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May 28th, 2010 (Permalink)

Blurb Watch: Shrek Forever After

Compare and contrast:

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May 27th, 2010 (Permalink)

A Puzzle in Memory of Martin Gardner

In honor of Martin Gardner, here is a logic puzzle adapted from one of his Scientific American columns. It concerns three businessmen who have a business lunch together every weekday. Here are the clues:

  1. If Abner orders a martini, so does Bill.
  2. Either Bill or Charley always orders a martini, but never both at the same lunch.
  3. Either Abner or Charley or both always order a martini.
  4. If Charley orders a martini, so does Abner.

At their next lunch, which if any of the three businessmen will order a martini and which if any will not?


Source: Martin Gardner, "Boolean Algebra", Mathematical Circus, p. 95.

May 24th, 2010 (Permalink)

Obituary: Martin Gardner

The prolific and wide-ranging science writer Martin Gardner has died. Among his many books was Fads and Fallacies in the Name of Science, which seems to have launched the modern skeptic movement and is still well worth reading. Some of the topics covered in Fads and Fallacies have turned out to indeed be fads, and are largely forgotten today―such as the theory that the earth is hollow and pyramidology, which were popular in the nineteenth century. Others discussed by Gardner are, unfortunely, still with us, such as dowsing and scientology.

Gardner also wrote the "Mathematical Games" column in Scientific American for many years, and it was reading Gardner's puzzle books―as well as Raymond Smullyan's―that got me interested in puzzles and how they could be used to learn about logic and fallacies, as well as to exercise one's reasoning abilities.

In addition, Gardner was a model for how to write about technical subjects for a lay audience. He never wrote down to his readers, but treated us as if we were as intelligent as he was, which was no doubt untrue. As a result, you might not understand everything he wrote on a first reading, but he wrote so clearly that it was never his fault!

Source: Douglas Martin, "Martin Gardner, Puzzler and Polymath, Dies at 95", The New York Times, 5/23/2010

Update (5/27/2010): The latest issue of eSkeptic reprints a long, fascinating, and philosophically sophisticated interview with Gardner by Michael Shermer from 1997. Check it out.

Source: "Martin Gardner 1914-2010: Founder of the Modern Skeptical Movement", eSkeptic, 5/26/2010

May 21st, 2010 (Permalink)

The Best Contextomy of the Year…

…thus far. Movie marketers love to use blurbs such as the following one for the new movie Racing Dreams: "The Best Film of the Year…". But how can a reviewer dub a film the best of the year when the year is not even half over? In this case, it's because those three little dots at the end of the blurb conceal two important little words:

…I probably shouldn't have been as surprised as I was to discover that the best film at this year's festival, thus far―and indeed the best film of the year, thus far―is "Racing Dreams"….

Of course, the best film of the year thus far, in April when the article was written, is not necessarily the best film of the year, period. But it is the best film of the year period period period.


May 12th, 2010 (Permalink)

New Book, Too

The latest issue of The Skeptical Inquirer has a positive review by editor Kendrick Frazier of the new book Nonsense on Stilts by Massimo Pigliucci (why does every Italian skeptic seem to be named "Massimo"?). The magazine was on the rack in a bookstore that I visited, but is not yet listed on SI's website. The following part of the review mentions something that sounds especially intriguing:

…[L]ate in the book…is a very useful chapter on what actually makes for an expert. "Who's an expert?" is a question you don't hear every day, but it is exceedingly pertinent to many public issues. [Pigliucci] begins, not surprisingly, with Plato's Socratic dialogue Charmides but ends very concretely with a valuable five-point guide by Alvin Goldman that a novice can use to determine whether someone is a trustworthy expert. (P. 55)

It may not surprise Frazier, but I was surprised. I read Charmides a long time ago, but remember nothing about it. Nor am I familiar with Goldman's five-point guide. The issue of how to judge expertise has an important bearing on appeals to expert opinion, and the fallacy of appeal to misleading authority is the result of such a judgment gone wrong.

The same issue also has a positive review of Damian Thompson's Counterknowledge, which I listed as a new book over a year ago (see the Resource, below). The Skeptical Inquirer seems to be as slow about reviewing books as I am. In the meantime, I've actually read Counterknowledge, but was somewhat disappointed by it. It's certainly not a bad book, and if you don't know much about the topic it might make a good introduction. However, it seemed superficial to me, and I didn't learn much that I didn't already know. Counterknowledge is a book, like Unspeak before it, that just doesn't live up to its wonderful title.


Resource: New Book, 2/1/2009

Update (5/16/2010): I've now reread the Charmides and I'm still surprised, though less so. Charmides is Plato's dialogue on temperance, but there is a section near the end dealing with the idea of temperance as a kind of knowledge, which is the standard Socratic view of the virtues. The question arises as to how one who lacks a type of knowledge can judge whether another has it, which is the situation confronting a layperson trying to decide whether someone is an expert, for instance, a parent selecting a teacher to educate a child.

