Folk Psychology
Eliminativist Materialism
&
Instrumentalism
Follow-up to question last week: “how can
anyone still take the massively modular
theory of mind seriously, given all the
counter-evidence?”
Folk Psychology
Folk psychology (FP):
Folk: ordinary people, non-professionals
Psychology: The theory and practice of
explaining, predicting and manipulating other
people’s thinking and behavior
Folk psychology: the common sense
understanding of the mind
Examples of folk psychology in action
A: Why is John studying hard?
B: He wants to pass the test, and he thinks that if he
studies hard he will pass.
A: Why did you tell Paul that I was sick?
B: Because I wanted him to think that you wouldn’t be here,
so he wouldn’t come over to see you.
Folk psychology uses beliefs and desires to explain
behavior.
Beliefs and desires are propositional attitudes.
Propositional attitude: a mental state relating a person to a proposition
i.e. intentional mental states expressible with a “that” clause
examples: beliefs, desires, hopes, fears
“I believe that it is raining”, “I hope that it will stop”, “I fear that it will
not”
FP relies on propositional attitudes.
If George desires A, believes that B will cause A, then George desires
B (other things being equal.)
Folk psychology = belief-desire psychology = propositional attitude
psychology
LOTH and Folk Psychology
The main motivation for the language of thought hypothesis,
and its biggest strength is that it coheres with folk
psychology.
LOTH naturalizes folk psychology
That is, it provides a naturalistic explanation of how
beliefs and desires can exist in the brain, how they
can interact, and how they can lead to action
Naturalistic: materialistic, not supernatural
Through LOT, beliefs and desires are reduced to symbols, symbols can
be manipulated according to logical laws (e.g. if “P” and “if P then Q”,
then “Q”).
Example: If John believes X, and X entails Y, John believes Y.
Example: If John fears X, John desires that not X.
Conclusions can be implemented directly as actions:
I want milk & I believe that I can get milk at the store  I should go to
the store  I go to the store
Reason can be mechanized.
LOTH is a realist theory of propositional attitudes.
i.e. in LOTH, propositional attitudes are said to be literally instantiated in
the brain as symbolic sentences.
Beliefs and desires are literally sentences written in the brain in encoded
mentalese (or natural language).
Eliminativism towards Folk Psychology
Paul Churchland’s stance:
1) Folk psychology is a theory
2) The theory is wrong
3) Folk psychology should be eliminated.
Churchland’s stance (cont.)
The “theory theory” of folk psychology:
Folk Psychology is a theory
FP posits the existence of entities: beliefs, desires, etc.
as literally instantiated in the brain.
FP posits laws governing the interaction of these entities,
and the relation between these entities and action.
FP makes predictions based on these hypotheses.
Churchland’s stance (cont.)
Folk psychology is a bad theory
1) Explanatory failures
2) Stagnant and unproductive
3) Not coherent with other scientific
knowledge
1) Explanatory failures
FP fails to provide any explanation for many processes
of the mind
e.g. mental illness, creative imagination, intelligence
differences between individuals, sleep, ability to perform
physical actions such as catching a ball, memory, and
especially learning, e.g. learning concepts
Note: Churchland admits that these failures do not show FP
is wrong, but they do show FP is limited. A supporter of
FP can argue, that FP does not attempt to answer most
of these concerns. It is primarily a theory concerning
conscious thought, decision-making and action, and is
not concerned with physical actions, sleep, mechanics of
memory, etc.
2) Stagnant and Unproductive.
Churchland calls FP a theory of
“retreat, infertility and decadence”.
i) Retreat: domain of FP used to extend to
wide range of natural phenomena such as
angry sea, jealous moon, angry volcano, etc.
ii) Infertility and decadence: No progress
made in FP since ancient Greek times. Still
use same concepts to explain people’s
actions, with about same degree of success
at predicting and manipulating people’s
behavior.
3) Not coherent with other scientific knowledge in other
fields
e.g. evolutionary theory, biology and neuroscience.
Other disciplines support each other, FP is isolated.
Churchland claims that science can explain human
being’s constitution, development and behavioral
capacities through physics, chemistry, evolutionary
theory, biology, physiology and neuroscience and that
using these explanations, science can outperform FP
even in its own field.
Folk psychology should be eliminated.
FP should be replaced by a neuroscientific understanding
of the brain that does not posit such entities as beliefs,
desires, etc.
Churchland’s alternatives to FP
Churchland provides two highly-speculative, science
fictiony ideas of what could someday replace folk
psychology:
A) New language.
With new understanding of the structure of the brain, we
may develop a new, more powerful language for deeper
communication. This new language could completely
replace all natural languages. New language would not
use concepts of belief, desire, etc., so FP would be
eliminated .
B) Communication by physically connecting brains together.
The corpus collosum is a cable of neurons connecting the two hemispheres
of our brains.
