12 years!

I just realized that I recently passed the 12 year mark of blogging here at Philosophy Sucks! The top-5 most viewed post haven’t changed all that much from my 10 year reflections. Philosophy blogging isn’t what it used to be (which is both good and bad I would say) but this blog continues to be what it always has: A great way for me to work out ideas, jot down notes, and get excellent feedback really quickly (that isn’t facebook). Thanks to everyone who has contributed over these 12 years!

The five most viewed posts written since the ten year anniversary are below. 

5. Prefrontal Cortex, Consciousness, and….the Central Sulcus?

4. Do we live in a Westworld World?

3. Consciousness and Category Theory

2. Integrated Information Theory is not a Theory of Consciousness

  1. My issues with Dan Dennett 

 

Theories of Perception and Higher-Order Theories of Consciousness: An Analogy

I recently came across a draft of a post that I thought I had actually posted a while ago…on re-reading it I don’t think I entirely agree with the way I put things back then but I still kind of like it

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When one looks at philosophical theories of perception one can see three broad classes of theoretical approaches. These are sometimes known as ‘relationalism’ and ‘representationalism’ (and ‘disjunctivism’). According to relationalism (sometimes known as naive realism) perception is a relation between the perceiver and the object they perceive. So when I see a red apple, on this view, there is the redness of the apple and then I come to be related to those things in the right way and that counts as perceiving. Often a ‘window’ analogy is invoked. Perception is like a window through which we can look out into the world and in so doing come to be acquainted with the ways that the objects in the world are. Representationalism on the other hand holds that perception involves, well, representing the world to be be some way or other, and this may diverge from the way the world is outside of perception.

I think a similar kind of debate has been occurring within the differing camps of higher-order theories of consciousness. In this debate the first-order state, which represents properties, objects, and events in the physical environment of the animal, takes the place of the physical object in the debates about perception. If one takes that perspective then one can see that we have versions of relationalism and representationalism in higher-order theories. Relationalists take the first-order state, and it’s properties, to be revealed in the act of becoming aware of it. Representationalists think that we represent the object as having various properties and that the experiences we have when we dream or hallucinate are literally the same ones we are aware of in ordinary experience. This is the famous argument from hallucination.

I think that the misrepresentation argument against higher-order theories of consciousness is actually akin to the argument from hallucination, and shows roughly the same thing, viz. that the relationalist version of higher-order theory is not in a position to explain what it is that is in common between “veridical” higher-order states and empty higher-order states. As long as one accepts that these cases are phenomenologically the same, and some versions of higher-order theory commit you to that claim, then it seems to me that you must say that we are aware of the same thing in each case. In the perception debate representationalists tend to say that what we are ware of in each case are properties. So take my experience of a red ripe tomato and my “perfect” hallucination as of a red ripe tomato. In one case I am aware of an actual object, the tomato, and in the other case I am not aware of any object (it is a hallucination). But in both cases I am aware of the redness of the tomato and the roundness of it, etc, in the good case these properties are instantiated in the tomato and in the bad case the are uninstantiated but they are there in both cases. The representationalist can thus explain why they two cases are phenomenologically the same: in each case we represent the same properties as being present.

I think the representational version of higher-order theories of consciousness have to similarly commit to what it is that is in common between veridical higher-order states and empty ones which none the less are phenomenologically indistinguishable. In one case we are aware of a first-order mental state (the one the higher-order state is about) and in the other case we are not (the state we represent ourselves as being in is one we are not actually in, thus the higher-order state is empty). So it must be the properties of the mental states that we are aware of in both cases. So if I am consciously seeing a red ripe tomato then I am in a first-order state which represents the tomato’s redness and roundness, etc and I am representing that these properties are present and that there is a tomato present, etc (this state can occur unconsciously but we are considering its conscious occurrence). To consciously experience the redness of the tomato I need to have a higher-order state representing me as seeing a tomato. And what this means is that I have a higher-order state representing myself as being in a first-order visual state with such and such properties. The ‘such-and-such properties’ bit is filled in by one’s theory of what kinds of properties first-order mental states employ to represent properties in the environment. Suppose that, like Rosenthal, one thinks they do so by having a kind of qualitative (i.e. non-conceptual, non-intentional) property that represents these properties. On Rosenthal’s view he posits ‘mental red’ as the way in which we represent the physical property objects have when they are red. He calls this red* and says that red* represents physical red in a distinctive non-conceptual non-intentional way.

