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May 26th, 2005 (Permalink)

Contextomies on the Left, Contextomies on the Right

May 25th, 2005 (Permalink)

What's New?

May 22nd, 2005 (Permalink)

Letter from the Editor

"I'm an editor, and I sometimes come across a claim along the lines of 'It's terrible how everyone is making fun of [insert category of people here]. If everyone were making fun of [insert some other category of people here] in the same way, there would be a public outcry.' It seems to be related to the claim '[Insert category of people here] are victims of the last socially acceptable prejudice.' Are these fallacies?"―Karen Grooms

The form of argument that you describe is a type of argument from analogy:

(Suppressed Premiss) Groups A and B are similar.
It's wrong to treat Group A in a certain way.
Therefore, it's wrong to treat Group B in the same way.

This type of argument is not necessarily fallacious: it is cogent when the two groups are similar in ways relevant to the type of treatment mentioned in the second premiss. If there is no difference between the groups that would justify a difference in treatment, then such a difference is, of course, unjustified.

Arguments of this form are uncogent if the two groups being compared are dissimilar in some relevant way. If there is some difference between the two that justifies a difference in treatment, then the argument commits a fallacy of weak analogy.

For example, it was wrong to deny women the vote but not men, not because there are no differences between men and women, but because there are no differences relevant to voting. In contrast, there is nothing wrong with denying the vote to children while allowing adults to vote, as there are differences between the two groups which are relevant to voting, such as maturity and knowledge. If one were to argue that denying women the vote was wrong, therefore denying children the vote is wrong, one would argue fallaciously.

So, you need to look at the specifics in order to evaluate arguments of this type. Are the two groups being compared similar in all ways relevant to their treatment, or is there some difference that would justify different treatment? Justice means both treating like cases alike and treating different cases differently.

Thanks for the question, Karen.

May 20th, 2005 (Permalink)

May I Puzzle You?

What city in the contiguous United States is large enough in area that the entire population of the world could fit inside it so that each person would have a plot of land large enough to stand on? The "contiguous United States" refers to the "lower 48", that is, all of the states except Alaska and Hawaii.


May 17th, 2005 (Permalink)

Letter to the Editor

In past "Letter to the Editor" features, I've reprinted letters from newspapers and magazines that illustrate fallacious reasoning. It is true that letters to the editor often commit fallacies, but sometimes they criticize fallacies committed in articles in the periodicals in which they are printed. Here's a nice example of one of the latter type of letters, exposing a causal fallacy:

"I am troubled by the conclusion drawn in 'College may endow memory to old brains' (SN: 3/26/05, p. 205). The report says that college-educated adults do better on memory tests, displaying pronounced frontal brain activity, than do their less-educated peers. Might it not be just as reasonable to hypothesize that those who are able to 'recruit the frontal brain into a memory system' do better in school and are, therefore, more likely to extend their educations?"―Kathryn Klein, Redwood City, Calif.

Source: Science News, 5/7/2005, p. 303

May 14th, 2005 (Permalink)

Update on the Lancet 100,000

The United Nations Development Program has released a report of a large household survey done in Iraq last year, called the "Iraq Living Conditions Survey 2004" (ILCS). It used cluster sampling, as did the study published last October in Lancet by Roberts, et al., but the new study's sample was much larger: 21,600 households surveyed by UNDP, as opposed to less than a thousand by Roberts, et al. The Lancet report produced the estimate of 100,000 Iraqi war dead which has been reported ad nauseum, while its enormous margin of error was frequently unmentioned. Here is the relevant part of the analytical section of the new report:

"The number of deaths of civilians and military personnel in Iraq in the aftermath of the 2003 invasion is another set of figures that have raised controversy. The ILCS data indicates 24,000 deaths, with a 95 percent confidence interval from 18,000 to 29,000 deaths. … Another source (Roberts et al. 2004) estimates the number to be 98,000, with a confidence interval of 8,000 to 194,000. The website 'Iraq Body Count'…estimates that between 14,619 and 16,804 deaths have occurred between the beginning of 2003 and 7 December 2004 (IBC 2004)."

