Reading Read Chapter 2 of Kim Can skip or skim over 3546 Read Descartes Selections pgs 115 in the reader Focus especially on pages 13 57 and 12 14 The mind body problem The mystery is how minds could possibly arise out of seemingly mindless matter ID: 244705
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Slide1
Substance DualismSlide2
Reading
Read Chapter 2 of Kim (Can skip or skim over 35-46)
Read Descartes Selections (
pgs
1-15) in the reader.
Focus
especially on pages 1-3, 5-7 and 12
-14.Slide3
The mind body problem
The mystery is how minds could possibly arise out of seemingly mindless matter.
Atoms, molecules, photons, etc. do not have minds.
Humans do.
But a human being is just a particular kind of animal.
Animals are physical things: they are entirely composed of molecules, atoms, etc.
If you bunch up a bunch of mindless particles in some super special way you get something that things, feels, believes, and fears.
How can this be?Slide4
The mind body problem
These issues are the focus of this course.
The Mind Body Problem
What is the relationship between
minds
and
physical things
?
Are minds physical things?
If not, how are they related to physical things?
If so, how are they differentiated from other physical things? What makes them so special?
How do you get minds from mindless matter?Slide5
The three ways it could be
Monism
Physicalism
:
All that exists are physical things. At bottom there is nothing but the sorts of things that figure in the language of physics. So minds are just some sort of complex physical thing.
Idealism:
All that exists are
minds
and
mental states
. There is no such thing as physical objects. Tables, chairs, and so on are just
ideas
of one kind or another. (Berkeley)
OR
Dualism:
Both minds and physical things exist and they are fundamentally different kinds of things. That is minds could exist independently of physical things and vice versa.Slide6
Mind as Soul
Substance dualism is the theory of mind that has (by far) the most adherents.
This is true both from a historical perspective, and as a report of people’s current beliefs.Slide7
Mind as Soul
On this view, the mind is something
fundamentally different
from the body.
It is not identical to the body
It can survive the death of the body
It could even inhabit a
different
body.
It could exist even if the physical world were entirely destroyed.Slide8
Mind as Soul
When people imagine their
soul
persisting after their deaths, it is typically the
mental characteristics
that they think are important.
Memories
Desires
IntentionsSlide9
Mind as Soul
The idea of our minds or souls being separable from our body is deeply ingrained.
Possibility of existence after the death of the body
Freaky Friday style body-swap cases
Ghosts/spirits
Astral projection
Reincarnation
Post Armageddon existenceSlide10
Substance Dualism
These things only seem possible if minds can exist entirely independently of physical bodies.
Substance Dualism
:
There are two fundamentally different substances in the world: minds and bodies.Slide11
Substance Dualism
Substance:
Is the stuff that has or instantiates properties
Has the capacity for independent existenceSlide12
Substance Dualism
According to the dualist:
Physical
things
have physical properties like mass, momentum, spatial location and so on.
Minds
have mental properties like believing, desiring, having a sensation, and so on.
A human being has both a mind and a physical body.Slide13
Reasons to Be a Dualist
By far the most common reason for someone to be a dualist is
their religion
.
As philosophers we must evaluate the arguments for and against the position.Slide14
Descartes’ Arguments
Descartes gives several arguments for substance dualism and others have been inspired by his writings.
We will look at three:
The Argument from Doubt
The Divisibility Argument
The Conceivability ArgumentSlide15
Cartesian Preliminaries
Descartes begins his
Meditations on First Philosophy
by attempting to call into question
all
his beliefs.
He is seeking a firm foundation on which to build the rest of his knowledge, so he will be
certain
of what he knows and what he doesn’t.
If
he can
possibly be deceived
about something, he resolves to withhold judgment on the matter.Slide16Slide17
Cartesian Preliminaries
Evil Demon
Suppose that you have no body at all, and there is nothing in the universe but
you
and an all-powerful evil demon. The demon deceives you by giving you a series of experiences as of a physical world in which you have a body, interact with other people and so on. But
none of this is happening
. Really, you are just a disembodied soul floating in the void being massively deceived.
