Transcript MIND LECTURES 3

MIND LECTURES 3
Searle on Intentionality and Mental Causation
Intentionality
• Intentionality is a property of multiple kinds of things. For
example, there is the intentionality of thought, language, and
signs.
• Intentionality is a kind of property in virtue of which something
x is about or directed at something y. It is an aboutness
property.
• The problem of intentionality is simply the task of explaining
how something can be about or directed at something else.
Intentionality
Searle:
The problem of intentionality is the mirror image of the problem of
consciousness. Just as it is supposed to be extremely difficult to fathom how
mere bits of matter inside the skull could be conscious, or could through
interactions create consciousness, so it is difficult to imagine how mere bits of
matter inside the skull could “refer to” or be about something in the world
beyond themselves, or could through such interactions create such a reference.
I am now thinking that the sun is 93 million miles away from the Earth. My
thoughts definitely refer to, or are about, the sun.. Now what is it about the
thought that enables it to reach as far as the sun? Do I send mental rays all the
way to the sun, just as the sun sends light rays all the way to earth?
Intentionality
• Examples:
Mary is nice. (existing entity)
Santa Clause is fat. (non-existent entity)
Her first born will be called ‘Jim’. (future existent)
Her dead mother was called ‘Jane’. (past existent)
What explains how the mind can refer in each of these cases?
Is there a single property for all of the cases?
Intentionality and Priority
• Intentionality is at least recognized to exist in two separate
places:
– Intentionality of thought: Jones believes that Mary is nice.
– Intentionality of language: The sentence “Mary is nice”.
Searle maintains that the intentionality of thought is prior to
language.
Searle argues that intentionality of language cannot explain the
intentionality of thought.
How should we understand this claim? Is it conceptual priority or
metaphysical priority?
Derived vs. Original Intentionality
A thing has derived intentionality when it has its intentionality in
virtue of something else that has intentionality either originally or
derivatively.
A thing has original intentionality when it is the kind of thing which
can bestow intentionality to other things, and for which there is
further source from which its intentionality derives.
Signs and Language have derivative intentionality. It is because we
intend to use them in a certain coordinated way that they come to
be about something.
Humans have original intentionality, since they can bestow
intentionality to other things, such as signs.
Three Questions about Intentionality
How is intentionality possible?
Given that intentionality is possible, how is the content of intentional
states determined?
How does the whole system of intentionality work?
The Possibility of Intentionality
Searle
Functionalism about intentionality does not work, since it reduces
intentionality to causal co-variation which is not sufficient.
Interpretativism about intentionality does not work, since it maintains
that intentionality is only part of an act of attributing an
interpretation of something. It maintains that people really don’t
have beliefs and desires. We simply use belief – desire talk to
interpret others.
Searle
The Possibility of Intentionality
[Intentionality] is … a form of representation. We ought to hear the
question, “How is it possible to think about Santa Claus if Santa
Claus does not exist?” as like the question, “How is it possible to
make up a story about Santa Claus if Santa Claus does not even
exist?
We should not think of intentionality as a relation like hitting
something or sitting on something. That is the wrong model for
intentionality.
The structure of intentionality I:
Content and Mode
• Intentional states have both a content and a psychological
mode.
• Jones believes that Mary is in the next room.
• Jones hopes that Mary is in the next room.
• Both have the same propositional content, but the two states
are different because believing and hoping are different
psychological modes.
The structure of intentionality II:
Aspectual Shape
• Two intentional states can have the same extensional content
without having the same aspectual shape.
• The Morning Star = The Evening Star = Venus
• Jones loves the morning star.
• Jones hates the evening star.
• The aspectual shape renders coherent how it is that Jones can
have opposing attitudes towards the same object.
The structure of intentionality III:
Direction of Fit
• Intentional states can be distinguished by their direction of fit –
• Mind-to-World direction of fit – the content is such that it is
responsible to the world. Jones’s belief that the world is flat is
evidentially governed by the world. Were he to find out that the
world is round, he is to revise his belief so as to fit it to the world.
• World-to-Mind direction of fit – the content is such that it dictates
how the world should be. Jones’s desire for milk is a demand that
the world should be such that he has milk. The world is to be made
to accord with the mental state.
The structure of intentionality IV:
Conditions of Satisfaction
• Intentional states have conditions of satisfaction.
For example:
John’s belief that Mary is 13 is true only if Mary is 13.
John’s desire for ice cream is satisfied only if John gets ice cream.
In both cases there is a condition under which the psychological state is
satisfied. The kind of satisfaction condition is different. Beliefs requires
truth, desire requires fulfillment.
The structure of intentionality V:
Causal Self-Referentiality
• Perceptions, Intentions, and Memories are all causally selfreferential.
• Memory requires that the remembered event be the actual cause of
the memory.
• Perception requires that the thing perceived be the actual cause of
the perception.
• Intention requires that the intention cause the action that was
intended to be performed.
Cognition
Volition
Perception
Memory Belief
Intention
in action
Prior
Intention
Desire
Causal Self
Reference
Yes
Yes
No
Yes
Yes
No
Direction of Fit






