Transcript Descartes-and-Armstrong-Revision

Descartes: Philosophy of
Mind
Unit 4
Descartes’ Overall Conclusions
• HE ARGUES FOR SUBSTANCE DUALISM:
MIND AND BODY ARE TWO ENTIRELY
DISTINCT SUBSTANCES.
• HE ARGUES THAT THE MIND IS A BETTER
KNOWER THAN THE BODY
• HE ALSO ARGUES FOR
INTERACTIONISM: MIND AND BODY
INTERACT CAUSALLY.
Methodological Scepticism
• Descartes says his senses
can’t be trusted because
they often mislead us
• He gives the examples of
dreaming and the deceitful
demon.
• He says he can doubt what
he sees, his memory, and
even that he has a body.
Argument 1: The Cogito
• Descartes finds one thing he can be
sure of.
• In order to have these doubts there
must be something to do the doubting.
• Even if he is being deceived, he must
exist in order to be deceived.
• He concludes “I think, therefore I am”
- cogito ergo sum.
Archimedes Analogy
• Descartes believes that the
cogito was the foundation of all
other knowledge
(Foundationalism).
• Like Archimedes, who wanted
to find a firm place from which
he could move the entire
universe, Descartes wanted to
find a firm place to base all
knowledge on.
First Evaluation of the Cogito
• Kierkegaard argues that the cogito is just a
tautology.
• A tautology is any statement that is true by
definition. For example, “All sisters are female”
or “All Bachelors are unmarried”.
• As such a tautology is really a useless statement
because you are just repeating yourself or
defining a word.
• Some people think that the cogito is a tautology
because the word “thinking” already includes an
“I”. The word thinking just means that a person
must exist to do the thinking.
Second Evaluation of the Cogito
• Hume and Lichtenberg argue that Descartes is not
warranted in assuming that just because some thinking
is going on there must be some person doing the
thinking.
• There may be thinking without an “I”.
• Lichtenberg argues that Descartes should not say “I
think, therefore, I exist” but “I think, therefore, thinking
is going on”.
• However, Descartes responded to
this by denying that the cogito was
an argument.
Third Evaluation of the Cogito
• Russel argues that the word “I” implies
personal identity - an individual person
that is the same throughout time.
• He says that Descartes has not proved
that the thing which is currently doing
the thinking is an “I” because he has
not proven that it has personal
identity.
• How does he know that the being that is
doing the thinking is the same being
today that it was yesterday or ten years
ago.
What is the “I”?
•
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He is a NOT man because this leads to too many
other time consuming questions.
He is NOT a body, as he cannot be sure he has a
body.
He is NOT a soul, which has the attributes of
nutrition, sense perception, movement and
thinking. Nutrition, sense perception and
movement are all dependent on the body, which we
cannot be sure of.
This leaves only one alternative: he is a thinking
thing (also an attribute of the soul)
The “I” is also an Imagining and
Sensing Thing
• He could use the imagination to find out what other
things the “I” is.
• However, Descartes says he can “invent” anything in his
imagination, even that which is not real.
• Imagination also involves contemplating bodily things
and we cannot be sure of bodily things.
• While Descartes cannot be sure that the things that he
imagines are real, he can be sure that he does imagine.
• While he can doubt the contents of his sense
experiences, he cannot doubt that he seems to sense.
• He also doubts, understands, affirms, denies, wills, etc.
• All of these things are really just aspects of thinking.
The Wax Argument
• As the wax is heated and melts each of its sensory attributes
changes.
• If we only had our sense experiences of the wax, we would think
that the wax in its original form was a different thing to the
melted wax.
• Thus, the senses don’t enable us to know the wax, which is a
flexible, changeable and extended thing.
• It is not through my imagination that I know the wax because
we cannot imagine all of the infinite forms the wax might take.
• CONCLUSION: If sensory perception and imagination have
been eliminated, my mind alone must know the wax.
Evaluation of the Wax Argument
• Hume would say that our
senses see the wax
transforming as it is heated and
assume that it is the same piece
of wax not two different pieces
of wax – one hard and one
melted. Hume would agree that
the senses don’t give us
certainty of the physical world
but, as an empiricist, he thinks
that we may not have certainty
at all.
The Coats and Hats Example
• If Descartes looks out into the street, he may see people
walking about in hats and coats.
