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January 27th, 2007 (Permalink)

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Fallacy: Scope Fallacy

Acknowledgment: Thanks to John Congdon.

January 26th, 2007 (Permalink)

New Book, Too

Jay "Figaro" Heinrichs has a book coming out next month entitled Thank You for Arguing. He also operates a website on rhetoric that has some entries on fallacies. He takes a rhetorical approach to argument, rather than a logical one, so it should prove interesting to see what he has to say about fallacies in his book. Look for a review here in the near future.

Source: Jay Heinrichs, It Figures, see "Figaro on Fallacies"

January 23rd, 2007 (Permalink)


Slate's Jack Shafer has an article about Steven Poole's book Unspeak―which I mentioned about a year ago―together with a follow-up full of examples sent in by readers. I'm afraid that I haven't read Poole's book yet, so what little I know about it comes from Shafer's article.

According to Shafer, "unspeak" is:

…[A] phrase or word that contains a whole unspoken political argument…. Such gems of unspeak, such as pro-choice and pro-life…represent an attempt to say something without saying it, without getting into an argument and so having to justify itself.

This sounds like loaded words or what Jeremy Bentham called "question-begging epithets". Apparently, Poole distinguishes between "unspeak" and "doublespeak", which is right if you follow William Lutz' classification of doublespeak into four types, since loaded language is not one of them. However, some of the examples that Shafer gives are euphemisms, which is one of Lutz' types of doublespeak. For example, Shafer mentions "collateral damage", which is an infamous example of a military euphemism. There's a more recent example of Pentagon doublespeak: "Daisy cutter sanitizes the killing power of the daisy-cutter bomb." So, "daisy cutter" is euphemistic, rather than question-begging.

Many other examples cited by Shafer or sent in by his readers don't seem to fit the definition of "unspeak". As a result, I get the impression from Shafer that "unspeak", as Poole uses it, is rather too fuzzy a concept to be useful for thinking about the abuse of language. The book still promises to be rich in examples of loaded words, euphemism, and doublespeak.

Of course, the book may be better than the impression that Shafer gives of it, so I will try to review it here in the near future. It would help if the publisher sent me a copy!


Resource: Check it Out, 2/11/2006

Fallacy: Loaded Words

Update (1/24/2007): Steven Poole emailed to call my attention to an excerpt from the introduction to his book available online, explaining what he means by "unspeak". There are some additional extracts online, and an accompanying weblog discussing issues related to loaded language. In addition to links to some reviews of the book, there is an unusual "review of the reviews". Since I intend to review the book in the future, this gives me pause.

By the way, I'm struck by the fact that the title of the book is spelled: "UNSP$AK". As a logician, this reminds me of the following quote from the philosopher Hilary Putnam:

I think part of the appeal of mathematical logic is that the formulas look mysterious―You write backward Es!

Source: Steven Poole, "Extract: Introduction", Unspeak

January 21st, 2007 (Permalink)

Check it Out, Too

Nigel Warburton, author of the excellent Thinking from A to Z, has a new―at least to me―weblog called "Virtual Philosopher", though he is an actual philosopher. He has already posted a number of entries relating to logic and "critical thinking", including some on additional entries for a new edition of Thinking A → Z. For instance, he has entries on the sunk cost fallacy―which I am occasionally asked about―the principle of charity, poisoning the well, weasel words, and others.

Source: Nigel Warburton, Virtual Philosopher

January 20th, 2007 (Permalink)

New Book

Madsen Pirie has published a revised and updated version of his Book of the Fallacy, under the new title How to Win Every Argument: The Use and Abuse of Logic. I haven't read the new version yet, but I have frequently recommended the earlier version to Fallacy Files readers. Unfortunately, The Book of the Fallacy is expensive if you can find it at all. Hopefully, How to Win Every Argument will be better, easier to acquire, and more affordable. Now, if only the publisher would send me a review copy!

January 18th, 2007 (Permalink)

Check it Out

"I've often run into the argument that 'We don't let prostitutes sell their bodies, so we shouldn't let people sell body parts.' … Sounds logical, no? Except that 'selling your body' is a metaphor. Prostitution doesn't actually involve sale of the body as a good."

