Brain Hammer

Jennifer Matey gave a very nice talk at William Paterson University last week, “Visual Constancies and the Representational Nature of Visual Experiences”. Much of talk concerned issues contested between direct and representational realists about perception (with some side-notes about disjunctivists). An interesting methodological/metaphilosophical issue came up in the ensuing discussion (interesting to me, perhaps, because I was the one who brought it up). It goes something like this.

From a certain point of view it’s quite hard to see exactly what’s contested between the direct and the representational realist and it’s likewise hard to tell how to adjudicate the dispute. To get in the right frame of mind, imagine trying to explain the debate to a Rortyean Antipodean: a person who speaks a language a lot like English, though it’s shot through with a lot more neuroscientific vocabulary than most English speakers know and is utterly devoid of words like “perception”, “experience”, “awareness”, “consciousness”, and “qualia”. Imagine further that the Antipodean has come across a direct realist (DR) and a representationalist (R) in the process of examining a brain in a vat (Vatty) and its non-envatted neural doppleganger (Normy). Both R and DR agree that Vatty and Normy are in the same neural state when Normy is facing a tree with open eyes in a well-lighted environment. Both R and DR agree that that Normy but not Vatty is having a veridical experience of a tree. But what is it that they are disagreeingabout? And more to the point of this post, what could they say to the Antipodean to convince him to pick a side on this issue?

The Antipodean can see quite clearly that there are relational properties involving trees that Normy’s brain but not Vatty’s instantiates. And the Antipodean can see quite clearly that there are non-relational neural properties that Normy’s and Vatty’s brains have in common. What the Antipodean doesn’t get, is what else there might be to say here. Are DR and R fighting over which parts of the universe to draw a line around and apply the label “physical substrate of visual awareness” to? If so, why bother?

When I get in the Antipodean’s frame of mind I’m tempted to assert the following general methodological principle: if you can’t explain what you’re talking about to an Antipodean, then maybe you’re not talking about anything.

Philosopher Thomas Metzinger emailed me a bunch of cool stuff he’s doing with some neurosicentists to utilize virtual reality to induce out-of-body experiences.

From “The embodied self: Using virtual reality to study the foundations of bodily self-consciousness“:

The “I” one thinks of as “myself” is inextricably attached to one’s bodily location. In patients with certain neurological conditions this sense of spatial unity can break down, causing disturbing sensations such as out-of-body experiences in which the global self is localized outside one’s body limits (often called disembodiment).

Previous experiments have shown that people may attribute fake body parts to their own bodies. In the “Rubber Hand Illusion”, a person’s unseen hand is stroked synchronously with a visible fake hand, and then the person is asked to point to his own hand. Subjects invariably err in the direction of the fake hand, attributing it to their own bodies. Because the attribution does not involve the whole body, the sense of global bodily self-consciousness is not affected. EPFL Professor Olaf Blanke, graduate students Bigna Lenggenhager and Tej Tadi, and philosopher Thomas Metzinger hypothesized that the same approach could be used to study the concept of global bodily self consciousness by using a single, coherent body representation instead of just a body part.

See also:
New Scientist, “Out-of-body experiences are ‘all in the mind’”
New York Times, “Studies Report Inducing Out-of-Body Experience“.

Andrew Brook and I just completed a paper forthcoming in a special issue on neuroeconomics of Analyse & Kritik.

Link to uncorrected page proofs [here].

ABSTRACT: A movement dedicated to applying neuroscience to traditional philosophical problems and using philosophical methods to illuminate issues in neuroscience began about twenty-five years ago. Results in neuroscience have affected how we see traditional areas of philosophical concern such as perception, belief-formation, and consciousness. There is an interesting interaction between some of the distinctive features of neuroscience and important general issues in the philosophy of science. And recent neuroscience has thrown up a few conceptual issues that philosophers are perhaps best trained to deal with. After sketching the history of the movement, we explore the relationships between neuroscience and philosophy and introduce some of the specific issues that have arisen.

[Update 10/4/2007: There’s a nice little write-up of this over at Mind Hacks. Thanks, Vaughn!]

[Update 10/6/2007: And another one over at Neurophilosophy. Thanks, Mo!]

[Update 10/10/2007: Discussion over at MetaFilter.]

