 |
Web Hosting by Netfirms | Free Domain Names by Netfirms |
|
|
|
Ever since anyone began to think about the nature of the mind (and before this people must have slept easier) there has been a debate about whether the mind is basically a physical thing or a, how shall I say this, non-physical thing. Perhaps the word should be ‘spiritual’ but that brings in too many unwanted meanings. At any rate, no one has yet solved the puzzle—if there is a solution: the mind might be a mixture of physical and ‘spiritual’ elements. In an attempt to solve the puzzle, some philosophers of mind have postulated a very grand theory that carries the humble name of Physicalism. As Frank Jackson puts it, physicalism is "the challenging thesis that it [the actual world] is entirely physical."[1] In this way, philosophers of mind hope to tie explanations of the mind to the way we explain everything else. ‘Why should the mind be different from every other thing in the universe?’ they ask. In rejoinder, I’d like to ask, why couldn’t it?
Frank Jackson isn’t satisfied with wholly physical theories of mind. He discusses a simple argument meant to show that physicalism, insofar as it claims to (someday) wholly explain mental phenomena in physical terms, is false. Allow me to give a short synopsis of his argument here. First of all, in a thought experiment he imagines a woman named Mary who lives her whole life and receives her whole education without once seeing a color. She talks to people via a black and white television, reads books which are printed in black and white and contain no color pictures. Somehow, we must also imagine, if this thought experiment is to be at all successful, that she is never given a mirror and in no way comes into contact with colored foods and never looks at her own body. We have to imagine this because the situation would be cruel enough without performing some heinous color removal operation on Mary (as if this were possible). I guess we will just have to live with the fact that she eats a plain, colorless diet. But I digress. The point is that she learns everything there is to know about "completed physics, chemistry, and neurophysiology, and all there is to know about the causal and relational facts consequent upon all this, including of course functional roles."[2] Even though she knows all this, upon her triumphal release from this odd philosophical prison she "will learn what it is like to see red"[3] (for example) and this will rightly be called learning. And since Mary already knew everything there was to know about the physics and physiology of seeing color, the fact that she learns something upon finally seeing a color shows that physicalism is false.
Now before I jump all over this with criticism I’d like to make sure that I haven’t forgotten something. Jackson makes "Three Clarifications" about the knowledge argument and we should consider them too. His first clarification is very simple. It’s not a matter of Mary being unable to imagine colors; she just doesn’t know what it’s like to see something colored. Mary’s powers of imagination are not in question here. The point is that whether she can imagine seeing red or not, she does not know what it looks like to see it with her own eyes. The second clarification is that Mary could not have found out what it was like to see red by making logical inferences. She is supposed to already know all it is possible to know in that manner and when she does see red this knowledge of what it is like to see red is different from the knowledge she has from logical inferences. Thirdly, Jackson explains that what Mary learns is not something about herself, namely that she can see colors. What she learns is what the experience of others is like. "All along their experiences (or many of them, those got from tomatoes, the sky,…) had a feature conspicuous to them but until now hidden from her (in fact, not in logic)."[4] And since she already knew all the physical facts there are to know, the fact that she learns something in addition to all that she already knows poses a problem for physicalism. That is that there are facts that are not accounted for in the physicalist account.
Fortunately we the skeptics are provided with three objections right in Jackson’s text. He attempts to show that none of them is adequate to the task of demonstrating a flaw in his argument. But we shall see about that. All three of the objections come from Paul M. Churchland and the first objection concerns, apparently, a misformulation of the knowledge argument which emphasizes an apparent but deceptive equivocation of the sense of "knows about". That isn’t really that interesting. What interests us is Jackson’s schematization of the knowledge argument as he formulates it. He asserts that the main thrust of the argument is that there are facts about brain states and their properties which Mary doesn’t know even though she knows the entire physical story. How she knows something isn’t that important, it’s what she knows that’s important. She learns what the experience of others is like. The truth that Mary becomes acquainted with in learning what the experience of others is like, Jackson claims, is not accounted for in the physicalist story.
Let me restate Jackson’s short formulation of the knowledge argument.
(1) Mary (before her release) knows everything physical there is to know about other people.
(2) Mary (before her release) does not know everything there is to know about other people (because she learns something about them on her release).
Therefore
(3) There are truths about other people (and herself) which escape the physicalist story.
But the nature of these truths is as yet unclear. Does Mary gain an ability upon her release that was contingent on the mere availability of colorful items, or does she learn something else? Jackson contends that what Mary learns concerns the subjective experience of others. Through her experience of seeing color, she comes to realize what it’s like when other people see color (and presumably experience other qualia, though Jackson does not say this). In making the case that Mary gains not just abilities upon her release but also factual knowledge, Jackson explains that Mary might wonder for a moment about whether she knows what others’ experiences are like or not. She doesn’t cut skepticism any slack though and she decides that she does know what others experience when they see the color red.
