Wednesday, January 31, 2007


Astronomers know -- or seem to know -- the most remarkable things on the slenderest base of evidence. Largely on the basis of the spectral analysis of light (often supplemented with verbal reports about rare events in very small pieces of the world called physics laboratories), they reach conclusions about the origin and early history of the universe, about unfamiliar events at virtually unimaginable distances, about the destiny of the sun in some billions of years. It could, of course, all have been one giant projection screen overhead that we'd have punctured with our first moon probe.

Why assume that as things happen here, they happen everywhere? -- that as things happen now, they've happened always and will happen forever? Hume compared us (didn't he?) to fleas on the back of a dog, watching a hair grow and saying "ah, that's how the universe works!"

Some days, I feel very much like such a flea. Hume used this idea, or something like it, in defense of atheism, or something like it; but in me it works the other way. Our science does a pretty good job with our local little hair, Earth, and the nearby hairs (Mars, etc.) seem to grow under much the same rules; but should I be so confident there isn't a whole dog somewhere underneath whose operation I haven't even begun to imagine?

Nor can we even remember or keep straight the growth of our little hair. I search for the Hume quote. I can't find it in his Dialogues Concerning Natural Religion, which would have been my guess. I have a sense that I heard my colleague Howie Wettstein attributing the quote to him. So I email Howie and he tells me that the part about the flea on the dog is pure invention on my part but the back half of the quote is accurate; but now he can't find it in Hume either.

Finally we trace it to the source: Dialogues Concerning Natural Religion, Part II:

From observing the growth of a hair, can we learn any thing concerning the generation of a man?

(In context, Hume is challenging the assumption implicit in the argument from design that we can transfer what we know about the workings of small, local things to the workings of universe as a whole.)

Howie remarks that it's like that old game "telephone": Hume said it, Howie misremembered it to me, I misremembered it to my students and to you just now. All the more reason for humility, Hume might say.

Tuesday, January 30, 2007

Philosophers Carnival #42 is...


(Thanks Justin and Garrett!)

Monday, January 29, 2007

Is It Fair to Expect Ethicists to Behave Better?

Suppose I'm right and ethicists don't behave better than anyone else (see these posts). Shall we accuse them of hypocrisy? Consider a concrete example: Kant is remarkably strict in his denunciation of lying (famously saying that you shouldn't even lie to a murderer at the door about the hiding place of his innocent target). Should we hold him to higher standards of truthfulness in his personal behavior than others? Is there something particularly bad about Kant falsifying his tax return?

The obvious and natural answer is yes. Yet I'm struck by this analogy: A doctor goes to a third world country. Every time she takes a day off, ten people die who wouldn't otherwise have died. Suppose she takes a day off to go fishing, knowing that she doesn't need to fish, that a vacation isn't necessary to her continued functioning, that should could have worked that day without any loss to her future efficiency. She just wants to fish, and she thinks she deserves the time off. Shall we accuse her of preferring a day of fishing for herself to the lives of ten other people, and thus fishing at the expense of their lives? In a sense her choice does seem repugnant in that way. Yet also the accusation seems unfair. Had she chosen a pleasant career as a philosophy professor, or a cosmetic surgeon, she could take a day off without deadly repercussions. Her choice to go abroad instead was morally admirable. Surely, she deserves a "me day" at least as much as the rest of us.

I draw the conclusion that we should be careful about requiring people to shoulder an additional moral load because of their choice of profession (setting aside cases in they shoulder such a load to compensate for a wicked profession). Considering myself: I chose to specialize in philosophy of psychology, not ethics. Do I therefore have fewer moral obligations? Is it more permissible for me to lie, disrespect my students, ignore the disadvantaged? To say so seems not only unfair to ethicists but to create a kind of prudential incentive to avoid ethics -- perhaps even to avoid thinking about ethics -- if one wishes to remain (comparatively!) un-blameworthy for one's actions.

(I was brought to this thought reading Richard Posner's comment [in his 1999 book, p. 69] that ethics professors seem just as eager to reduce their teaching loads as anyone else -- and that therefore they must either think their teaching ineffectual or value the cultivation of morality less than they say. At first, this seemed to me a fair and interesting criticism; and maybe it still is....)

