MIND-BRAIN IDENTITY THEORY (THEORIES OF MIND)

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Mind as the Brain: The Mind-Brain Identity Theory

CONTENTS :

Introduction
Behaviorism
Identity Theory
Functionalism
Causal Functionalism
Mental Causation
Consciousness
Mental Content
Physicalism
Structural Identity Theory

Mind as the Brain: The Mind-Brain Identity Theory

Overall identificatory trend

Aristotle

thought the heart was the organ of thought
and cooling the blood was the function of the brain

Descartes

brain not the organ of thought or engine of thought -- the mind/soul actually did the thinking
thought the brain was where mind/soul interacted with body: the seat of the soul

Contemporary Common Sense: people use "in the mind" and "in the brain" more or less interchangeably

Mind-Brain Correlations

Reason for this identificatory trend is discovery of "a pervasive and comprehensive system of correlations between mental events and brain processes" (p.47)

brain lesions can disturb virtually every mental function

stroke victims frequently lose speech comprehension
various brain injuries cause various sorts of memory loss
concussions cause us to lose consciousness

chemical changes in the brain affect thought and experience

caffeine makes us alert
alcohol decreases our inhibitions and affects our moods
LSD makes us see things
anesthesia causes us to lose consciousness
analgesics relieve our pains

Mind-Brain Correlation Thesis: For each type M of mental event that occurs to an organism o, there exists a brain state of kind B (M's "neural correlate" or "substrate") such that M occurs to o at time t if and only if B occurs to o at t.

Lawful regularities, not mere accidental co-occurences, we suppose.
Supervenience obtains: "change in your mental life cannot occur unless there is some specific (perhaps still unknown) change in your brain state" (p.48)

Discussion

MBCT, subject to the two provisos, holds that mentality lawfully supervenes on brain function
This, if true, is "something we know from observation and experience, not a priori" (p.49): the correlations are the supporting evidence.

Explaining Mind-Brain Correlations

Correlations call for explanation.
Examples of options from outside psychology

causal interrelation: things are correlated because one causes the other

whenever the temperature stays below 20ºF for several days hereabouts
the water in ponds hereabouts freezes

common external causal origin: things are correlated due to having one and the same cause

all the clocks in the store show the same time
because they were all set that way by the shopkeeper
and have been keeping accurate time since

ongoing external causal regulation: correlated due to a single ongoing cause

all the clocks in the store show the same time
despite being inaccurate clocks
because the shopkeeper's assistant keeps going around the shop synchronizing them

dual aspect: the "different" phenomena are just two aspects of what's really a single phenomenon

temperature of a confined gas & pressure of the confined gas
temp. = total kinetic energy & pressure = momentum imparted to the container walls
duck-rabbit illustration: whatever happens to the duck's bill happens to the rabbit's ear

identity: the different phenomena are really one and the same phenomenon

whenever there's a massive static electrical discharged in the atmosphere lightning flashes
because the massive atmospheric static electrical discharge is what the lightning is
whatever happens to Howard Hauser happens to my father because HH is my father

collateral effects: things are correlated due to the one being a side effect of what causes the other

the tides and the phases of the moon correspond
because the phases are a side effect of the relative positioning of sun, moon, and earth that causes the tides

Explanatory models for mind-brain correlation

Causal Interactionism: Descartes: mutual causal interrelation
Preestablished Harmony: "Leibniz ": God as shopkeeper
Occasionalism: Malbranche: God as shopkeeper's assistant
Dual Aspect Theory: Spinoza: no deus ex machina required
Mind-body Identity Theory: Kim, Lewis, Armstrong, Smart
Epiphenomenalism: T. H. Huxley

Emergentism: Samuel Alexander, David Chalmers: the correlations are inexplicable "brute facts"

lawlike correlations can be discovered to hold
but why they hold cannot be explained & must simply be accepted "with natural piety" (Alexander)

Arguments for Psychoneural Identification

J. J. C. Smart's Argument in "Sensations and Brain Processes"

Occam's razor: Principle of Parsimony or Simplicity

Occam said, "Do not multiply entities beyond necessity."
More broadly understood as a council of ontological, linguistic, and theoretical simplicity

Everything else we know of consists of some arrangement of physical constituents
To suppose the mind -- or consciousness -- to be something nonphysical would be to acknowledge a wholly novel type of thing
So it would be a considerable gain in simplicity to identify mental processes with physical processes.