[Update 11/9/2007: Discussion over at Conscious Entities]

[Update 11/9/2007: In the month of October, this paper received 2,973 hits. The next highest hit Mandik paper that month was “Action-Oriented Representation” at a mere 136. Yikes!]

The Philosophy Department at Georgia State University in Atlanta, Georgia is accepting applications from qualified undergraduates for its two $15,000 Neurophilosophy Fellowships, to be awarded by the Brains & Behavior program. The Brains & Behavior program aims to take the neurosciences at Georgia State to a position of international prominence by promoting interdisciplinary collaboration between faculty and students from partnering departments. B&B Fellows in the Philosophy Department complete a Masters degree, receive a stipend of $15,000 plus tuition and they do not have to serve as graduate assistants or instructors. More information on the requirements for the fellowship can be found here:

http://www2.gsu.edu/~wwwphl/philosophy/neurophilosophy/BBFramesIndex.html

Big Brain

Originally uploaded by Pete Mandik.

It seems to be an open question whether distinctively neural properties are essential to the instantiation of mental properties. One can buy into reductive physicalism and reject neural reduction bases in favor of chemical or thermodynamic reduction bases, just to name a few. Perhaps, then, systems that have no distinctively neural properties—no brains and no neurons—nonetheless have certain chemical or thermodynamic profiles that suffice for mentality. Perhaps. But I doubt it. I hope that I may be forgiven for being so brief about this, but I think there are three reasons (at least) for thinking that the physical reduction of the mental should be a neural reduction.

The first reason for believing in neural reduction is that no non-controversial examples of entities that implement consciousness or cognition exist without brains, or at least, neural networks. It is uncontroversial that alert human adults have mental states. It is also uncontroversial that they have brains. Things are much more contested for the brainless. While it is arguable that my laptop has mental properties, it is also arguable that it does not. It is also arguable, by the way, whether or not my laptop has neural properties. I do, after all, run neural network simulations on it (Mandik 2003). How many properties are literally shared by the simulation and the simulated? We need not settle this now. What is clear is that there’s controversy about the mental prowess of the brainless. And while some brain-havers may lack mentality (who knows what to say about the vegetative patients? (Begely 2006) ), there are no uncontroversial confirmations of mind-havers lacking brains. Let’s talk about the mind-having brain-havers a bit more under the heading of “reason #2 for thinking that the physical reduction bases of mentality will be neural.�

The second reason for believing in neural reduction is that there is no reason to doubt that that it is in virtue of their brains (or their brains plus something else) that creatures like us implement consciousness or cognition. Putting the parenthetical “plus something else� to the side for the moment, let us entertain briefly how unpromising non-neurocentric theories have been. Mental properties are had by organisms either in virtue of the whole organism or part and it is easy to see that it can’t be the whole organism. Amputees retain their mentality, and while my appendectomy doesn’t exactly count as an amputation, comparing its relative effect to one’s mentality to the potential effects of a lobotomy is like comparing nothing to something. That the seat of our soul is some proper part of us is old news, but the appendix never had a chance and the Aristotelian coronary hypothesis was rejected long ago. So much of what we know about where drugs need to go to go to work and what brain injuries impair what mental functions has tipped the scales pretty clearly in favor of neruo-centrism. But, must it be merely neuro-centric? Can’t it be exhaustively neural? Here we have to pause to consider various embodied, embedded, and externalist proposals for including the body and even chunks of the environment of the organism as part of the supervenience base of the organism’s mental properties. There are a couple of things to say about this. The first is that none of it removes the brain from the center of the story. The second is to echo Fodor’s (1989) suggestion that we individuate neural properties widely.

The third reason for believing in neural reduction is that no reductive research program has been as productive as neurocentric ones. One might even be so bold as to suggest that non-neurocentric reductionists have no research program at all. There have been, in recent decades, three major proposals that have been physicalistic without reducing mentality, a la behaviorism, to the behavior of whole organisms: classic computationalism, connectionism, and (certain versions of) dynamic systems theory. Classicism got wedded, in many people’s minds, to non-reductive physicalism, largely due to the influence of Fodor (1974) and Putnam (1967). Dynamic systems theory included proposals of a specifically neural character, (e.g. Freeman 1991) while others looked like warmed-over behaviorism (van Gelder, 1995). Either way, dynamic systems theory was confronted with some devastating objections (see Glymour (1997), Grush, (1997) and Eliasmith (2001) for a taste). The main point here, though, is not any knock-down refutations of non-neurocentric research programs. The point here is that neurocentric research programs have been massively productive both in theory and in application.

