I’ve posted a new paper considering research on neural correlates of consciousness, here.
In the paper I argue that the search for neural correlates of consciousness (NCC) is at the forefront of current scientific interest in consciousness. It is frequently asserted that the NCC project is the starting point for a science of consciousness. This is especially true for those researchers who aim to give a neurobiological theory of phenomenal consciousness—members of what I have termed the new science of consciousness. Many prominent new scientists hold that the first step in developing such a theory is to find neural activity that specifically correlates with the contents of a subject’s phenomenal consciousness. If these researchers are correct in their assessment of the importance of the NCC project, then the new science will rise or fall with the search for neural correlates of the contents of phenomenal consciousness. In this paper, I assess the empirical prospects of this research project. I challenge the claim that phenomenal consciousness exists, concluding that new scientists are erroneously trying to correlate neural activity with the contents of phenomenal consciousness. To see this, we need to begin by articulating the phenomena that new scientists are interested in (the contents of phenomenal consciousness) and the data that are collected during NCC experiments (records of the behavioral reports of subjects and measures of their neural activity). I argue that the data that are collected in these experiments are insufficient evidence to establish the reality of the hypothesized phenomena of interest. This is shown by considering two alternative interpretations of the standard NCC experiment—viz. an eliminativist interpretation and a disjunctivist interpretation.
Comments welcome and appreciated!
search for neural correlates of consciousness (NCC) is at the forefront of current scientific interest in consciousness. It is frequently asserted that the NCC project is the starting point for a science of consciousness. This is especially true for those researchers who aim to give a neurobiological theory of phenomenal consciousness—members of what I have termed the new science of consciousness. Many prominent new scientists hold that the first step in developing such a theory is to find neural activity that specifically correlates with the contents of a subject’s phenomenal consciousness.[1] If these researchers are correct in their assessment of the importance of the NCC project, then the new science will rise or fall with the search for neural correlates of the contents of phenomenal consciousness. In this paper, I assess the empirical prospects of this research project. I challenge the claim that phenomenal consciousness exists, concluding that new scientists are erroneously trying to correlate neural activity with the contents of phenomenal consciousness.
To see this, we need to begin by articulating the phenomena that new scientists are interested in (the contents of phenomenal consciousness) and the data that are collected during NCC experiments (records of the behavioral reports of subjects and measures of their neural activity). I argue that the data that are collected in these experiments are insufficient evidence to establish the reality of the hypothesized phenomena of interest. This is shown by considering two alternative interpretations of the standard NCC experiment—viz. an eliminativist interpretation and a disjunctivist interpretation.
[1] This is not the only goal that one can have in conducting research under the “NCC” label. Nonetheless, the search for neural correlates of the contents of phenomenal consciousness is arguably the most common project amongst NCC researchers and has often been considered the standard NCC project. For example, Jakob Hohwy writes (2007, 465, emphasis in the original): “The standard NCC approach is primarily interested in the neural substrate for having one rather another content represented in consciousness (e.g. a percept of a face rather than of a house).” See Chalmers (1998, 2000), Hohwy (2007), and Rees (2007) for discussions of NCC research; see also the articles collected in Metzinger (2000).
October 14, 2009 at 10:15 am |
I have read the paper and bearing in mind note 6 and I am nonetheless unhappy with note 7, as whilst I can see that you wish to avoid being oversimplistic about phenomenal consciousness I am unconvinced that your added complications clarify matters.
But you mention monkey experiments, and it is interesting to note that like humans, monkeys experience an ‘uncanny valley’ effect. http://www.sciencedaily.com/releases/2009/10/091013123353.htm etc.
November 7, 2009 at 5:38 pm |
I think this paper sees a conceptual problem where there isn’t one. Phenomenal qualities are all those qualities we experience in objects. We do not experience non-phenomenal qualities, though those qualities may have an impact on our behavior or even other phenomenally experienced qualities. When you state the skeptical position you argue, “the qualities she is acquainted with are not phenomenal qualities.” This sentence contradicts itself. We cannot be acquainted with qualities that are not phenomenal.