How parsimonious?

ontologically

token simplicity: fewer phenomena
type simplicity: of a single (physical) sort

linguistic/conceptual: mentalistic talk becomes replaceable by neurophysiological talk in principle

greater complexity of neuro-descriptions offset by increased accuracy
and we reduce the number of primitive (undefined) terms

theoretic simplicity

if we identity B and M their correlation becomes self-explanatory
simpler than other would-be explanations
and much simpler than emergentist nonexplanation

brute emergence laws are "nomological danglers" (Feigl)
they're not derivable from more basic laws
so they're much more expensive than derivable high level generalizations

Armstrong's Argument

Invocation of scientific precedent: identification of genes with DNA molecules

gene =_def. occupant of such and such a causal role, i.e., the role of "an internal factor in the organism that is causally responsible for the transmission of heritable characteristics."
DNA molecules, we discover, are what perform that causal role.
Conclusion: genes = DNA molecules

Analogous situation: pain and C-fiber activation

pain =_def. effect of bodily damage & cause of pain-behavior syndrome
neurophysiology reveals C-fiber activation occupies this role.
Conclusion: pain = C-fiber activation.

Worries about this argument:

"Is `pain' definable in this way? (p.55)
"[I]s the deliverance of neurophysiological research as simple and clear-cut as it is represented in this argument?" (p.55)

octopi don't have c-fibers & possibly octopi have pains
perhaps pain is "multiply realized": it's different types of physical phenomena in different organisms

An Argument from Mental Causation

Neuroscience discovers c-fiber activation plays the causal role associated with pain.
So c-fiber activation causes pain-behavior: What to make of this?
Alternatives: which do you choose

pain <> c-fiber activation

overdetermination: two independently sufficient causes: highly improbable at best
epiphenomenalism: pain doesn't cause the behavior: contrary to appearances (for starters)

pain = c-fiber activation :-)

no overdetermination
the causal efficacy of pain maintained

What Does "Identity" Mean?

Hoary distinction

qualitative identity

"equality in some magnitude or
being instances or tokens falling under the same kind or type" (p.57)
the sense in which twins are identical: close resemblance

numerical or strict identity:

being one and the same individual.
the sense in which LH and the teacher of PHL347 are identical

Knowledge of strict identities: filberts are hazelnuts?

a priori or "logical"

5 + 4 = 9
women are human females
Venus is Venus

a posteriori or "empirical"

the-number-of-planets = 9
water is H2O
Hesperus is Phosphorus

Mind-brain identities are would-be empirically known

"pain" doesn't mean (have the same sense as) "c-fiber activation"
"pain" just happens to refer to c-fiber activation
it just so happens that pains are c-fiber activations
analogous scientific identifications

heat = mean molecular kinetic energy
lightning = massive atmospheric static electrical discharges
Venus = the second planet from the sun

Leibniz's Laws (of strict identity)

The Indiscernibility of Identicals (often simply called "Leibniz's law")

"uncontroversial and manifestly true" (p.58): fundamental logical principle concerning identity
"If X is identical with Y, X and Y share all their properties in common -- that is, for any property P, either both X and Y have P or both lack it." (p.58)

*The Identity of Indiscernibles

highly controversial: metaphysical speculation
"If X and Y share all their properties in common, X is identical with Y." (p.58)

Argumentative Application

X is P
Y is not P
Conclusion: X <> Y
Example

The President lives in the Whitehouse.
Al does not live in the Whitehouse.
Conclusion: Al is not the President

Token Physicalism and Type Physicalism

Standard formulation of physicalism: mental events are physical events in the brain.
Two readings of this identity claim.

Token physicalism: "Every event that falls under a mental-event kind also falls under a physical event kind (or every event that has a mental property has some physical property)." (p.59)
Type physicalism: "Mental-event types are physical event types; alternatively, mental properties are physical properties." (p.59)

Two analyses of events

Davidsonian (after Donald Davidson): "takes events as basic concrete particulars in the world"

basic means unanalyzable
on this view to say pain = c-fiber activation says that a single event has (possibly) different properties

being painful
being C-fiber-activation

it supports the token identity reading (though one might still make the stronger claim about types)
test case: my most regrettable practical joke = the hotfoot I gave the Provost

Kim's View: takes events to be analyzable as property instantiations

Kim's analysis: "an event is the exemplification (or instantiation) of a property by an object at a time." (p.60)
on this view to say pain = c-fiber activation says that the properties themselves are identical

having pain just is
having activated c-fibers.

the token reading is insupportable: event identity requires property identity
Kim identity: "The event of x's instantiating property P at time t = the event of y's instantiating property P at time t' if and only if x = y, property P = property Q, and t = t'.
test case: my most regrettable practical joke <> the hotfoot I gave the Provost

not because some other joke I played -- putting the tack on the Dean's chair -- was worse
couldn't be identical since the property of being a most regrettable practical joke and the property of being a hotfooting of the Provost are clearly different

not all most regrettable jokes are Provost hotfootings
not all Provost hotfootings are (the giver's) most regrettable jokes

A most regrettable consequence contra Kim?