[From “Supervenience and Neuroscience”]

Update: Futher discussion of this post on Paul Baxter’s blog [link].

A book I co-authored, Cognitive Science: An Introduction to the Mind and Brain, is out now. [Link to Routledge’s page for the book.] If you have a mind and/or a brain, but have not yet been introduced to them, this may be the book for you.

Also out now is The Blackwell Companion to Consciousness. With a title like that, you can probably guess it was published by Blackwell. [Link to guess-who’s page for the book.] If you are conscious and in need of a companion, this may be the book for you. This book contains many excellent chapters by many excellent people. It also contains a chapter by me: “The Neurophilosophy of Consciousness.” [Link to draft of my chapter.] Here’s the abstract:

The neurophilosophy of consciousness brings neuroscience to bear on philosophical issues concerning phenomenal consciousness, especially issues concerning what makes mental states conscious, what it is that we are conscious of, and the nature of the phenomenal character of conscious states. Here attention is given largely to phenomenal consciousness as it arises in vision. The relevant neuroscience concerns not only neurophysiological and neuroanatomical data, but also computational models of neural networks. The neurophilosophical theories that bring such data to bear on the core philosophical issues of phenomenal conscious construe consciousness largely in terms of representations in neural networks associated with certain processes of attention and memory.

Regarding the books, both volumes bear handsome cover illustrations of bald heads. Until someone figures out a better way to draw a picture of the mind, we are going to be stuck with bald heads.

Supervenience and Neuroscience. Draft. Comments welcome.

ABSTRACT: I assume physicalism and argue against non-reductive physicalism on the following grounds. Extant forms of non-reductive physicalism spell out their commitment to physicalism in terms of a notion of supervenience incapable of ruling out obviously unappealing scenarios that I call “doubled-qualia” and “mental-mental-supervenience.” Such scenarios involve multiple minds supervening on all and only the same physical properties. Such scenarios can be ruled out by a natural extension of the supervenience thesis that I call “fine-grained supervenience.” I argue further that the combination of non-reductive physicalism with fine-grained supervenience leads to a regress. I argue further still that if the regress is to be avoided, the form of reductive physicalism most preferable is one in which mental properties reduce to neural properties.

[Link to full text of article]

Related posts: Doubled Qualia; A Regress for Non-reductive Physicalism; Fine-grained Supervenience, Cognitive Neuroscience, and the Future of Functionalism

Mandik, P. (in press). The Neurophilosophy of Subjectivity. In John Bickle (ed.), Oxford Handbook of Philosophy and Neuroscience. New York: Oxford University Press.

ABSTRACT: The so-called subjectivity of conscious experience is central to much recent work in the philosophy of mind. Subjectivity is the alleged property of consciousness whereby one can know what it is like to have certain conscious states only if one has undergone such states oneself. I review neurophilosophical work on consciousness and concepts pertinent to this claim and argue that subjectivity eliminativism is at least as well supported, if not more supported, than subjectivity reductionism.

[Link to full text of article]

P.S. People who love (hate) Hyperbolic Mary may be interested in this article. She appears toward the end of it and it provides some further context for why she’s supposed to matter.

Flow Crash

Originally uploaded by Pete Mandik.

Paul Churchland, in his recent “Chimerical Colors: Some Novel Predictions from Cognitive Neuroscience” (2005), describes very odd color experiences that are predicted by a neural model of chromatic information processing. In brief, the differential fatiguing and recovery of opponent processing cells gives rise to afterimages with subjective hues and saturations that would never be seen on the reflective surfaces of objects. Such “chimerical colors” include shades of yellow exactly as dark as pitch-black and “hyperbolic orange, an orange that is more ‘ostentatiously orange’ than any (non-self-luminous) orange you have ever seen, or ever will see, as the objective color of a physical object” (p. 328). Such odd experiences are predicted by the model that identifies color experiences with states of neural activation in a chromatic processing network. Of course, it’s always open to a dualist to make an ad hoc addition of such experiences to their theory, but no dualistic theory ever predicted them. Further, the sorts of considerations typically relied on to support dualism—appeals to intuitive plausibility and a priori possibility—would have, you’d expect, ruled them out.