Friday, January 26, 2007

Echolocation and Knowledge

Wednesday I argued that you can probably echolocate considerably better than you think you can. Let me amplify on that idea.

First, we not only have the capacity to echolocate, but we do actually use echolocatory information in negotiating through our daily environment. Our sense of the space we're in and the objects that surround us is continually confirmed or altered by echolocatory information. Here's an example Mike Gordon and I used in our 2000 essay on human echolocation: Wenger Corporation's "virtual room" can electronically simulate the acoustics of a very large room within a small space. According to Mike, when unsuspecting listeners walk into such a room, they quickly sense that something is amiss. Typically, they glance upward at the ceiling to see if it is unusually high. Now that I'm attuned to it, I'm struck by the acoustic difference between the typical classroom and a carpeted room with lots of soft furniture. If I'm thinking of it as I walk through a doorway, I notice the acoustic transition between rooms and the echolocatory sense I have of the doorframe as it passes near my ears. Even if I weren't thinking about it, a classroom that sounded like a living room or a doorway that gave me no echolocatory sense of its frame, would likely disconcert me -- you, too, I'd wager, independent of any intellectual apprehension you have, or not, of your capacities for echolocation.

Second, there's something it's like to echolocate. It's not an entirely nonconscious capacity. We have auditory experience of the direction and distance (and maybe also the texture and shape) of silent objects. This experience is both ordinary and pervasive.

Yet, despite the two points above, we have very little apprehension of this experience. For example, in the 18th and 19th centuries, blind people who navigated by echolocation were struck by their remarkable ability to avoid unseen objects in novel environments -- and many of them hypothesized that they did so by feeling pressure on their faces. In fact, the capacity was generally known as "facial vision". Yet, 20th-century researchers established that this was an auditory, not a tactile capacity (for example, by covering their faces and not their ears and vice versa). Most normally sighted subjects who participate in echolocatory experiments (as Mike and Larry and others have noted, and as I have seen informally) are surprised at the results, and many have the impulse to think they are feeling pressure on their faces.

If we assume -- as I think is probably warranted -- that echolocatory information is not generally felt as pressure on the face, then these people have gone wrong about a pervasive and fundamental aspect of their ongoing conscious experience; and most of us, even if not wrong in quite that way, are strikingly ignorant about this aspect of our stream of experience.

We should, I think, turn the epistemology of Locke and Descartes on its head: What we know best and most directly are outward objects (the size of the room, the shape of the desk before me); what we know only partially, tentatively, and after reflection is our sensory experience of that world.

Wednesday, January 24, 2007

Human Echolocation

Can you echolocate? -- that is, hear the locations and properties of silent objects by noticing how sound reflects off them? Most people say no -- perhaps none more eminently than the philosopher Thomas Nagel in his influential essay “What Is It Like to Be a Bat?”:

bat sonar [echolocation], though clearly a form of perception, is not similar in its operation to any sense that we possess, and there is no reason to suppose that it is subjectively like anything we can experience or imagine.

It's clear, though, that we sometimes gain information about things by noticing how sound reflects from them. You can tell the difference in sound when a wall by the freeway suddenly ends, then starts again. We're all familiar with the sound difference between a footfall or shout heard in a large room and one heard in a small room (an auditorium vs. a bathroom, say). In such cases, we detect the distance of silent walls by hearing the sound reflected from them. Larry Rosenblum (a psychologist here at UCR) has tested this more formally with ordinary blindfolded undergraduates. Much to the surprise of most of them, they could distinguish differences in distance between walls 36 to 144 inches away.

Close your eyes and hold your hand in front of your face. Say "shhhh" while moving your hand up and down, forward and back, right and left. Better, get a friend to move her hand around while you do this. You can hear where the hand is, no? Close your eyes and walk toward a wall, saying "hi, hi, hi, hi...". Can't you hear how far the wall is? With a couple of practice trials, most people find it fairly easy to stop within a few inches of the wall without touching it.

