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?
Jackson is a Materialist In this essay, Jackson is a materialist-- Dualism isn t really a live option for him. But he rejects a popular version of materialism that he calls physicalism. Physicalism agrees with materialism that the only substance is matter. But it also says something stronger, namely that the world can in principle be explained using only the language of physics. Jackson s own view is known as epiphenomenalism.
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 after-image. 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 smells 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. Jackson accepts this. His goal is to reject this.
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; that is, 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 material (this is what materialism claims and dualism denies); and 2) everything can, in principle, be fully described and explained by physical theories. The existence of qualia, Jackson argues, conflicts with 2), but not with 1). That is, rejecting 2) doesn t necessarily force us to accept substance dualism.
Analysis
Jackson: Dualism is not the only alternative to Physicalism Jackson thinks that physicalism is false but does not because of this 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?
Epiphenomenalism
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 byproduct of the material activities of the brain and nerve-system. [Oxford English Dictionary]
Epiphenomenalism: Definitions: Epiphenomenalism is the view that mental events [such as having qualia] 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 [what it s like to be conscious] 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.
P h y s. S t I m u l i Dualism vs. Epiphenomenalism Mental State B e h a v. R e s p o n s e
Mental States and Causality
So, Epiphenomenalism says that qualia (e.g., what red looks like to us) are caused by events in the physical world; i.e., it s real (we really have such experiences), but do not themselves cause changes in the physical world; i.e., even though conscious states are caused by the material world, what it s like to be conscious doesn t have any effect whatsoever in the world.
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 material, This is simply what materialism claims. 2) everything can, in principle, be fully described and explained by physical theories. This is what makes physicalism more than mere materialism. For Jackson, the existence of qualia is incompatible with 2), but not incompatible with 1). We don t really know what qualia are. So, epiphenomenalism does not imply substance dualism. For Jackson, the existence of qualia proves that there are facts that aren t facts about physics, but it doesn t prove that there is any substance other than material substance.