Split-brain patients have had the corpus collosum cut, and the result is that
the two halves of their brain do not communicate well. So, the corpus
collosum provides communication between the two halves of our brains.
Churchland’s idea: someday people may be able to connect brains (i.e. the
brains of two different people) with an artificial corpus collosum. Two
people could understand each other like two halves of one brain
understand each other. Again, communication by natural language, and
hence FP, would be obsolete.
Responses to Eliminativism
Response to “FP is stagnant”.
One response is to deny that FP in itself is stagnant.
FP has incorporated many modern ideas from
psychology, such as unconscious or repressed desires,
phobias, personality types, such as neurotic, anal
recessive, etc.
“Folks” (non-professionals) do now use these concepts,
even when not in proper psychological way. So-called
“psycho-babble”.
So FP is adaptive, flexible, and able to incorporate
ideas without collapsing.
Responses to FP is stagnant (cont.)
Sterelny’s response:
• FP is an important component of cognitive
psychology (e.g. representative theory of the mind).
• Cognitive psychology is progressive and undertakes
research programs to understand learning, memory,
etc.
• Therefore, FP is not stagnant.
FP is an important component of cognitive
psychology also answers Churchland’s other
points of FP’s explanatory failures and FP’s not
cohering with science. If FP is an important part
of cognitive psychology, and cognitive
psychology attempts to answer the failures
Churchland mentions, and coheres with other
scientific disciplines, then FP is indirectly
engaged in answering explanatory failures and
cohering with modern scientific advances.
Folk Psychology  Cognitive Psychology 
progressive, scientific, investigating sleep,
learning, etc.
Possible rejoinders by eliminativists
i) Deny that folk psychology is an important
component of cognitive psychology. Fodor’s
theories obviously rely on the concepts of FP,
but others, like Steven Stich, think that cognitive
psychology should be free from FP concepts.
ii) Deny that cognitive psychology is progressive
and coherent with modern science. Churchland
thinks Cognitive Psychology is wrongheaded
precisely because of its reliance on FP concepts.
Churchland’s Attack on a Functionalist
Characterization of FP
The target:
A functionalist definition of propositional attitudes (as posited
by FP):
Beliefs, desires, etc. may not correspond to any particular
physical objects in the brain, but are defined as functional
states.
Churchland’s response:
Compares functional definition of FP entities to (fictional)
functional definition of the entities and principles of alchemy
Alchemy
A medieval science engaged in:
• combining and mixing elements,
• concocting medicine
• attempting to transform base
metals (iron, lead, etc.) into gold
Alchemy had an elaborate theory,
including the idea that all elements
were made up (or “ensouled by”)
four fundamental spirits: Mercury,
Sulpher, Yellow Arsenic and Sal
Ammoniac.
Alchemy was replaced by the rise of
modern chemistry.
The Alchemy-FP comparison
Churchland imagines alchemists trying to save alchemy by
creating a functional definition of alchemy terms
e.g. “ensouled by mercury” means “having certain properties
such as being shiny, liquifying under heat, etc.”
Alchemists could continue using alchemy concepts, while
admitting that all elements are not literally, physically made of
up Mercury, Sulpher, Yellow Arsenic and Sal Ammoniac.
Churchland’s argument: It would be pointless for alchemists to
try to save alchemy this way. Better to admit that alchemy is a
bad theory and eliminate it.
Likewise, people should not try to save Folk Psychology in
this empty way (redefining terms as functionalist concepts).
Better to admit FP is a bad theory and eliminate it.
Sterleney’s response to Alchemy comparison:
Churchland makes a good point, but says that he only
proves that functionalist terms may be empty, but not
that they always are.
Many terms used in science are functionalist, such as
definition of heart, eye and gene. So functionalist terms
can be useful.
Cognitive psychology functionalist terms are useful.
Instrumentalism and the Intentional
Stance
Daniel Dennett’s response to eliminativism.
Explained in “Two Contrasts: Folk Craft vs.
Folk Science, and Belief vs. Opinion”
Dennett’s position:
1)
FP is essentially a craft, not a theory
2)
Even if FP has a theory, the theory could be wrong, but
the practice still good.
3)
FP is a type of intentional stance. The intentional
stance is useful.
1) FP is essentially a craft, not a theory.
• Dennett calls it “Folk Craft”
• FP is fast, efficient, sometimes wrong.
• Compare folk physics
Folk physics is fast: people respond quickly
to the situation of water running off table (by
jumping away to avoid getting wet) and yet
respond differently and equally quickly when
the table has lip to catch the water (no need
to jump back). But folk physics is sometimes
wrong, e.g. siphon.
• Likewise, folk psychology is fast and
efficient, but sometimes wrong, and can be
improved on by science.
2) Even if FP has a theory, the theory could be
wrong, but the practice still good.
• Dennett’s example: airplane pilot. A pilot may
have the wrong theory of flying and yet be a
good pilot.