Update (1/19/2007): John Congdon comments:

Many would consider prostitution involving sale of the body as an evil.

Source: Eugene Volokh, "Be Careful Believing Your Own Metaphors", The Volokh Conspiracy, 1/17/2007


January 13th, 2007 (Permalink)

How to Read a Press Release

Which of the following passages is from a press release describing a new study?

  1. States With Higher Homicide Rates Have Higher Levels of Gun Ownership

    Boston, MA -- In the first nationally representative study to examine the relationship between survey measures of state level rates of homicide and household firearm ownership, researchers at the Harvard Injury Control Research Center found that more households have guns in states where homicide rates among children, and among women and men of all ages, are higher. The study appears in the February 2007 issue of Social Science and Medicine.
  2. States With Higher Levels of Gun Ownership Have Higher Homicide Rates

    Boston, MA -- In the first nationally representative study to examine the relationship between survey measures of household firearm ownership and state level rates of homicide, researchers at the Harvard Injury Control Research Center found that homicide rates among children, and among women and men of all ages, are higher in states where more households have guns. The study appears in the February 2007 issue of Social Science and Medicine.

If you guessed that the second passage is from the real press release, you're ready for a job in public relations! I created the first, phony release by simply switching around the phrases referring to the rate of firearm ownership and the homicide rate.

Both press release excerpts above are accurate descriptions of the results of the study, but each suggests a different causal relationship. The study itself only shows a correlation between firearm ownership rates and firearm homicide rates; it doesn't show what, if any, causal relationship exists between firearms ownership and homicide. It's just as plausible that people who live in states where there is a high rate of firearms homicide arm themselves in fear as that firearms ownership leads to more homicides. There may well be a feedback loop between the two: fear of gun crime leads to more firearms ownership, and the easy availability of firearms in the home leads to more crimes committed with guns, which leads to greater fear of gun crime, etc.

One of the conventions of language use is that the order in which facts are related parallels the order in which they occurred. Another convention is that facts that are mentioned together should be relevant to one another, and a causal relationship is one form of relevance. For instance, "Mary got pregnant and got married" tells a very different story than "Mary got married and got pregnant". In the first case, you might well assume that the pregnancy causally contributed to Mary's decision to wed. In the second case, you would probably be surprised to discover that Mary became pregnant after divorcing her husband.

Simply by ordering the terms in the way it does, the press release suggests a causal relationship between gun homicide rates and ownership rates that isn't justified by the study, as the study's authors indicate: "…causal inference is not warranted on the basis of the present study alone". It almost never is.

The press release isn't literally inaccurate, but it sets up a logical boobytrap that may cause the unwary reader to conclude that the study shows something more interesting than it really does.


Fallacy: Cum Hoc, Ergo Propter Hoc

January 12th, 2007 (Permalink)

Lessons in Logic 1: Introduction

This is the first in a new series of approximately monthly lessons providing an introduction to the basic concepts and techniques of logic. Fallacies are, of course, types of logical mistake. To understand why some types of reasoning are incorrect you need to know what it is to reason correctly. These lessons aim to provide that knowledge, to refresh your memory if you have already studied logic, or to allow you to test your understanding.

Learning logic is less a matter of memorizing information than it is one of developing skills. For this reason, learning logic is more like learning a physical skill, such as swimming, than like studying many other academic subjects. One learns a skill by trial and error, so success is achieved through practice. Each subsequent lesson will teach a specific skill.

Memorization is the wrong approach to studying logic. You will remember many things, but you should do so by using them repeatedly, rather than trying to memorize them. This is why the most important part of these lessons is the exercises. The text shows you how to do the exercises, but you should learn the most from actually doing them.

Logic is like a snowball rolling downhill, accumulating in layers, with the later lessons building upon the nucleus formed by the earlier ones. For this reason, it is important to start at the beginning, unless you already know some logic. If you master each lesson, the next one should be easy.

Q: What is logic?

A: Logic is the science of reasoning. It is the science which studies how one reasons correctly and incorrectly.

Next Lesson: Statements

January 3rd, 2007 (Permalink)

Check it Out

The BBC has a couple of articles showing why you shouldn't trust celebrity appeals about health or the environment.


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