Other researchers have found that ordinary people can use echolocation to discriminate the shapes of objects of equal surface area (circle vs. square vs. triangle) and in some cases the texture of objects (fabric, plexiglass, carpet, wood). Apparently, you can hear if that thing in front of you is circular!

(I've replicated some of these last results informally in my office, and I'm not entirely certain that subjects aren't just hearing differences in loudness -- e.g., a triangle with its apex up reflects more sound when you talk at it from a relatively lower position and less sound when you raise your mouth higher, while circles and squares are more symmetrical. On the other hand, sometimes it seems to me that I have an almost instantaneous impression of the shape in these experiments.)

If you're really good -- for example if you're blind and rely upon echolocation as one of your principal means of navigating the world, you might be able to do even this.

Sometime in the next week or so, I'll post on some of the philosophical issues I see arising from these facts....

Monday, January 22, 2007

Philosophy Grad School Applications -- Reflections from the Other Side

Update: I've started an expanded series of reflections on this topic here.

I'm on the admissions committee this year for U.C. Riverside's Philosophy graduate program. Since many readers of this blog are aspiring grad students (or recently were) or sometimes advise students applying to philosophy graduate school, I thought I'd share some of my thoughts on the process.

Letters of recommendation (advice for letter writers): Reading hundreds of letters of recommendation, things become something of a blur. Most letters say "outstanding student" or "I'm delighted to recommend X" or "I'm confident X will succeed in graduate school in philosophy". It would be strange not to say something of this sort, but still -- my eyes start to glaze over. I suspect that trying to detect nuanced differences in such phrases is pointless, since I doubt such nuances closely track applicant quality. More helpful: (1.) Comparative evaluations like: "best philosophy major in this year's graduating class"; or "though only an undergraduate, one of three students, among 9, to earn an 'A' in my graduate seminar"; or "her GPA of 3.87 is second-highest among philosophy majors". (2.) Descriptions of concrete accomplishments: "Won the department's prize in 2005 for best undergraduate essay in philosophy"; or "President of the Philosophy Club".

Regarding those little checkboxes on the cover sheet ("top 5%, top 10%" etc.): My impression is that letter writers vary in their conscientiousness about such numbers and have different comparison groups in mind, so I tend to discount them unless backed up by specific comparison assessments in the letter.

Letters of recommendation (advice for applicants): Three strong letters makes a better impression than three strong letters and one mediocre letter. We can forgive applicants for not having the full three letters in on time, since we know professors are often flaky -- but still a gentle email reminder to your letter-writers around the time of the deadline might help. Also, it's a little strange when a letter-writer's description of your interests diverges from your own. So show your them at least your statement of purpose (preferably your whole application). You might also offer the letter writers a "brag sheet" describing any concrete accomplishments you have or specific hardships you've overcome (though be judicious about the latter).

Lists of awards, resumes, etc.: Long lists of minor accomplishments tend to blur before my eyes. Of course you made honor roll!

GRE scores: UCR requires them. I don't take them that seriously, but some others do. High GRE scores can help applicants win extra fellowship money. We certainly admit some students with mediocre GRE scores. At UCR I'd say below 1250 is a strike against an applicant, above 1400 is a bonus.

Writing sample:
I skim the whole sample of every plausible applicant and try to read a few pages in the middle carefully. First, the sample must be clearly written and show a certain amount of philosophical maturity. (I can't say much about how to achieve these things other than to be a good writer and philosophically mature; I think they're hard to fake.) Second, what I look for in the middle is that the essay gets into the nitty-gritty somehow. In an analytic essay, that might be very detailed analysis of the pros and cons of an argument, or of its non-obvious implications, or of its structure. In a historical essay, that might be a very close reading of a passage or a close look at textual evidence that decides between two competing interpretations. Many otherwise nicely written essays stay largely at the surface, simply summarizing an author's work or presenting fairly obvious criticisms at a relatively superficial level. Applicants should be sure to have at least one professor look over the sample, critiquing it specifically for its suitability in an application.