• However, all he has really seen with his eyes is some hats
and coats; he hasn’t actually seen the people under them.
• His belief that there are people walking around in the
street is actually an inference he has drawn using his
judgment.
• Descartes says that judgment is an activity of the mind.
• Thus, his belief that there are people in the street is
really an act of his mind not his senses or imagination.
The Mind is Better Known than the
Body
• Descartes states that not only does his mind know
things more clearly than his body/senses, he also
knows of his mind more clearly than he knows the
physical world.
• After all, his perceptions of the piece of wax may
be entirely illusory; however, when he is
perceiving the piece of wax, he cannot doubt that
he is perceiving, nor that he is understanding
those perceptions through acts of the mind.
• Both the perceiving and the understanding prove
that he exists.
Mind/Body Dualism
• Thus, Descartes has divided his world clearly
into two parts.
• The first is the mind, which is certain, nonphysical, unchanging and not extended.
• The second is the extended material world,
including the body, which is changing and is able
to be doubted.
Mind/Body Dualism cont
• (P1)I can conceive of myself being conscious in a world in
which there are no material entities (including bodies).
• (P2) But, if I am conscious at a given time, then I exist at
that time (Cogito).
• (P3) Therefore, I can conceive of myself existing without a
body, without corporeal attributes.
• Thus, having a body is not an essential part of who we are,
which is a thinking thing, a mind. Thus, mind and body
are separate.
First Criticism of Mind/Body Dualism
• We know that mind and body
causally interact because our
thoughts cause our behaviours.
• How can a non-physical entity,
such as a soul, causally interact
with a physical body?
• Descartes just claims that they
interact without explaining how.
Second Evaluation of Mind/Body
Dualism
• Just because the concept of mind is different from the concept of
body, it does not follow that mind and body are different
substances.
• Ryle says Descartes has made a category mistake by thinking that
mind and body belong in different categories when they are the in
the same category.
• Ryle gives the example of a person who goes to Oxford University
and is shown the buildings, parks, churches and people. After the
tour he says “I have seen the buildings and people but where is the
university?”. The person thinks the buildings and the university are
two different categories of things when they are really the same
thing.
• Likewise, just because our mind and body are separate things and
we use different concepts to describe them it doesn’t follow that they
must be made of two different substances.
Third Evaluation of Mind/Body Dualism
• If the essence of my being is thinking, and I stop
thinking (when asleep), then I must cease to exist.
• Descartes suggested in his Replies that I am just
not always aware that I am always thinking.
• But isn’t this contradictory? If I am not aware of it
how can I be certain that I am thinking?
Armstrong’s Overall Conclusion
• Armstrong is a materialist. He believes that the
mind is a material or physical thing.
• He is also an Identity Theorist. He believes that
the mind is identical to the brain.
• Thus, he rejects Descartes Dualism.
• Essay tip: This should be clearly stated in your
introduction, along with your answer to the essay
question, your own opinion, etc.
Armstrong: Philosophy of Mind
Unit 4
Armstrong’s Overall Argument
P1. Mental states are the inner causes of
behaviour.
P2. The inner causes of behaviour are
brain states and processes.
Therefore: Mental states are identical with
brain states and processes.
Argument for Premise 2
• P1. Science is the only discipline where learned
individuals ever reach consensus.
• P2. It is rational to believe what learned individuals
agree upon.
•  It is rational to believe what scientists agree upon.
• P3. Scientists agree that the causes of behaviour are
neural (brain) states and processes.
•  It is rational to believe that the inner causes of
behaviour are neural states and processes.
First Evaluation
• His view of science is questionable. Is science
the only discipline that ever reaches consenses
about what is true and are scientific truths that
reliable anyway? (think about Kuhn and
Nietzsche’s criticism of science).
Argument For Premise 1: Traditional
Behaviourism
• Behaviourism was the
dominant materialist theory
of mind in the 1950s.
• Traditional Behaviourism:
The mind is not something
behind behaviour, but simply
part of the behaviour.
• Rejection: However, people
can have certain mental states
and not act on them. Thus,
mind and body are not the
same thing.
Dispositional Behaviourism
• Dispositional Behaviourists, like Gilbert Ryle, say that mental
states are dispositions to behave in certain ways.
• They say that to have a certain disposition is just to say how one
would act if the conditions were right.
• For example, to say that a vase is fragile is to say what would
happen to it if it were dropped, struck by a hammer, etc.