Can you rule out this possibility with absolute certainty?Slide18
Cartesian Preliminaries
Descartes concludes that it is
possible
that you are deceived about the existence of every physical thing, including your own body.
Does this mean you could be deceived about
everything
?Slide19
The Cogito
“No: if I convinced myself of something then I certainly existed. But there is a deceiver of supreme power and cunning who is deliberately and constantly deceiving me. In that case too, I undoubtedly exist, if he is deceiving me; and let him deceive me as much as he can, he will never bring it about that I am nothing so long as I think I am something. So, after considering everything very thoroughly, I must finally conclude that this proposition
I am, I exist
, is necessarily true whenever it is put forward by me or conceived in my mind.” (Reader 1) Slide20
The Cogito
As he puts it elsewhere:
Cogito ergo sum.
I think therefore I am.Slide21
Cartesian Preliminaries
But what kind of thing is he? Easy!
“A thing that thinks…A thing that doubts, understands, affirms, denies, is wiling, is unwilling, and also imagines and has sensory perceptions.”Slide22
Argument from Doubt
The Argument from Doubt
I cannot doubt that I exist. (Cogito)
I can doubt the existence of any physical thing. (Evil Demon)
Therefore, I am not identical to any physical thing.
Therefore, I am a thinking thing that is not identical to any physical thing.
If the argument is sound, it shows that there is at least one non-physical thing, and dualism is established.Slide23
Argument from Doubt
The Argument from Doubt
I cannot doubt that I exist. (Cogito)
I can doubt the existence of any physical thing. (Evil Demon)
Therefore, I am not identical to any physical thing.
Therefore, I am a thinking thing that is not identical to any physical thing.
If the argument is sound, it shows that there is at least one non-physical thing, and dualism is established.Slide24
Argument from Doubt
What justifies the inference from (1) and (2) to (3)?
Leibniz’s Law:
For all x and y, if x is the very same thing as y, then x and y have all the same properties.Slide25
Argument from Doubt
Any physical thing has the property of
possibly being doubted by Descartes.
Descartes’ mind does not have this property.
Therefore, by Leibniz’s law, they are not identical.Slide26Slide27
Lennay
Kekua
(Artist’s Approximation)Slide28
Ronaiah
Tuiasosopo
Slide29
A Fallacious Inference
Manti
Te’o
reasons as follows:
I believe that
Lennay
Kekua
is dead.
I don’t believe that
Ronaiah
Tuiasosopo
is dead.
Therefore,
Lennay
Kekua
is not identical to
Ronaiah
Tuiasosopo
. Slide30
Argument from Doubt
The problem is that what a person
believes
,
doesn’t believe
, or
doubts
doesn’t tell us very much about
how things are.
For this reason you can’t apply Leibniz’s Law to
intentional properties:
Properties that essentially involve intentional states of some subject (e.g. being believed, doubted, desired, etc.)Slide31
The Argument from Doubt
Therefore, the Argument from Doubt relies on a
fallacious inference
and should be rejected.Slide32
The Divisibility Argument
The Divisibility Argument (Version #1)
My body is divisible.
My mind is not divisible.
Therefore, my mind is not identical to my body.Slide33
The Divisibility Argument
In at least one sense, it seems the mind
is
divisible.
I have individual beliefs, memories, desires, and so on.
Some of these could be removed and replaced with others
I also have different
cognitive faculties
: reasoning, perception, sensation, memory, language comprehension, etc.
If I receive a brain injury I could lose some of these things in the same way I could lose an arm or a leg.
Descartes’ seems to deny that the mind can be fragmented in this way, though it isn’t clear
why.Slide34
The Divisibility Argument
The Divisibility Argument (Version #2)
If you cut off my leg something has been taken from my body.
Nothing has been taken from my mind.
Therefore, my mind and body are distinct.Slide35
The Divisibility Argument
Two responses:
My mind
does
lose something, namely the capacity to feel my leg.
A
physicalist
need not say that the mind is identical to
the entire body
.
If the mind is the brain, say, then this is consistent with Descartes observations here.