Transcripts: Overall GPA matters, but even more so one's upper-division grades in philosophy. We like to see mostly A's. A few A-'s or lower grades are okay. It also depends on the institution: A 3.8 average in philosophy from Stanford looks different from a 3.8 average from a Cal State. Unfortunately, master's programs, small liberal arts schools, and foreign universities vary widely in how rigorously they grade, making transcripts hard to assess. Guidance from the letter writers (e.g., this is the highest GPA among graduating seniors) can help considerably here.

Statements of Purpose: These are hard to write well. Many are somewhat, or even painfully, corny: "Ever since I was seven years old, I've puzzled over the timeless problems of philosophy." Others seem phony; others seem arrogant or like a sales pitch. Fortunately for candidates, we're used to it. The best statements, to my mind, simply describe the applicant's areas of interest in philosophy, with perhaps some description of particular sub-issues of special interest. We then ask ourselves: Do the applicant's interests fit with what we can teach?

Personal Contact or Connections: Such things don't help much, I suspect, unless they bring substative new information. If a professor at UCR at some point in the past had a good substantive, philosophical conversation with an applicant and mentions that to us, that might help a bit. But seeking out professors for such purposes could backfire if it seems like brown-nosing, or if the applicant seems immature, arrogant, or not particularly philosophically astute.

New Blog for Florida Philosophy Students...

here. (Welcome to the blogosphere!)

Friday, January 19, 2007

Evil and Failure to Reflect

Today I'd like to consider a view somewhat in tension with my series of posts on what I call the "problem of the ethics professors" -- the problem being that they don't seem to be any more virtuous than the rest of us. (Empirical data here and here.)

It's tempting, perhaps, to suppose in light of ethicists' remarkably ordinary blend of virtue and vice, that philosophical moral reflection is of no use to moral development. But that conclusion is troublingly cynical. If philosophical reflection about ethics -- which is, really, often nothing more than just thoughtful consideration of what's right and wrong -- yields no moral benefit, what's the point? Just to know better our wickedness? It's pretty darkly pessimistic to suppose that reflection, and consideration of the best historical and contemporary writing on virtue, duty, and justice, is powerless to produce moral improvement.

It's appealingly worldly, perhaps, to think poorly of the morality of ethicists; but then, I think, you owe yourself a story about how and why philosophical reflection fails. And I doubt the easiest stories here ("the problem with ethicists is that they ignore the Bible" or "philosophical ethics suppresses moral emotion") will work, at least not without considerable supplementation.

Here are two further thoughts that incline me not to dismiss the value of moral reflection so lightly.

First, there's the remarkable lack of moral reflection common among the perpetrators of great crimes. I'm struck by this, especially, in reading Holocaust literature. It's a famous theme, of course, in Hannah Arendt's portrayal of Eichmann, an expert in the logistics of shipping Jews to death. Albert Speer's well-known book Inside the Third Reich -- conceived while serving prison time for his role as an architect in Hitler's inner circle -- is to my mind amazingly unreflective about the moral dimensions of his activity, focusing instead on such issues as Hitler's movie-watching habits and how the Allies should have attacked ball-bearing factories. I can't help but wonder whether more morally reflective people would be less likely to be swept up in such evil. (Of course, there's the case of Heidegger....)

And second: In the famous Milgram experiment, subjects are persuaded to shock (they think) a screaming, protesting (and eventually eerily silent) man in an adjoining room for the sake of an experiment on learning. They begin by giving a mild shock as "punishment" for a wrong answer, with instructions to increase the level of shock with each wrong answer. Eventually, they believe they are delivering shocks of 300 and even 450 volts (marked "danger" and "xxx" on the instrumentation) to the victim. When subjects protest, they are placidly told, by a man in a lab coat, that they are to continue and that the shocks cause no permanent tissue damage. It's hard to know for sure, but I suspect that most subjects who paused for a while to genuinely reflect, in a philosophical way (why am I shocking this man? do we have any right to keep him here despite his protests? might there be some real risk to his life or health that his experiment doesn't justify?), would refuse to continue to shock the victim. No?

Philosophical moral reflection, powerless to improve behavior? We should not adopt that view lightly. But then we're left again with the problem of the ethics professors.

