Qualia Inversion: Sound and Color (A Contest with a "Valuable Prize"!)

If you're the kind of person who reads philosophy blogs, you've probably heard of inverted qualia thought experiments. The most famous example is red-green inversion: The red-green invert is someone who has reddish color experiences when she looks at green things (grass, leaves) and has greenish color experience when she looks at red things (blood, ripe tomatoes). Since the invert, like the rest of us, learns the meaning of color terms by example, her language and behavior is entirely, or at least virtually, indistinguishable from anyone else's. She uses the English word "red" to refer to the color of blood and "green" to refer to the color of grass, despite the difference in her color experiences of those things.

In a talk at UC Riverside a couple of weeks ago, Saul Kripke asserted that no philosopher had ever suggested the possibility of sound-color qualia inversion -- that is, the possibility of a person who experiences sound qualia when stimulated by light and color qualia when stimulated by sonic vibrations. Let's be clear that Kripke was not denying the possibility of synaesthesia. He was not denying that people sometimes (for example) experience colors alongside sounds when stimulated by sounds. Kripke's claim, rather, was that no philosopher had contemplated a true sound-color qualia invert -- someone who normally experiences sound rather than color when stimulated by light and color rather than sound when stimulated by sonic vibration and whose language and behavior from the outside is indistinguishable from that of non-inverts.

Kripke said this twice. I told him I was pretty sure he was wrong and that I had read such a discussion. Kripke challenged me to send him the citation. After a little research, I turned up my source: an unpublished essay by one of my graduate students, Nathan Westbrook. When I asked Nathan whether he knew of any precedents, he said he didn't. I also tried asking someone who had recently published a review of the qualia inversion literature; he too said he didn't know of anyone who had advanced that type of example.

But given the huge number of philosophy articles published each year and the prominence of qualia inversion examples, I feel sure someone must have discussed this kind of case somewhere. Therefore, I offer a challenge: Find a published discussion of sound-color qualia inversion. The winner will receive a "valuable prize" -- hm, what can I offer? How about: a drink of your choice (coffee, beer, whatever) on me, next time we are in the same city. (Okay, maybe that's no so valuable.)

Rules:

* The contest is open until June 14th or until someone delivers a satisfactory example, whichever comes later.

* To be satisfactory, the discussion must be published in a reputable philosophy journal or press.

* To be satisfactory, the discussion need not ultimately endorse the possibility of color-sound qualia inversion, just take it seriously.

* If more than one satisfactory example is submitted, the person who submits the best example will be declared the winner, where I will judge "best" impressionistically, criteria including but not limited to: the length and quality of the discussion, the prominence of the writer or venue, and how seriously the possibility is taken.

* If more than one person submits the best example, the first person to submit the best example will be declared the winner.

* Submit your example as a comment on this post or by email to me.

For the record, I lean toward thinking that sound-color qualia inversion is possible in a conceptual/metaphysical/pulling-it-out-of-my-a-priori-hindquarters-for-the-little-that's-worth sense of possibility.

Color experiences famously differ along three dimensions: hue, saturation, and lightness or brightness. They also differ in egocentric, subjective location. To work an inversion with sound, we need a one-to-one mapping of dimensions of variation. Subjective location would appear to be easy, since both colors and sounds have subjective location. Since brightness and saturation are both unidimensional, we might be able to map them one-to-one onto pitch and volume, which are also unidimensional. Hue varies in a bit more complex a way, with red-green as opposites and blue-yellow as opposites, but perhaps patterns in the overtone series could be used. Probably the hue-overtone series mapping would require some tweaking to work, but presumably human-like beings with a slightly different set of visual and auditory capacities could exhibit a clean mapping (e.g., if the beings were only capable of discriminating certain patterns in overtone variation). Another complication is our much higher sensitivity to variation in visual as opposed to auditory position. But I don't see why, for the purposes of the thought experiment, we shouldn't be liberal about such matters: The sound-color invert, for example, might be an invert only of a relatively poor-sighted person and/or might have an exquisite appreciation of subtle variations in the position of sound sources subjective location of sound qualia.