Direction of
Causation


None


None

Means World to Mind.

Means Mind to World.
The structure of intentionality VI:
The Background
• Any particular intentional state depends on a network of other
intentional states.
– Beliefs don’t, for example, come in isolation. I cannot believe that the car is
red without also believing something about cars in general.
• All networks terminate in a background of non-intentional states
that include abilities and dispositions.
– If John intends to go skiing he can do so only if he has the ability to ski in
addition.
• In general, any particular intentional state depends on a set of
non-intentional states and abilities.
Intentionality Summarized
Searle:
For any intentional state, there is a distinction between the type of state it is, and its
content. Where the content is a whole proposition, it will represent states of affairs
in the world and it will do this with one of the three directions of fit, mind-to-world,
world-to-mind, or null. Intentional states that have a non-null direction of fit are thus
representations of their conditions of satisfaction. And given the network of
intentionality, even those states that have the null direction of fit, and even those
that do not have a whole propositional content, are still largely constituted by
states that do have a non-null direction of fit.
Intentionality Summarized
Searle:
If I am sorry that I stepped on your foot, I must believe that I did so
and wish I had not done so. And if I admire Jimmy Carter I must have
a set of beliefs and desires about Jimmy Carter.
In general, intentionality is representation of conditions of satisfaction.
Testing For Intensionality: Failure of Substitution
A linguistic environment E is intensional when it fails substitution.
Substitution principle: If Fa and (a = b), then Fb.
No failure of substitution
1. John is looking at the evening star.
2. The evening star = The morning star.
3. So, John is looking at the morning star.
Failure of substitution
1. Lois believes that Superman can fly.
2. Superman = Clark Kent.
3. Lois believes that Clark Kent can fly.
Testing For Intensionality: Existential Generalization
A linguistic environment E is intensional when it fails Existential Generalization.
Existential Generalization principle: If Fa, then there exists an x, Fx.
No failure of existential generalization
1.
2.
John lives in Nevada.
So, there is some place X such that John lives at X.
Failure of existential generalization
1.
2.
John is looking for the lost city of Atlantis.
So, there is something that John is looking for.
How is intentional content determined?
• Internalism: Intentional content is only determined by features in the
head. If two subjects are alike in all internal features, then they
have all the same intentional states. The physical and social
environment do not determine a subject’s intentional content.
• Externalism: Intentional content is determined in part by features
external to the head, such as the physical and social environment in
which the subject is embedded. It is possible for two subjects to be
exactly alike in all internal respects, but to differ in their intentional
states because of a difference in their environment.
Twin-Earth Thought Experiment
• Oscar lives on Earth, he is not a scientist, he possesses a lot of the
common knowledge that non-scientists have about water, he
believes that it is a colorless, odorless liquid, that fills 60% of the
Earth’s surface, and falls from the sky in the form of rain.
• T-Oscar lives on Twin-Earth, he is not a scientist, he possesses a lot
of the common knowledge that non-scientists have about water, he
believes that it is a colorless, odorless liquid, that fills 60% of the
Earth’s surface, and falls from the sky in the form of rain.
• On Earth ‘water’ picks out H2O. On Twin-Earth, ‘water’ picks out
XYZ.
• Do Oscar and T-Oscar mean the same thing when they use
‘water’? Are their beliefs about the same thing?
Twin-Earth Thought Experiment
• Internalism maintains that Oscar and Twin-Oscar mean the same
thing by each of their uses of ‘water’, since the two individuals have
the same associated beliefs about water. Where D is the common
knowledge associated with water on Earth and Twin-Earth, Oscar
and T-Oscar both share D. What they don’t share is being in the
same environment.
• Externalism maintains that Oscar and T-Oscar do not mean the
same thing by their uses of ‘water’ because the what ‘water’ is