This is not a necessary feature of higher-order theories but it gives us a way to talk about the issues in a definite way. So the upshot of this discussion is that it is these properties which are common between veridical and hallucinatory higher-order states. When one has a conscious experience of seeing a red ripe tomato but there is not a first-order visual representation of the tomato or its redness, etc, one represents oneself as being in first-order states which represent the redness and roundness of the tomato, one is aware of the same properties one would be in the veridical case but these properties are uninstantiated.

 

Consciousness Science & The Emperor’s Arrival

Things have been hectic around here because I have been teaching 4 classes (4 preps) in our short 6-week winter session. It is almost over, just in time for our Spring semester to start! Even so February has been nice with a couple of publications coming out.

The first is Opportunities and Challenges for a Maturing Science of Consciousness. I was very happy to see this piece come out in Nature Human Behavior. Matthias Michel, Steve Flemming, and Hakwan Lau did a great job of co-ordinating the 50+ co-authors (Open access viewable pdf here). As someone who was around as an undergraduate towards the beginning of the current enthusiasm for the science of consciousness it was quite an honor to be included in this project!

In addition to that Blockheads! Essays on Ned Block’s Philosophy of Mind and Consciousness is out! This book has a lot of interesting papers (and replies from Ned) and I am really looking forward to reading it.

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Hakwan Lau and I wrote our contribution back in 2011-2012  and a lot has happened in the seven years since then! Of course I had to read Ned’s response to our paper first and I will have a lot to say in response (we actually have some things to say about it in our new paper together with Joe LeDoux) but for now I am just happy it is out!

Prefrontal Cortex, Consciousness, and…the Central Sulcus?

The question of whether the prefrontal cortex (PFC) is crucially involved in conscious experience is one that I have been interested in for quite a while. The issue has flared up again recently, especially with the defenders of the Integrated Information Theory of Consciousness defending an anti-PFC account of consciousness (as in Christof Koch’s piece in Nature). I have talked about IIT before (here, here, and here) and I won’t revisit it but I did want to address one issue in Koch’s recent piece. He says,

A second source of insights are neurological patients from the first half of the 20th century. Surgeons sometimes had to excise a large belt of prefrontal cortex to remove tumors or to ameliorate epileptic seizures. What is remarkable is how unremarkable these patients appeared. The loss of a portion of the frontal lobe did have certain deleterious effects: the patients developed a lack of inhibition of inappropriate emotions or actions, motor deficits, or uncontrollable repetition of specific action or words. Following the operation, however, their personality and IQ improved, and they went on to live for many more years, with no evidence that the drastic removal of frontal tissue significantly affected their conscious experience. Conversely, removal of even small regions of the posterior cortex, where the hot zone resides, can lead to a loss of entire classes of conscious content: patients are unable to recognize faces or to see motion, color or space.

So it appears that the sights, sounds and other sensations of life as we experience it are generated by regions within the posterior cortex. As far as we can tell, almost all conscious experiences have their origin there. What is the crucial difference between these posterior regions and much of the prefrontal cortex, which does not directly contribute to subjective content?

The assertion that loss of the prefrontal cortex does not affect conscious experience is one that is often leveled at theories that invoke activity in the prefrontal cortex as a crucial element of conscious experience (like the Global Workspace Theory and the higher-order theory of consciousness in its neuronal interpretation by Hakwan Lau and Joe LeDoux (which I am happy to have helped out a bit in developing)). But this is a misnomer or at least is subject to important empirical objections. Koch does not say which cases he has in mind (and he does not include any references in the Nature paper) but we can get some ideas from a recent exchange in the Journal of Neuroscience.

One case in particular is often cited as evidence that consciousness survives extensive damage to the frontal lobe. In their recent paper Odegaard, Knight, and Lau have argued that this is incorrect. Below is figure 1 from their paper.

Figure 1a from Odegaard, Knight, and Lau

This is brain of Patient A, who was reportedly the first patient to undergo bi-lateral frontal lobectomy.  In it the central sulcus is labeled in red along with Brodman’s areas 4, 6, 9, and 46. Labled in this way it is clear that there is an extensive amount of (the right) prefrontal cortex that is intact (basically everything anterior to area 6 would be preserved PFC). If that were the case then this would hardly be a complete bi-lateral lobectomy! There is more than enough preserved PFC to account for the preserved conscious experience of Patient A.