There is, despite your efforts, a confounding of “phenomenal” in this paper. In the first sense it is used as philosophers use it; a “what it is like”. In the second sense, it is a scientific phenomena. The problem with the paper is that it treats the first as though it were the second. The scientific phenomena being studied in these tests are not phenomenal consciousness directly. Rather, it is the correlation between the two sets of data (phenomenal consciousness on the one end and brain regions or single neurons on the other).
“It might be that Searle was claiming to have first-person data that he was acquainted with redness, for example, and was also noting that
he took that redness to be a quality of a phenomenally conscious mental state of his (although he had no first-person data to this effect)”
I am at a loss as to how you can claim that Searle would have had no first-person data to this effect. Redness is a phenomenally conscious state, period. If Searle says he saw it, and he’s not lying to us, we immediately have reason to believe he has “data to the effect that the redness was phenomenally conscious”. If he saw the redness, and there was a “what it was like” to be Searle seeing the redness, then what he saw was phenomenally conscious.
Furthermore, the disjunctivist approach is really just a verbal quibble. What one is familiar with is indeed a ripe, red tomato. But one couldn’t be familiar with it if it weren’t phenomenally conscious in the first place. It does not matter whether color exists in the world or not, or even if what we see is an illusion or not. All of these experiences are phenomenal. The question raised by disjunctivism is phrased wrong, and should be: “What are the sources of our phenomenal experience?”, not “Is our experience of the outside world, or merely phenomenal?”. The having of an experience is the very definition of phenomenal.
Claiming that phenomenal consciousness does not exist is like claiming that poems do not exist. Anyone who reads a poem knows that it exists. The question isn’t of existence but of origin and (more importantly) significance. NCC studies are more than capable of getting at both.
It’s possible I’ve really misunderstood the paper; I’d love to see your responses to these objections if you have the time.
November 8, 2009 at 10:33 am |
Hey Ross,
Happy to give responses, although I might need some clarifications from you to do so adequately!
First, let me note that I wasn’t arguing that there is a “conceptual problem”; rather, I claimed that there is an evidential problem. I defined the key concept (phenomenal consciousness) in a standard way following the philosophical and scientific literature and then asked what scientific evidence there is for the existence of this phenomenon, focusing on NCC research. Now, perhaps the issue is that you understand “phenomenal” and “phenomenal consciousness” in a different way than I do. If so, then my paper just doesn’t speak to your concerns as I am explicitly targeting a specific, standard definition of “phenomenal consciousness.” Thus, I write in the paper that “it is thought that each one of us has mental states that are phenomenally conscious in virtue of having distinctive phenomenal qualities (typically referred to as qualia) that we are at least sometimes acquainted with.” On this definition, however, it is not a conceptual truth that “the qualities she is acquainted with are not phenomenal qualities” contradicts itself. What I am concerned with is what evidence there is for thinking that the qualities that we are acquainted with are qualities of our mental states. You assert that the qualities we are acquainted with are phenomenal, but don’t provide any support for this, leading me to suspect that you might just understand “phenomenal” in a different way. (Which is fine, but not relevant to my argument.)
I don’t think that I am confounding “phenomenal” in this paper. In particular, while I agree with you that the NCC experiments at issue are looking to get a “correlation between the two sets of data (phenomenal consciousness on the one end and brain regions or single neurons on the other),” this doesn’t create a confound. As I discuss in the paper, such correlations require data about phenomenal consciousness (as follows directly from what you say); my concern is whether we have any such data.
You write that you are at a loss as to how I could claim that Searle has no first-person data to the effect that the redness that he is acquainted with is quality of a phenomenally conscious mental state of his, asserting that “redness is a phenomenally conscious state, period.” Do you mean that redness is a quality of a phenomenally conscious mental state? If not, how do you understand phenomenally conscious states? Regardless, what is the justification for this assertion? Note, that I am not denying that Searle was acquainted with redness, but asking for evidence that the quality that he was acquainted with was a quality of his mental state (that is, a phenomenal quality). That the redness he is acquainted with is a phenomenal quality is not implied by his being acquainted with it, at least not without some further argument. Perhaps, however, you simply mean something else by “phenomenal” such that it is true by definition that if Searle is acquainted with a quality that quality is phenomenal; if so, we’re talking past one another because that isn’t the understanding of “phenomenal” that I am interested in.
