Wednesday, August 27, 2014

Visual experiences aren’t always transparent
In 1976, when I delivered the John Locke Lectures at Oxford, I often spent time with Peter Strawson, and one day at lunch he made a remark I have never been able to forget. He said, "Surely half the pleasure of life is sardonic comment on the passing show".  This blog is devoted to comments, not all of them sardonic, on the passing philosophical show.
Hilary Putnam

Back on 6/11 (Escher Colors) I wrote;
“My own experience thus prepared me to accept one of the points that Block makes: the view (common to ‘representationalists’ and at least some ‘disjunctivists’ in the philosophy of perception) that the phenomenal quality of a subject’s visual experience upon looking at (hearing, feeling, smelling, etc.) a certain portion of her environment is exhausted by the objective appearance-properties (e.g., looking such-and-such a shade from such-and-such a point in space under such-and-such lighting conditions) of that portion of the environment is untenable. This view is, of course, a strong form of ‘naïve realism’, and while I think naïve realists are right to say that what we see (hear, feel, smell, etc.) when we perceive objects and events in our environment are properties of those objects and not properties of our qualia (something Block also thinks is right, as his paper makes clear), it is a mistake to say that describing what we perceive in objective terms also completely describes the phenomenology of the perceptual experience.”

In today’s post I want to discuss an argument representationalists (aka “strong representationalists”,  and “intentionalists”) often use to defend the view that I criticized, the argument from the “transparency” of phenomenal character. Here is how a leading representationalist, Michael Tye, opens his presentation of the argument:

