Transcript Lecture 11: Philosophical Issues December 10, 1999

Philosophy of Mind
I. Introduction
II. Ontological Issues
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I. Introduction
The philosophy of mind: Attempts to answer the
questions like:
- Does the mind exist?
- What is the nature of the mind?
- How is the mind related to the body (i.e., brain)?
- Can a machine have a mind?
- How can a mind emerge from purely physical processes (i.e.,
mind-body problem)?
- What is the relation between conscious awareness (mind)
and neuronal activity in the brain (body)?
- How exactly do neurobiological processes in the brain give
rise to consciousness?
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Some Observations about Mind
1. The mind is mental (vs. physical) in nature,
encompassing a variety of mental phenomenon such as
Sensation, Perception, Feeling, Emotion,
Thinking, Pain, Dreams, Love, …
2. These mental states are subjective and private:
They cannot be witnessed by other observers (e.g., color
perception)
- Does a surface-to-air missile have mental states?
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(e.g.,) Color Perception
Imagine two persons who have same experiences of the
world but with different colors:
Alice’s world
Mike’s world
Red
<==> Green
Green
<==> Blue
Blue
<==> Red
Can this difference be discovered by observing their
behaviors and brain states?
 The difference may lie only in the quality of their visual
experiences, but not in any physically and behavioral
identifiable ways.
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Qualia
 Philosopher’s term for the introspectively accessible,
distinctively subjective experiences of mental states.
(e.g.)
- Perceptual experience (seeing red, hearing music, smelling the
sea air)
- Bodily sensations (pains, feeling itchy)
 Not all mental states possess qualia:
- Experience of suddenly understanding of a math problem
 Hotly debated, hypothetical construct that is nonphysical
- Are qualia irreducible (i.e., intrinsic qualities of their bearers)?
- How do qualia relate themselves to the world outside?
(this is the mind-body problem)
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3. An infinite recursion problem
Is it possible or even allowed for one mind to study
and understand another?
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The mind-body problem is a “hard” problem:
Ill-defined?
Unanswerable?
Forever unknowable?
Asking a wrong question?
Not a single problem but multiple problems?
Language/ definition?
Too sacred to attempt to answer?
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II. Ontological Issues
The ontology of mind is the study of the nature of mental
states and their relation to physical states.
Theories of the Mind:
1. Materialism (only matter exists)
2. Immaterialism/Idealism (only mind/ideas exists)
3. Dualism (both mind and matter exist)
4. Functionalism (neither matters but functions)
(Note: What follows is based on the Stanford Encyclopedia of Philosophy
(http://plato.stanford.edu/entires))
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1. Materialism
 Nothing exists but matter. Mental states are nothing but
sophisticated states of the brain (physical system), and
thus can be reduced to bio-physico-chemical
phenomenon.
- Pattern of neural firings defines mental state
- Reductionism in neuroscience
Counterarguments:
- How can we account for qualia (seeing red, feeling
happy/angry), thoughts, desires, intentions, expectations,
beliefs…?
- What else??
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2. Immaterialism/Idealism (Berkeley)
 Everything that exists is mental, and there is no such
things as the material. No material things exist.
 The world (self and surrounds) is nothing but a pure
creation of the mind. Reality, as we know it, consists
wholly of minds and their ideas. No mind, no reality.
 Material things are nothing but collections of “ideas”
 “Esse est persipi aut percipere.”
(To be is to be perceived or to perceive)
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 Do not deny the existence of what “appears” to be the world around
us such as trees, buildings, people, sky,… According to Berkeley,
however, what such objects turn out to be are no more than bundles
or collection of ideas, all created in the bearer’s mind or
“consciousness”.
 Observer-dependent reality in Buddhistic psychology:
“Seeds and plants, beams and structurally intact roofs – none of them are entities with
permanent, totally independent existence [outside the mind]… In the absence of
human beings, reality as human beings perceive it would cease to be.”
(M. Ricard, The Monk and the Philosopher, 1998)
 Quantum Physics and Reality:
What is the sound of a tree falling deep in the woods when no one is around to hear it?
(R. Pine, Science and the Human Prospect, 1988)
“What we observe is not nature itself, but nature exposed to our method of questioning.”
(W. Heisenberg)
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3. Dualism (Pluto, Decartes)
 Mind and matter/body are two completely different kinds
of substances, each capable of existing independently of
the other and one being causally linked to the other.
 Mental states are not reducible to physical states.
- Sensation of pain (mind) vs physical object that caused the pain
(matter/body)
 The question that arises naturally is then:
-How is the mind related to the body? (mind-body problem)
Counterarguments??
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4. Functionalism
 A mental state is nothing but physical sates described
“functionally.”
 A mental state is defined by the function it serves or
performs, and is characterized in terms of its role in
relating inputs to outputs and its relations to other
mental states, nothing more and nothing less.
(e.g.) Feeling pain (mental state):
(1) Input: injury/trauma to body
(2) Causal relation: produce the belief that something is wrong
with the body and the desire to be out of that state
(3] output: moaning or wincing
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 Multiple realizability of functionalism:
According to the functionalistic view, any other physical system
that undergoes the same causal sequence as above can be
characterized as a mental state of “feeling pain.”
- DNA solving Hamiltonian path problem vs PC solving the same
problem
- Software-vs-hardware analogy
- Neither materialism nor dualism
- No mind-body problem
- Popular view in cognitive science
Counterarguments:
- Color perception (sense of red vs green)
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Discussion of the Paper “Where Am I?” by D C Dennett
Hamlet
Fortinbras
Yorick
UAV
Hubert
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