Review
Dualism vs. Materialism
Dualism:
•  There are two fundamental,
distinct kinds of
“substance,”
–  Matter: the “stuff” the
material world is composed
of; and
–  Mind: the “stuff” that that has
mental awareness, the kind of
thing that can be the subject of
conscious experience.
Materialism:
•  There is one fundamental
kind of substance:
–  Matter: the “stuff” the
material world is composed
of.
–  There is no other basic kind of
stuff. Everything that exists
is, in the final analysis,
composed of matter (i.e.,
atoms, etc.)
Metaphysical, yet Personal
•  Dualism and Materialism are different
metaphysical positions.
–  They make different claims about the fundamental
nature of reality.
•  But the debate arises from a highly personal
question:
–  What is it to be me?
–  What kind of thing am I, as a conscious being?
“The Qualia Problem”
Frank Jackson
The Question
“I am what is sometimes known
as a ‘qualia freak’.”
(OK, you’re a freak! But…)
What in the world are qualia?
Quale
•  The “felt quality” of a conscious experience.
–  “Quale” is singular, “Qualia” is plural.
•  There is something that “it’s like” to be
conscious, to have a sensation, to see an afterimage.
•  “Qualia” is a word introduced to help us talk
about what “it’s like” to be conscious.
What are qualia?
•  “… the hurtfulness of pains, the itchiness of
itches, pangs of jealousy, … the characteristic
experience of tasting a lemon, smelling a rose,
hearing a loud noise, or seeing the sky.”
•  The “raw-feels” of conscious experience:
–  What it’s (consciously) like to feel pain, see a
color, smell a rose, hear a sound, etc.
Quale, Anyone?
•  Conscious experience “from the inside.”
•  Each person has their own awareness of
what their own consciousness “feels
like” (what a rose like to them, what green
looks like to them, etc.), but no direct
experience regarding anyone else.
•  Qualia are necessarily subjective, and so,
what they are like cannot be captured by any
objective description.
The Position
Jackson’s claim:
•  1) The existence of qualia is incompatible with
the truth of physicalism.
•  2) But qualia exist.
•  3) So, physicalism must be false.
•  Terminology:
–  Jackson uses “physicalism” to describe a specific
version of materialism.
What is physicalism?
•  “The theory that all information [truth] is ultimately
physical information [truth]—information [truth]
about physical states and physical events, couched
exclusively in physical terms.”
•  I.e., the view that …
–  1) everything that exists is physical (material)
•  (this is simply what materialism says) , and that
–  2) everything can, in principle, be fully described and
explained by physical (material) theories.
•  I.e., a “completed” physics could explain everything.
Physicalism vs. Materialism
•  As Jackson uses these terms:
–  Materialism—The metaphysical claim that the
only fundamental substance is matter.
•  Materialism involves a rejection of dualism.
–  Physicalism—The above plus the claim that
everything can (in principle) be explained by the
laws of physics.
•  So, for Jackson, physicalism is a specific version of
materialism.
Jackson’s View
•  The way Jackson uses these terms,
“physicalism” says something more than
“materialism.”
–  “Physicalism” = “Materialism” + “every fact is
a physical fact; every truth is a truth of
physics.”
•  This is important because Jackson will
accept materialism but reject physicalism.
The Argument
Jackson’s Argument:
•  1) The existence of qualia is incompatible with the
truth of physicalism.
•  2) But qualia exist.
•  3) So, physicalism must be false.
•  Jackson thinks …
–  2) is known by experience to be true. (We all know that
there is something that it is like to be conscious.);
–  but 1) must be argued for (which he is about to do), in
which case, 3) will follow.
The knowledge argument for qualia:
•  1) Suppose that one knew everything there is to know
about the make-up of the physical world and the
physical theories explaining it.
•  2) One would still not (in virtue of this knowledge)
know what it was like to feel pain, smell a rose, etc.
•  3) “Therefore, knowing all this is not knowing
everything …. There is something that physicalism
leaves out.”
The Argument:
An Illustration
Fred’s color experience:
•  Suppose that Fred sees two shades of red that no one
else can differentiate (i.e., both shades “look the
same” to everyone else).
–  He can consistently discriminate the two different colors.
–  He tells us that they “look” (to him) very different.
•  Suppose we know everything there is to know about
Fred’s brain and eyes.
•  Even so, this would not allow us to know what “the
other red” looks like.