Wednesday, January 17, 2007

Liberating On Liberty (from the Library)

Whew! I got some good linkage from my last post on ethicists stealing books, lifting this blog into the rarefied territory of almost thousand visitors a day -- peanuts for the likes of and ordinary for Cognitive Daily -- but virtually a populist revolution for me.

The previous post about missing ethics books focused entirely on books first published in 1960 and later. I promised a separate analysis of classic, older texts. Here it is.

I looked at 10 classic (pre-1900) texts outside of ethics and 12 classic ethics texts. Selection criteria were a bit complicated; but please let me know, readers, if you think there are classic philosophy books I should have included on the lists below but did not include that are: (a.) influential, (b.) widely checked out, (c.) either clearly in ethics or clearly outside of ethics (not a blend), and (d.) generally published under separate cover (not as part of a general anthology including both ethics and nonethics texts by that author). The libraries I looked at were: UC Berkeley, UC Irvine, UCLA, UC Riverside, UC San Diego, UC Santa Cruz, Harvard, Stanford, Cornell, Columbia, Princeton, Michigan, and Texas.

I looked at missing books both as a percentage of books off-shelf (where "off shelf" means either checked out or missing/lost) and as a percentage of holdings. Data were collected over winter break so as to minimize effects due to texts being assigned for a particular class. (I will collect comparison mid-term check-out data in a month or so.)

The results, then, by book:
(Author, Title, Missing as % of off shelf, Missing as % of holdings)
Aquinas....Summa Theologica.......8.1%....1.2%
Aristotle..Nichomachean Ethics...11.6%....1.9%
Bentham....Principles of Morals..14.3%....1.4%
Kant.......Metaphysics of Morals.12.5%....1.7%
Kant.......Second Critique.......12.9%....1.7%
Locke......Treatise of Gov't.....19.3%....2.3%
Mill.......On Liberty............30.4%....5.0%
Rousseau...Social Contract.......30.0%....3.4%
Total Ethics.....................19.4%....2.6%

Bacon......New Organon.............3.3%...0.6%
Brentano...Psychology Empirical....0.0%...0.0%
Frege......Geach & Black trans.....0.0%...0.0%
James......Principles of Psych.....6.3%...1.7%
Kant.......First Critique.........10.1%...1.8%
Kant.......Third Critique..........3.6%...0.9%
Locke......Essay Concerning Human.16.3%...1.6%
Total Non-Ethics..................8.7%....1.4%

In sum, the classic ethics texts were about twice as likely to be missing, overall, than the non-ethics texts (p < .001; one-proportion tests, two-tailed).

A few books were outliers, with substantially higher checkout numbers (Plato [132] and Aristotle [95]) or substantially lower (Berkeley [18], Brentano [6], Frege [17 and 7], Bentham [21], and Kant Metaphysics of Morals [16]). (Instability due to small sample size may explain the highly variable results on some of the latter books, esp. Frege.) Excluding these books left short lists of books with very comparable holdings and checkout rates, and large enough holdings and checkouts for some statistical stability. Ethics books were still about twice as likely to be missing. (The odds ratios actually went up a bit.)

Looking by book, excluding those books with fewer than 25 off shelf, almost all the books with above-average missing rates are ethics books; almost all those with below-average rates are non-ethics. This effect was so pronounced that even with such a small sample of books (6 non-ethics, 10 ethics), the difference in the mean percentage missing was statistically detectable (7.6% vs. 20.4%, p = .001; 1.2% vs. 2.6% p = .005).

P.S.: I should add that due to the different types of courses classic ethics and non-ethics books are typically assigned for, and due to the high -- and perhaps not comparable -- rates of checkout by undergraduates, I think these data are not as revealing as the data described in my earlier post, which focused on a larger set of more comparable books, likely to be checked out only by professors and advanced students.

Monday, January 15, 2007

Philosophy Graduate Students Say the Most Peculiar Things

In the holiday spirit, I thought I'd post a few of the more memorable utterances of my fellow graduate students when I was a Berkeley in the 1990s. To give credit where credit is due, I'll use their names. I don't think they'll be embarrassed -- they shouldn't be! -- and I hope they'll forgive me if they are. (I'll remove their names from this post if they request it.)

