Philosophy 4610Philosophy 4610Philosophy of MindPhilosophy of Mind

Week 3: Objections to DualismWeek 3: Objections to Dualism

Logical BehaviorismLogical Behaviorism

Descartes: Mind and BodyDescartes: Mind and Body

So far, Descartes has argued that he exists as a So far, Descartes has argued that he exists as a thinking thingthinking thing defined by its capability of defined by its capability of thinking, perceiving, and imagining.thinking, perceiving, and imagining.

He has also argued that, since God exists and is He has also argued that, since God exists and is not a deceiver, there is reason to believe that not a deceiver, there is reason to believe that the external world exists and is (more or less) the external world exists and is (more or less) how we perceive it to be.how we perceive it to be.

In the Sixth Meditation, he now will consider how In the Sixth Meditation, he now will consider how his his mind mind (or (or thinking substancethinking substance) is connected to ) is connected to his his bodybody (or (or extended substanceextended substance))

Descartes: Mind and BodyDescartes: Mind and Body

ExtensionExtension is the property of is the property of taking up taking up spacespace. If something has a size or a . If something has a size or a shape, it is “extended.”shape, it is “extended.”

According to Descartes, the body (like all According to Descartes, the body (like all bodies or objects) is bodies or objects) is extendedextended but not but not thinkingthinking. The mind is . The mind is thinkingthinking but not but not extendedextended. .

Descartes: Mind and BodyDescartes: Mind and Body Descartes has two arguments for the real Descartes has two arguments for the real

distinction between mind and body:distinction between mind and body: 1) The body can be separated from the mind, or 1) The body can be separated from the mind, or

the mind from the body.the mind from the body. 2) Mind is 2) Mind is indivisibleindivisible, whereas bodies are , whereas bodies are

divisibledivisible: “For when I consider the mind, or : “For when I consider the mind, or myself in so far as I am merely a thinking thing, I myself in so far as I am merely a thinking thing, I am unable to distinguish any parts within myself am unable to distinguish any parts within myself … By contrast, there is no corporeal or extended … By contrast, there is no corporeal or extended thing that I can think of which in my thought I thing that I can think of which in my thought I cannot easily divide into parts; and this very fact cannot easily divide into parts; and this very fact makes me understand that it is divisible.” (86)makes me understand that it is divisible.” (86)

Descartes and DualismDescartes and Dualism

According to Dualism, what is responsible According to Dualism, what is responsible for thinking and consciousness is not the for thinking and consciousness is not the brainbrain (which takes up space and is (which takes up space and is physical) but rather the physical) but rather the mindmind, which is not , which is not physical. The (physical) brain is closely physical. The (physical) brain is closely connected with the (nonphysical) mind, but connected with the (nonphysical) mind, but they are still different things.they are still different things.

Descartes and DualismDescartes and Dualism According to Descartes, the According to Descartes, the

eyes perceive objects and eyes perceive objects and then focus the image on a then focus the image on a central part of the brain. central part of the brain. This part of the brain then This part of the brain then “transmits” the information to “transmits” the information to the non-physical mind. The the non-physical mind. The mind may then transmit mind may then transmit back a signal telling the back a signal telling the brain and body how to move brain and body how to move or act.or act.

Descartes and DualismDescartes and Dualism

Descartes thought this “transmission” of Descartes thought this “transmission” of information from the physical brain to the information from the physical brain to the non-physical mind and vice-versa worked non-physical mind and vice-versa worked through the through the pineal glandpineal gland, a central part of , a central part of our brains. our brains.

We now know that the pineal gland helps We now know that the pineal gland helps to regulate hormones in the brain as a to regulate hormones in the brain as a whole.whole.

Descartes vs. Modern Science: Descartes vs. Modern Science: Dualism vs. PhysicalismDualism vs. Physicalism

Does Descartes’ story Does Descartes’ story about the link about the link between the physical between the physical and the non-physical and the non-physical make sense?make sense?

