Burge on the Origins of Perception

Saturday I attended a workshop on the predicative structure of experience sponsored by the New York Consciousness Project, which is sponsored by the New York Institute of Philosophy . Speaking was Tyler Burge and Mark Johnston with commentary by Alex Byrne and Adam Pautz respectively. I may write a separate post on Johnston’s talk but here I want to say something about Burge’s talk.

The first thing that Burge wants to do is to clarify the notion of representation in the claim that perception is representational. For a state to be representational is for veridicality conditions to be an ineliminable part of the scientific explanation of the formulation of the state. Thus representational states, in this sense, are not states that merely co-vary with some thing in the world. For instance, the level of mercury in a simple thermometer causal co-varies with the temperature but Burge wants to deny that the mercury level in the thermometer represents the temperature in his preferred sense. This is because the scientific explanation of how the mercury level cam to be such-and-such proceeds “from the inside” so to speak, and does not need to bring in notions like true or false. He admitted that we could, if we want, adopt a certain stance towards the state and call it representational. But there is still something unique about the kind of states that psychologists are interested in. The central task of perceptual theories, for Burge, is that of discovering the conditions under which we correctly, or accurately represent the world and when we fall into mistakes, i.e. illusions. The idea of “getting it right” does not enter into the explanation of why the mercury is at a certain level in the thermometer. To illustrate this idea Burge kept going back to saying that the explanation for the level of mercury being thus-and-so as opposed to -such-and-such would be the same whether or not we just started with the proximal stimulation or not. The basic idea seemed to be this; when we calibrate a mercury thermometer we take the contraption and put it in ice as it is melting (i.e. the just melted ice-water) and wait for the mercury to stabilize. We then do the same for boiling water and then assign 0 to the first and 100 to the second and divide the rest into 100 equal parts. Does it really make sense to say that the thermometer got the temperature right in the first step? Can we make sense of the notion that it got it wrong? Wherever it settles we call 0 so how could it be mistaken? Or to put it slightly differently, how could we make sense of the notion of it being under some illusion? These kinds fo considerations don’t even seem to apply. Now as already said we can adopt this sort of talk if we want to, but if it is really the case that nothing is lost when we stop talking that way then it is just a stylistic thing. When we talk about representational states in perception we are immediately confronted with truth-value talk. And Burge wagered that psychology as a science would not give up this notion.

For my own part I find this distinction quite plausible but I don’t see why it then follows that no causal or teleological theory can work. The special category isn’t representation, it is mental representation.

But back to Burge. The second thing that he wanted to clarify was the notion of perception. He first distinguished between mere sensory registration, which is just statistical co-variation, and perception. For a state to be a perceptual state it must be in the business of objectifying the world. That is, it is in the business of offering a solution to the underdetermination problem. The classic example is the construction/recovery of a 3-d image from the 2-d image projected onto the retina. There are an infinite number of ways that the brain could generate a 3-d image from that information but of course the perceptual systems are in the business of ignoring most of those. This fact is then used in the explanation of various visual illusions. The mark of perceptual systems are perceptual constancies. So, consider color. We Human Beings are pretty good at telling the actual color of a thing in a variety of lighting conditions. That is, our perceptual systems somehow take a range if inputs and treat them as the same. The same is true for length and etc. He distinguishes perception from any kind of mere sensory registration and seemed to think that olfaction and taste were non-perceptual senses. The reason that he gave was that there were no smell constancies. We don’t seem equipped to be able to track the same smell under a bunch of different environmental conditions.

Finally, and perhaps the most interesting part of the discussion, he defended his claim that talk about perceptual as representational and perceptual processes as computational does not commit us to a purely syntactic view of how it is implemented. So by way of illustration consider the way that we talk about the logical category of being a predicate. We can give a purely syntactic description but the level of explanation that matters is the level at which semantic information plays a role in individuating the state. This is somewhat like a point that has always bothered me. In logic we pretend that we are dealing with purely syntactic rules, but they are useless unless they are individuated semantically. But anyway, Burge’s point was that he thought that we would not even be able to get to the point where we could individuate perceptual states in a purely syntactical way, unlike the logic case where we can (so he thought). He speculated that the reason so many people think that you must do computational psychology purely syntactically is because of an antecedent position on the mind/body problem. It is because people start with the assumption that this stuff must ultimately be physical and so we must only apply to physical properties (viz. syntax). But Burge objected that we should do psychology autonomously and the see what the mind-body problem looks like afterwards. There is nothing in computational theory that would force us to opt for a purely syntactic theory of computation and so, Burge claimed, no reason that people who accept the language of thought hypothesis, even for perception, were committed to these computations being done on the basis of purely syntactical properties of the computata (if that is a world).