 “Representationalism is a thesis about the phenomenal character of experiences, about their immediate subjective ‘feel’. At a minimum, the thesis is one of supervenience: necessarily, experiences that are alike in their representational contents are alike in their phenomenal character. So understood, the thesis is silent on the nature of phenomenal character. Strong or pure representationalism goes further. It aims to tell us what phenomenal character is. According to the theory developed in Tye 1995, phenomenal character is one and the same as representational content that meets certain further conditions. One very important motivation for this theory is the so-called transparency of experience. [1]
—and here is how he goes on to explain “transparency”:
“Focus your attention on the scene before your eyes and on how things look to you. You see various objects; and you see these objects by seeing their facing surfaces. Sense- datum theorists claimed that the facing surfaces of the objects are themselves seen by seeing further immaterial surfaces or sense-data. The sense-datum theory is unacceptable, however, for a whole host of familiar reasons. Intuitively, the surfaces you directly see are publicly observable physical surfaces. They are at varying angles to the line of sight and varying distances away. They can be photographed. In seeing these surfaces, you are immediately and directly aware of a whole host of qualities. You may not be able to name or describe these qualities but they look to you to qualify the surfaces. You experience them as being qualities of the surfaces. None of the qualities of which you are directly aware in seeing the various surfaces look to you to be qualities of your experience. You do not experience any of these qualities as qualities of your experience. For example, if blueness is one of the qualities and roundness another, you do not experience your experience as blue or round.”
For normal adult viewers, this paragraph does describe “how it seems”; in philosophers’ jargon, it describes part of the phenomenology of visual experience. But Escher Colors did criticize an assumption that is clearly implicit in what Tye writes, the assumption that the “qualities” I seem to perceive are qualities that a physical surface could actually have, (NB: Tye, like Byrne is a physicalist about colors). In Escher Colors I argued that there is no such thing as “really” being the exact shade that something seems to be when I look with my left eye (the right eye being closed) as opposed to “really” being the exact shade that it seems to be when I look with my right eye (the left eye being closed); those “Escher colors” may, phenomenologically, seem to be qualities of physical surfaces but they can’t be. That was the point of that post. But the purpose of the present post is not simply to remind you of that. Tye’s intention is to use the phenomenological “transparency” of visual experience to argue for the thesis that “phenomenal character is one and the same as representational content that meets certain further conditions”; and for that purpose, transparency (understood as Tye does) needs to be a necessary property of all visual experiences - an intrinsic  property of such experiences. The purpose of this post is to argue that there is impressive empirical evidence that transparency is not intrinsic, but is the result of learning.
Held’s experiments (1)
There is strong experimental evidence that in certain cases, described by Richard Held in two different series of experiments many years apart, some non-human mammals and even some humans do not visually perceive colors and shapes as “out there”. I conclude that “transparency” is (normally) the result of early learning (but, contrary to  Block’s view, mentioned in my previous post, not something we can override if we try and we know how to do it. At least I see no evidence for this claim.) The first visual experiences of many mammals, including both cats and humans, are not experienced by those organisms as properties of surfaces “out there”. “Out thereness”, recognition of things as having locations in places accessible to both sight and touch, requires that the correlations between visual space and sensorimotor (tactile, or “haptic”) space be learned. The disposition to learn such correlations quickly may well have been selected for in the evolutionary history of our visual and haptic systems, but some hours or days of learning are still needed. Here is some background.
In 1963, when Richard Held and I were colleagues at MIT, he showed me the following experiment that he and Alan Hein performed[2]: two kittens were placed in baskets that were at the opposite ends of a pole that was free to rotate around a vertical axle[3]. One basket had holes that permitted the kitten in that basket, kitten A, to push against the floor and thus to determine how the basket would move, at least to a limited extent. Kitten B’s basket had no holes; willy nilly, kitten B experienced spatial motion when kitten A moved – the mirror image of kitten A’s spatial motion, in fact - but no sensorimotor feedback. When kitten B was taken out of its basket, it had no recognition of any sensorimotor affordances at all. If one poked a finger towards its eyes, it stuck out its paws (an innate reflex), but not in the direction of the approaching finger. If it were put near the edge of the table, it would fall off (or would have fallen if there were not something to catch it) as often as not. But when Kitten A was taken out, it was able to position its paws in front of the threatening finger, it never walked off the edge of the table, etc. The results strongly suggest that the kitten that had not learned those correlations did not see the visual data it experienced as “out there”, and so the phenomenal aspects of its visual experiences were not transparent.
Held’s experiments (2)
In 1688 William Molyneux sent a message to the philosopher John Locke asking: “Suppose a man born blind, and now adult, and taught by his touch to distinguish between a cube and a sphere of the same metal ... Suppose then the cube and sphere placed on a table, and the blind man be made to see: query, whether by his sight, before he touched them he could now distinguish and tell which is the globe, which the cube ...?”[4]
In 2011 a team of researchers including Held and led by Pawan Sinha of MIT, published a negative answer to Molyneux’s question.[5] Similar results were reported earlier by a group referred to by Held in “Visual-Haptic Mapping and the Origin of Crossmodal Identity”[6]. The research involved studying youngsters who had been blind from birth, after they had lenses surgically implanted under the auspices of Project Prakash in India. Here is  the Abstract of “Visual-Haptic Mapping”:
“We found that the congenitally blind person who gains sight initially fails to identify seen objects with their felt versions: a negative answer to the Molyneux question. However, s(he) succeeds in doing so after a few days of sight. We argue that this rapid learning resembles that of adaptation to rearrangement in which the experimentally produced separations of seen and felt perceptions of objects are rapidly reunited by the process called capture. Moreover, the original ability to identify objects across modalities by the neonate may be assured by the same process.”
—And here is a description of the subjects studied by Ostrovsky et al:
“subjects’ responses were driven by low-level image attributes; [when asked to point to objects] they pointed to regions of different hues and luminances as distinct objects. This approach greatly oversegmented the images and partitioned them into meaningless regions, which would be unstable across different views and uninformative regarding object identity. A robust object representation is difficult to construct on the basis of such fragments”  (Ostrovsky, Y., et al. 2009. “Visual parsing after recovery from blindness”. Psychological Science 20, 1484-1491. 
In sum, these subjects’ visual experiences were anything but “transparent” to them. The representational content of visual experiences is something we learn to recognize. It is not intrinsic, and a fortiori not identical with their phenomenal character.

[1] Michael Tye, “Representationalism and the Transparency of Experience”, Noûs 36 (1), 137-51.

