Transcript Qualia - David Kelsey`s Philosophy Home Page

Introduction to Philosophy
Lecture 14
Minds and Bodies #3 (Jackson)
By David Kelsey
Contemporary dualism
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Dualism revisited:
– Contemporary philosophical defenders of dualism have rather different
views from those Descartes had.
• They are more interested in consciousness.
• Even if Physicalism can explain a lot of things, it can’t explain conscious
experience.
Qualia
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Conscious Experience:
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When philosophers talk about consciousness, we have a very precise type of issue in
mind.
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By Conscious experience, philosophers mean issues about what it’s like to have
certain experiences:
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What it’s like to see red.
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These mental states are called qualia.
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Also called raw feels or sense data.
More on Qualia
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Qualia:
– The easiest way to get the idea of qualia is to think about people who are
experiencing the same things you are, but have different qualia.
• The colorblind person…
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The Qualia of Driving:
– Have you ever had the experience of a long drive?
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Zoning out and the missing Qualia…
Inverted Qualia
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Inverted Qualia:
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Suppose that there’s someone who, from birth, when they see red, has just the
experience you have when you see blue and vice versa.
Their red and blue qualia are reversed, or inverted.
They call the color of a ripe tomato ‘red’ even though their qualia is like your blue
qualia…
Can you tell from someone’s behavior that they’re suffering from inverted qualia?
Physicalism and Qualia
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Qualia: trouble for Physicalism:
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What we’ve said about qualia so far is already trouble for some kinds of physicalism.
The Behaviorist can’t allow for the possibility of inverted qualia, since people with
inverted qualia would behave just like the rest of us.
What about the identity theorist?
Jackson
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Frank Jackson (1943-present)
An Australian philosopher.
Most famous for his knowledge argument for dualism.
He has actually given up dualism now, but he still thinks the argument is valid.
He is known for giving very convincing, commonsensical arguments
Jackson &
What Mary didn’t know
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The Mary Thought Experiment:
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Imagine a woman Mary
Mary is a brilliant scientist who’s been imprisoned for life in a room painted entirely
black and white.
Even Mary herself is painted.
She conducts experiments (viewing the results through black and white TV) and learns
every physical fact about the mind.
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The physical properties of color and the eye’s response to light…
What Mary doesn’t know:
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Even after Mary has learned every physical fact, she still doesn’t know what it’s like to
see the color red.
Imagine what happens when she steps outside of the room for the first time and sees a
ripe tomato.
Thought Experiments
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Thought experiments:
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Jackson’s example of Mary is a thought experiment.
A thought experiment is a constructed case which is used to test our intuitions about
some philosophical puzzle...
So Jackson constructs the Mary thought experiment to test our intuitions
about Dualism.
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In particular, the Mary experiment is supposed to lead us to the intuition that Mary
learns a non-physical fact…
The Knowledge Argument
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The Knowledge argument:
– Jackson takes the Mary thought experiment as evidence against
Physicalism
– His argument is known as the Knowledge argument:
• 1. Mary knows every fact about the physical world.
• 2. Mary learns a fact about qualia, which she didn’t previously know, when she
steps out of the black and white room.
• 3. Thus, facts about qualia are facts about the nonphysical.
• 4. Thus, Physicalism is false.
• 5. Thus, Dualism is true.
Epiphenomenalism
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Epiphenomenalism:
– A thing is epiphenomenal if and only if it can be caused by other things, but
never causes anything itself.
– According to Jackson, Qualia are epiphenomenal.
• Qualia are caused by physical states, such as brain states, but they do not have
any physical effects.
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So there are two types of Dualists:
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Interactionists like Descartes: the non-physical aspects of the mind have physical
causes and physical effects.
Epiphenomenalists like Jackson: the non-physical aspects of the mind have physical
causes but no physical effects.
Epiphenomenalism and beliefs
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Although the Epiphenomalist thinks Qualia are non-physical states, he does
allow that some mental states are physical states.
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Belief states and desire states are physical states:
• According to the Epiphenomenalist, only physical states can cause other physical
states.
• And Belief states and Desire states are physical states because they cause
actions.
• Beer in the fridge example…
Objection #1: Zombies
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The Problem of other minds:
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Epiphenomenalism suffers from the problem of other minds…
Someone who lacks all Qualia is called a zombie.
According to epiphenomenalism, zombies would be physically just like us…
So how could I tell that you’re not a zombie?
Objection #2: Could we know that
epiphenomenalism is true?
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Could we even know Epiphenomenalism was true:
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Suppose epiphenomenalism was true.
Suppose I’ve convinced you all with Jackson’s argument.
At no point did qualia play any causal role in the argument that convinced you.
How then can the Knowledge argument be a good reason to believe its
conclusion?
Physicalism and Qualia
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Qualia are a problem for Physicalism:
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How should the Physicalist think about qualia?
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What should the Physicalist say about inverted qualia?
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How should the Physicalist reply to the knowledge argument? Two options:
• Mary wouldn’t learn anything new when she leaves the black and white room.
• Mary would learn something, but not a new fact.
Denying the Intuition
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The first Physicalist response is to Deny the intuition:
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Maybe we can’t imagine Jackson’s Mary experiment:
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Some physicalists deny that Mary would learn anything new when she leaves the black
and white room.
The point of the description of the case, the black and white room, etc., was to get us to
have the intuition that she would say ‘Ah, ha!…’.
But we can only have the intuition if we are genuinely able to imagine the case as
described.
…because we can’t imagine what someone would do who knew every physical fact.
Jackson’s reply:
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but you only have to imagine Mary knows every relevant fact.
The Ability hypothesis
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The Second Physicalist response: Mary doesn’t learn a new fact:
– Mary doesn’t learn a new fact, she acquires the ability to distinguish red
things from dark grey things…
– Riding a bike:
• Learning to see red is like learning to ride a bike: they can’t be learned in a
book…
• So Knowing how to do something is not the same as knowing that something is
true.
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Jackson’s reply:
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But Mary always had the ability to distinguish red things from dark grey things.
Is this response adequate?