On Kim's view no single joke I played could be my most regrettable.
But mustn't my most regrettable joke be one of the jokes I played?

Which to accept?

Occam's razor: ontology

Anti Davidson: needs one less primitive type of entity
Anti Kim: needs a LOT MORE token events

Expressive economy v. power

Pro Davidson: the complication is necessary

allows us at least express the Token Identity hypothesis
and to say what we want to say about our most regrettable jokes, etc.

Pro Kim: economy of expression

Alleged theoretic benefits for Kim

provides an analysis of what events are
the token Identity hypothesis is not worth expressing.

In defense of type physicalism: it's the only physicalism worth having

"the classic formulation of the identity theory due to Smart and Feigl is type physicalism" (p.60)
"token physicalism is a weak doctrine that doesn't say much" (p.60-61)

"says nothing about the relationship between mental properties and physical properties" (p.61)
"Token physicalism, therefore, can be true even if mind-body supervenience fails." (p.61)

"there could be a molecule-for-molecule physical duplicate of you who is wholly lacking in consciousness, that is, a zombie" (p.61)
by Kim's definition of "minimal physicalism, token physicalism falls outside the scope of physicalism altogether" (p.61)

Reductivism v. nonreductivism

type physicalism is reductive in its "claim that there are no mental properties over and above physical properties" (p.61-62)
type physicalism "arguably entails that there are no Cartesian mental substances" (p.62)

"either immaterial mental substances have physical properties, which is prima facie absurd
or they can have no properties of much interest" (p.62)

they would have no work to do
and (talk of them) would be dispensable

type physicalism "entails there are no mental facts over and above physical facts"
Davidsonian token physicalism

takes physical events as basic

Kim might say this is mere ad hoc stipulation
whereas property i.d.s are things for which we have evidence

this, arguably, gives you the same entailments regarding

Cartesian substances
& mental facts

Is type physicalism too strong to be true?

Objections to the Identity Theory

An Epistemological Objection

LL: Identical things have identical properties.

Pain has the property of being known to medieval peasants..
C-fiber activation lacks the property of being known to medieval peasants.
:. pain <> c-fiber activation.

Reply: LL fails for properties properties like being known creating opaque contexts

Compare a similar opaque context

Oedipus knew he was marrying the Queen of Thebes.
Oedipus didn't know he was marrying his mother.
:. The Queen of Thebes wasn't his mother

Alas, poor Oedipus, she was. The argument is invalid.

de re reading -- sense in which Oedipus (but also the peasants) did know

knew he was marrying her (knew they were experiencing that)
and she unbeknownst to him was his mother (that unbeknownst to them was c-fiber firing)

de dicto reading -- sense in which Oedipus (and the peasants) didn't know

of course he knew he was marrying her
didn't know that she was his mother (i.e., that this dictum described her)

The Location Problem

LL: Identical things have identical properties.

physical property instances (e.g., c-fiber activations) have spatial locations.
mental property instances (e.g., pains) have no spatial locations
:. mental properties (e.g., pains) <> physical properties (e.g., c-fiber firings)

Reply: Mental properties are located where their physical correlates are

unprincipled reply

define a new concept pain* locatable pain
do pain and pain* have the same extension?
if all pains are pain* and pain*s = c-fiber firings, then pains = c-fiber firings

principled reply

all property instantiations are locatable: they occur where their objects are located
so, mental property instantiations occur wherever the objects which instantiate them are located

Phenomenal Properties of Mental Events: LL again

LL: Identical things have identical properties.

physical property instances (activations of the visual cortex) have no phenomenal properties (being orange).
mental property instances (e.g., pains, color experiences) have phenomenal properties
:. mental properties (e.g., pains) <> physical properties (e.g., c-fiber firings)

Reply: Physical property instances have phenomenal properties

the seeming absurdity

are the c-fiber firings themselves pounding when I have a pounding headache
does the activation of the visual cortex glow orange when I seeing orange?

go adverbial

pounding pain will correlate with one type of c-fiber activation and smarting pain with another
one sort of visual cortex activation may being seeing orange (and some other seeing purple) does not entail the activation being orange.