Boly et al have a companion piece in the journal of neuroscience and a response to the Odegaard paper (Odegaard et al responded to Boly as well and made these same points). Below is figure R1C from the response by Boly et al.

Figure R1C from response by Melanie Boly, Marcello Massimini, Naotsugu Tsuchiya, Bradley R. Postle, Christof Koch, and Giulio Tononi

Close attention to figure R1C shows that Boly et al have placed the central sulcus in a different location than Odegaard et al did. In the Odegaard et al paper they mark the central sulcus behind where the 3,1,2 white numbers occur in the Boly et al image. If Boly et al were correct then, as they assert, pretty much the entire prefrontal cortex is removed in the case of patient A, and if that is the case then of course there is strong evidence that there can be conscious experience in the absence of prefrontal activity.

So here we have some experts in neuroscience, among them Robert T. Knight and Christof Koch, disagreeing about the location of the central sulcus in the Journal of Neuroscience –As someone who cares about neuroscience and consciousness (and has to teach it to undergraduates) this is distressing! And as someone who is not an expert on neurophysiology I tend to go with Knight (surprised? he is on my side, after all!) but even if you are not convinced you should at least be convinced of one thing: it is not clear that there is evidence from “neurological patients in the first half of the 20th century” which suggests that the prefrontal cortex is not crucially involved in conscious experience. What is clear is that is seems a bit odd to keep insisting that there is while ignoring the empirical arguments of experts in the field.

On a different note, I thought it was interesting that Koch made this point.

IIT also predicts that a sophisticated simulation of a human brain running on a digital computer cannot be conscious—even if it can speak in a manner indistinguishable from a human being. Just as simulating the massive gravitational attraction of a black hole does not actually deform spacetime around the computer implementing the astrophysical code, programming for consciousness will never create a conscious computer. Consciousness cannot be computed: it must be built into the structure of the system.

This is a topic for another day but I would have thought you could have integrated information in a simulated system.

Mary, Subliminal Priming, and Phenomenological Overflow

Consider Mary, the super-scientist of Knowledge Argument fame. She has never seen red and yet knows everything there is to know about the physical nature of red and the brain processing related to color experience. Now, as a twist, suppose we show her red subliminally (say with backward masking or something). She sees a red fire hydrant and yet denies that she saw anything except the mask (say). Yet we can say that she is primed from this exposure (say quicker to identify a fire truck than a duck subsequently or something). Does she learn what it is like to see red from this? Does she know what it is like to see red and yet not know that she knows this?

It seems to me that views which accept phenomenological overflow, and allow that there is phenomenal consciousness in the absence of any kind of cognitive access, have to say that the subliminal exposure to red does let Mary learn what it is like for her to see red (without her knowing that she has learned this). But this seems very odd to me and thus seems to me that this is a kind of a priori consideration that suggests there is no overflow.

Of course I have had about 8 hours of sleep in the last week so maybe I am missing something?

 

Papa don’t Teach (again!)

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The Brown Boys

2018 is off to an eventful start in the Brown household. My wife and I have just welcomed our newborn son Caden (pictured with older brother Ryland and myself to the right) and I will soon be going on Parental Leave until the end of April. Because of various reasons I had to finish the last two weeks of the short Winter semester after Caden was born (difficult!). That is all wrapped up now and there is just one thing left to do before officially clocking out.

Today I will be co-teaching a class with Joseph LeDoux at NYU. Joe is teaching a course on The Emotional Brain and he asked me to come in to discuss issues related to our recent paper. I initially recorded the below presentation to get a feel for how long the presentation was (I went a bit overboard I think) but I figured once it was done I would post it. The animations didn’t work out (I used powerpoint instead of Keynote), I lost some of the pictures, and I was heavily rushed and sleep-deprived (plus I seem to be talking very slow when I listen back to it) but at any rate any feedback is appreciated. Since this was to be presented to a neuroscience class I tried to emphasize some of the points made recently by Hakwan Lau at his blog.

Ian Phillips on Simple Seeing

A couple of weeks ago I attended Ian Phillips’ CogSci talk at CUNY. Things have been hectic but I wanted to get down a couple of notes before I forget.

He began by reviewing change blindness and inattentional blindness. In both of these phenomena subjects sometimes fail to recognize (or report) changes that occur right in front of their faces. These cases can be interpreted in two distinct ways. On one interpretation one is conscious only of what what is able to report on, or attend to. So if there is a doorway in the background that is flicking in and out of existence as one searches the two pictures looking for a difference and when one is asked one says that they see no difference between the two pictures one does not consciously experience the door way or its absence. This is often dubbed the ‘sparse’ view and it is interpreted as the claim that conscious perception contains a lot less detail in it than we naively assume.