But if you remove part of the brain this
does
(typically) have mental effects. Slide36
The Conceivability Argument
“First, I know that everything which I can clearly and distinctly understand is capable of being created by God so as to correspond exactly with my understanding of it. Hence, the fact that I can clearly and distinctly understand one thing apart from another is enough to make me certain that the two things are distinct, since they are capable of being separated, at least by God……On the one hand I have a clear and distinct idea of myself, in so far as I am simply a thinking, non-extended thing; and on the other hand I have a distinct idea of body, in so far as this is simply an extended, non-thinking thing. And accordingly, it is certain that I am really distinct from my body, and can exist without it.
” (Reader 7)Slide37
The Conceivability Argument
The Conceivability Argument
If I can conceive of some state of affairs without contradiction, then that state of affairs is possible
. (Premise)
I can conceive of myself as existing without my body.
(Evil Demon)
Therefore, it is possible for me to exist without my body.
It is not possible for my body to exist without my body existing
. (Logic)
Therefore, I am distinct from my body. (by LL)Slide38
The Conceivability Argument
The Conceivability Argument
If I can conceive of some state of affairs without contradiction, then that state of affairs is possible
. (Premise)
I can conceive of myself as existing without my body.
(Evil Demon)
Therefore, it is possible for me to exist without my body.
It is not possible for my body to exist without my body existing
. (Logic)
Therefore, I am distinct from my body. (by LL)Slide39
The Conceivability Argument
The entire force of the argument depends on premise 1: the claim that conceivability entails possibility.Slide40
Arnauld’s Triangle
Steve knows about right triangles, but does not know the Pythagorean theorem (a
2
+b
2
=c
2
)
Suppose we ask him if it is possible to build a room in the shape of a right triangle with the following dimensions: 4x7x10.
He may very well say yes!Slide41
Arnauld’s Triangle
Furthermore, he may try to imagine the room, plan where he would put furniture in it, etc.
But such a room is impossible!
Hence, the fact that Steve can
conceive
of such a room does not entail that the room is
possible
.Slide42
Amnesia Case
Suppose I have amnesia and don’t remember my name.
I hear about this terrible instructor: Tim Butzer.
I imagine a world in which Tim Butzer is dead and I am attending a party to celebrate his timely demise.Slide43
Amnesia Case
But since I
am
Tim Butzer, it is impossible for Tim Butzer to be dead, and for me to be attending a party!
Hence, conceivability does not entail possibility.Slide44
Hesperus and Phosphorus
Hesperus is the first visible star in the evening and Phosphorus is the last visible star in the morning.
Someone could imagine a case in which Hesperus is in the sky while Phosphorus is not.
Indeed they may think this happens every evening!Slide45
Hesperus and Phosphorus
But Hesperus and Phosphorous are actually both Venus!
So every time Hesperus is in the sky Phosphorous is too (they are the same thing).Slide46
Conceivability and Possibility
All three cases share a common feature: the subject in each is ignorant of some key facts about the case.Slide47
Conceivability and Possibility
But it seems as if Descartes (or we) could be in precisely the same situation with regards to the relationship between minds and bodies.Slide48
Conceivability and Possibility
Since conceivability does not entail possibility Descartes’ argument is not sound.
Therefore, we have no good argument for substance dualism.Slide49
Arguments Against Dualism
We have not seen any argument that establishes that dualism is true.
But this does not mean it is false. Slide50
Princess Elisabeth: Philosophical BadassSlide51
Elisabeth’s Objection
According to Descartes’ own physics physical things are causally affected by:
Momentum
Contact
Quality or shape of a surface
The these all require
extension
and/or
spatial location.
But the soul has none of these properties. So how does it cause the body to move?Slide52
Elisabeth’s Objection
This is a problem because Descartes accepts the following:
Interactionism:
Minds interact causally with physical things.