Socrates describes how the world would be if we had this ability as a "dream":

If temperance really ruled over us and were as we now define it, surely everything would be done according to science: neither would anyone who says he is a pilot (but is not) deceive us, nor would any doctor or general or anyone else pretending to know what he does not know escape our notice. This being the situation, wouldn't we have greater bodily health than we do now, and safety when we are in danger at sea or in battle, and wouldn't we have dishes and all our clothes and shoes and things skillfully made for us, and many other things as well, because we would be employing true craftsmen? (173A-C)

But there is a difficulty in realizing Socrates' "dream":

…[I]f the temperate man or anyone else whatsoever is going to tell the real doctor from the false, how will he go about it? …
[T]he man who conducts the examination correctly will examine the doctor in those matters in which he is a medical man, namely health and disease. … And he will look into the manner of his words and actions to see if what he says is truly spoken and what he does is correctly done[.] … But, without the medical art, would anyone be able to follow up either of these things? No one, in fact, could do this, it seems, except the doctor…. If he could, he would be a doctor in addition to his temperance. (170E-171C)

In other words, it seems as though one needs to be an expert oneself in order to tell whether someone else is an expert. If that is true, then Socrates' "dream" can never be realized, since each one of us would have to become an expert in everything. So, perhaps Pigliucci chose the Charmides to begin his chapter on expertise because it poses the problem so clearly, though it provides no solution.

What residual puzzlement I have is due to wondering why the Charmides out of all of Plato's dialogues, when the importance of expertise and the problem of finding it are recurrent issues. Plato even had some positive things to say about how to do so elsewhere, but that's for a later installment in what's turning into a miniseries. Stay tuned!

Update (5/20/2010): Another of Plato's dialogues that has some things to say about expertise is the Laches. The set-up is a discussion among some Athenian men about whether they should train their sons to fight in armor, and this eventually leads―as all such Socratic dialogues lead―to a discussion of a virtue, specifically, courage. The puzzle from Charmides about how a non-expert can judge whether someone else is an expert is not raised, as far as I can tell, but some suggestions about what the layperson can do are given. To decide whether to educate the sons in armored fighting, Socrates suggests the following approach:

…[I]t is…necessary to investigate first of all whether any one of us is an expert in the subject we are debating, or not. … Then, in keeping with what I said just now, how would we investigate if we wanted to find out which of us was the most expert with regard to gymnastics? Wouldn't it be the man who had studied and practised the art and who had good teachers in that particular subject? (185A-B)

So, Socrates recommends two tests of expertise in a subject: education and experience. However, the character that the dialogue is named after, Laches, raises a problem:

Laches: What's that, Socrates? Haven't you ever noticed that in some matters people become more expert without teachers than with them?

Socrates: Yes, I have, Laches, but you would not want to trust them when they said they were good craftsmen unless they should have some well-executed product of their art to show you―and not just one but more than one. (185E-186A)

So, there's an additional test when the test of education fails, namely, to sample the supposed expert's work―and not too small a sample!

These three tests raise a couple of problems that aren't addressed in the dialogue:

  1. How can a layperson judge the worth of education? There are diploma mills that will grant worthless degrees to anyone who pays a fee, and in Plato's day there were sophists that he would have considered to be charlatans.
  2. How can a layperson judge the skill exhibited in a sample of work? Most of the examples of expertise that Socrates gives are craftsmen such as potters, or athletes such as gymnasts, and laypeople can tell the difference between the work of an unskilled potter or gymnast and an expert one. However, in the modern world, many technical subjects are so arcane that it may take an expert to tell expert work from amateur junk.

I expect that there will be at least one more installment in this examination of the nature of expertise.

Source: Plato, Laches & Charmides, translated, with an introduction and notes, by Rosamond Kent Sprague (1973).

Fallacy Files cereal 100% Natural
May 10th, 2010 (Permalink)

Cancer: It's 100% natural!

Here's a Slate article from a couple of years ago, which I didn't see at the time, on cancer and the appeal to nature:

…[R]ecent cancer-causing culprits in the news include pesticides, power lines, and solvents. This thinking cleaves to a popular motif: The natural world is less toxic and more healthful than the industrial one. To avoid cancer, you should buy organic produce, drink unpasteurized milk from specialty dairies, eat more fiber to cleanse the colon of carcinogens, and avoid cheap cosmetics. To protect one's family, in short, become a paranoid consumer of everyday "artificial" products. Unwittingly, we've seriously impeded cancer prevention with this not-so-useful distinction between the natural and artificial. It's distracted us from the uncomfortable truth that most cancers are caused by the natural environment around us. As a result, we expend great effort and ink on low-yield strategies to prevent cancer, even though the better ones lie within our grasp. … A smarter strategy would simply focus on the most preventable exposures causing the most malignancies, without any regard for what's natural and what's man-made.

