What is it to Have a Mind?

What is it to Have a Mind?

What is it to Have a Mind?

Two Central Questions:

(1) What are minds?(2) How do minds relate to/interact with bodies?

What is it to Have a Mind?

Recall our list of mental states:• Thoughts• Beliefs• Desires• Current experiences and sensations• Emotions

What is it to Have a Mind?

A mind is something that can be in such states as these.

But what is a mind and how does it relate to physical things like our bodies?

Substance Dualism

It is common to think that we are not just physical things, but that we have a non-physical nature.

Substance Dualism

Substance Dualism: There are substances of two fundamentally and irreducibly distinct kinds in the word: mental stuff, and material stuff.

Substance Dualism

According to substance dualism minds are immaterial things that are not made up of physical matter.

This lines up closely with the idea of that we have a soul or a spirit.

Substance Dualism

It is probably true that the vast majority of people are substance dualists:• Most major religions endorse something of

this kind • Many people believe they can survive the

death of their bodies• You see this assumed in fiction all the time

(books and movies about ghosts).

Leibniz’s Law

In order to make sense of Descartes’ arguments it is useful to have the following principle:

Leibniz’s Law: If A and B are numerically identical then A and B share all of the same properties.

Kinds of Identity

Qualitative Identity: A and B are qualitatively identical if and only if A and B have all the same properties.

Numerical Identity: A and B are numerically identical if and only if they are one and the same thing.

Kinds of Identity

So Leibniz’s law says that if A and B are numerically identical then they must also be qualitatively identical.

(Not the reverse)

Leibniz’s Law

In other words, if A and B have different properties then they cannot be the same thing.

Leibniz’s Law

An example of how you might use the principle:

1. Superman is flying across the sky.2. Jimmy Olsen is not flying across the sky.3. Therefore, Superman is not Jimmy Olsen.

Argument from Doubt

Argument from Doubt1. I can doubt the existence of my brain and

body.2. I cannot doubt the existence of my mind. 3. Therefore, my mind is not the same thing as

my brain or body.

Argument from Doubt

I can doubt the existence of my brain and body.

This premise is supported by thinking about the evil demon scenario.

In such a case I don’t have a body or brain, so I can consistently doubt that I have a body or brain.

Argument from Doubt

I cannot doubt the existence of my mind.

This follows from Descartes’ cogito. I cannot consistently doubt that I have a mind, because doubting is a mental state!

Argument from Doubt

Therefore, my mind is not the same thing as my brain or body.

Follows from the premises by Leibniz’s law.

My body has a property that my mind lacks (being able to be doubted by me to exist) so they can’t be the same thing!

Argument from Doubt

If this argument works, then it establishes that substance dualism is true:

• My mind is not identical to my body• Therefore they must be two, different things.

A Fallacious Inference

There is problem with how Leibniz’s Law is applied in the argument from doubt.

A Fallacious Inference

Consider the following argument:

(1) Lois Lane doubts that Clark Kent can fly.(2) Lois Lane does not doubt that Superman can

fly.(3) Therefore Superman is not identical to Clark

Kent.

A Fallacious Inference

What if Manti Te’o reasoned as follows:

(1) I believe that Lennay Kekua is dead.(2) I don’t believe that Ronaiah Tuiasosopo is

dead.(3) Therefore, Lennay Kekua is not identical to

Ronaiah Tuiasosopo.

Announcements

Your papers will be handed back on Friday along with the last essay prompt.

Finish reading Descartes’ and Elizabeth’s correspondence

Argument from Doubt

Argument from Doubt1. I can doubt the existence of my brain and

body.2. I cannot doubt the existence of my mind. 3. Therefore, my mind is not the same thing as

my brain or body.

A Fallacious Inference

Consider the following argument:

(1) Lois Lane doubts that Clark Kent can fly.(2) Lois Lane does not doubt that Superman can

fly.(3) Therefore Superman is not identical to Clark

Kent.

A Fallacious Inference

What is going wrong?

You can’t use what we believe, doubt, or can doubt about things in order to prove that they are not identical using Leibniz’s Law.

A Fallacious Inference

So we need an argument that does not make use of Leibniz’s law in this fallacious manner.

Fortunately Descartes gives us one!

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.” (Sixth Meditation)

The Conceivability Argument

The Conceivability Argument1. If I can conceive of some state of affairs without

contradiction, then that state of affairs is possible.2. I can conceive of myself as existing without my body. 3. Therefore, it is possible for me to exist without my

body.4. It is not possible for my body to exist without my

body existing.5. Therefore, I am distinct from my body. (by LL)

The Conceivability Argument

The entire force of the argument depends on premise 1: the claim that conceivability entails possibility.

