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 23^rd (“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 ‘SSR_GREEN’ -- 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, http://www.huevaluechroma.com/012.php#chroma):

“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, cut-the-knot.org, 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

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[1] See http://plato.stanford.edu/entries/pain/notes.html

[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 http://web.mit.edu/abyrne/www/colors&reflectances.html. 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.

[5] See https://www.google.com/search?q=m%C3%BCller-lyer+illusion&espv=2&tbm=isch&tbo=u&source=univ&sa=X&ei=bXHuU5eAN46HyASSxQE&ved=0CCsQsAQ&biw=741&bih=455

[6] http://mintaka.sdsu.edu/GF/explain/optics/color/intro.html

A Response to my Color Anti-realist Friend

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

My old friend JW writes:

“I am not clear if you are claiming the ‘greenness’ that I can successfully ascribe through repeated experience of my lawn as colour constancy to be itself a physical property of the object in a particular state (which position teasingly I refer to as ‘farbe an sich’), because elsewhere you recently said that there is no such thing as ‘being' green.  

“Or, are you saying that other physical properties of the object cause me (and most others with my kind of eyes) to see light of such and such a frequency in such and such a scatter under such and such an illumination as the same green (more or less) as my lawn was yesterday - given that it has rained on both days - which is good for the garden in this heat - even if the look of it is different from morning to evening, from day to day.  This would mean that green objects have the same or similar physical properties but not necessarily that these properties are in and of themselves green, just green inducing to my kind of eyes?”

I want to share my responses to my friend’s questions, so that he and the other readers of this blog will be clear on what I am saying and what I am not saying. One thing I did not say was that there is no such thing as being green.

Escher colors again

What I wrote, in my post of June 11 (“Escher Colors”) - after pointing out that even for normal viewers there is a slight (but noticeable if one attends to it) difference between the shade of color an object appears when viewed with the left eye closed and when viewed either either both eyes open or with the right eye closed - was:

“Yes, the question “is the wall (or the sand, in the beach case) really the shade of gray (or yellow, in the case of the sand) that it appears to be when I use my right eye or the shade it appears to be when I use both eyes, has no answer, “makes no sense”—there is no metaphysical fact to the matter to decide this “question”; but, in another way, it seems to make sense.  It takes reflection, however brief, to convince oneself that there is no such thing as the wall (or the sand) being colorwise as it looks to my left eye as opposed to its being as it looks to my right eye. It seems, at least for a moment, as it something may “really be” that color.  But there is no such thing as that color!   The color, or better the exact shade of gray or yellow or whatever,  that the wall seems to be when I use my right or left eye isn’t the sort of thing that a color on a paint chart is; the wall could really be, say, purple-gray₃₂, but there is no such thing as it’s really being “gray*”, where gray* is the “shade” that the wall “seemed to be” when I used my left eye to view the wall on that occasion.  Subjective colors are impossible colors.  Like an Escher building, they seem to be real and simultaneously to be impossible. As long I can remember how the “gray*” wall looked, I can say truly that “it looked gray*”, but “gray*” occurs intentionally, not referentially, in “looks gray*”; there is such a thing as “looking gray*” to a person at a time, but no such thing as really being gray*. Subjective colors aren’t colors; they are Escher colors.

Obviously, my friend misremembered the claim that there is “no such thing as really being gray*”, not only by forgetting that it was gray and not green, but my omitting the “*”. There is such a thing as being gray, but no such thing as being gray*.

But what is “gray*”? The short answer is that there is no such thing. The longer answer is that, in “looks gray*”- an expression I can use to describe a color experience as long as I remember what that look was[1] - “gray*” is, in scholastic terminology, syncategoramatic. It contributes to the meaningful denoting expression “looks gray*” – which denotes a subjective look – without denoting anything on its own. That’s  why there is no such thing as being (to shift the example) green* but absolutely there is such a thing as being green. Don’t lose the star!

The importance of distinguishing colors from color looks

It seems to me that a major reason that my friend gets me wrong is that, like Russell, in Problems of Philosophy, he conflates colors and color looks. Russell wrote:

“To make our difficulties plain, let us concentrate attention on the table. To the eye it is oblong, brown, and shiny, to the touch it is smooth and cool and hard; when I tap it, it gives out a wooden sound…but as soon as we try to be more precise our troubles begin. Although I believe that the table is ‘really’ of the same color all over, the parts that reflect the light look much brighter than the other parts, and some parts look  white because of reflected light. I know that, if I move, the parts that reflect the light will be different, so that the apparent distribution of colors on the table will change. It follows that if several people are looking at the same table at the same moment, no two of them will see exactly the same different distribution of colors….” (p. 8, 1912 edition)

Here Russell moves immediately from a difference in “the apparent distribution of colors”, to “not the same distribution of colors”, that is, he takes a difference in apparent colors, or color looks, to be ipso facto a difference in actual colors. And two pages later Russell writes,

“When, in ordinary life, we speak of the color of the table, we only mean the sort of color it will seem to have to a normal spectator from an ordinary point of view under usual conditions of light. But the other colors which appear under other conditions have just as good a right to be considered real; and therefore, to avoid favoritism, we are compelled to deny that, in itself, the table has any one particular color.”