Fred’s color experience (cont.)
•  Suppose that we all have operations to make our
brain and eyes work just like Fred’s.
•  After the operation, we will see the two shades of
red, and know what the “other shade” looks like.
•  So, we will then know something new, something
that we didn’t know before the operation, even
though we knew everything there was to know
about the operation of Fred’s brain.
The Conclusion
Jackson’s conclusion:
•  “ … one can have all the physical information without
[thereby] having all the information there is to
have” (without, that is, knowing what it feels like to have a
given experience).
•  Physicalism says that everything can be explained in terms of
physical explanations.
•  But, we have just shown that we can know all the physical
explanations there are to know without knowing everything,
i.e., without knowing what qualia are like.
•  So, the existence of qualia proves that physicalism must be
false.
Qualia vs. Physicalism:
•  Physicalism:
–  1) everything that exists is physical (material);
and
–  2) everything can, in principle, be fully
described and explained by physical (material)
theories.
•  The existence of qualia, Jackson argues,
conflicts with 2), but not necessarily with 1).
–  That is, rejecting 2) doesn’t necessarily imply
substance dualism.
Analysis
Jackson: Dualism is not the only
alternative to Physicalism
•  Jackson thinks that physicalism is false
– but does not therefore infer that substance
dualism must be true.
•  That is, he rejects physicalism but does not
reject materialism.
•  So, what is the alternative?
–  How can he accept materialism and deny
physicalism?
“The Bogey of Epiphenomenalism”
•  Epiphenomenalism: “ … the idea that qualia are
causally impotent with respect to the physical world.”
–  i.e., the view that even though qualia exist and are caused
by events in the physical world
•  (e.g., the way the world interacts with our sense organs and central
nervous system),
–  qualia do not themselves cause changes in the physical
world
•  (i.e., they are “causally impotent” with respect to it).
Definitions:
•  Epiphenomenon:
–  a phenomenon that occurs with and seems to result
from another but has no reciprocal effect or
subsequent influence;
•  A causally inert byproduct.
–  Applied to consciousness regarded as a by-product
of the material activities of the brain and nervesystem. [Oxford English Dictionary]
Definitions:
•  Epiphenomenalism:
–  Epiphenomenalism is the view that mental events are
caused by physical events in the brain, but have no
effects upon any physical events. Behavior is caused
by muscles that contract upon receiving neural
impulses, and neural impulses are generated by input
from other neurons or from sense organs. On the
epiphenomenalist view, mental events play no causal
role in this process. [Stanford Encyclopedia of Phil.]
Epiphenomenalism
•  There is something “it’s like” to be conscious, to
feel pleasure or pain; something that it feels like
to be happy or sad, etc.
•  But none of this has any causal impact on the
world.
•  That is, nothing would be any different if we
were all “zombies,” if we had no “inner life.”
•  So, yes, we have an “inner life,” but this has no
effect on anything.
Dualism vs. Epiphenomenalism
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Mental State
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Mental States and Causality
So, Epiphenomenalism says that what red
looks like (to us) …
•  … is caused by events in the physical world;
–  i.e., its real (we really have such experiences), but
•  … does not itself cause changes in the physical
world;
–  i.e., it is not a necessary part of any theory or
explanation of what goes on the physical world,
including human behavior.
An Objection Rebutted
Qualia are an excrescence*:
“They do nothing, they explain nothing…”
•  “This is perfectly true, but no objection to
qualia….”
–  “ … it rests on an overly optimistic view” of
what human beings can know.
•  I.e., just because we can’t explain them, this
doesn’t mean that they don’t exist.
•  *excrescence: 1. The action of growing out or forth.
Also, immoderate growth, overflow, abnormal
increase. [Oxford English Dictionary]
Summary
Qualia and Physicalism:
•  Physicalism:
–  1) everything that exists is physical (material),
–  2) everything can, in principle, be fully described and explained by
physical (material) theories.
•  For Jackson, the existence of qualia is …
–  incompatible with 2), but
–  not necessarily incompatible with 1).
•  We don’t really know what qualia “are.”
•  So, epiphenomenalism (i.e., qualia exist, but are causally impotent)
doesn’t necessarily entail substance dualism, i.e., there is something that
physicalism can’t explain, but that doesn’t necessarily mean there is a nonphysical substance—
–  Maybe, there are non-physical properties (a.k.a property dualism).