• My example: Traditional Chinese Medicine
(TCM)
Theory: yin and yang, 5 elements: fire, wood,
earth, metal, water, meridians
Theory appears to be wrong. Nothing in the
body corresponds to yin and yang, meridians,
etc. However, practice still has value. If TCM
is sometimes more effective than western
medicine, TCM may be worth saving in spite
of wrong theory.
Don’t throw away the baby with the bathwater.
3) FP is a type of “Intentional Stance”.
Three stances:
Intentional Stance
Design Stance
Physical Stance
(Similar to 3 levels of description: environmental level,
computational level and physical level)
Intentional stance:
Attributing beliefs and desires to people (animals,
computers, etc.) to predict and manipulate behavior
.
Intentional stance -- natural human way to explain animal
behavior, behavior of computers, etc.
e.g. the mosquito flies erratically because it doesn’t want to
get caught
e.g. the chess-playing computer thinks it should get its
queen out early
Computers (and mosquitos) are too complicated to explain
via the physical stance, or even the design stance.
So the intentional stance is necessary and unavoidable.
Taking the intentional stance is automatic for humans, see:
http://www.pnas.org/cgi/content/full/0308220101/DC1#F1
The intentional stance is fast and effective.
Is it an accurate description of what goes on in
the brain? That concerns the design stance,
and the physical stance.
Dennett: the details of the design and physical
make-up don’t matter to intentional stance.
Example: raccoon trap. To catch a raccoon,
suppose the raccoon is rational. Then you
can outwit him. What goes on in the
raccoon’s brain? Who knows?
Intentional stance is necessary for
understanding other people. Evolutionary
psychology not detailed enough for specific
use. Physics, biology, neuroscience, etc. too
detailed to be practical. Nothing approaches
FP in usefulness, and likely never will
Dennett’s Intentional Stance vs. Fodor’s
Language of Thought Hypothesis
Dennett:
• FP is a useful fiction, an abstraction (like a center of gravity)
• Beliefs and desires are not literally encoded in the head
• No literal language of thought
• Fodor’s theory of language of thought is a little like folk
theory that a cold consists of a collection of sneezes, some
of which escape. Does Fodor believe we must have a
collection of sentences in our heads, just because some
sentences come out of our mouths?
Dennett likes to make up possible erroneous folk theories to illustrate how a
folk theory can seem obviously right to the folk, but yet be wrong.
Dennett has another example of possible wrong folk theory: tiredness is
caused by “fatigues” in the body. In this (fictional) culture, the way to say
“I’m tired” translates literally to “I have fatigues”. Imagine a scientist trying
to explain that they are wrong:
Scientist: “There are no such things as fatigues”
Folk: “You don’t believe in fatigues? Try running around the block a few
times – then you’ll believe in fatigues!”
Scientist: “I know what it is to have fatigues, but there are no such things
as fatigues!”
Note: the scientist wants to say “I know what it is to be tired”, but the only
way to say that in this language is to say “I know what it is like to have
fatigues.”
Cognitive scientists have a similar problem when they try to say “I don’t
believe there are beliefs.”
Dennett on Belief vs. Opinion
Many beliefs are implicit beliefs.
E.g. you believe:
sheep are not ants
sheep do not fly
sheep do not dissolve in water
etc. etc. etc.
But have you ever thought about these things?
So it is wrong to say that these beliefs are in the head.
Belief is the propensity to agree with a statement or to
act in a certain way.
• Other beliefs are explicit. If you ask me if sheep are
mammals and I answer, “yes, sheep are mammals”,
this belief becomes an explicit belief. I am aware of
this belief, and it is now represented in my head.
• Dennett calls implicit beliefs “beliefs” and explicit
beliefs “opinions”.
• For Dennett, LOTH has a problem: only explicit
beliefs (i.e. opinions) count as beliefs in LOTH,
because only explicit beliefs are explicitly
represented in the head. But most beliefs are implicit!
So, LOTH is not an adequate theory of thought.
Midterm Quiz
The midterm will be divided into two sections.
In the first section, you will be given 5 words, and asked to
define them, with examples when appropriate.
Each definition in Section 1 will be worth 10 points.
The 5 words will be chosen from the following terms:
The computational stance
Supervenience
Double dissociation
Qualia
Homuncular functionalism
Undischarged homunculus
Multiple realizability
Informationally encapsulated
The Language of Thought Hypothesis
The causal theory of semantics
Midterm Quiz (cont.)
In the second section, you will be given 3 questions, and asked to answer 2.
Each question will be worth 25 points.
The questions will be chosen from the following:
1) What is the concept formation argument in favor of an innate mentalese?
2) Explain the systematicity and productivity parallels between thought and
language.
3) Compare a functionalist definition of a mental state with an identity theory
definition. What advantages pertain to the functionalist definition?
4) What characteristics make face recognition a good candidate for a
modular function of the brain?
5) Why does Churchland maintain that folk psychology is a bad theory?