In my Bastille Day post (“The Manifest Image Is Not Wrong”), I wrote that this sort of view leads to a wholesale skepticism about the veridicality of what Sellars famously called “the manifest image. In Russell’s case this “leading to” is immediate. The very next sentence in Problems of Philosophy reads: “The shape of the table is no better. We are all in the habit of judging as to the ‘real’ shapes of things, and we do this so unreflectingly we come to think that we actually see the real shapes. But if our table is ‘really’ rectangular, it will look from almost all points of view as if it had two acute angles and two obtuse angles.” (He makes similar points about texture, solidity, etc.) And just as he concluded from the fact that the table has different color looks when viewed from different positions, that has “no one particular color”, so he now concludes that “the ‘real’ shape is not what we see” (page 11), and, further down the same page, “The real table, if there is one (sic), is not immediately known to us at all, but must be an inference from what is immediately know.”

 (Since none of the properties of the object can actually be seen or felt, the “object” becomes an inferred unobservable.)

The answer to the question in my friend’s first paragraph is that I am saying “the ‘greenness’ that I can successfully ascribe through repeated experience of my lawn as color constancy to be itself a physical property of the object in a particular state” and I am also saying (his second paragraph, but I have intentionally deleted the word “other”) “physical properties of the object cause me (and most others with my kind of eyes) to see light of such and such a frequency in such and such a scatter under such and such an illumination as the same green (more or less) as my lawn was yesterday - given that it has rained on both days - which is good for the garden in this heat - even if the look of it is different from morning to evening, from day to day.  This would mean that green objects have the same or similar physical properties” – BUT where he continues “but not necessarily that these properties are in and of themselves green, just green inducing to my kind of eyes” I would say that a particular distribution of those properties (technically, a reflectance profile) is identical with being (physically, really, green [in hue, neglecting here saturation and brightness]).  (That properties can be identical even though the concepts expressed by the corresponding predicates are quite different is something I first argued for and applied to the philosophy of mind in a paper published in 1967[2].) In sum, I believe that hues are identical with reflectance profiles, and that this identity is an empirical one, an identity we discover through theory building and confirmation.

But this would, of course, be absurd, if hues were identical with subjective looks like gray*. (Russell’s “apparent colors”, which he later says are in a “private space”).  But they are not. What looks are, and the distinction I draw between objective looks and subjective looks will be taken up next in this series of posts.

Epistemology

To close, I need to say a word about my difference with Russell over epistemology.

[I discuss these differences in more detail in “Naïve Realism and Qualia”, forthcoming in Adam Pautz and Daniel Stoljar (eds.) Themes from Block (MIT)]

Russell takes it that perception starts with sense data. That is why things in the environment can only be inferences.  I take it that we are essentially embodied creatures, and our knowledge starts with transactions between our bodies, including our brains and sense organs, and the external environment. Perception (as Tyler Burge has recently emphasized in his path-breaking book The Origins of Objectivity) involves representation of objects and features of the environment by perceptual systems; and our perceptual systems do not begin by examining the organism’s own qualia. And the properties our perceptual systems represent are not dispositions to produce qualia. I am a functionalist, but my functionalism today is a liberal functionalism[3]: the functional states involved in perception are not computational states, as I once thought, but object-involving states, states with “long arms”. If knowledge were something that begins in “private spaces”, as Russell held, there is no way it would ever get outside!

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[1] In a terminology Ned Block uses, I think in “Wittgenstein and Qualia”, “looks gray*” is  ineffable, meaning by that, not the in principle ineffability that philosophers rightly view with suspicion, but that there is at present no name for that look in public language, nor, since it is a purely  subjective look, any way of introducing such a name until we know more about the neural correlates of the various subjective looks.

[2] “Psychological Predicates.” Art, Mind and Religion, ed. W. H. Capitan and D. D. Merrill (Pittsburgh, Penn.: University of Pittsburgh Press, 1967), 37-48. Repr. as “The Nature of Mental States” in Mind, Language and Reality (1975), 429-440.

[3] For an explanation of the term “liberal functionalism” see chapter 3, “Corresponding with Reality”, of my Philosophy in the Age of Science

Quine's "Underdetermination Doctrine"

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

What follows this introductory paragraph are the opening paragraphs of chapter 16 [A Proof of the Underdetermination "Doctrine"]  of my Philosophy in the Age of Science. Because the confusion they address, between Quine’s “underdetermination doctrine” and “the Quine-Duhem Thesis” is still widespread, I have decided to post just those paragraphs. They point out that in  “On Empirically Equivalent Systems of the World,”  a paper I heard him read at a symposium in Stuttgart a year or two before it was published, Quine admitted that the underdetermination doctrine admitted of a trivializing interpretation, and proposed a way to rule it out, but confessed that, when so modified, it was something he could not prove. In homage to his memory, I decided to look for a proof. The reader who is interested in these matters can find my proof (which uses heavy-duty mathematical logic)  in my chapter, and can find further information in the book by Yemima Ben-Menahem I cite below.