Minds can cause the body to move
Action on my body can cause mental states
And well he should!Slide53
Elisabeth’s Objection
“I confess it would be easier for me to concede matter and extension to the soul, than the capacity to move a body and to be moved, to an immaterial thing.” Slide54
Reading
Read:
Kim: 61-71
Ryle “Descartes’ Myth” (Reader 30-37)Slide55
Descartes’ Picture of Mind/Body CausationSlide56
Descartes’ Picture of Mind/Body Causation
The idea seems to be that since the gland is
so small
and
so central
in the brain, that any little movement could have big results.Slide57
Descartes’ Picture of Mind/Body Causation
But thinking in this way completely misses the point of Elizabeth’s objection:
It isn’t that it would be very hard for an immaterial thing to move a material thing
Her point is that it is impossible, even in principle, an immaterial thing to move a physical thing!Slide58
Descartes’ Responses
Here is a (somewhat unfair) summary of Descartes’ responses to Elizabeth:
Mind-body causation is like gravity (but gravity isn’t like that).
Mind-body union is a third substance (maybe?)
Mind-body interaction can’t be understood by philosophizing, so stop it.Slide59
Causal Overdetermination
According to every systematic theory of physics since Newton, every physical event in the universe
has a physical cause.
This is in tension with the dualist’s claims that
some
physical events have mental causes.Slide60
Causal Overdetermination
Say that I raise my hand.
According to our best physics, there is a physical cause sufficient to produce this action.
According to the dualist there is also a
mental cause
for this action.Slide61
Causal Overdetermination
What the dualist has to say to be consistent with our best science is that my raising of my arm was
causally
overdetermined
.Slide62
Causal Overdetermination
Causal
Overdetermination
:
An event A is causally
overdetermined
if it has multiple causes, each of which would have been sufficient on its own to cause A.Slide63
Causal Overdetermination
There are many events in the clip that would prevent O.J. from making the arrest:
Getting his leg caught in the door
Getting shot 15 times
Burning his hand
Being blinded by cake
Getting caught in a bear trap
Falling off the boatSlide64
Causal Overdetermination
So, O.J.’s failing to make the arrest was
causally
overdetermined
.
Causal
overdetermination
is clearly possible and sometimes happens.Slide65
Causal Overdetermination
However, as the clip
also
illustrates, such cases tend to be a matter of total coincidence.
As a result, though such cases are certainly possible, it seems that they are coincidental and rare.Slide66
Causal Overdetermination
The dualist must say that every time any person moves her arm, there is both a physical cause and a mental cause.
But this amounts to saying that there are
an enormous number
of mere coincidences happening all the time.Slide67
Causal Overdetermination
This massive coincidence calls out for some sort of explanation on the part of the dualist.
If mind’s and bodies interact, what explains the massive causal
overdetermination
that results?Slide68
The Moral
Elisabeth’s Objection and the problem of causal
overdetermination
seem to entail that
dualism
and
interactionism
are inconsistent.
But why can’t the dualist just deny interactionism?Slide69
Denying Interactionism
The problem for any view like this is to explain observed facts:
Every time I decide to raise my arm it goes up.
Every time someone punches me I feel pain.
Every time I want to move to the other side of the room, my body walks over there.
Etc.Slide70
Denying Interactionism
If my mind does not causally interact with my body, how are we to explain these very common observations?Slide71
Occasionalism
Malebranche suggested that every time you want to make your body move, God takes it as an occasion to intervene and cause your body to move in the way intended.
This doctrine is called
occasionalism
.Slide72
Occasionalism
According to
occasionalism
the laws of physics are violated every time I “move” my body.
Every time any person move’s their body is literally a miraculous event!Slide73
Pre-Established Harmony
Leibniz suggested that the apparent interaction was due to a
pre-established harmony:
God set up the universe with two distinct causal orders: the mental and the physical.
He set them up in such a way that though they never causally interact, they will always be in sync.
So when the mental event of my wanting to raise my arm happens, the pre-established harmony guarantees that my arm will go up.Slide74
Pre-Established Harmony
Think of two clocks set to the same time. They don’t causally interact, but they can be such that they always agree on the time.
Leibniz’ idea is that the relationship between the mental and physical is a lot like that.Slide75
Acts of Desperation
Both Malebranche’s view and Leibniz’ seem to be theoretic acts of desperation.Slide76
Acts of Desperation
Since dualism is inconsistent with this kind of interaction, it must be rejected.
Let’s adopt Elizabeth’s suggestion and consider the possibility that the mind is a material thing of some kind.