[2] Held, R. and Hein, A (1963) Movement-Produced Stimulation in the Development of Visually-Guided Behavior. Journal of Comparative and Physiological Psychology, vol. 56, 5: 872-876.
[3] For a picture, see:
[4] Morgan MJ. Molyneux's Question: Vision, Touch, and the Philosophy of Perception. Cambridge University Press, 1977. Quoted by Held in “Visual-Haptic Mapping and the Origin of Crossmodal Identity”,
[5] Richard Held, Yuri Ostrovsky, Beatrice de Gelder, Tapan Gandhi, Suma Ganesh, Umang MathurPawan Sinha. “The Newly Sighted Fail to Match Seen with Felt”, Nature Neuroscience 14 (2011), 551-553.
[6] Ostrovsky, Y., et al. 2009. Visual parsing after recovery from blindness. Psychological Science 20, 1484-1491.

Tuesday, August 19, 2014

A Snippet from a Forthcoming paper
In 1976, when I delivered the John Locke Lectures at Oxford, I often spent time with Peter Strawson, and one day at lunch he made a remark I have never been able to forget. He said, "Surely half the pleasure of life is sardonic comment on the passing show".  This blog is devoted to comments, not all of them sardonic, on the passing philosophical show.
Hilary Putnam

The following paragraphs are from my “Perception Without Sense-Data”, forthcoming in Willy Essler and Michael Frauchiger (eds.), Themes from Putnam (Ontos)
Indeed, it may seem obvious that, if there are sense data, then they are what knowledge of the world is “based on”. What else do we have, after all?  Even before we try to see more clearly what the alternatives before us really are, here is a point to keep in mind: the fact (if you agree with me that it is a fact) that our experience has a qualitative and non-conceptual dimension does not entail that we perceive qualia. Indeed, Moore himself thought that it is difficult to perceive qualia, and Shoemaker has argued that we cannot perceive them. As Block writes[1],
“Shoemaker’s view is shared by Fred Dretske, Gilbert Harman, Michael Tye and many others who advocate what G. E. Moore termed the diaphanousness (or sometimes the transparency) of experience. Harman puts the point by saying that the more one tries to attend to one’s experience of the tree, the more one attends to the real tree instead.  Although Moore is sometimes cited as the originator of this point, he did not actually accept it.  I have heard him quoted saying ‘... the moment we try to fix our attention upon consciousness and to see what, distinctly, it is, it seems to vanish: it seems as if we had before us a mere emptiness. When we try to introspect the sensation of blue, all we can see is the blue; the other element is as if it were diaphanous.’  But these words are followed by what I regard as a more significant truth:  ‘Yet it can be distinguished if we look attentively enough, and know that there is something to look for.’”

Hilla Jacobson and I are currently working on a book on the quest for naive realism in contemporary philosophy of mind. Our view is neither Shoemaker’s (that  there is no such thing as attending to one’s qualia) or Block and Moore’s view that we have to perform a special act of “looking attentively enough” (unless what they mean to point out is just that we have to  conceptualize  differently when we attend to the qualitative aspect of what is presented in an experience as opposed to its representational content). We can attend both to the objective color (for example) of something (that shirt is blue) and to  the “look” of that color, and, indeed, to various “looks” that it (potentially) has—how it looks from here, for example, or how it looks in the daylight, and also to more subjective looks. In  the case of veridical perception, all of those looks are genuine properties of the object seen.

Friday, August 15, 2014

Different Looks
In 1976, when I delivered the John Locke Lectures at Oxford, I often spent time with Peter Strawson, and one day at lunch he made a remark I have never been able to forget. He said, "Surely half the pleasure of life is sardonic comment on the passing show".  This blog is devoted to comments, not all of them sardonic, on the passing philosophical show.
Hilary Putnam

In my previous post I said that "what looks are, and the distinction I draw between objective looks and subjective looks, will be taken up next in this series of posts.” The present post cashes this promissory note.

Looks are dispositional properties of objects not qualia 
In accordance with the grammar of such noun phrases as “the pink look of your dress in this sunset light”, I take a look to be a property of an object. There is another use of “look” in which a real object is not required, viz in sentences of the form: “It looked to P as if…… The function of such locutions is usually to report a misperception or an illusion or a hallucination (“it looked to Mr. Tipsy as if there were a pink elephant in front of him”); the statement does not imply that any real object had a pink elephantish look. [As a comment from "Anonymous" reminds us, there is also the use to "hedge" an assertion - "It looks like the runner was safe".]   But if I truly say that an object looks so-and-so, then, regardless of whether it is actually so-and-so, in those circumstances, it has a disposition to seem so-and-so to the person in question. In precisely what sense it “seems so-and-so” distinguishes the different sorts of looks I will describe, but in all of these cases, if I speak truly, then I describe a disposition that a real object has at least momentarily.