Prior to the publication of “On What There Is” in 1948, W.V.O. Quine was known to most philosophers (if they had heard of him at all) as a “logician.” But now it is universally acknowledged that the series of Quine’s philosophical papers and books that began with that famous essay are among the most important to have been published in (approximately) the second half of the twentieth century. One of the most famous theses in that series of works is “the doctrine that natural science is empirically underdetermined.”[i] Yet I have observed that Quine’s “doctrine” is widely misunderstood, and its logical status is, in fact, murkier than most readers imagine. The purpose of the present essay is to remove the murk and to prove the doctrine.

The principal misunderstanding I have observed is the idea that underdetermination follows immediately from “the Quine-Duhem thesis,” by which is meant the thesis that theoretical claims cannot be either conclusively falsified or conclusively confirmed by isolated experiences. If those experiences appear to falsify a theory, it is always possible to revise parts of the theory (including what the logical empiricists called the “coordinating definitions”), or, if worse comes to worse, to reject the observation sentences that we use to report those experiences. However this claim has literally nothing to do with the “underdetermination” doctrine. That doctrine, to which Quine gave considerable weight in his writings,[ii] says that even if we do not reject any observation sentences that we take to have been verified, and even if we do not allow any changes to the theory, still, if there is at least one theory that has a given set of observational consequences, then there will always be more than one.

Another misunderstanding that I have observed, even among those who do not confuse “the underdetermination doctrine” with “the Quine- Duhem thesis,” is that the underdetermination doctrine is, somehow, logically obvious. But it is not obvious, and in her brilliant book on conventionalism, Yemima Ben-Menahem reminds us that in a little-known lecture Quine surprisingly confessed that the doctrine risks being either trivial or, at best, unprovable! As Yemima Ben-Menahem has pointed out, in the original version of “On Empirically Equivalent Systems of the World,” Quine suggested a way of stating the doctrine that would avoid triviality, but concluded that so restated, the truth of the doctrine “is an open question.”[iii] However, all of this rethinking was excised from “On Empirically Equivalent Systems of the World” before that essay was collected in Pursuit of Truth![iv]

As Ben-Menahem explains the problem:

Underdetermination crumbles under a problem that seems utterly trivial at first. Quine invites us to consider two theories that are identical except for a permutation of terms, for example “electron” and “proton.” What is the relation between these theories? Taken at face value, they are clearly incompatible, for each affirms sentences the other denies, for instance, "The negative charge of the electron is..." It is likewise clear that these incompatible theories are empirically equivalent—they have exactly the same empirical import. The question is whether this would count as an example of underdetermination, that is, whether such a minor permutation of terms suffices to render the two theories empirically equivalent but incompatible alternatives. Rather than taking them at face value is it not more reasonable to regard them as slightly different, though perfectly compatible, formulations of the same theory?[v]

She goes on to explain that Quine endorsed the latter alternative. He wrote, “So I propose to individuate theories thus: two formulations express the same theory if they are empirically equivalent, and there is a construal of predicates that transforms one theory into a logical equivalent of the other.”[vi]

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[i] W.V. Quine, “On Empirically Equivalent Systems of the World,” Erkenntnis, 9 (1975): 313-328; quotation from p. 313.

[ii] For example, in W.V. Quine, “On the Reasons for the Indeterminacy of Translation,” Journal of Philosophy, 67 (1970): 178-183, Quine gives the underdetermination of theory by data as one of the two principal reasons for his famous (and controversial) thesis of the indeterminacy of translation.            

[iii] W.V. Quine, “On Empirically Equivalent Systems of the World,” Erkenntnis, 9 (1975): 313-328; quotation from p. p. 327.

[iv] W.V. Quine, Pursuit of Truth (Cambridge, Mass.: Harvard University Press, 1990/2004).{ADDED TODAY: This was a mistake. Quine did not "collect" this paper in Pursuit of Truth; but he did write (p.96) "Effort and paper have been wasted, by me among others, over what to count as sameness of theory and what to count as mere equivalence. It is a question of words; we can stop speaking of theories and just speak of theory formulations. I shall still write simply 'theory', but you may understand it as 'theory formulation' if you will." He does not mention that this makes the underdetermination doctrine trivial.]

[v] Yemima Ben-Menahem, Conventionalism: From Poincaré to Quine (Cambridge. Cambridge University Press, 2006), 246.

[vi] Quine, “On Empirically Equivalent Systems of the World,” 320.