Now all of this is only by way of clarifying what perceptual representation is (!) and after this is done he goes on to talk about the structure of perceptual representations. This is getting long so I will make it short now and perhaps come back to it later for a fuller account. The basic idea seemed to be that perceptions must be composed of a general attributive part and a part that indicates some particular thing (singular reference part). So, for example, to perceive that one object is to the left of another object is to have a state that represents the general relation of ‘to the left of’ as being instantiated by these two particular objects. In both its general, attributive aspect, as well as the singular aspect perception is always trying to demonstrate some particular. It can fail to do that but it is always trying to do so. He seemed to want to model this on demonstratives. As I said there is much more to be talked about, including his view that the difference between conscious and unconscious perceptions might lie in some aspect of the states mode of presentation, but it is getting late and this is already too long!

Advertisements

Swamp Thing About Mary

On Friday I attended Pete Mandik’s Cogsci talk at CUNY. The talk was excellent; entertaining and with a spirited discussion of many interesting topics. This paper represents one of a two part project that Pete is pursuing that involves Swamp Mary. One project employs Swamp Mary against dualists while the other employs her in an in-house dispute between what Pete call ‘gappy’ and ‘non-gappy’ physicalism. Friday’s talk was the latter and is based on his paper Swamp Mary Semantics: A Case for Physicalism without Gaps.

Pete’s distinction is recognizable as meant to capture type-a and type-b physicalism. More generally it is the distinction between a priori and a posteriori phsyicalism. Or at least one may get that idea from the way Pete characterizes the distinction. He says that the issue is over whether or not what we can “classic Mary” in her pre-release condition is in a position to know what it is like to see red. Pete claims that the gappy physicalist will deny that she does while the non-gappy physicalist does not. Swamp Mary is then presented as a challenge to the gappy physicalist. In short the challenge goes as follows. Swamp Mary is a physical duplicate of post-release Mary, the one who has seen red and so knows what it is like to see red, but Swamp Mary has never herself seen red since she is a swamp being who, we can stipulate, has had no experiences herself at all. She is a duplicate of a being that has had the experience of seeing red but hasn’t herself had the experience. Nonetheless, Pete urges, it is natural to say that Swamp Mary knows what it is like to see red. This is natural since post-release Mary knows what it is like to see red and Swamp Mary is a physical duplicate of post-release Mary. But since it is also natural to say that Swamp Mary has never seen red, or had an occurrent red quale, it is now mysterious why it is supposed to be the case the pre-release Mary doesn’t know what it is like to see red. If Swamp Mary can know what it is like to see red without ever having a red quale then it ought to be the case that pre-release Mary can also know what it is like to see red without having seen it. Thus, Pete concludes, physicalist should be non-gappy physicalist and hold that Mary can know what it is like to see red in her pre-release state.

Pete then goes through various responses that might be made by the type-b physicalist and tries to show that they all have problems. He does this by examining four different psychosemantic theories, which he also claims to be exhaustive, and arguing that they cannot provide the relevant explanation (i.e. of the difference between pre-release Mary and Swamp Mary’s knowledge of what it is like to see red). The four categories of psychosemantic theory are: 1. Quotation 2. Actual Cause 3. Nomological 4. Descriptive-homomorphic/isomorphic. Briefly, 1 is supposed to capture any kind of self-presentational view about phenomanl concepts like that of Chalmers or perhaps Block. 2 is supposed to capture any kind of teleological or causal theory of content while 3 is supposed to capture anything that resembles Fodor’s psychosemantics (think ‘asymmetric dependance’ here). Finally, 4 is supposed to capture any kind of conceptual role kind of theory. The problems for each of these, to make a long story short, are that 1 and 2 cannot explain how Swamp Mary does know what it is like to see red while 3 & 4 end up having problems explaining why pre-release Mary doesn’t know what it is like to see red.

There is a lot of detail that I am leaving out but in general Pete is trying to construct an argument against a central claim of the type-b physicalist. This is the intuition, shared by many, that one cannot really have the full concept RED without having the red quale present in ones consciousness. Or to put it more common sensically, one cannot know what it is like to see red unless one has (a) had a red experience and (b) has the ability to think, or otherwise identify, that the experience is red while one is having it. Pete has the intuition that Swamp Mary knows what it is like to see red and yet neither (a) nor (b) seem to be met and therefore concludes that the type-b physicalist is wrong. I suggested in discussion that Pete was running over the distinction between ‘knowing what it is like’ in the general sense, and ‘knowing what it is like FOR one’. To know what it is like for one too see red requires that one have, or be able to recall, a red experience and to be able to say, so to speak, to one’s self ‘this is what it is like to see red’. To know what it is like in the generic sense is to know what it is like to see red in the way that pre-release Mary is typically thought of by the type-b physicalist. She can know a lot about what it is like to see red. She can know that it is more like seeing something pink than it is like seeing blue, and all other kinds of facts. But intuitively she doesn’t know what it is like for her to see red. Once we have this distinction in mind we no longer have a problem with Swamp Mary. Swamp Mary knows what it is like in the generic sense, in just the same way as pre-release Mary, but she does no know what it is like for her to have the experience, again just like pre-release Mary. To put this in different terminology, both pre-release Mary and Swamp Mary lack the “pure” phenomenal concept, though they have many others. On the other hand, if we think that Swamp Mary does know what it is like in this way it will be because she has an ability to call up the red experience and identify it, whereas Classic Mary cannot do this.