It follows that whatever looks may be, they are not qualia. Qualia, in my view are properties of an organism (in today’s post, a human being). [In a forthcoming paper, Hilla Jacobson and I call this position “attributeism”, and we distinguish it from “adverbialism” which is a particular form of attributeism,  but that is not our subject today. Reichenbach, in Experience and Prediction was an attributeism but not an adverbialist. Attributeism is a position about the ontology of qualia (Reichenbach’s “impressions”), namely that they are attributes of organisms, while Adverbialism is a position, invented I believe by Ducasse[1], about the real logical form of statements like “I experience a red circular sense datum” – a logical form which is thought to be misleadingly expressed by the seven word sentence in quotation marks.] Others think of qualia as properties of “experience”, or as mental events. But in any case, no quale is a property of a vase or wall, although vases and walls are precisely the sorts of things that can have “looks”.

In my “promissory note” I spoke of a distinction between  “objective looks and subjective looks”, but a more complex taxonomy is certainly called for. In this post I will briefly indicate what I mean by “subjective looks”,  but leave further discussion to future posts.

Subjective looks
In the previous post the example of a “subjective look” was the exact shade something appears to me to be when I view it with my right eye closed and the exact shade it appears to me to be when I view it with the left eye closed. Because of variations in the pigmentation in the macular areas of the two eyes, those shades seem slightly different, but neither eye “sees it wrong”. The visual qualia are different, and neither eye “misrepresents” the object I look at (a gray wall or the sand on a beach), The difference in the qualia I experience are, to use Ned Block’s term, “ineffable”, not describable in public language as it stands now (see the previous post).  As Block points out[2], “…we can refer to [a quale] by saying ‘What it is like for that person to see red’.  What we cannot find is a color name ‘F’, such that what it is like for one of these people to see red can be expressed in the form ‘looking F’, and in that sense we can say that the experiential property is an ineffable quale.” Using this quale-terminology, subjective looks are dispositions to affect the visual qualia of the viewer; this is what Russell thought colors  are, but that was a mistake, as pointed out in my previous post. The visual system is designed to represent real colors, not subjective looks, and certainly not to represent “the sense data of normal viewers”.

More has to be said about subjective looks, in particular about what has been called their “transparency” or “diaphanousness”, but that is part of what I am leaving for later posts.
Intersubjective looks
I close with some remarks about looks that people with normal vision agree objects have under certain circumstances (which may be very deceptive, e.g., a white dress when  illuminated by a red light). But that is a genus that comprises more than one species (and I make no pretense to being able to list all of those species). For our purposes, we shall say something about just three species of intersubjective looks, namely:
(a) fully objective looks (ones that can be painted or photographed).
(b) illusions like the Müller-Lyer that do not depend on the background against which the object is viewed.
(c) background-dependent illusions.

Fully objective looks
So my readers don’t have to scroll back to my post of July 23rd (“Colors and Their Objective Basis”), let me remind you that in that post I endorsed something that Alex Byrne and David R. Hilbert wrote[3], namely:

But is there a physical property that all and only (actual and possible) green objects share? Given our assumption about the general correctness of our color perceptions, the answer is (plausibly) yes. The property that all green objects share is a type of SSR [=Surface Spectral Reflectance - HP]. Very roughly, this property -- call it ‘SSRGREEN’ -- is the type of SSR that allows an object in normal illumination to reflect significantly more light in the middle-wavelength part of the spectrum than in the long-wavelength part, and approximately the same amount of light in the short-wavelength part as in the rest. Obviously, particular reflectances meeting these specifications -- for instance those of frogs, lettuce, and dollar bills -- may be otherwise very different.”

However, in that same place, Byrne and Hilbert give a somewhat exaggerated account of color constancy, when they write,
If two objects have the same SSR, in all visible illuminations they will reflect the same amount of light. If one object is substituted for another with the same SSR (assuming they are the same size) in the scene before the eyes, no visible color difference will result. The SSR of an object is (typically) an illumination-independent property: the SSR of an object does not change if the object is taken from a room to a sunny street, or if the lights are turned out. And this, arguably, is also a feature of color.”

