowing how' and

`knowing that' distinction, in a section of my chapter on

`Ryle's behaviourism [sic]' in W.O'Donohue and

R.Kitchener (eds.) HANDBOOK OF BEHAVIORISM which is

forthcoming from Academic Press.  In it I discuss the

distinction and suggest that it marks a failure on Ryle's

part to study the grammatical objects of psychological

verbs with the same thoroughness with which he explored

their aspectual characteristics.  This left room for

Roderick Chisholm to introduce his linguistified version

of Brentano's intentionality, thereby generating a new

piece of conceptual confusion for philosophers to pick



     This, of course, needn't undermine Ruth's thesis

which I would express in my behavioristic way by saying

that getting one's propositions right depends on a great

deal of contingency-shaped learning of semantic

conventions which in turn depends on the, part

contingency-shaped, part innate, pre-linguistic

categorization ability found in animals.


But please don't feel under any obligation to ask to see

either of these documents.  You've got enough on your

plate as it is.