about is partly determined by the environment that they are in.
Since Oscar is in an H2O environment and Twin-Oscar is in a XYZ
environment, it follows that they cannot mean the same thing by
each of their uses of ‘water’, even if they both share the same
beliefs about water.
Externalism and Self-Knowledge
EXT: Thought content is determined partly by the environment.
SK: A subject can know through self-reflection what the content of their thought is.
‘E’ is the name for the environmental condition that must obtain in order for Oscar
to be thinking a water thought vs. a twin-water thought.
Argument for incompatibility:
1. If Oscar is thinking that water is wet, then E obtains. Oscar knows (1) by reflection
on EXT.
2. Oscar is thinking that water is wet. Oscar knows (2) by self-knowledge and selfreflection.
3. So, E obtains. Oscar knows (3) by a priori deduction.
Core questions: Can Oscar know through reflection alone that E obtains? Doesn’t he
have to explore empirically his environment in order to know that E obtains? Couldn’t he
have been switched into a distinct environment? Should we drop externalism or our
views about self-knowledge?
Internal Mental Content and the World
Searle
If you ask, “How can a state of my brain have the content that Caesar
crossed the Rubicon?” It seems an impossibly difficult question. But if you
ask, “How can my conscious thought ‘Caesar crossed the Rubicon’ have
the content Caesar crossed the Rubicon?” Then it is no longer impossible
to answer.
I know the meanings of the words, I know how they relate to objects and
states of affairs in the world and in thinking the whole thought I am
aware that it has precisely this condition of satisfaction: Caesar crossed
the Rubicon.
Mental Causation
Searle’s Description of the problem:
1. The mind-body distinction: the mental and physical form distinct
realms.
2. The causal closure of the physical: the physical realm is causally
closed in the sense that nothing non-physical an enter into it and act
as a cause.
3. The causal exclusion principle: where the physical causes are
sufficient for an event, there cannot be any other types of causes of
that event.
4. Causal efficacy: mental states really do function causally.
The four propositions are inconsistent.
Mental Causation
Searle’s diagnosis:
Some reject Causal Efficacy, and embrace epiphenomenalism.
But better to reject Mind-Body Distinction.
The mind is just a higher-level description of the brain system.
One can also give a neuronal description of the brain system.
We are simply dealing with different levels of description.
Mental Causation
Searle
The relation of consciousness to brain processes is like the relation of the liquidity of a
body of water to the behavior of the H2O molecules… The higher level causes, at the
level of the entire system, are not something in addition to the causes at the micro-level
of the components of the system. Rather, the causes at the level of the entire system are
entirely accounted for, entirely causally reducible to, the causation of the microelements.
When I say that my conscious decision to raise my arm caused my arm to go up, I am
not saying that some cause occurred in addition to the behavior of the neurons when
they fire and produce all sorts of other neurobiological consequences, rather I am
simply describing the whole neurobiological system at the level of the entire system and
not at the level of the particular micro-elements.
The consciousness in the brain a separate entity or property; it is just the state that
the brain is in.
Mental Causation
Two confused questions on Searle’s View:
How can the mental effect the physical?
If the mental did function causally, wouldn’t it produce over determination?
The reason why they are confused. Both questions rest on the claim that: The
irreducibility of the mental to the physical does imply that there is something over and
above of the physical.
However, it is simply better to note that: mentality is ontologically irreducible, but
causally reducible.
Mental Causation
Causes
Intention in Action
Bodily Movement
Causes
Causes
Causes
Neuron Firing
Physiological Changes
Mental Causation
Rationality as a requirement on explaining human behavior:
1. Presupposition of freedom.
2. Explanation of action has to have a specification of a goal.
3. Intentional causation as part of the explanatory nexus.
1-3 are required for rational explanation of human behavior.