Section 2.2 You Are What You Eat Mind as Body McGraw-Hill © 2013 McGraw-Hill Companies. All Rights Reserved.

2.2-2 Empiricism  Empiricism claims that the only source of knowledge about the external world is sense experience.  Corollaries: (1) an idea corresponds to a real object only if it is derived from or reducible to sense impressions, and (2) a term is meaningful only if it stands for a real idea.

2.2-3 Hume on Meaning  “When we entertain, therefore, any suspicion that a philosophical term is employed without any meaning…we need but enquire, from what impression is that supposed idea derived? And if it be impossible to assign any, that will confirm our suspicion.”

2.2-4 Logical Positivism  20 th century version of empiricism.  A statement is meaningful only if it can be verified by sense experience.  Verifiability theory of meaning: the meaning of a statement is its method of verification.

2.2-5 The Argument from Logical Positivism to Logical Behaviorism 1.The meaning of a statement is its method of verification. 2.The way we verify claims about mental states is by observing behavior. 3.Therefore, what we mean when we say that someone is in a mental state is that they have a behavioral disposition.

2.2-6 Logical Behaviorism  According to logical behaviorism, mental states are behavioral dispositions.  A behavioral disposition is a tendency to behave in certain ways in certain circumstances.

2.2-7 The Argument from Ordinary Language to Logical Behaviorism  Not all nouns refer to things, e.g., “waltz.”  To dance a waltz is to dance in a certain way.  Similarly, to have a mind is to behave in a certain way.

2.2-8 Thought Experiment: Ryle’s University Seeker  “A foreigner visiting Oxford or Cambridge for the first time is shown a number of colleges, libraries, etc….He then asks, “But where is the University?”  The visitor makes a category mistake in assuming that the University exists in the same way that the buildings exist.  Cartesian dualists make the same mistake in assuming that minds exist in the same way that bodies do.

2.2-9 Qualitative Content  To be in certain mental states, like pain, is to have a certain sort of feeling.  The felt quality of mental states is known as their qualitative content.

Thought Experiment: The Perfect Pretender  Imagine someone who cannot feel pain but nevertheless has learned to behave as if he or she can feel pain.  This possibility shows that having the right behavioral dispositions is not a sufficient condition for being in pain.

Thought Experiment: Putnam’s Super-Spartans  “Imagine a community of ‘super-Spartans’…They may, on occasion, admit that they feel pain, but always in pleasant, well- modulated voices…”  This possibility shows that having the right behavioral dispositions is not a necessary condition for being in pain.

Putnam’s Argument Against Behaviorism 1. If having certain behavioral dispositions were a necessary condition for being in a certain mental state, then it would be impossible to be in that state and not have those dispositions. 2. But, as the example of the super- Spartans shows, that is possible. 3. Therefore, having certain behavioral dispositions is not a necessary condition for being in a certain mental state.

Thought Experiment: Chisholm’s Expectant Nephew  Logical behaviorism claims that all talk about mental states can be translated into talk about behavioral dispositions.  Suppose Jones expects to meet his aunt at the railway station in 20 minutes.  Can this be translated into a statement that just refers to behavioral dispositions?

The Identity Theory  According to the identity theory, mental states are brain states.  It follows that anything that does not have a brain cannot have a mind.

Phineas Gage and Mind/Brain Dependency  An explosion drove a steel bar through the head of Phineas Gage.  He survived but his personality was radically different.  Thus proving that the mind is dependent on the brain.

Neurophysiological Evidence for Mind/Brain Dependency  Phylogenetic – More evolved brains have greater cognitive abilities  Developmental – More mature brains have greater cognitive abilities  Clinical – Brain damage results in loss of mental function  Experimental – Electronic stimulation of the brain produces mental events  Experiential – Chemically altering the brain results in altered states of consciousness

Identity and Indiscernability  If two things are identical, then whatever is true of one must be true of the other and vice versa.  So if mental states are identical to brain states, whatever is true of mental states must be true of brain states and vice versa.

Thought Experiment: Nagel’s Bat  “I have said that the essence of the belief that bats have experience is that there is something that it is like to be a bat.”  We can know everything there is to know about a bat’s brain without knowing what it’s like to be a bat.  So mental states cannot be identical to brain states.

Nagel’s Argument 1. If mental states were identical to brain states, then it would be possible to know everything about the mind by knowing everything there is to know about the brain. 2. But, as the example of the bat shows, that’s not possible. 3. Therefore, mental states are not brain states.

Thought Experiment: Lewis’s Pained Martian  “…there might be a Martian who sometimes feels pain, just as we do, but whose pain differs greatly from ours in its physical realization.”  This possibility shows that having a brain is not a necessary condition for being in a mental state.

Thought Experiment: Putnam’s Conscious Computer  “It must be physically possible…to produce something with the same program [as the brain] but quite a different physical or chemical constitution.”  This possibility shows that having a brain is not a necessary condition for having a mind.

Multiple Realizability  What Lewis’s and Putnam’s thought experiments show is that minds can be realized in things other than brains.  In other words, minds are “multiply realizable.”

Lewis’s and Putnam’s Arguments 1. If the identity theory were true, then it would be impossible for anything without a brain to have a mind. 2. But, as Lewis’s pained Martian and Putnam’s conscious computer show, things without brains can have minds. 3. So the identity theory is not true; having a brain is not a necessary condition for having a mind.

Thought Probe: Speciesism  Suppose you fell in love with someone who seemed to be the most intelligent, witty, and caring person you’ve ever met.  Now suppose that “person” turns out to be an android.  Would you conclude that he or she doesn’t have a mind? Would you still love him or her?

Thought Experiment: Searle’s Brain Replacement  Imagine that your brain starts deteriorating and is gradually replaced by computer chips.  There are 3 possible outcomes: (1) your mind is unaffected; (2) your mind is destroyed but your behavior is unaffected; or (3) you are paralyzed but your mind is unaffected.  (1) refutes the identity theory; (2) refutes behaviorism; (3) refutes both the identity theory and behaviorism

Thought Probe: Neural Prostheses  Suppose you had a failing brain and your only hope for survival was to have your neurons replaced by silicon chips.  Would you do it?  Suppose that those who’ve had it done report that they feel no different. Would you still do it?

Thought Experiment: Your Mother the Zombie  “Imagine…that your mother’s a zombie.” Imagine that your Mother has no conscious experience—no feelings whatsoever—but nevertheless behaves as if she does.  Would you claim that she does not have a mind?