55-Year-Old Philosophers vs. 55-Year-Old Scientists

I continue to be struck by my finding, last week, that great philosophers produce their most influential work at a very broad distribution of ages. (Nifty chart here; if it's blurry click a second time to enlarge.) Physicists and mathematicians, in contrast, are reputed to peak early. Einstein notoriously said "A person who has not made his great contribution to science before the age of thirty will never do so".

Stephan and Levin (1992) have compiled data on the age at which Nobel-Prize-winning scientists did the work leading to the Nobel Prize. (The data could use updating, admittedly.) Their data confirm that scientists do tend to peak fairly early (even if not as early as Einstein suggests) -- in their mid-thirties. The graph below contrasts the distribution of ages at which scientists did the work earning them the Nobel with the (approximate) distribution of ages at which leading philosophers born before 1920 did their most influential work (see the earlier post for my method; one tweak on that method: I used Google Scholar to break the two ties).

Note that while chemistry, physics, and medicine all peak sharply in the 30s, philosophy distributes evenly across the 30s, 40s, and 50s. Note also that although there is almost no Nobel work done by scientists in their 60s or older (0.8%, according to Stephan and Levin), in my sample -- admittedly small, just 46 philosophers -- 8.7% of great philosophers' most-cited work was done at age 61 or older.

So take heart, my gray-haired friends!

Paul Hoffman

Yesterday, Paul Hoffman died of a heart attack. He was a great scholar and colleague. I will miss him terribly.

At a talk on Monday, John Fischer announced his own coming talk on why immortality might not be so bad, to be given Wednesday. Howie Wettstein said from the audience, "we should all live so long". We all heard it as a joke, of course. One of Paul's last acts as a philosopher was to argue during the question period after John's talk that he saw no impossibility whatsoever in the idea of enjoying continual bliss in a never-ending embodied life.

One of the wonderful things about Paul as a colleague was his immunity to groupthink, his ability to bring to discussion a different perspective and fresh set of considerations. I always enjoyed hearing what he had to say, especially when we disagreed. Paul's forthright independence of mind was also, I suppose, what made him such an interesting historian of philosophy.

The Rise of Ethics and Feminism

A philosophical discussion arc, as I defined the term a couple weeks ago, is a curve showing changes over time the use of a name or a word as a "keyword" in philosophy books and articles listed in The Philosopher's Index (which dates back to 1940).

Previous posts showed discussion arcs of various prominent philosophers. But I've also been searching by topic and subfield. One striking general result I've found is the rise of discussion in ethics relative to other philosophical subfields.

Here's a chart of the enormous increase in total rate of philosophical publication since the 1940s, with keyword searches related to subfield. (Note that the y-axis is scaled logarithmically. Note also that "*" is a truncation symbol, so that (for example) ethic* returns "ethic", "ethics", "ethical", etc. The rate of increase in the 1940s is somewhat inflated by the increase in the length of listed article abstracts.)

[If this or any other chart displays incorrectly, click on it to bring up a cleaner jpg.]

I don't know whether to find it alarming or exciting that if trends continue philosophers will soon be producing 100,000 articles and books per five-year period in some subfields.

What I am interested in here is not so much the absolute numbers, though, as the relative numbers. And not even the relative numbers per se, which may be somewhat misleading (since not all and only epistemology articles contain epistem* as a keyword, and the keyword false negatives and positives may differ by subfield), but rather the changes over time in relative numbers. In the chart above, for example, you will see that in the 1990s ethics (EMP: ethics, moral, political) crossed lemmings (language, epistemology, metaphysics, and mind). Assuming relatively constant false negatives and positives over time within each subfield, the crossover suggests that ethics has been growing faster than has language, epistemology, metaphysics, and mind.