• Ryle is not saying that the vase itself has any inner properties
that give it a fragile disposition and cause it to break.
• Ryle does not believe that dispositions are inner mental states
that cause behaviour.
• Since he is still a Behaviourist, Ryle denies that mental sates
are inner states. Like Traditional Behaviourists, he says mental
states (dispositions) are the same as outward behaviour.
Armstrong’s Analysis of Dispositional
Behaviourism
• Armstrong states that when Ryle starts to talk about
dispositions he does the very thing that Behaviourists are trying
to avoid. That is, he suggests that mental states are something
other than behaviour.
• If we can have a disposition without acting on it then
dispositions and behaviour cannot be the same thing.
• Armstrong says that dispositions do seem to be something
behind the behaviour, which causes behaviour.
• To say that a vase has a fragile disposition is to say that it has
inner properties that would cause it to shatter if dropped.
• Likewise, to have an angry disposition doesn’t just mean you
would act angry in certain situations it also means that you
have an inner mental state that causes your behaviour.
Why does Armstrong Analyse
Behaviourism
• Armstrong believes that Behaviourism is
problematic but a step in the right direction.
• Armstrong believes that while mental states
cannot be identified with behaviours, mental
states are linked to behaviours.
• Armstrong believes that dispositions are the
inner mental states that cause behaviour
(premise 1 of original argument)
Comparisons
• Both Armstrong and the Behaviourists are
materialists.
• Both Ryle and Armstrong think that mental states
are dispositions
• In contrast to Ryle, Armstrong things
dispositions/mental states are inner properties
that cause behaviour.
• Like Descartes, Armstrong thinks mental states
cause behaviour, while Behaviourists thinks that
mental states are behaviour.
• Unlike Descartes, Armstrong thinks that mental
states are physical things (neurological processes).
The Problem of Consciousness
• Armstrong rejects a possible criticism of his theory, which is that his
theory of mind may not explain consciousness.
• Consciousness is when we are aware of our thoughts and actions as
opposed to just acting without being aware of our thoughts and
actions.
• Thus, consciousness seems to be more than just a disposition to
behave in certain ways.
• As Armstrong says, automatic, habitual behaviour like automated
driving, involves having dispositions to behave in certain ways but
we are not conscious of what we are doing.
• A conscious driver would be more aware of what they were seeing
and doing.
• What is consciousness then if it is more than just having
dispositions that cause behaviour?
Armstrong’s Solution
• Consciousness is just a disposition to behave in certain ways.
However, it is a particular type of disposition.
• We can chose to pay attention to our mental states or to ignore
them. When we pay attention to our mental states we are
conscious.
• Conscious mental states are dispositions that are directed
towards other inner states, and not towards the outside
environment.
• The automated driver is not aware of their own mental states
and thus is not fully conscious of what they are doing.
• If the automated driver had a disposition to pay attention to his
mental states he would be conscious of them.
• Thus, consciousness is a disposition to scan one’s on mind – to
pay attention to particular mental states.
First Evaluation of Materialism
• The Knowledge Argument for Qualia: The knowledge
argument is intended to show that a complete physical
knowledge of the mind would fail to provide us with a
complete knowledge of the mind.
• Thus, there must be some
non-physical aspect of
the mind.
• Frank Jackson created a
scenario commonly called
“Black and White Mary” to
explain this problem.
Second Evaluation of Materialism
• The Impossibility of Artificial Intelligence: If
the mind is a completely material thing the like
the brain it seems logically possible that we
should be able to replicate it (Turing).
• But Artificial intelligence is seeming more and
more like an impossibility. Does this lend
weight to the claim that we have some non
physical soul like mind?
• In his “Chinese Room Argument”, John Searle
argues that artificial intelligence is impossible
because computers are not capable of
understanding.
• Is there some non-physical part of the brain that
scientists just can’t recreate?
Evaluation of Materialism
• Neuroscience, especially brain
scan technology, suggests that
the mind is just the brain.
• Incidents of brain injury also
back up materialism by showing
how the personality is connected
to the brain (Phineus Gage).
Other Concerns with Materialism
• If materialism is true we wouldn’t have freewill
because all physical things are subject to the laws
of cause and effect.
• If materialism is true we wouldn’t have personal
identity because all physical things change.
• If materialism is true life would be meaningless
because we are mortal creatures.