David Barton, sitting in his usual spot on the couch in the graduate student lounge (a place he occupied sometimes for long stretches): "Work, schmerk. Kant, Schmant. For all x, schmex."

Josh Dever, sitting in a hottub, holding up the chlorinator: "This is the name I'll give to my first child." Someone else: "You'll name her 'chlorinator'?" Josh: "No, her name will be this object. If you want to refer to her, you'll have to include this chlorinator in your sentence." (Josh never did follow through with this intention, though.)

An undergraduate had written a paper on Kierkegaard including the following sentence: "Being a knight of faith is like falling off a never-ending cliff into water, hitting various flying things along the way." What can a T.A. do with that? John Holbo struck upon the perfect solution: He circled "flying things" and wrote in the margin "do you mean birds?", then photocopied the page and put it on a corkboard in the graduate student lounge.

Friday, January 12, 2007

Do Ethicists Behave Better Than the Rest of Us? Peer Opinion

Do you think that ethicists, in general, behave morally better, worse, or about the same non-ethicists? I've often posed this question to other philosophers in informal conversation. Most of my interlocutors say "about the same" or "worse"; only a few say that ethicists behave overall better (which would seem to comport with my findings that ethicists steal more books).

Josh Rust and I distributed a questionnaire on this issue at a meeting of the American Philosophical Association a few weeks ago. Josh sat at a table near the book exhibit and offered people snacks in exchange for filling out a questionnaire. The questionnaire came in two versions. Version A asked respondents to compare the moral behavior of the ethics professors they knew first to the behavior of non-ethicists in philosophy and second to that of non-academics of similar socio-economic background. Version B asked similar questions about the moral behavior of the specific ethicist in their department whose name comes next in alphabetical order after theirs (looping from Z to A if necessary). All questions used a scale of 1 to 7, from substantially morally better (1) to about the same (4) to substantially morally worse (7).

54 respondents completed Version A. The mean result on Question 1 (ethicists vs. non-ethicists in philosophy) was exactly 4 ("about the same"). On Question 2 (ethicists vs. non-academics of similar social background) the mean result was 3.9 -- which was not statistically different from 4, given the relatively small sample size. In other words, philosophers when asked their general opinion about ethicists, thought they behaved about the same as non-ethicists.

One interesting trend in the data had to do with academic rank: Undergraduates and distinguished professors were the most sanguine about the behavior of ethicists, assistant professors the least sanguine. Here are the mean responses to Question 1, divided by rank (the means for Question 2 are very similar):

Undergraduate: 3
Graduate student: 3.8
Adjunct instructor, lecturer, or post-doc (non-tenure track): 4.1
Assistant professor (tenure track): 4.6
Associate professor: 4.3
Full professor: 4.3
Distinguished professor: 3.3

Given the small sample, though, it's hard to know whether the appearance of a trend here (with the grimmest views around tenure-time!) is simply chance.

On Version B, the results looked better for the ethicists, with means of 3.4 (Question 1) and 3.2 (Question 2), both statistically different from 4.0. In other words, philosophers thought, on average, that the ethicist next after them in the department roster behaved both better than the rest of the department and than non-academics of similar social background.

So which is it? Do ethicists behave better or not? Which version of the questionnaire better reflects real philosophical opinion? An argument can be made either way. Version A might be misleading due to something like what psychologists call a saliency or availability effect: When asked to think about the moral behavior of ethicists, perhaps the first cases to come to your mind will be cases of particularly nasty ethicists. Version B attempts to control for that, but people may be overly charitable to individuals when asked to compare them to a group -- it may be easier or more comfortable to attribute below-average moral behavior to a group than to a particular individual you know.

Josh and I hope to sort some of these issues out with a longer questionnaire to be distributed at another meeting -- if we can get permission!