“What one is familiar with is indeed a ripe, red tomato. But one couldn’t be familiar with it if it weren’t phenomenally conscious in the first place.” You hold that the ripe tomato itself is phenomenally conscious? Or do you mean something like the “experience of the ripe tomato”? Assuming the latter, note that this uses “experience” in the different way than I do in the paper, treating it as a synonym for “phenomenally conscious mental state” (as suggested by your saying that “the having of an experience is the very definition of phenomenal”); but, then, this is simply begging the question and I deny that we “have experiences” in this sense. Rather, I suggest that the experience of seeing a ripe tomato is a larger event that involves not only the subject doing the seeing, but the ripe tomato being seen… and this event is not itself a mental state and hence not a phenomenally conscious mental state.
November 8, 2009 at 3:50 pm |
Thanks for replying. Your responses are helping me clarify my own thoughts on the matter.
“’it is thought that each one of us has mental states that are phenomenally conscious in virtue of having distinctive phenomenal qualities (typically referred to as qualia) that we are at least sometimes acquainted with.’ On this definition, however, it is not a conceptual truth that “the qualities she is acquainted with are not phenomenal qualities”
Do you mean it is not conceptually false? I think it is, though. What would acquaintance be, if not phenomenal?
“Do you mean that redness is a quality of a phenomenally conscious mental state?”
I say that when Searle says he sees redness, it is a quality of a phenomenally conscious mental state, yes. Whether that state is ultimately explicable in terms of a third-person account of the physical things involved (the tomato, Searle’s eyes, his brain, etc) is a different question than whether the experience was phenomenal. If he claims he has had the experience of seeing the tomato, and we postulate that he is not lying, it was a phenomenally conscious experience.
“what is the justification for this assertion?”
The lack of an alternative concept, I’d say. Logical necessity.
“Perhaps, however, you simply mean something else by ‘phenomenal’ such that it is true by definition that if Searle is acquainted with a quality that quality is phenomenal”
I wouldn’t define phenomenal consciousness as “being acquainted with”, but I am construing the statement, “an acquaintance with a mental phenomenon is a phenomenally conscious state” as analytic. I do not (yet) see a possible alternative to doing so.
I’m using phenomenal consciousness in the way Nagel used it: “what it is like to be”. By that definition, it seems odd to think that we might be acquainted with something, yet not have any phenomenal consciousness of it. If we are acquainted with something, but do not have phenomenal consciousness of it, how do we retell the experience? There must have been a “what it was like” to have the experience, or we can’t describe what it was.
“Rather, I suggest that the experience of seeing a ripe tomato is a larger event that involves not only the subject doing the seeing, but the ripe tomato being seen… and this event is not itself a mental state and hence not a phenomenally conscious mental state.”
Okay, I agree that as you outline it, the whole event described from a third-person perspective is not a mental state. There certainly is a mental state involved in the process though, or Searle would not be able to report that he had seen a tomato at all. It seems to me that part of that mental state (perhaps not all of it) must be phenomenally conscious if Searle was able to report about it.
November 9, 2009 at 7:53 am |
No problem; I appreciate the comments!
“What would acquaintance be, if not phenomenal?” Well, non-phenomenal. That is, the issue is the nature of the qualities and I am claiming that it is not obvious that the quality of redness that I am acquainted with in looking at a ripe tomato, for example, is a quality of my mental state (that it is phenomenal). An alternative is that the quality is non-phenomenal (that it is not a quality of my mental state); in that case, it would not be anything phenomenal that I was acquainted with.
“I say that when Searle says he sees redness, it is a quality of a phenomenally conscious mental state, yes.” Again, I’m going to want justification for thinking that the redness is a quality of Searle’s mental state and I don’t buy the response of the lack of an alternative. Again, the alternative is that the quality is not a quality of his mental state (that it is a quality of the tomato or the light that it reflects).