Phenomenal Properties must be Irreducible or M-B identifications to be empirical

empirical: based on observation

like genes = DNA
unlike bachelors = unmarried adult males

so we must pick out pains as something other than c-fiber firings
doesn't follow that this otherwise is phenomenal
Ed is experiencing a circular purple afterimage

Armstrong's causal analysis: Ed is in a state apt to be caused by staring into photoflashes and apt to cause you to say you're "seeing" something purplish and circular".
Smart's "topic neutral analysis: Something is going on in Ed that is like what goes on when he is looking at a purple circle in good light.
May be doubted whether these proposals do justice to the first person case.

when I report the afterimage (or pain)
without thinking about what it's like to view purple circles in good light (or be stuck with a pin),
nor contemplating the typical effects of photoflashes

The Cartesian Objection & "Pain" as a Rigid Designator &

Descartes argument

disembodied thought is possible (conceivable without contradiction: Kim agrees)
if thought = corporeal motion then this wouldn't be possible
:. thought <> corporeal motion

The Objection: "pain = c-fiber activation" you physcialists say is a "contingent identity"

"x = y" can be a contingent identity only if "x" or "y" is nonrigid
But "pain" and "c-fiber activation" are both rigid

no event which is a c-fiber activation could have been not a c-fiber activation
no event which is a pain could have been not painful

So any possible identity here must be necessary not contingent.

First Reply: If "pain" means "occupant of such and such causal role" (a la Armstrong) then "pain" is nonrigid

just as someone else could have been President
something else (than c-fiber firings) could have occupied the pain role
in that world this other such-and-such would be pain
rejoinder: Armstrong style accounts fail to capture the essence of pain

the ouchiness of it
without this it's not the same event -- experience of pain -- at all

Second Reply: Let "pain" be rigid. So the identity is necessary. So?

So, it doesn't seem the mind-brain correlation is necessary (Kim)

conceivably (or at least it's consistent to suppose) there could be

pains that weren't correlated with c-fiber firing: disembodied "thoughts" as Descartes imagined
c-fiber firings that weren't correlated with thought: "zombie" firings

"The correlation may be lawlike -- that is nomologically necessary -- but doesn't seem to be necessary without qualification." (p.69)
Issue: on Kim's analysis of events aren't all event designations rigid & all event i.d.s necessary?

events = property instantiations, so
P-events are Q-events if and only if P=Q, i.e. iff [](x)(Px <-> Qx)

More "so?": Other cases of identities formerly thought contingent but now widely thought necessary

Kripkean necessities known a posteriori
Include many of the identity theorists favorite examples

water = H₂0
lightning = massive static electrical discharge
heat = molecular motion

Kripke: problem of explaining the appearance of contingency in the mind-brain case (Kripke, Naming and Necessity, p.151)

would be explanation of the similar appearance in the heat = molecular motion case

when we erroneously think we're imagining heat <> molecular motion
"what really seemed possible was that molecular motion should have existed without being felt as heat"

"In the appropriate sentient beings is it analogously possible that a stimulation of C-fibers can exist without being felt as pain?" No.

"for it to exist without being felt as pain is for it to exist without there being any pain"
"in flat out contradiction with the identity theory itself"

if M = B
where B goes M goes likewise.

Multiple Realization Argument

Supporting considerations: pains (and other mental properties) are variously realizable

creatures with brains quite unlike ours seem nevertheless possessed of various sorts of mentality

mollusks (e.g., octopi) exhibit pain syndrome effects
though lacking c-fibers (they say)

creatures with brains even more unlike ours might be mentally endowed

ETs with silicon brains
computers

pain producing devices might be as variously realizable as water containing devices

buckets & glasses & bowls
pipes & hoses & bladders
sponges & tissue
etc.

even more compelling for less biologically basic mental properties, e.g., beliefs & wishes

might be wide type variations between similar belief states -- that snow is white -- between different human individuals
or even for the same individual at different times

I say aloud "snow is white"
I "say" subvocally "snow is white"
I imagine a Godlike voice intoning "snow is white".
i write "snow is white" in white on a blackboard
I imagine "show is white" written in black chalk on a whiteboard
I say/imagine/write "le neige est blanc" instead
etc.

such mental states may be as various in their physical realizations as monetary transactions: I give you $100

could write you a check
could get a money order
$100 worth of gold
a $100 T-bond
I hand you my credit card at Meijers and say "the first 100 is on me"
etc.

Argument

Pain (& other mental states) are so variously realizable (as above).
:. No (illuminating) mental-state-type to physical-state-type correlations exist

at least not across species for biologically basic mental phenomena like pain
probably not at all for attitudes like beliefs and wishes

Mental properties of various species and individuals are more likely to share higher level functional characteristics

differential sensitivity to internal conditions threatening to the operational integrity of the system more likely typical than
excreting such and such neurochemicals, electrically spiking at some particular frequency, etc.

Upshot: Nonreductive physicalism

No illumination from the bottom up.
Psychology should seek to discover laws higher (functional) levels.

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