This can only be an intentional oversimplification. If things were that simple the white dress would still look white even when there is a gorgeous red sunset! In fact, writers on color seriously qualify what they say about color “constancy”, (although the ones I have seen fail to distinguish objective failures of “constancy”, failures that can be “captured” by a good painter or photographer, and subjective and even idiosyncratic failures of subjective colors to be “constant”.  An example of such qualification is the following by David Briggs (Dimensions of Color,

For an object in a natural scene, the capacity of our visual system for colour constancy means that its perceived hue is determined to a large extent by the dominant wavelength of its reflectance under white light, as long as the illumination of the scene is not too strongly coloured. Nevertheless, an object can vary considerably in perceived hue depending on surrounding, interspersed and previously viewed colours, and even on the attitude of the viewer. In viewing an image, our capacity to extract object colour information from a visual scene can cause us to perceive hues very different from the actual image hues.”  [emphasis added –HP][4]
As for the “ontology” of such objective looks: when the look of a color (hue) in a particular situation can be displayed by a photograph or a painting, the “objective look” is simply the color shown by the photograph or painting; the “look” of one hue can sometimes be a different hue.
illusions like the Müller-Lyer[5] that do not depend on the background against which the object is viewed
When we move from hues to lengths a difficulty emerges! A photograph of a Müller-Lyer illusion is just another Müller-Lyer illusion; what makes it an illusion is that two lines appear to be of unequal length when they are actually the same length; but the lines in the photograph are also of the same length (measure them!) and they too appear to be of unequal length.  The photograph qua physical object does not show “the unequal lengths the lines appear to have”, in the way that a photograph of a white dress in red light can show the color the dress appears to have. In that sense, the “look” of the lines is not fully objective, yet, since everyone appears to describe the illusion in the same way, it is an intersubjective look.
Background dependent illusions
Andrew T. Young writes (“Introduction to Color”):
Incidentally, what the human visual system considers “light” or “dark” depends very strongly on the perceived context. If I had displayed the orange square here[6] against a white background instead of a medium-gray one, you'd have perceived it as brown rather than orange. There are some vivid demonstrations of this context effect at Edward Adelson's checker-shadow illusion,, and the paper by R. Beau Lotto and Dale Purves, “An empirical explanation of color contrast” (Pub. National Acad. Sci. 97, 12834–12839 (2000), which you can download as a PDF file if your institution subscribes to PNAS.”
Although the “objectivity” of the look (orange or brown) is virtually nil, the intersubjectivity is apparently as great as that of the Müller-Lyer illusion.

The account according to which all this is explained by similarities in the sense-data (qualia) of normal subjects suffers from a lack of present empirical evidence. What is clear is that (1) our visual systems are built to construct representations of the color – the real color – of surfaces from data such as arrays of light falling on our retinas, data that woefully underdetermine the “right” representation, and they get it right in an enormous range of cases. They do that by using clever algorithms (Edwin Land was the pioneer here with his Retinex – retina+cortex – algorithm). But the algorithms work only under certain conditions of illumination and background. Thus various representations and misrepresentations sometimes arise. This explanation` does not require us to know how similar or dissimilar the qualia of different people actually are.
to be continued

[1] See
[2] Ned Block, “Wittgenstein and Qualia,” in M. Baghramian, Reading Putnam. However, Block identifies subjective looks with the corresponding qualia, and I disagree for the reason just given.
[3] Byrne and Hilbert Readings on Color, Volume 1: The Philosophy of Color, MIT Press, 1997; online at My agreement with Byrne on the physical nature of the colors of surfaces does not imply agreement with his “intentionalist” view of the nature of subjective  colors, and of phenomenal experiences generally, namely that “the propositional content of experiences in a certain modality (for example vision) determines their phenomenal character. In other words, there can be no difference in phenomenal character without a difference in content.” [Alex Byrne, “Intentionalism Defended”, The Philosophical Review, Vol. 110, No. 2 (April 2001) , p. 204. Emphasis in original.] This disagreement will be the subject of a future post.
[4] For a review of the literature see David H. Foster, “Color Constancy”, Vision Research 51 (2011) 674–700.