I’m not defining “phenomenal consciousness” in terms of acquaintance, rather I use acquaintance to specify the qualities at issue (the qualities that are claimed to be phenomenal qualities and in virtue of which a mental state is phenomenally conscious). Whether phenomenal qualities can exist without somebody being acquainted with those qualities is one of the questions that I am very happy to be able to avoid by denying that there are any such qualities in the first place!
On its own, I don’t know what the phrase “what it is like to be” means. In a normal conversation, I wouldn’t take this sort of phrase to suggest phenomenal consciousness but to be asking for an evaluation: “What was it like to be a pall-bearer at your Grandfather’s funeral?” “It was sad and very hard, but I was also glad that I could be there and be a part of celebrating the life he had lived.” If it is to be used as a synonym for “phenomenal consciousness,” however, then something more needs to be said. I’ve stated a standard liberal definition and it is one that fits with worries over qualia – with worries about the “redness of red” and so on and so on. Further, I don’t understand what you mean by the phrase “yet not have any phenomenal consciousness of it.” I’m not using “phenomenal consciousness” in a way that readily allows for a transitive usage. The question I am after is whether the quality (the it?) is *itself* phenomenal—whether the quality at issue is a quality of my mental state.
“Okay, I agree that as you outline it, the whole event described from a third-person perspective is not a mental state. There certainly is a mental state involved in the process though, or Searle would not be able to report that he had seen a tomato at all. It seems to me that part of that mental state (perhaps not all of it) must be phenomenally conscious if Searle was able to report about it.”
I agree that Searle seeing a tomato involves mental states. I also accept that in seeing the tomato and reporting on it, Searle is conscious (as opposed to unconscious) and that he is conscious of the tomato (that he is aware of its redness, etc.). What I deny is that any of these mental states must be phenomenally conscious because I deny that the redness is a quality of the mental state. (Or, to be more careful, in this paper I question what evidence there is for thinking that such qualities are phenomenal qualities.)
November 9, 2009 at 4:19 pm |
“Whether phenomenal qualities can exist without somebody being acquainted with those qualities is one of the questions that I am very happy to be able to avoid by denying that there are any such qualities in the first place!”
I’m not asking whether phenomenal qualities can exist without somebody being acquainted with them (I think such a thing might very well be impossible). Rather, how can someone be acquainted with qualities without those qualities being phenomenal? I know the experience would have to be “non-phenomenal”, but then how could it be reported on?
“On its own, I don’t know what the phrase “what it is like to be” means. In a normal conversation, I wouldn’t take this sort of phrase to suggest phenomenal consciousness but to be asking for an evaluation: ‘What was it like to be a pall-bearer at your Grandfather’s funeral?’ ‘It was sad and very hard, but I was also glad that I could be there and be a part of celebrating the life he had lived.’”
I take “what it is like to be” to be signifying the most general quality of experience. Certainly being a pall-bearer at a funeral is a specific kind of experience, but it would not be possible if this more general kind of experience were not already present in it. When I wake up in the morning, this kind of experience starts up. When I fall into a dreamless sleep, it subsides. It is the spotlight with which I illuminate the contents of the world. It did not exist before I was born, and (likely) will not continue after I die. This most general quality of experience is what I take to be phenomenality. We may have non-phenomenal experience, (such as when I drive to a routine destination and am not paying attention), but there isn’t any “what it is like to be,” in the most general sense, in those experiences.
“The question I am after is whether the quality (the it?) is *itself* phenomenal—whether the quality at issue is a quality of my mental state.”
Okay, but if reported by a subject, how could the quality be anything other than a quality of a mental state? Perhaps the quality “redness” exists in the ripe tomato, but it must exist in Searle’s mind, too! You agree that Searle is seeing the redness of the tomato, and that he is conscious. Well, then Searle’s mental state must also include the quality of redness. If it did not, Searle would be at a loss as to what color the tomato really was.
It’s possible that Searle wasn’t paying attention when we showed him the ripe tomato and scanned his brain. Instead, he was thinking of blueberries, so that made up his phenomenal experience. But if that’s the case, all we need to do is ask him. “What were you thinking about just now? The tomato in front of you, or something else?” As long as Searle really was paying attention to the tomato, though, our fMRI scans should be well-grounded.