Does it involve a Does it involve a “miracle” that we can’t “miracle” that we can’t explain scientifically?explain scientifically?

Descartes vs. Modern Science: Descartes vs. Modern Science: Dualism vs. PhysicalismDualism vs. Physicalism

Some philosophers have described the view of Some philosophers have described the view of modern science as “physicalism.” According to modern science as “physicalism.” According to physicalism, everything that exists and that we physicalism, everything that exists and that we are made up of is ultimately are made up of is ultimately physicalphysical or or material. There is the physical body, and the material. There is the physical body, and the brain, but there is no additional non-physical brain, but there is no additional non-physical mind or soul. mind or soul.

If physicalism is true, then all our thought, If physicalism is true, then all our thought, consciousness, and behavior can be explained consciousness, and behavior can be explained in terms of the brain and nervous system. All in terms of the brain and nervous system. All that we are is our bodies and our brains.that we are is our bodies and our brains.

Gilbert Ryle: “Descartes’ Myth”Gilbert Ryle: “Descartes’ Myth” Ryle (1900-1976) paid Ryle (1900-1976) paid

attention to the attention to the languagelanguage that we use in that we use in describing our own describing our own mental states and mental states and events.events.

In his most famous In his most famous book, book, The Concept of The Concept of MindMind, he argued that , he argued that Descartes’ dualism is Descartes’ dualism is wrong and confused.wrong and confused.

Ryle vs. the “Official Doctrine”Ryle vs. the “Official Doctrine”

According to Ryle, Descartes formulated a According to Ryle, Descartes formulated a dualistic picture of mind that has become the dualistic picture of mind that has become the “official doctrine.” According to this doctrine:“official doctrine.” According to this doctrine: ““With the doubtful exceptions of idiots and infants in With the doubtful exceptions of idiots and infants in

arms every human being has both a body and a mind. arms every human being has both a body and a mind. Some would prefer to say that every human being is Some would prefer to say that every human being is both a body and a mind. His body and his mind are both a body and a mind. His body and his mind are ordinarily harnessed together, but after the death of ordinarily harnessed together, but after the death of the body his mind may continue to exist and function.” the body his mind may continue to exist and function.” (p. 32) (p. 32)

The Ghost in the MachineThe Ghost in the Machine

Ryle also called the “official Ryle also called the “official doctrine” of dualism the doctrine” of dualism the doctrine of the “Ghost in the doctrine of the “Ghost in the Machine.” It treats human Machine.” It treats human beings as if they consist of beings as if they consist of two parts: a mechanical body two parts: a mechanical body (that is essentially a (that is essentially a machine) and a “spiritual” machine) and a “spiritual” mind that has no physical mind that has no physical existence (and so is like a existence (and so is like a “ghost”).“ghost”).

Problems with dualism: Problems with dualism: Other MindsOther Minds

If dualism is true, then each person’s inner If dualism is true, then each person’s inner mental life is mental life is privateprivate -- known only to them. -- known only to them.

If that’s the case, then how can I know that If that’s the case, then how can I know that anyone else (besides myself) has a mind at all? anyone else (besides myself) has a mind at all?

““Yet [dualism] presupposed that one person Yet [dualism] presupposed that one person could in principle never recognize the difference could in principle never recognize the difference between the rational and irrational utterances between the rational and irrational utterances issuing from other bodies, since he could never issuing from other bodies, since he could never get access to the postulated immaterial causes get access to the postulated immaterial causes of some of the utterances. Save for the doubtful of some of the utterances. Save for the doubtful exception of himself, he could never tell the exception of himself, he could never tell the difference between a man and a robot.” (p. 37)difference between a man and a robot.” (p. 37)

Ryle: Dualism is a Ryle: Dualism is a ‘category mistake’‘category mistake’

According to Ryle, sometimes According to Ryle, sometimes our ideas arise from a certain our ideas arise from a certain kind of mistake, what he called kind of mistake, what he called a “category mistake”a “category mistake”

We would make such a We would make such a mistake if, having seen a mistake if, having seen a soccer match and all of the soccer match and all of the different players, we ask to different players, we ask to see the “team spirit”see the “team spirit”

Ryle and category mistakesRyle and category mistakes

We make a We make a category mistakecategory mistake whenever we whenever we describe things that are actually on two different describe things that are actually on two different logical levels as if they were on the same level, logical levels as if they were on the same level, and interacted with each other.and interacted with each other.