Fred Dretske was a well known defender of a view on which distinguishes two components of seeing. There is what he called ‘epistemic seeing’ which, when a subject sees that p, “ascribes visually based knowledge (and so a belief) to [the subject]”. This was opposed to ‘simple seeing’ which “requires no knowledge or belief about the object seen” (all quoted material is from Phillips’ handout). This ‘simple seeing’ is phenomenally conscious but the subject fails to know that they have that conscious experience.

This debate is well known and been around for a while. In the form I am familiar with it it is a debate between first-order and higher-order theories of consciousness. If one is able to have a phenomenally conscious experience in the absence of any kind of belief about that state then the higher-order thought theory on which consciousness requires a kind of higher-order cognitive state about the first-order state for conscious perception to occur, is false. The response developed by Rosenthal, and that I find pretty plausible, is that in change blindness cases the subject may be consciously experiencing the changing element but not conceptualize it as the thing which is changing. This, to me, is just a higher-order version of the kinds of claims that Dretske is making, which is to say that this is not a ‘sparse’ view. Conscious perception can be as rich and detailed as one likes and this does not require ‘simple seeing’. Of course, the higher-order view is also compatible with the claim that conscious experience is sparse but that is another story.

At any rate, Phillips was not concerned with this debate. He was more concerned with the arguments that Dretske gave for simple seeing. He went through three of Dretske’s arguments and argued that each one had an easy rejoinder from the sparse camp (or the higher-order camp). The first he called ‘conditions’ and involved the claim that when someone looks at a (say) picture for 3-5 minutes scanning every detail to see if there is any difference between the two, we would ordinarily say that they have seen everything in the two pictures. I mean, they were looking right at it and their eyes are not defective! The problem with this line of argument is that it does not rule out the claim that they unconsciously saw the objects in question. The next argument, from blocking, meets the same objection. Dretske claims that if you are looking for your friend and no-one  is standing in front of them blocking them from your sight, then we can say that you did see your friend even if you deny it. The third argument involved that when searching the crowd for your friend you did saw no-one was naked. But this meets a similar objection to the previous two arguments. One could easily not have (consciously) seen one’s friend and just inferred that since you didn’t see anyone naked your friend was naked as well.

Phillips then when on to offer a different way of interpreting simple seeing based on signal detection theory. The basic intuition for simple seeing, as Phillips sees it, lies in the idea that the visual system delivers information to us and then there is what we do with the information. The basic metaphor was a letter being delivered. The delivery of the letter (the placing of it into the mailbox) is one thing, you getting the letter and understanding the contents, is another. Simple seeing can then be thought of as the informative part and the cognitive noticing, attending, higher-order thought, etc, can be thought of as a second independent stage. Signal detection theory, on his view, offers a way to capture this distinction.

Signal detection theory starts with treating the subject as an information channel. They then go on to quantify this, usually by having the subject perform a yes/no task and then looking at how many times they got it right (hits) versus how many times the got it wrong (false alarms). False alarms, specifically, involve the subject saying the see something but being wrong about it, because there was no visual stimulus. This is distinguished from ‘misses’ where there was a target but the subject did not report it. The ‘sensitivity to the world’ is called d’, pronounced “d prime”. On top of this there is another value which is computed called ‘c’. c, for criterion, is thought of as measuring a bias in the subjects response and is typically computed from the average of hits versus false alarms. One can think of the criterion as giving you a sense of how ‘liberal’ or ‘conservative’ the subjects’ response is. If they will say they saw something all the time then the seeming have a very liberal criterion for determine whether they saw something (that is to say they are biased towards saying ‘yes I saw it’ and is presumably mistaking noise for a signal). If they never say the say it then they are very conservative (they are biased towards saying ‘no I didn’t see it). This gives us a sense of how much of the noise in the system the subject treats as actually carrying information.

The suggestion made by Phillips was that this distinction could be used to save Dretske’s view if one took d’ to track simple seeing and c to track they subjects knowledge. He then went on to talk about empirical cases. The first involved memory across saccades and came from Hollingworth and Henderson, Accurate Visual Memory for Previously Attended Objects in Natural Scenes, the second f rom Mitroff and Levin Nothing Compares 2 Views: Change Blindness can occur despite preserved access to the changed information, and the third Ward and Scholl Inattentional blindness reflects limitation on perception, not memory. Each of these can be taken to suggest that there is “evidence of significant underlying sensitivity in [change blindness] and [inattentional blindness],”.

