PHIL 255: Philosophy of Mind, Week 6

Announcements (corrected Oct. 18):

Thursday, Oct. 27: The exam will be written in other classrooms:

Surnames A-P: HH 336.

Surnames R-Z: HH 123..

6a, Consciousness

Review of metaphysical positions

What is reality?

1. Idealism: reality is mental.

2. Dualism: reality is mental and material; a person is a mind and a body.

3. Materialism: reality is matter and energy; minds are material.

Versions of materialism

1. Behaviorism.

We should not talk about minds and mental states, only about observed behavior.

2. Identity theory:

A mind is a brain. A mental state (e.g. a belief) is a brain state. A mental change is a brain process.

3. Functionalism:

A mind is some kind of material state, not necessarily the brain. A belief is a functional state. Mind supervenes on matter.

4. Eliminativism:

Minds are material, but we should not try to explain minds, since folk psychology is false. There are no beliefs.

Eliminative materialism

Folk psychology

In everyday life we explain people's actions on the basis of their beliefs and desires. E.g. Fred went to the diner because he was hungry and believed that the diner has good food.

Paul Churchland claims that folk psychology is a theory, i.e. a set of explanatory hypotheses that might be false.

What is the relation between folk and scientific psychology?

1. Identity theory: folk theory reduces to neuropsychology.

2. Dualism: no reduction is possible; folk psychology is about what souls do.

3. Functionalist: no reduction, because of multiple realizability.

4. Eliminativism: no reduction, because folk psychology is false, like folk theories in physics, biology, and medicine.

What is wrong with folk psychology?

1. It fails to explain much of thinking, e.g. mental illness, creativity, etc. + Learning.

2. It has not progressed, unlike science.

3. Folk psychology is isolated from scientific explanations.

Reply: Much of folk psychology may be approximately true, e.g. talk of beliefs, desires, emotions.

So folk psychology should be revised, not eliminated.

Summary: how materialists deal with major objections

   Intentionality  Freedom  Morality  Consciousness
 Behaviorism  deny  deny  deny or social  deny
 Identity theory  causal  deny or redefine  social  brain process
 Functionalism  causal  deny or redefine  social  physical process of different kinds
 Eliminativism  causal  deny  social  deny or modify

What is consciousness?

John Searle's structural features of consciousness (from The Rediscovery of the Mind):

1. Finite modalities: 6 senses and stream of thought.

2. Unity: experiences are tied together.

3. Intentionality: we are conscious of things.

4. Subjective feeling: qualia (qualitative experiences)

5. "Only a being that could have conscious intentional states could have intentional states at all." p. 132.

6. Figure-ground, gestalt structure.

7. Familiarity.

8. Overflow: reference beyond immediate content.

9. Center and periphery.

10. Boundary conditions.

11. Mood.

12. Pleasure/unpleasure dimension.

Graham's 6 philosophical roles for consciousness

1. Qualitative character is an impediment to materialism.

2. Skepticism about other minds: are they conscious?

3. Causal explanations, e.g.pain causes behavior.

4. Personal identity.

5. Self-consciousness.

6. Morality

Jackson's argument vs. materialism

Nothing physical science can describe succeeds in capturing the red look of a ripe tomato. So, consciousness is not physical.

No matter how much science Mary knows, she doesn't understand conscious experience unless she has it.

Materialism replies:

Animal consciousness

Are animals conscious?

If they are, what are the consequences for morality?

Can we understand what it is like to be a bat? An eagle? A monkey?

Does the neurophysiology of animals suggest they have consciousness?


6b, Epiphenomenalism

Consciousness epiphenomenalism:

Qualitative experience is the causal result of physical processes, but does not causally influence physical processes.

Consciousness is real, but is an effect, not a cause.

For more notes on consciousness, see weeks 8-13 of the 2000 version of this course.



Phil 255

Computational Epistemology Laboratory.

Paul Thagard

This page updated October 18, 2005