For Ryle, ‘the mind’ is just a way of describing For Ryle, ‘the mind’ is just a way of describing the things that the person does (just as ‘team the things that the person does (just as ‘team spirit’ is just a way of describing the things that spirit’ is just a way of describing the things that the team does). Descartes’ mistake is to think of the team does). Descartes’ mistake is to think of it as a it as a thingthing that exists on the same level as the that exists on the same level as the body and interacts with it. body and interacts with it.

Carnap: Carnap: “Psychology in Physical Language”“Psychology in Physical Language”

Carnap (1891-1970) was a Carnap (1891-1970) was a dedicated physicalist who dedicated physicalist who believed that everything in believed that everything in the world is physical the world is physical

He argues that we can take He argues that we can take anyany sentence that seems to sentence that seems to describe a mental describe a mental experience or event and experience or event and rewrite it in a completely rewrite it in a completely physicalphysical language. language.

Carnap and Logical BehaviorismCarnap and Logical Behaviorism Logical BehaviorismLogical Behaviorism is the view that is the view that

when we talk about “the mind,” we are when we talk about “the mind,” we are really just talking about the behavior of the really just talking about the behavior of the body (and hence about something that we body (and hence about something that we can describe completely in physical terms.can describe completely in physical terms.

For instance, we might translate, “Abner is For instance, we might translate, “Abner is angry” as: “Abner’s face is red; his fist is angry” as: “Abner’s face is red; his fist is shaking; and he is yelling.”shaking; and he is yelling.”

How might we translate other “mentalistic” How might we translate other “mentalistic” sentences?sentences?

Logical Behaviorism: objectionsLogical Behaviorism: objections

Logical behaviorism seems plausible for Logical behaviorism seems plausible for mental states that are always closely mental states that are always closely connected to behavior. But what about my connected to behavior. But what about my mental state of mental state of thinking about the thinking about the weekendweekend or or dreaming of a better futuredreaming of a better future??

It seems clear that sometimes our It seems clear that sometimes our behavior does not manifest our true behavior does not manifest our true mental states: for instance we may be mental states: for instance we may be acting, or covering up how we truly feel.acting, or covering up how we truly feel.

Logical behaviorism: dispositionsLogical behaviorism: dispositions

According to Carnap, at least some mental According to Carnap, at least some mental states are actually not actual behaviors but states are actually not actual behaviors but rather rather dispositions to behavedispositions to behave. To say that I am . To say that I am thinking about the futurethinking about the future is just to say that I is just to say that I would say “yes” would say “yes” ifif I were asked whether I was I were asked whether I was thinking about the future.thinking about the future.

Just as a glass can be “fragile” even if it is not Just as a glass can be “fragile” even if it is not actually breaking, I can be in a certain mental actually breaking, I can be in a certain mental state even if I am not actually exhibiting it right state even if I am not actually exhibiting it right now. now.

Dualism and logical behaviorism: Dualism and logical behaviorism: SummarySummary

Descartes thought that mind and body were two Descartes thought that mind and body were two completely separate substances, interacting completely separate substances, interacting through the pineal gland.through the pineal gland.

Ryle criticizes this view for failing to explain our Ryle criticizes this view for failing to explain our knowledge of others’ minds and for giving an knowledge of others’ minds and for giving an implausible picture of human beings as “ghosts implausible picture of human beings as “ghosts in machines.”in machines.”

Carnap’s physicalist picture – Carnap’s physicalist picture – logical behaviorismlogical behaviorism – identifies the mind with outer, public behavior – identifies the mind with outer, public behavior and with dispositions to behave.and with dispositions to behave.