He concluded by talking about blindsight as a possible objection. Dretske wanted to avoid treating blindsight as a case of simple seeing (that is of there being phenomenal consciousness that the subject was unaware (in any cognitive sense) of having). Dretske proposed that what was missing was the availability of the relevant information to act as a justifying reason for their actions. He then went on to suggest various responses to this line of argument. Perhaps blindsight subjects who do not act on the relevant information (say by not grabbing the glass of water in the area of their scotoma) are having the relevant visual experience but are simply unwilling to move (how would we distinguish this from their not having the relevant visual experience)? Perhaps blindsight patients can be thought of as adjusting their criterion and so as choosing the interval with the strongest response and if so this can be thought of as reason responsive. Finally, perhaps, even though they are guessing, they really can be thought of as knowing that the stimulus is there?

In discussion afterwards I asked whether he though this line of argument was susceptible o the same criticism he had leveled against Dretske’s original arguments. One could interpret d’ as tracking conscious visual processing that the subject doesn’t know about, or one could interpret it as tracking the amount of information represented by the subjects mental states independently of what the subject was consciously experiencing (at leas to some extent). So, one might think, the d’ is good so the subject represents information about the stimulus that is able to guide its behavior, but that may be going on while the subject is conscious of some of it but not all of it, or different aspects of it, etc. So there is no real reason to think of d’ as tracking simple (i.e. unconceptualized, unnoticed, uncategorized, etc) content that is conscious as opposed to non-conscious. He responded that he did not think that this constituted an argument. Rather he was trying to offer a model that captured what he took to be Dretske’s basic intuition, which was that there was the information represented by the visual system, which was conscious, and then there was the way that we were aware of that information. This view was sometimes cast as unscientific and he thought of the signal detection material as proving a framework that, if interpreted in the way he suggested, could capture, and thus make scientifically acceptable, something like what Dretske (and other first-order theorists) want.

There was a lot of good discussion, a lot of which I don’t remember, but I do remember Ned Block asking about Phillips’ response to cases like the famous Dretske example of a wall, painted a certain color, having a piece of wallpaper in one spot. The little square of wallpaper has been painted and so is the same color as the wall. If one is looking at the wall and doesn’t see that there is a piece of wallpaper there, does one see (in the simple seeing kind of way) the wallpaper? Phillips seemed to be saying we did (but didn’t know it) and Block asked whether it wasn’t the case that when we se something we represent it visually and Phillips responded by saying that on the kind of view he was suggesting that wasn’t the case. Block didn’t follow up and didn’t come out after so I didn’t get the chance to follow up on that interesting change.

Afterwards I pressed him on the issue I raised. I wondered what he thought about the kinds of cases, discussed by Hakwan Lau (and myself) where the d’ is matched but subjects give differing answers to questions like ‘how confident are you that you saw it?’ or ‘rate the visibility of the thing seen’. In those cases we have, due to matched d’, the same information content (worldly sensitivity) and yet one subject says they are guessing while the other says they are confident they saw it (or rates its visibility lower while the other rates it higher (so as more visible)). Taking this seriously seems to suggest that there is a difference in what it is like for these subjects (a difference in phenomenal consciousness) while there is no difference in what they represent about the world (so at the first-order level). The difference in what it is like for them seems to track the way in which they are aware of the first-order information (as tracked by their visibility/confidence ratings). If so then this suggests that d’ doesn’t track phenomenal consciousness. Phillips responded by suggesting that there may be a way to talk about simple seeing involving differences in what it is like for the subject but didn’t elaborate.

I still am not sure how he responds to the argument Hakwan and I have given. If there is differing conscious experience with the same first-order states each in each case then the difference in conscious experience can only be captured (or is best captured) by some kind of difference in our (higher-order) awareness of those first-order states.

In addition, now that I have thought about it a bit, I wonder how he would respond to Hakwan’s argument (more stemming from his own version of higher-order thought theory) that the setting of the criterion in Phillips’ appeal to it in blindsight cases, depends on a higher-order process and so amounts to a cognitive state having a constitutive role in determining how the first-order state is experienced. This suggests that an ‘austere’ notion of simple seeing where there is no cognitive states involved in phenomenal consciousness is harder to find than Phillips originally thought.