The reading for today is Ch 1 of Philosophy of Mind A Beginners Guide Substances and Properties The properties of a thing are the ways that that thing is the features characteristics ID: 271471
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Slide1
DualismSlide2
The reading for today is Ch. 1 of
Philosophy of Mind: A Beginner’s Guide
.Slide3
Substances and Properties
The
properties
of a thing are the ways that that thing is, the
features
,
characteristics
, or
qualities
of that thing.Slide4
Name Some Properties!Slide5
Substances and Properties
Substances
(objects, individuals) are the things that have (possess, instantiate) properties (features, characteristics, qualities).Slide6
Substance Dualism
According to the
substance dualist
, there are two kinds of substances: physical substances and mental substances.Slide7
Physical Properties
Physical substances have physical properties:
Size
ShapeLocationMassCharge
Spin, etc.Slide8
Mental Properties
Mental substances have mental properties [mental states]:
Emotions
SensationsPerceptionsThoughts
MoodsSlide9
Substance Dualism
The substance dualist thinks that
no
physical substance has mental properties and no mental substance has physical properties.
Minds don’t have size, shape, location, etc. and brains don’t have moods, thoughts, pains, etc.Slide10
From the Reading
“[According to substance dualism] Your body is like a probe, sent by NASA to explore a different planet. The probe sends pictures back to mission control, where scientists decide what the probe should do next. Instructions are then sent back to the probe which responds accordingly. The probe itself is entirely unintelligent” (p. 10). And it has no feelings, emotions, pains, etc.Slide11
Arguments for substance dualismSlide12
Short Circuit
When I was 4 years old, the movie
Short Circuit
came out.
In it, a robot gets struck by lightning and becomes sentient.Slide13
Throughout the movie, various characters argue that the robot can’t be sentient (have a mind), because robots can’t _____:
Things with minds can _____
Robots can’t ______
Therefore, no robot has a mind.Slide14
Robots Can’t _____
Be expressive
Exhibit curiosity
Engage in playfulnessSpeak fluidly
Learn new things
A
ppreciate
beauty
Expect
future conscious
experiencesSlide15
Robots Can’t _____
Have a fear
of death
Act originally Enjoy dancing and music
Have a sense
of humor
Conform to moral
laws out of principle
Mentally associate disparate things
Exhibit
spontaneous emotional
responsesSlide16
Similar arguments can be made for substance dualism. Instead of “Robots can’t _____,” the substance dualist argues that there are things minds can do that “
No physical object
can _____”:
Minds can _____
No physical object can _____
Therefore, no physical object is a mind.Slide17
Is it possible for physical objects to do these sorts of things– learn new things, be creative and original, fear death, make plans for the future, experience redness…?Slide18
Descartes
René Descartes (1596-1650) was a French natural philosopher and mathematician. He is the father of modern (Western) philosophy, and he argued for substance dualism.Slide19
The Cogito
Descartes famously said “I think, therefore I am” (“Cogito ergo sum”).
He argued that it is not possible for him to doubt his own existence.
O
nly things that exist can doubt
. Slide20
The Deceiver
But Descartes thought it
was
possible for him to doubt that he had a body.
Sure, it looks and feels like he has a body. But couldn’t an all-powerful God make it
seem
like Descartes had a body, when he really didn’t?Slide21
I cannot doubt that I exist.
I can doubt that my body exists.
Therefore, I am not my body.
I am my mind.
Therefore, my mind is not my bodySlide22
Leibniz
Gottfried Wilhelm Leibniz (1646-1716), like Descartes, was a natural philosopher and mathematician.
Among his many achievements, he formulated a law of logic called Leibniz’s Law.Slide23
Leibniz’s Law
Also known as “the indiscernibility of
identicals
”If X = Y, then X and Y have all the same properties.
[Converse] If X and Y
don’t
have all the same properties, then X ≠ Y.Slide24
Example
Property: being red
My car is red (has the property of being red.