Wednesday, January 10, 2007

Doubts about (One Kind of) "Purkinje Afterimage"

The eminent 19th century physiologist and vision scientist Johann Purkinje wrote:

Often I have been surprised that blinking the eyes does not disturb sight, assuming that during the blink complete darkness must occur. On closer observation however, I found that the visual field of the open eye, with all its lights and images for a short time remains before the mind, after the eyelids are closed. The more attentively I comprehend a single not very extensive image, the longer I am able to hold it with closed eyes before the mind. This afterimage is precisely to be distinguished from dazzling images [Blendungsbilde; afterimages caused by bright light?]. The afterimage can only be held longer by free activity and disappears as soon as the will diminishes, though it can by the same action be called back again; dazzling images float automatically before the mind, disappearing and appearing again for objective reasons.

[Translations of other related passages are posted in the Underblog here.]

Later psychologists in the introspective tradition (right through Brown's 1965 influential review of the literature on afterimages) often took for granted that such momentary positive images exist, though Purkinje's remarks about the the involvement of the will and the distinction from "Blendungsbilde" were largely neglected.

Close your eyes. Blink a few times. What do you think? Are there "Purkinje afterimages" of this sort?

I think I sometimes experience a positively colored "dazzling image" that quickly fades -- for example, if I look for five seconds at the flourescent light overhead, I seem to experience an afterimage of its bright bars for a fraction of a second after I close my eyes, and before the usual "flight of colors" sets in. Maybe I also have the experience after staring at my computer screen awhile. But I can't find such a momentary image when I'm looking in ordinary conditions at ordinary reflective surfaces -- my bookcase, for example.

I wonder how much Purkinje, in this passage, is driven by a perceived need to explain the lack of interruption in the blink. To the extent that's what's driving him, I'm suspicious -- partly because I think it possible that a blink does momentarily disturb visual experience, and partly because Dennett has convinced me (in his marvellous book Consciousness Explained) that often we don't notice even fairly large gaps and lacunae in our visual experience (temporal gaps, blind spots, impoverished information from the periphery) if there's no particular epistemic need that's going unfulfilled.

There are also temporal issues. Brown describes the "first positive phase" of the afterimage as starting after about 50 milliseconds and continuing for about 50 milliseconds. That's pretty fast! Given the speed of neural processing, our experience in general probably runs some tens of milliseconds behind environmental input (at least unexpected input). So there are issues, at least, about how one draws the line between ordinary visual experience, possibily slightly delayed relative to a brief and unexpected stimulus, and "afterimages", conceived as something distinct from that.

I also worry that once the existence of such images was admitted into the introspective literature, later authors would be reluctant to deny their existence, from fear of being seen as less introspectively expert than those who make such fine judgments about their afterimages: "Well Purkinje saw it, and I see it. If you don't, maybe you're just not well enough attuned to your own experiences, well enough practiced at introspection!"

Tuesday, January 09, 2007

Philosophers Carnival #41 is...


(Thanks to Westminster Wisdom!)

Monday, January 08, 2007

Still More Data on the Theft of Ethics Books

Last month, I noted that ethics books are more likely to be stolen than non-ethics books in philosophy (looking at a large sample of recent ethics and non-ethics books from leading academic libraries). Missing books as a percentage of those off shelf were 8.7% for ethics, 6.9% for non-ethics, for an odds ratio of 1.25 to 1. However, I noted three concerns about these data that required further analysis. I've now done the further analysis.

Here are the concerns:

(1.) Older books are more likely to be missing, and the ethics books were on average a couple years older than the non-ethics books.

I addressed this concern by eliminating from the sample all books published prior to 1985. This brought the average age of the books to the same year (1992.9 for ethics, 1992.7 for non-ethics). On these reduced data, the ethics books were still more likely to be missing: 7.7% to 5.7%, for an odds ratio of 1.35 to 1 (p = .015).

(2.) Ethics books are more likely to be checked out than non-ethics books in philosophy, and there is a tendency for books that are more checked out to have a higher percentage of the off-shelf books missing -- not just a higher percentage of the holdings missing, but a higher ratio of missing to off-shelf-but-not-missing.