The new survey has a much smaller margin of error than the Lancet study, its confidence interval is within the interval of the previous study, and its result is closer to the I.B.C. figures. For these reasons, the true number of deaths is probably closer to 24,000 than to 100,000.



Update to the Update (5/18/2005): Reader Zhou Fang writes:

"The Lancet figure cannot be directly compared with the UN figure, because they use different criteria for counting things. The UN figure referred to direct loss of life due to war, whilst the Lancet report included indirect effects by a death-rate comparison, e.g., things like more murders and accidents due to loss of public order, and deaths due to malnutrition from disrupted food supplies. Furthermore, the Lancet report covered an 18-month period, while the UN reported only the numbers for a 12 month period. It is possible to argue that the Lancet and the UN figures are in fact fully consistent."

You're right that the Lancet and ILCS surveys are not measuring exactly the same thing. This is a frequent problem with statistical studies that attempt to count something, for they have to define it precisely in order to do so, and different ones often define vague and ambiguous concepts differently. However, it doesn't mean that the studies are incomparable; only that one has to be clear about exactly what they are measuring in order to compare them. It's not comparing apples and oranges, but comparing oranges and grapefruit. I should've mentioned this as a problem in the original post; in fact, I should've originally mentioned that the Lancet study took a rather expansive view of what constitutes a civilian casualty.

That said, I don't think that your characterization of the differences between the two studies is correct. The ILCS estimate appears to be based on only one question from the long survey that asks the subject to classify the deaths of "regular household member"s as due to (p. 48, HM05):

  1. Disease
  2. Traffic accident
  3. War related death
  4. During pregnancy, childbirth or within 40 days after
  5. Other (specify)

Assuming that these categories are mutually exclusive, it seems to be left to the subject to decide what is a "war related death", with the exceptions of disease, traffic accidents, and deaths related to pregnancy or childbirth. This is broader than "direct loss of life due to war", though it's hard to know just how the respondents interpreted the question.

I agree with you that it is possible to argue that the Lancet and ILCS figures are consistent; in fact, that's what I meant to argue. My criticism of the Lancet study was always that it was very imprecise: I pointed out that the confidence interval of the ILCS estimate was contained within that of the Lancet to emphasize the fact that the two results are consistent, but that the newer study is more precise and probably gives a more accurate estimate than the misleading "100,000".

Source: "Iraq Multiple Indicator Rapid Assessment Household Questionnaire", Fafo AIS

May 13th, 2005 (Permalink)


Police ID Wendy's Finger Owner

Was it Wendy?

May 11th, 2005 (Permalink)

Calling Dr. Who!

The M.I.T. Time Traveller convention was last Saturday, so set the dials on your TARDIS. No time travellers were reported to have shown up, so if you do go and announce that you're from the future, be prepared to be met with incredulity. You might want to attend "incognito to avoid endless questions about the future."

Of course, the failure of the convention to attract any obvious time travellers is some evidence that time travel is impossible. However, despite what many physicists, philosophers, and even logicians believe, the usual argument aiming to show that time travel into the past is impossible commits a modal scope fallacy. Philosopher Norman Swartz has a fascinating article analyzing an example from a logic text, of all places.

Of course, lest we commit the Fallacy Fallacy, we cannot conclude that time travel is possible simply because one argument that it is impossible is fallacious. There may be a valid argument that time travel is logically impossible, or more likely, that it is metaphysically or just plain physically impossible. If so, that would explain why no Dr. Whos showed up at the M.I.T. conference.