I agree that that's a smarter, and more logical, strategy. However, I'm a bit surprised that the author never once mentions tobacco, which is of course natural―as American Spirit cigarette ads always remind us―though setting it on fire and inhaling the smoke is less so. Apparently, about a third of cancer deaths could be prevented if people would just stop smoking cigarettes (see Source 1, below).


  1. Denise Grady, "U.S. Panel Criticized as Overstating Cancer Risks", The New York Times, 5/6/2010
  2. Darshak Sanghavi, "Natural Disasters: Why do we focus on the least important causes of cancer?", Slate, 5/7/2010

May 8th, 2010 (Permalink)

Where's the harm?


In 1999, [AIDS] denialism secured its highest-profile advocate: Thabo Mbeki, who was then president of South Africa. Having studied denialist literature, Mbeki decided that the consensus on Aids sounded too much like a "biblical absolute truth" that couldn't be questioned. The following year he set up a panel of advisers, nearly half of whom were Aids denialists…. The resultant health policies cut funding for clinics distributing ARVs [antiretrovirals], withheld donor medication and blocked international aid grants. Meanwhile, Mbeki's health minister, Manto Tshabalala-Msimang, promoted the use of alternative Aids remedies, such as beetroot and garlic. All this might not have been so devastating had South Africa not been in the throes of an Aids epidemic. … In 2007, Nicoli Nattrass, an economist and director of the Aids and Society Research Unit at the University of Cape Town, estimated that, between 1999 and 2007, Mbeki's Aids denialist policies led to more than 340,000 premature deaths. Later, scientists Max Essex, Pride Chigwedere and other colleagues at the Harvard School of Public Health arrived at a similar figure.

As bad as the idea that HIV doesn't cause AIDS is, the idea that those who advocate it should be tried and punished is perhaps even worse. One reason that we can have some confidence in the scientific consensus on the cause of AIDS is the fact that people are free to disagree, to argue against it, and present their evidence without fear of punishment. The consensus view is sometimes wrong―though it's the way to bet―and it could have extremely bad consequences if it were defended by appeal to force rather than reason. Moreover, the scientific consensus would soon become nothing more than a political consensus controlled by politicians rather than scientists. In a democracy, there's already a remedy available for politicians who promote pseudoscience, which is to vote them out of office.

Source: Jon Cartwright, "Unconventional thinkers or recklessly dangerous minds?", Times Higher Education, 5/6/2010

May 7th, 2010 (Permalink)

New Book

The book You've Got to Be Kidding!: How Jokes Can Help You Think, by John and Donald Capps, looks like it should be fun. It appears to be similar in intent to Cathcart & Klein's Aristotle and an Aardvark. The authors, a philosopher and a psychologist, describe the book as follows:

…[W]e think it makes a lot of sense for a philosopher and a psychologist to collaborate on a book about jokes and critical thinking. We agree that jokes often reflect the abandonment of logic and reason. We also believe, however, that some jokes make a lot of sense. The fact that some do and some don't is precisely what makes them a valuable resource for critical thinking. (P. xi)

The Capps write elsewhere:

Jokes make good illustrations of the logical fallacies that are a regular feature of critical thinking courses. Figuring out which logical fallacy a joke illustrates can be a valuable exercise in critical thinking. (P. 1)

Here's a chance to practice on a sample joke:

A doctor said to his patient, "I can't find the cause of your illness," then paused thoughtfully and added, "but frankly I think it's due to drinking." "That's OK," replied the patient, "I'll come back when you're sober." (P. 41)

Name that Fallacy!

I can't find a companion website for the book, but you can read the Preface, Introduction, and a few pages from the discussion of a specific fallacy, on Google books―that's where I got the excerpts above.

I would ask for a review copy, but they seem to have stopped sending them to me.

May 6th, 2010 (Permalink)


Jef Clark, of the father and son team that wrote the entertaining book Humbug! (see the Resource, below, for my review), has died at the young age of 61.

Source: "Podcast - Episode 35 - The Best of Jef", Humbug!, 4/19/2010

Resource: Book Review: Humbug!, 3/1/2006

Solution to a Puzzle in Memory of Martin Gardner: Abner and Bill will order a martini, while Charley will not.

There's more than one way to skin this puzzle. Gardner used the puzzle to show how to solve such problems with Venn diagrams. Here's another approach: From clue 2, we know that exactly one of Bill and Charley will order a martini, that is, one will but the other will not. So, there are only two possibilities: Bill does not order a martini but Charley does, or Bill orders one but Charley doesn't. Let's examine these alternatives separately:

  1. Bill doesn't order a martini and Charley does. If Bill doesn't order one, then neither does Abner, by clue 1. Also, if Abner doesn't have one then neither will Charley, by clue 4; but that's impossible, since we assumed that Charley was ordering one. Therefore, the other alternative must be the correct one:
  2. Bill orders a martini and Charley doesn't. If Charley doesn't order a martini, then Abner will, by clue 3. So, we now know the complete line-up: Abner orders a martini, so does Bill, but Charley abstains.

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