I addressed this concern by further reducing the sample, eliminating all the "popular" ethics and non-ethics books -- those cited at least 5 times in the relevant entries of the Stanford Encyclopedia of Philosophy. (This left only fairly obscure books, presumably known to and borrowed by only professors and advanced students in the field.) This actually seems to have increased the effect: 8.5% to 5.7%, for an odds ratio of 1.48 to 1 (p = .026).

(3.) Finally, some people were concerned that maybe law students were driving the effect. Therefore, finally, I eliminated from analysis all "law" books, defined as those books for which at least 10% of the U.S. holdings were in the four law libraries included in the analysis (UCLA, Harvard, Stanford, and Cornell law). This had little effect: 8.3% to 5.7%, odds ratio 1.46 to 1 (p = .044). Also, the percentage of ethics books missing from the four US law libraries was only 7.0%, versus 8.3% for the US non-law libraries.

So it's not (supposedly vicious) law students. And it's not a bunch of (supposedly conscience-impaired) undergraduates stealing Rawls. The effect is large, and statistically significant, just looking at books likely to be borrowed only by professional ethicists and students with a serious scholarly concern with ethics.

Based on these data, it seems indeed that ethicists do steal more books!

Coming soon: I did a similar analysis of the thefts of "classic" texts in ethics and non-ethics -- e.g., Mill's On Liberty vs. Descartes' Meditations. Any predictions?

Friday, January 05, 2007

Online Journal Psyche Seeks New Editors

The online journal Psyche seeks two new editors in chief (one philosophical, one empirical) to replace Timothy Bayne. A copy of the advertisement is here in the Underblog. If you're an established scholar with an interest in shaping a major journal and a new scholarly medium, please consider applying!

Thursday, January 04, 2007

Directional Olfaction?

Philosophers tend to take it for granted that our sense of smell is directional or spatial only in a very attenuated sense: We can infer where a scent is coming from (using background knowledge), or we can piece it together by moving about and noticing if the smell is getting stronger or weaker, but at any particular instant a smell is either here or not here, to some degree of intensity. Scents are not fundamentally and intrinsically experienced as coming from a particular direction. (This view goes back at least to Condillac, in his famous example of the statue endowed only with a sense of smell.)

An interesting article, by Jess Porter and others, in the current issue of Nature Neuroscience challenges this view. Subjects were blindfolded, equipped with noise-blocking earmuffs, and given knee- and elbow-pads and workgloves, then asked to track an olfactory trail that bent across a lawn (produced by a string that had been soaked in diluted odorant). They crawled on hands and knees, noses near the ground. Most could in fact follow the trail. (Woof!)

Each nostril draws smell from slightly different regions of space (a fact Porter and colleagues presented as "contrary to the common notion" but which at least used to be widely known among research psychologists -- as discussed, e.g., in Titchener's [1901-1905] Experimental Psychology). This raises the possibility of directional, "stereo" smelling -- discerning the directionality of a scent by the difference between its strength in the two nostrils.

To support this idea, Porter and her colleagues had subjects perform the task with one nostril closed or wearing a "nasal prism device" intended to mask the stereo effect by creating one "virtual nostril". As predicted, these manipulations significantly impaired performance on the scent-tracking task.

Unfortunately, it seems to me that those last results might be explainable by supposing a general decrease in olfactory sensation, rather than a specific cancelling of the stereo effect, since it's not clear that the researchers tested sufficiently whether having one nostril closed or wearing the "nasal prism" impaired olfactory ability generally.

(Thanks to Paul Hoffman, by the way, for the pointer to the Porter article.)

Tuesday, January 02, 2007

Harvard's Collection in Klingon

I recently noticed that Harvard lists "Klingon" among the languages in its book collection -- languages you can use to limit your search in its electronic catalog. Unfortunately, limiting my search for "Kritik der Reinen Vernunft" (Critique of Pure Reason) to Klingon yielded no results. Neither did I have any success with "Kritik der Praktischen Vernunft" (Critique of Practical Reason).

Why this distressing lack of attention to Kant among the Klingons?

The University of California, by the way, does not list Klingon among its languages in its online library catalog, Melvyl. I should send a note to the collection development people here at UC Riverside. We can't have Harvard showing us up like this now, can we?