The following chart displays that fact more clearly:

In the 1950s, about half as many books and articles had an ethic*/moral*/polit* keyword as a language*/epistem*/metaphys*/mind* keyword. Now there are more EMPs than lemmings.

Nor have other major subfields fared better, as you can see below:

The ethicists are taking over! (If only they would behave better.)

Feminism is now a major philosophical research specialization, as was not the case before the 1970s. The chart below displays its explosive rise. (In the denominator is EMPlemmings: all articles using any of the EMP or lemmings keywords.) Notice that the rise is almost entirely in the 1970s to early 1990s. The trend has been flat to declining since then.

The same chart shows a U-shaped curve for discussion of race. I double-checked a sample of the 1940s articles to see if they really did treat race or ethnicity as a substantive topic (rather than, say, using a phrase like "the human race" in the abstract simply to mean people), and almost all did use "race" in the intended way. In the context of World War II, race was I suppose a rather hot issue! Interesting that it should be less so, at least in the philosophy journals, in the heyday of the civil rights movement.

At What Age Do Philosophers Do Their Most Influential Work?

In an earlier post, based on an unsystematic sample, I estimated age 38. Today, with a broader and more systematically collected sample, I'm retracting that. Mostly.

Here's what I did:

First, I created a massive super-bibliography consisting of all the bibliographies from non-historical entries in the Stanford Encyclopedia of Philosophy. I then examined the SEP citation patterns of all philosophers born from 1550 to 1919 who were cited in at least nine distinct entries -- 53 highly influential philosophers in total.

Next, I noted which of these authors' works were the most cited in the SEP (an imperfect measure of influence, of course, but it avoids my having to rely on my own even more imperfect judgment); and I estimated the age at which that work was produced as publication date minus birth year minus 2. (Minus two because the average person spends half of the year at which she turns age X at age X-1 and because of the typical delay between writing and appearance in print.)

(A few more methodological details: Wittgenstein's Investigations, published posthumously, I estimated as produced at about age 55, based on historical evidence. In the case of multi-edition or multi-volume work, I considered the first-published work. In the case of a tie in number of citations (which happened twice) I took the midpoint as my estimate. Two authors I excluded because they had no single work cited more than three times in front-page, non-historical SEP bibliographies: Peirce and Dewey. And because the question concerned relative productivity over the life span I excluded five authors who died before age sixty: Descartes, Nietzsche, Austin, Ramsey, and Prior.)

Here, then is the final list, arranged by age:

[If Reid isn't displaying correctly, another version of the chart is here.]

The mean estimated age of this group is 44. The mean age remains 44 if I tweak the measure by adding in any works cited at least half as often as the most-cited work and then take the midpoint of the resulting age range. I would guess that 44 is probably a smidgen on the old side as an estimate of the age at which philosophers' most influential work is done, since most work brews for several years before finally appearing in print. In that sense, the 38-year-old estimate isn't perhaps too far off.

But to my eye the more striking fact about the chart is this: How straight the line is from the mid-20s to the early 60s. If this were a bell-shaped distribution around 44, we should see flatter slopes at the beginning and the end -- as we do in fact see starting in the mid-60s. The straightness of the line suggests that there's isn't so much a peak age at which the most elite work in philosophy has been done but instead a long plateau from the mid-20s into the 60s, then tapering off.

There are various potential explanations for the tapering off that seems to start in the mid-60s; I wouldn't rush to the conclusion that the tapering reflects cognitive decline. Other possibilities include decline in health and the prioritizing of other goals.

Most Cited Journals in the Stanford Encyclopedia of Philosophy

I am going to give you a seriously flawed list. There's your warning, front and center! I think Brian Leiter's list of top general philosophy journals is more plausible as a list of best-regarded general analytic philosophy journals. But for what it's worth, below are the most cited philosophy journals in the non-historical entries of the Stanford Encyclopedia of Philosophy.