But isn’t this just the point? Mary knows all the physical facts about human beings, including how the brain and nervous system functions, what effects light waves of varying frequencies have on the light sensitive cells in the eye, and what labels different sets of wavelengths have. (That is, Mary knows that from so-and-so many angstroms to so-and-so many, the light is called ‘red’ when perceived by humans). We presume that she knows all the ins and outs, all the complexities involved and that no logical consequences escape her. So what stops us from saying that there is a physical description of what we call the subjective experience of the color red? What stops us is the fact that Mary doesn’t know ‘what it’s like’ to see red even though she knows everything about what happens when she (or anyone else) sees red.
But this fact is far from fully established. Jackson never claims that the knowledge argument demonstrates that physicalism is false. His "claim is that the knowledge argument is a valid argument from highly plausible, though admittedly not demonstrable, premises to the conclusion that physicalism is false."[5] That is, if you could be sure that Mary really would learn something upon being released from her cruel prison, then you would have the demonstration that physicalism is false that some of us desire and that some of us fear. (Now how should everything be explained?!) And since Jackson doesn’t try to come up with a demonstration of this crucial point, I’m going to try to outline what way (if any) is open to someone who will demonstrate that Mary learns something about the experience of others when she is released.
In order to do this we must know whether we should distinguish between ‘what an experience of something is like’ and ‘what happens when we experience something’. ‘What something is like’ might be just a phrase of reference for the experience one has when a given series of physical events occur. Or it might be something separate from the series of physical events. In the former case, the two phrases in question have identical meanings and should not be distinguished from one another. In the latter case we must postulate some kind of dualism wherein mind is something different from body and we have all the problems of how the mind and body can interact at all when they are really two different kinds of things.
Perhaps we can still avoid postulating dualism at all in supposing some experiences to be non-physical in nature. There could be some non-physical event that occurs that is the real essence of our subjective experiences but the problem is that there is no physical way to verify this! As far as we know mental events are physical events. If they are something else then this remains (and will always remain) to be discovered. It is forever beyond discovery because subjective events are beyond the reach of science. Science deals with concepts in its descriptions of phenomena and subjective feelings are things that cannot be described by rational concepts. So there is no possible confirmation for Jackson’s contentious premise that Mary learns something upon her release from the colorless cave. Sure she finds out what it is like for she herself to see red but that has no bearing on whether the physical description she had of seeing color was the whole story or not.
This is because although knowing a physical process doesn’t mean you know what it’s like to be a part of that process, not knowing what it’s like to take part doesn’t mean that you don’t know what that process is like. What it’s like to see red is what it’s like to undergo the physical process that happens when a person perceives a red thing. Just because Mary has never been a subject of this experience doesn’t mean that she doesn’t have a correct and complete description of how the process works. When you consider it carefully, it is self-evident that the description of a thing—no matter how accurate—is not identical with the thing itself. Reading the dictionary definition of a train is not the same as seeing one, hearing one, riding on one, or feeling the vibrations of its passage. In a sense you learn something when you finally have the privilege of riding a real train. You learn that the definition you had was right (or slightly wrong as the case may be).
In Mary’s case she knows the most perfect and accurate description of sensory perception that we can conceive of. Don’t forget: she knows completed physics. No physical event is beyond her ability to describe. So with her complete description of the sensory perception of the color red, she can tell you what happens when anyone sees it, including herself when she finally escapes. The fact that her description is not identical with actually perceiving color is obvious.
But the importance of this fact is negligible. Say for a moment that it is possible to render a perfect and accurate picture of what the so-called quale of red is. So in addition to the physical description of what happens when a person perceives red we have a description of what the experience is like. This description too would be distinct from the experience itself! And so we would need a further description and yet another and so on. All the knowledge argument shows is that no description is identical with the object of description, no matter how perfect the description. It doesn’t pose a problem for physicalism at all. That is unless physicalism can’t account for the apparent incorporeality of descriptions.
Churchland’s other two objections are spurious and won’t be discussed here. Instead I’d like to emphasize my own unsupported opinions about the nature of the mind as regards whether it is a strictly physical thing or not. For instance, I think that there is no good argument for the existence of incorporeal elements in the functioning of the mind but at the same time I am more than willing to entertain the idea that there are such elements. As I said above, subjective experiences are not possible to put in terms of rational concepts. So the failure of rational concepts to describe them does not surprise me and I do not expect argumentation or experimentation to ferret out the whole truth about the non-physical aspects of our minds. If there are such things then our conceptual tools will forever be inadequate to the task of describing them. So Jackson is hardly to be blamed for his failure to fully demonstrate an inadequacy in physicalism.
Notes:
[1]: from "What Mary Didn’t Know" by Frank Jackson, anthologized in The Nature of Mind edited by David M. Rosenthal, pg. 392 back