Finally, does saying this really make one a gappy/type-b phsyicalist? I claim that it doesn’t. I agree that in the way the Mary thought experiment is usually set up we arrive at the conclusion that pre-release Mary cannot know what it is like for he to see red. This is because she lacks the appropriate concept, the pure phenomenal concept. In order to acquire this concept she needs to have the experience. But once she does there is no longer any gap between the physical and phenomenal. Once Mary has the pure phenomenal concept she is able to know what it is like to see red in the complete way necessary to make deductions from physical facts to phenomenal facts without relying on the pure phenomenal concept (or introspection) for justification of any step in the deduction. Thus in order to really count as a gappy physicalist in Pete’s sense we would have to deny that even once Mary had this concept she would be unable to know what it is like for her to see red just on the basis of the physical facts. This is much less plausible to me.

After the talk at the bar we started to talk about the role that intuitions should play in philosophy. This discussion was started by thinking about the experience principle. Why does anyone think that it is true that in order to fully have the concept of red one must have seen red, or had a red experience? I claimed that have prima facie evidence for this claim from the fact that it is intuitively obvious to many philosophers. I agree, basically, with Michael Devitt’s view that intuitions, especially those of experts, should count as defeasible evidence. Thus, we can have a priori justification for believing something but not a priori knowledge in the traditional sense. The mere fact that most philosophers think that Mary couldn’t know what it was like for her to see red from within her room should count as evidence, not for epiphenomenalism or dualism, but rather for the experience principle. That is what is really being tested there. Now, I agree that this is defeasible evidence. We could come to have reason to reject the idea. I *think* I can at least negatively conceive of a situation where pre-release Mary comes to know what it is like to see red without seeing it first. She will know that when people see red they are in a certain brain state. She will also know that people talk about knowing this state in a special first-person way and that they can only do this when in the relevant brain state. She might then conclude that to know what it is like to see red in this sense requires that she be in this brain state. Since she is not allowed to have the stimulus that will produce the brain state she must find some other way to produce the brain state. She might then realize that when one imagines seeing red one goes into something like the brain state that one is in when one actually sees red. Could she come to token this brain state without the stimulus? Well, obviously she could rig some kind of autobrain stimulation to stimulate the area and produce the experience. But is it absurd to think that she could do this without brain stimulation? That is, could she imagine what red looked liked without ever having seen it? I am not sure…my intuitions tend to go with the experience principle but I can’t see anything contradictory about the scenario just described…

There is more to say about all of this but this is getting too long already!

Two Ways to (Not) Think About Unicorns

Listening back to the discussion Pete and I had, as well as my previous post on this stuff, and something occurred to me. There really are two different ways of thinking about the concept “unicorn”. One way is the way that I have been thinking about it ad that is as a regular natural kind term like ‘horse’, ‘tiger’, etc. Concepts like this, according to me, are best treated along the lines of a causal-historical account like the Kripkean inspired theory that Devitt produced. But there is another way of thinking about unicorn, one that thinks of it as like ‘bachelor’ rather than ‘tiger’. Terms like that are best treated in terms of a conceptual-role theory. So, it is the relations between the concept ‘bachelor’, ‘unmarried’, and ‘male’ that makes my thought that all bachelors are unmarried males true. If one thought about ‘unicorn’ like this, one might think that it is the conceptual relations between ‘unicorn’, ‘horse’, and ‘horn’ have that make it the case that when I am thinking about unicorns I am thinking about horned horses. That is, one might think of the concept ‘unicorn’ as being defined as ‘horse with a horn’. Now, it seems to me that we employ both kinds of representations in thought so then the question becomes one of which kind features in the content of higher-order thoughts. I claim that it is the former and not the latter and that that matters.

cfp: 3rd Online Consciousness Conference

Please post and distribute widely; apologies for cross-posting.

I am pleased to announce the call for papers for the third online consciousness conference. Invited speakers include,

Kathleen Akins, Simon Fraiser University

Paul Churchland, University of California San Diego

Steven Harnad, University of South Hampton

Jesse Prinz, The Graduate Center, CUNY

Papers in any area of consciousness studies are welcome, though the conference has as its theme this year ‘Neurophilosophy and the Philosophy of Neuroscience’. Selected papers from the conference relating to this theme, pending outside review, will be published in the annual special issue of Synthese “Neuroscience and its Philosophy”. Because of this contributions that are unpublished elsewhere and related to the theme are preferred, though exceptions can be made.

Papers should be roughly 3,000-4,000 words and subsequent presentations, should the presenter choose to make one, should be about 20 minutes (though longer papers/presentations are acceptable). Submissions, suitable for blind review, should be sent to consciousnessonline@gmail.com by January 5th 2011. Those interested in being referees or commentators should also contact me. Authors of accepted papers are urged to make, or have made, some kind of audio/visual presentation (e.g. narrated powerpoint or video of talk) though this is not required to present.

For more information visit the conference website: http://consciousnessonline.wordpress.com