Some caveats:

* This list reflects the perspective of the SEP editors and writers -- largely an "analytic"/anglophone perspective, among other things.

* I am excluding historical entries and historical journals.

* I checked all journals that I thought would plausibly be cited at least 100 times, but it's certainly possible that I have missed some. If you think there are journals that should clearly be on this list that are missing, feel free to let me know in the comments. Of course there are quite a few good journals below the 100 citation cut. Philosopher's Imprint especially comes to mind. It has published only 64 articles so far in its lifespan, so it hasn't had much of a chance yet to develop a big log of influential articles.

* The numbers are noisy and approximate for a variety of reasons. Four journals, as indicated below, had titles common enough as bibliographic phrases that I was forced to do statistical sampling.

* To the extent these numbers reflect prestige, they reflect prestige over time rather than current prestige.

* Journals that publish many articles (like Phil Studies, Philosophy of Science, and Synthese) will be relatively advantaged by this measure, while those that publish few articles (like Phil Review and Philosophy and Public Affairs) will be relatively disadvantaged. I tried dividing by the number of articles published in two sample years, but this made the rankings implausible in other ways as measures of prestige; so I leave the raw numbers and note exceptional cases.

For what it's worth, my own impression is that Phil Review, PPA, and BBS are underranked by this measure relative to their prestige -- presumably due to their low rates of publication -- while Phil Studies, Phil Science, and Synthese, though all excellent journals, are a bit overranked, presumably for complementary reasons. I'm also inclined to think PPR and Nous are a bit underranked relative to current prestige.

The 200 Most-Cited Contemporary Authors in the Stanford Encyclopedia of Philosophy

Yesterday, I posted a list of the forty most-cited contemporary authors in the Stanford Encyclopedia of Philosophy. A number of people have expressed interest in seeing further down my list, so I am expanding it to 200.

Some caveats:

* "Contemporary" means born in 1900 or later.

* I excluded historical entries, so historians of philosophy will be underreprested.

* Each author is counted only once per entry, and then only if that author receives a bibliographical line on the entry's main page, as either first or solo author.

* The distribution of entries in the SEP should be expected to overrepresent the interests and perspectives of the editors of the SEP, and in particular the SEP has a strongly "analytic"/anglophone perspective.

* This measure emphasizes breadth of influence over depth.

* Citation patterns in the SEP are heavily biased toward recent works, with 2000 being the most cited year. (For a chart see the update to yesterday's entry.)

The list of 200 is too long for the main blog page, so I am posting it

here in the Underblog.

The Forty Most-Cited Contemporary Authors in the Stanford Encyclopedia of Philosophy

As part of my background work on discussion arcs, I compiled all the bibliographic entries in the Stanford Encyclopedia of Philosophy, excluding the purely historical entries, and I noted which philosophers were cited in the most different entries.

(Some obvious shortcomings of the method: It favors breadth of influence over depth, the distribution of entries might differ from the distribution of philosophical research energy, and it might favor the perspectives and writings of the SEP editors. My aim, I should emphasize, is to generate a list of people whose discussion arcs might be interesting, not to generate a definitive measure of philosophical prominence. I'm sure I have also made some coding errors; corrections welcomed.)

With those caveats, then, here are the top forty contemporary philosophers on the list (in parens are the number of SEP entries citing them; I examined 664 SEP entries in total; "contemporary" means born 1900 or later).