Who would have, prior to familiarity with the neural theory, predicted experiences of a yellow as dark as black? One person who would not have thought there was such an experience as pitch-dark yellow is Ludwig Wittgenstein, who once asked “[W]hy is there no such thing as blackish yellow?” (1978, p. 106). I think it safe to say Wittgenstein would be surprised by Churchland’s chimerical colors. At least, I know I was, and I literally grew up reading Churchland. However, to be certain that we have an example of someone who is surprised—for I would like to conduct a thought experiment about them—let us consider someone, call him “Larry”, who has seen yellow and black and in general all the typical colors a normally sighted adult has seen. Suppose that Larry has never had a chimerically colored afterimage such as hyperbolic orange or pitch-dark yellow. Suppose further that Larry is aware of none of the neuroscience that predicts the existence of such experiences. Now, let us compare Larry to Hyperbolic Mary. Like Jackson’s Mary, Hyperbolic Mary knows all of the physical facts about how human color vision works, including the predictions of chimerically colored afterimages. Suppose also, that like Mary toward the end of Jackson’s story, Hyperbolic Mary has been let out of the black and white room and has seen tomatoes, lemons, grass, cloudless skies, and the like. In short, she has had the average run of basic color experiences. Let us stipulate that she has had all the types of color experiences that Larry has had. The crucial similarity between Mary and Larry is that not only have they seen all of the same colors, neither has had chimerically colored afterimages. Neither has experienced hyperbolic orange or pitch-dark yellow. The crucial difference between Larry and Hyperbolic Mary is that only Hyperbolic Mary is in possession of a theory that predicts the existence of hyperbolic orange and pitch-dark yellow. And here’s the crucial question:

Who will be more surprised upon experiencing chimerical colors for the first time, Larry or Hyperbolic Mary?

I think it’s obvious that Larry will be more surprised. I also think this has pretty significant implications for what we are to think the knowledge of what it is like consists in. One thing that knowing what it is like consists in is something that will determine whether one is surprised or not. Fans of Jackson’s Mary must grant this, for they are fond of explicating Jackson’s Mary’s ignorance of what it is like in terms of her alleged surprise at seeing red for the first time. Well, Hyperbolic Mary is less surprised than Larry on seeing chimerical colors for the first time. This shows that she must have more phenomenal knowledge—more knowledge of what it is like to have certain experiences—than did Larry. Mary was able to represent, in introspection, more properties of her experiences than Larry. And her introspective capacity was augmented by her neuroscientific concepts.

References:
Churchland, P. (2005). “Chimerical Colors: Some Novel Predictions from Cognitive Neuroscience.” In: Brook, Andrew and Akins, Kathleen (eds.) Cognition and the Brain: The Philosophy and Neuroscience Movement. Cambridge: Cambridge University Press.

Wittgenstein, L. (1978). Some Remarks on color, ed. G.E.M. Anscombe, Oxford: Blackwell.

Gray bananas look more yellow than equally gray non-bananas. Your conceptual categorization of a stimulus as a banana has something to do with the perceptual appearance of the stimulus. But what more can be said about this “having something to do with” stuff? More later.

Fig. 1. These bananas are bluer than they seem.

We asked human observers to adjust the color of natural fruit objects until they appeared achromatic. The objects were generally perceived to be gray when their color was shifted away from the observers’ gray point in a direction opposite to the typical color of the fruit. These results show that color sensations are not determined by the incoming sensory data alone, but are significantly modulated by high-level visual memory.

I saw Gegenfurtner demonstrate some of this in a talk he gave at the Pasadena Neurophilosophy conference in June ‘05. Gray bananas did indeed look more yellow than their equally gray non-banana counterparts.

So, what’s going on here? One hypothesis, call it the “phenomenal hypothesis” is that the activation of “high-level visual memory” influences, but is in no way constitutive of, the appearance. Another, call it the “conceptual hypothesis” is that the activation of high-level visual memory partially constitutes the appearance. I favor the latter hypothesis. Why? More later. Which do you favor? Why?
Reference: Hansen, T., Olkkonen, M., Walter, S. & Gegenfurtner, K.R. (2006). Memory modulates colour appearance. Nature Neuroscience, DOI:10.1038/nn1794.