Conceivability and Possibility

Despite the claim’s intuitive force, most philosophers think that it is false.

That is, it is possible for someone to conceive of something, without that thing being possible.

Arnauld’s Triangle

Steve knows about right triangles, but does not know the Pythagorean theorem (a2+b2=c2)

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!

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.

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.

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.

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!

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).

Conceivability and Possibility

All three cases share a common feature: the subject in each is ignorant of some key facts about the case.

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.

Conceivability and Possibility

Since conceivability does not entail possibility Descartes’ argument is not sound.

Therefore, we have no good argument for substance dualism.

Getting Clear on Dualism

According to the dualist:

• Minds and bodies are two fundamentally different kinds of things.

• Minds are immaterial.

Getting Clear on Dualism

But what does it mean for something to be immaterial?

Getting Clear on Dualism

Material things have certain kinds of properties:

• Spatial location• Extension• Mass• Motion• Solidity

Getting Clear on Dualism

Immaterial Object: Lacks spatial location, extension, solidity, motion, mass, or any physical properties

Dualists claim that minds are things of this kind.

Interactionism

But minds interact with physical things.• Mental events can cause physical events.• Physical events cause mental events.

Interactionism

Interactionism: Minds interact causally with physical things.

Interactionism

Interactionism is an enormously plausible thesis.

It seems to be one of the most basic and obvious facts about minds that they are able to interact with bodies.

Interactionism

The main problem for dualism is that it seems to be inconsistent with interactionism.

For Wednesday

Read the second Kim selection (157-164)

Enjoy the holiday!

Interactionism

Interactionism: Minds interact causally with physical things.

First Problem: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.

First Problem: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.

First Problem: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.

First Problem: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.

First Problem: 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 boat

First Problem:Causal Overdetermination

So, O.J.’s failing to make the arrest was causally overdetermined.

Causal overdetermination is clearly possible and sometimes happens.

First Problem: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.

First Problem:Causal Overdetermination

The dualist must say that every time any person moves her arm, there is both a physical cause and a mental cause.

First Problem:Causal Overdetermination

But this amounts to saying that there are a stupidly high number of mere coincidences happening all the time.

First Problem: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?

Second Problem: Elizabeth’s Puzzle

Princess Elizabeth of Bohemia presents an argument which seems to show that dualism simply cannot be consistent with interactionism.

Second Problem: Elizabeth’s Puzzle

Elizabeth’s Puzzle(1) Physical objects are caused to move by being

bumped into.(2) The ability to bump into things requires

extension, mass, shape, and motion.(3) Minds do not have properties like extension,

mass, shape and motion.(4) Therefore, minds cannot cause any physical

objects to move.

Second Problem: Elizabeth’s Puzzle

Elizabeth argues that if the soul is immaterial, by definition it does not have the kinds of properties that would allow it to causally interact with physical bodies.

Second Problem: Elizabeth’s Puzzle

What this shows is that if dualism is true, minds cannot cause bodies to move even in principle because, being immaterial, they lack the right kinds of properties.

Second Problem: Elizabeth’s Puzzle

“I confess that 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 being.” (179)

Second Problem: Elizabeth’s Puzzle

Elizabeth argues in terms of the physics of her day.

Today physicists recognize lots of other physical properties that can be causally relevant (charge, spin, field-strength, etc.)

Second Problem: Elizabeth’s Puzzle

But this doesn’t solve the problem for the dualist.

If something is immaterial it lacks physical properties. Whatever properties physicists uncover, the dualist is committed to saying that minds lack any of them.

Descartes’ Response

Descartes’ most infamous response located the soul’s causal powers on the body in the pineal gland.

Descartes’ Response

“The part of the body in which the soul directly exercises its functions is not the heart at all, or the whole of the brain. It is rather the innermost part of the brain, which is a certain very small gland situated in the middle of the brain's substance and suspended above the passage through which the spirits in the brain's anterior cavities communicate with those in its posterior cavities. The slightest movements on the part of this gland may alter very greatly the course of these spirits, and conversely any change, however slight, taking place in the course of the spirits may do much to change the movements of the gland.” (The Passions of the Soul)

Descartes’ Response

Descartes’ Response

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.

Descartes’ Response

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!

Denying Interactionism

What Elizabeth’s argument shows is that dualism is incompatible with interactionism.

Therefore, why shouldn’t the dualist simply deny that minds and bodies causally interact?

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.

Denying Interactionism

If my mind does not causally interact with my body, how are we to explain these very common observations?

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.

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!

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.

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.

Acts of Desperation

Both Malebranche’s view and Leibniz’ seem to be theoretic acts of desperation.

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.