November 11, 2009 at 9:45 am |
Cool; I was worried that we were just going around in circles, but it looks like we are making some progress. You write:
“Okay, but if reported by a subject, how could the quality be anything other than a quality of a mental state? Perhaps the quality ‘redness’ exists in the ripe tomato, but it must exist in Searle’s mind, too! You agree that Searle is seeing the redness of the tomato, and that he is conscious. Well, then Searle’s mental state must also include the quality of redness. If it did not, Searle would be at a loss as to what color the tomato really was.”
This stands in need of an argument. Why do you hold that for Searle to report on the quality of redness that he sees in looking at a ripe tomato that that quality must be a quality of his mental state? How would the redness he is acquainted with being a quality of his mental state enable him to report on it in a way that its being a quality of the tomato would not?
November 12, 2009 at 1:46 pm |
Is what you’re opposed to the duplication of redness both in the thing and in Searle’s mind? I think I can reformulate my position to avoid that. I suppose we could say that the redness only exists in the tomato and that his mental state “connects” to that redness directly via his eyes. But then when we study the neural correlate of this, we still have something to correlate his brain activity with. We’d be measuring whether he connects to the redness or not, right? In such a case I’d say that kind of connection would be what phenomenal consciousness is.
Do you think it’s possible to report on something without that reportage itself being a mental event? I can see maybe indirectly reporting on something. Studies on priming might be an example of such a thing. We can show that the words subjects come up with in certain word stem exercises can be altered based on how subjects were primed, even though they are not aware of the priming at all. This might be seen as reporting information that was not explicitly understood by the subject. But that kind of event is certainly different from the explicitly understood (and thus by my lights, phenomenally conscious) event we’re talking about here.
November 13, 2009 at 9:11 am |
I do think that locating redness in the mind/brain is a problem; in fact, it is a rather hard problem and, as such, one that we should demand solid reason to accept. Although that isn’t quite how I would put it, your reformulated position is basically the alternative that I push. On that position, however, we are no longer talking about phenomenal consciousness as it is typically formulated as the qualities at issue are not qualities of the perceiver’s mental states.
“But then when we study the neural correlate of this, we still have something to correlate his brain activity with. We’d be measuring whether he connects to the redness or not, right? In such a case I’d say that kind of connection would be what phenomenal consciousness is.”
Note that this is to define “phenomenal consciousness” in a different way that I am concerned with. Further, it strikes me as a strange place to introduce technical vocabulary, as I would have just called this “seeing.” And, I have no problem with finding neural correlates of seeing (or of seeing this or that); that is, I have no problem with the utterly non-controversial project investigating what neural activity is involved in seeing.
“Do you think it’s possible to report on something without that reportage itself being a mental event? I can see maybe indirectly reporting on something.”
I’m a little confused, here: Are you asking whether one can report on something without that report being mental? Whether one can report on something without that something that is reported on being mental? Whether one can report on something without the act of reporting being mental? All I’m really committed to here is the claim that there is no evidence that qualities like redness that we report seeing are mental qualities.
January 29, 2010 at 10:36 pm |
We might be able to understand each other better if Justin would list some things that are attributes of my mental state upon seeing red and, just as important, upon later visualizing a red tomato in my “mind’s eye.” In the latter case, the redness is certainly not a quality of an actual tomato.
February 1, 2010 at 12:03 pm |
Hi Paul (great name, BTW) -
It goes well beyond what I argue for in this paper, but I think that such mental states are best characterized as types of beliefs, although beliefs generated in a specific way (as part of an episode of perceptual acquaintance). In the case of visualizing (or hallucinating, perhaps dreaming), the mental state is similar — especially if we individuate mental states rather coarsely — in that it is also best characterized as a type of belief and has a similar content to the veridical case. But, when visualizing the belief is not generated in the same way and there is no actual redness involved. Of course, to many (but not all) it seems to them as if they are acquainted with redness in visualizing a ripe tomato, for example; but, I hold that this is a mistake (a delusion of perception, if you will). Of course, there is a great deal of work that needs to be done to support this (rather controversial) position and I don’t do that work in this paper. It is on the way, though!