PHI 101 Lecture Notes - Lecture 8: Saul Kripke, Type Physicalism, Mental Substance
13 Jan 2017
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Department
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Philosophy of Mind
1. Main Question: Is the Mind Identical to the Brain?
2. The Mind/Body Problems
a. Two ways to solve the mind/body problem
i. Dualism: the mind is distinct from the brain
1. The mind is mental substance
2. The brain is a physical substance
b. Physicalism: the mind is identical to the brain
i. The mind and the brain have exactly the same properties—there is no
property that the mind has the brain lacks
c. Dualism
i. Two ontological categories
1. Physical
2. Mental
ii. Rely on Liebniz’s Law
1. If a and b are identical, they have exactly the same properties:
there is no property belonging to a that does not belong to b
iii. If the mind and the brain are identical, they have to have all the same
properties
iv. Descartes’ First Argument: Indubitable Existence Argument
1. You can doubt that you have a body but you can’t doubt that you
have a mind
2. The mind has the property of indubitable existence
3. The mind is not identical to the brain
v. Objection:
1. Consider Lois Lane wants to marry Superman but not Clark Kent.
Clark Kent and Superman are not the same
a. Premises are true, conclusions are false
2. The fact that Lois Lane dsires one of these propositions to be true
and the other false does not show that Superman and Clark Kent
have different properties, or that Superman is not the same as Clark
Kent.
3. The propositions are different but the people are identical
a. Just because you have two different attitudes toward the
propositions does not mean that the entities have different
properties
4. You can have different propositional attidues towards the idea that
you have a mind and the idea that you have a brain. This does not
mean that the mind and the brain are not the same thing
vi. To say that my mind indubitably exists is just to say that I can doubt this
proposition
d. The Extension Argument for Dualism
i. The brain has the property of extension. The mind is not extended in space
and therefore does not have the property of extension. The mind and the
brain are not identical.
ii. This argument is circular.
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e. The Divisiblity Argument for Dualism
i. The brain is divisible but the mind is not. The mind and the brain are not
identical.
ii. You are just assuming that the mind is not divisible, so it is circular.
f. If the mind cannot be divided and does not have extension, then dualism does
indeed exist, but it is hard to say.
g. causality between the physical and nonphysical
i. how can we explain mental events that cause physical events
3. Physicalism
a. The mind is numerically identical to the brain.
i. It follows that every mental state is numerically identical to a brain state
ii. “numerically”- invoking Liebinz’s law
1. If a and b are identical, they have all their properties in common.
There is no property that a has that b lacks
b. The identity theory
i. A posteriori claim
1. The relationship between the brain and the body is something that
science discovers by observation and experiment
ii. Mind-brain
1. Numerical identity between mind and brain
2. All identities are necessary
a. Water is always going to be identical to H2O
c. Materialism
i. Hold that if 2 objects are different in any way at all, they must exhibit
physical differences
d. Principle of Parsimony
i. Identity theory is more simple than dualism
e. Ockham’s Razor
i. We should favor Physicalism because it is simpler/ We should prefer
explanations that minimize the number of entities, processes, and events
they osptulate. Don’t multiply entities beyond necessity
ii. This doesn’t make it true though
f. The identity relation
i. The identity relation is a necessary relation
1. Identities hold necessarily
2. If m=b, then m is necessarily identical to the b
ii. there are no contingent identities
g. entailments
i. if the identity theory is true, it would be a posteriori and necessarily true
that the mind is identical to the brain
1. this means that in no possible world, could you find a brain
without finding a mind and vice versa
h. Saul Kripke- Naming and Necessity
i. Arguments against the identity theory: the mind is identical to the brain
1. This would be an example of a necessary and a posteriori truth
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ii. Was not working in philosophy of mind at all. He was working on
philosophy of language, but what he writes about has implications on
identity theory.
iii. Demonstrates that philosophers had been mistaken in thinking that all
necessary truths were a priori
1. Kripke says that ALL identities are necessary, whether a priori or a
posteriori
iv. Shows that there are a posteriori necessary truths
1. Water is identical to H2O
v. A posteriori identities
1. Identities that are discovered through empirical observation are a
posteriori
2. When we start to think about the identity relation it becomes
obvious that if an object is identical to itself, that relation holds in
all possible worlds
vi. Argues that a posteriori necessary truths, such as heat is equal to
molecular motion are de re, not de dicto
i. W.V.O. Quine argued that all necessities were de dicto (at the level of language)
but Kripke challenges this assumption and presents a compelling argument for
why we should accept the view that a posteriori necessities are de re, not de dicto
i. De re Necessity: the model operator has narrow scope
1. Unicorn necessarily do not exist
a. There is no possible world in which you will find a unicorn
(unicorns do not exist in all possible worlds)
2. The proposition describes the necessity that arises because of the
essential (necessary) properties of the objects considered
ii. De dicto necessity: the model operator has wide scope
1. Necessarily, unicorns do not exist
2. The proposition describes necessity at the level of language
3. There is no possible world in which the proposition, “unicorns
exist” will be true
a. The proposition is false in all possible worlds
iii. Ex: The mind is necessarily identical to the brain
1. What kind of scope does this have?
a. Narrow because Necessarily, the modal operator, is located
in the middle of the sentence and only expands to part of
the sentence
b. This is de re
c. There is no possible world in which “the mind is not
identical to the brain” is true
iv. Ex: Necessarily, the mind is identical to the brain
1. Wide scope because it is at the beginning of the sentence
2. This is de dicto
j. What this has to do with the Identity Theory
i. The identity theorist has to show that the mind and the brain are
necessarily identical
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find more resources at oneclass.com
Document Summary
The mind is not extended in space and therefore does not have the property of extension. The mind and the brain are not identical: this argument is circular, the divisiblity argument for dualism, the brain is divisible but the mind is not. No: consider the identity between cicero and tully. It is impossible to imagine a possible world in which you find cicero without finding. D-fiber stimulation is what allows us to realize pain states. This rules out pain being identical to c-fiber stimulation, because if c-fiber stimulation is identical to pain, it couldn"t have been otherwise: it seems possible for the brains to come apart in a way that cicero and. For if pains caused beliefs that one is in pain, and the latter had physical effects, then pain would have effects in the physical world. Why is physicalism incomplete: after the operation, we will know more about fred and his color experiences.