1. Lewis, David (162)
2. Quine, W.V.O. (133)
3. Rawls, John (95)
4. Davidson, Donald (93)
5. Putnam, Hilary (88)
6. Kripke, Saul (84)
7. Armstrong, David (72)
7. Nagel, Thomas (72)
9. Fodor, Jerry (70)
10. Dennett, Daniel (69)
10. Jackson, Frank (69)
10. Williams, Bernard (69)
13. Nozick, Robert (68)
13. Searle, John (68)
15. Chisholm, Roderick (67)
16. Harman, Gilbert (60)
17. Dummett, Michael (58)
18. Dworkin, Ronald (57)
19. Nussbaum, Martha (55)
19. Raz, Joseph (55)
19. Van Fraassen, Bas (55)
22. Dretske, Fred (54)
22. Van Inwagen, Peter (54)
24. Chalmers, David (52)
24. Goldman, Alvin (52)
24. Kitcher, Philip (52)
27. Goodman, Nelson (51)
28. Strawson, P.F. (50)
29. Parfit, Derek (49)
29. Sober, Elliott (49)
31. Stalnaker, Robert (48)
32. Williamson, Timothy (47)
33. Geach, Peter (46)
33. Scanlon, T.M. (46)
35. Burge, Tyler (45)
35. McDowell, John (45)
37. Mackie, J.L. (44)
38. Plantiga, Alvin (43)
39. Adams, Robert (42)
39. Gibbard, Allan (42)
39. Lycan, William G. (42)

I find one omission particularly striking: Thomas Kuhn, cited in only 29 entries. (Karl Popper is a near miss at 37 entries.) Kuhn's omission probably reflects, in part, the SEP's underweighting of issues in general philosophy of science; it probably also reflects this measure's favoring of breadth over depth of influence.

The absence of "continental" figures like Foucault (13 entries) and Sartre (23 entries) reflects the generally "analytic"/anglophone pespective of the SEP (though Foucault and Sartre do have historical entries devoted to them).

Comparing these results with Brian Leiter's informal survey last year, the top three results are the same (setting aside Wittgenstein, Russell, and Heidegger, who are not "contemporary" by the present standard), though Leiter has Rawls beating Quine.

UPDATE, May 7:

Let me emphasize that I excluded historical entries, so historians of philosophy will be underrepresented in the data. Also, the SEP bibliographies strongly favor recent work, with the work from the year 2000 being the most cited (cited 2.5 times as often as the year 1980, for example). Here's a chart of citation year in the SEP:

That might be another factor influencing the poor showing of Kuhn (whose most cited work was in 1962) and, as Brian Leiter points out, of Hart, whose most cited work was in 1961 -- though Quine (1960) still does very well.

SECOND UPDATE, May 7:

I have expanded the list to 200.

Distribution of Subspecialites among Anglophone Research Philosophers

As background for my work on discussion arcs, I've analyzed the distribution of research interests among research-oriented philosophers. Maybe some readers will find the data interesting.

My sample of research philosophers is non-emeritus professors with their primary appointments in Leiter top-20 ranked Anglophone philosophy departments -- 548 professors total, by my count. I noted the areas of research interest these professors listed on their departmental websites. Most philosophers listed about three to seven areas.

First, I looked at area of specialization, counting only the first listed area:

Then I looked at all listed areas of interest:

I also broke down historical interest by time period (splitting out Asian as a separate category):

Two things jump out at me from these data: first, the almost complete lack of interest in Asian philosophy among Leiter top-20 faculty; and second, the much greater rate of interest in metaphysics and epistemology than specialization in them. Here is a chart displaying the ratio of interest to specialization in the various subfields.

Almost five times as many philosophers list epistemology among their areas of research interest as list it as their first area of specialization. Philosophy of action shows an even higher ratio, though the total numbers are smaller. In contrast, philosophers tend not to express research interest in ethics or philosophy of science unless they list them as their first specialization.

On Continental Philosophy:

I also looked at interest in "continental" philosophy -- that is, interest in 19th and 20th century figures in the German-French tradition, like Hegel, Nietzsche, Heidegger, Foucault, and Derrida. Although top-ranked Anglophone departments have a reputation for hostility to 19th and 20th century continental philosophy, 45 philosophers (8.2%) listed continental philosophy or a continental figure among their research interests, an average of 2.3 philosophers per department. About 20% of Anglo-American research philosophers who express a research interest in any area of history of philosophy express a research interest in continental philosophy.