May 2nd, 2005 (Permalink)

Reader Response

"I just came across the article 'Was Hitler A Vegetarian?' of Feb. 29th, 2004. The author stated that Rynn Berry was forced to narrow the definition of vegetarianism in order to prove that Hitler was not vegetarian. I don't know if the author of your article failed to read all of Berry's evidence regarding Hitler, but the term vegetarian was in no way redefined or narrowed. Berry presented quotes from several sources, including well-known biographer of Hitler Robert Payne, that confirmed that Hitler's diet always included sausage, caviar, ham, and squab. As Berry points out, by 1911, the Encyclopedia Britannica already defined vegetarianism as 'the use of foods from which fish, flesh, and fowl are excluded.' Only people who do not understand the concept of vegetarianism would think that it must be 'redefined' to exclude sausage, ham, caviar and squab. The Hitler argument muddies the issue of vegetarianism, which is already a maligned and misunderstood concept, and Berry presented conclusive evidence to lay the argument to rest. It is most unhelpful to have people perpetuate the Hitler-as-vegetarian fallacy, which the author of your article does by redefining the definition of vegetarianism to include ham and sausage."―Dorothy Mitchell

Dorothy, I have not read Berry's book, but the weblog entry was explicitly based on Berry's online article on the same topic. So, perhaps Berry provides better evidence in his book for his claim that Hitler was not a vegetarian. However, that has no bearing on the fact that his article is very poorly reasoned. Given the article as evidence, I doubt that Berry's book is much better.

I am not an historian nor an expert on Hitler, and the question of whether Hitler was a vegetarian doesn't interest me much. My main point was a strictly logical one: in trying to make his case that Hitler was not one, Berry had to redefine "vegetarian" as one who never eats meat, which is an overly narrow definition. At best, Berry shows in his article that Hitler occasionally ate meat, but that just isn't sufficient evidence to support his revisionist history. What would it take to support his claim? He needs to show that Hitler frequently ate meat, or that he made no sincere effort to avoid doing so.

Your claim that I was redefining "vegetarianism" to include eating ham and sausage is a straw man fallacy. I never denied that meat is excluded from a vegetarian diet, but a person who typically or habitually eats a vegetarian diet counts as vegetarian in common parlance. So, occasionally eating ham or sausage does not make one a non-vegetarian.

Unfortunately, you are making the same logical mistake that Berry made in taking seriously the guilt-by-association argument that links vegetarianism with Hitler. Instead of attempting to revise history, vegetarians should point out that this argument is fallacious. The answer to the question "Was Hitler a vegetarian?" should be "Yes, but so what?"

Source: Was Hitler a Vegetarian?, 2/29/2004

May 1st, 2005 (Permalink)

Cut it Out

In political doublespeak, a "cut" is usually an increase. If a politician claims to have "cut" deficit spending, it probably means that deficit spending increased less than predicted. Similarly, if a politician charges that his opponent wants to "cut" Social Security benefits, this typically means that the opponent wants benefits to increase less than they will if nothing is done.

Some Democrats are now charging that President Bush's Social Security proposal will "cut" benefits on middle-class retirees. So, it will actually increase their benefits, just less than the current system. Eventually, either Social Security benefits will have to be "cut" or taxes will have to be "cut".

Source: "Bush Proposes Slowing Growth of Social Security Benefits for Future Retirees", Annenberg Political Fact Check, 4/29/2005

Resource: More is Less, 10/21/2004

Answer to "May I Puzzle You?": Jacksonville, Florida.

This is not the sort of puzzle that you can figure out, but it does have a surprising answer. Jacksonville has a land area of 841 square miles. Given a world population of about 6 and a half billion people, that makes for a little over 3 and a half square feet for each person, which is enough to stand on, though just barely.

Part of what makes this answer so surprising is that Jacksonville is not the largest city in terms of population, nor even in the top ten. It is a good rule of thumb that the population size of a city varies directly with its area, so one assumes that Jacksonville would not be such a large city in area. However, in 1968, Jacksonville was consolidated with the surrounding county of Duval, creating the largest city in area in the lower 48. You might have guessed that Los Angeles would be the answer to the puzzle, but it is only 469 square miles.

This peculiarity of Jacksonville is sometimes exploited by people who argue that there is no problem of overpopulation. If the entire world population can fit in Jacksonville, they argue, then there must be room enough for many more people in the world. However, those who make this argument seldom mention the fact that Jacksonville is the largest city in area in the contiguous U.S. In this way, they lure the unwary into committing a fallacy of Accident.


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