That car is not red (does not have the property)
Since my car and that car don’t have all the same properties, that car is not my car.Slide25
Descartes’ Argument Again
Property: being a thing whose existence Descartes can doubt.
Descartes’ body has the property of being a thing whose existence Descartes can doubt.
Descartes does not have the property of being a thing whose existence Descartes can doubt.
Therefore, Descartes is not Descartes’ body.Slide26
The Masked Man FallacySlide27
I know that the masked man committed the robbery– I was there and I saw him.
I don’t know whether my brother committed the robbery.
Therefore, my brother did not commit the robbery.Slide28
Arguments against substance dualismSlide29
No Action at a Distance
At the time Descartes lived, it was commonly believed that for one object to exert a force on another, they had to contact one another.
But the mind, according to Descartes, is not spatially located, has no surfaces, and no mass. How can it contact and thus affect the body it controls?Slide30
No Explanations
The substance dualist has not given us an explanation for
how
the mind controls the body, in the way that a physicist can tell us how the mass of the various planets determine Earth’s orbit.Slide31
We Can Already Explain Bodily Movements
Why did I raise my hand?
Because a muscle in my arm contracted.
Why did the muscle contract?
Because of an electrical impulse in a nerve.
Why did the nerve have the impulse?
Because certain neurons in the brain fired.
Why did they fire?...Slide32
Substance Dualism Violates the Laws of Physics
Physics says that the motions of particles are completely determined by the physical forces that act on them (the strong nuclear force, the electro-weak force and gravity).
If a non-physical mind exerts a non-physical force that changes the motion of ANY particle in your body, then physics is wrong.Slide33
Unconscious Mental States
Philosophers used to think that all mental states were conscious. If you thought that, then you could say that consciousness is just part of being in the non-physical mind.
But now we know there are unconscious mental states. How can the substance dualist explain what makes some mental states conscious and others not?Slide34
Brain Damage
According to the substance dualist, mental processes occur in the mind, and not in the brain. (Many people like
s.d.
because it suggests we can live on after the death of the body.)
Why then do damage to the brain or degenerative brain diseases affect our ability to think? Slide35
Avoiding the problemsSlide36
Property Dualism
Property dualism denies that there are any non-physical substances.
Instead, it says that some physical substances, in particular, brains, have mental properties in addition to their physical properties.Slide37
Pros of Property Dualism
This can explain why brain damage, for instance, can change your mental states or your ability to have certain mental states.Slide38Slide39
Epiphenomenalism
Property dualism is often combined with epiphenomenalism.
Epiphenomenalism
says that brain events can cause mental states, but mental states
cannot
cause physical events.Slide40
Pros of Epiphenomenalism
The good thing about epiphenomenalism is that it doesn’t contradict physics.
Since mental states can’t cause any physical events, it’s true (as physics says) that the motion of any particle is determined only by the physical forces exerted on it.Slide41
Cons of Epiphenomenalism
The problem is that we have to deny two seemingly obvious facts about mental states:
Some mental states cause action.
Some mental states cause other mental states.Slide42Slide43
Abandon Dualism?
Why not just abandon dualism? Well, many have done that.
BUT, some philosophers think there are very good arguments for dualism. We will have several classes on them later. In general, they are arguments that conscious properties are not physical properties.Slide44
summarySlide45
Substance Dualism
Substance dualism says that there are two kinds of substances: physical substances with physical properties and mental substances with
mental properties.Slide46
For Substance Dualism
Arguments for substance dualism assume that physical things can’t have certain properties– creativity, originality, consciousness, etc.
Since some things do have those properties, it follows that the things that do are not physical things. Slide47
Against Substance Dualism
The primary reason for rejecting substance dualism is that it claims there are non-physical causes of events– but we have never found any!
Second, it predicts that the mind should not be affected by damage to the brain, but this is obviously contradicted by experience.Slide48
Epiphenomenal Property Dualism
Property dualism combined with epiphenomenalism can avoid these problems, but only at the cost of denying that mental states cause actions or other mental states.