en-us 2010 A weblog for the Fallacy Files website. http://www.fallacyfiles.org/ Q: I was wondering if you have good references about how to counter-argue each fallacy, which I find sometimes very hard, specially because many of them are heuristically valid (although not necessarily). Some are specially hard to argue since the person might not be convinced by a simple announcement that they used a fallacy, I find that a good strategy is to give a plausible counter-example, but sometimes it is very hard to find one quickly.--Leo Arruda.... http://www.fallacyfiles.org/archive052013.html#05212013 Adam, Beth, and their daughter, Cathy, like to visit their local public library to check out books. They always check out either mysteries or puzzle books, but never more than one book apiece. Either Adam or Beth will select a mystery novel. If Adam picks a mystery then Cathy will choose a puzzle book. If Cathy selects a puzzle book then Beth will check out a mystery. Adam and Beth won't both select the same kind of book. Who checked out a mystery on one trip to the library but a puzzle book a different time? http://www.fallacyfiles.org/archive052013.html#05172013 New salt study suggests that U.S. guidelines on sodium are too strict.... http://www.fallacyfiles.org/archive052013.html#05152013 Massimo Pigliucci has an interesting article in the most recent issue of Skeptical Inquirer magazine on the notion of the burden of proof (BoP). The onus probandi is probably most familiar from the law where--at least in the U.S.--the onus in a criminal trial is on the prosecution. Pigliucci doesn't mention it, but there is a presumption corresponding to the onus; in criminal law, it is that the defendent is presumed to be innocent. Of course, such a presumption can be overcome, otherwise no one would ever be convicted, but to do so the prosecution must present sufficient evidence of guilt to shift the onus to the defense. Exactly how much evidence and of what kind is necessary to overcome the presumption of innocence is, of course, a legal question that I won't go into since I'm not a lawyer. But, at the very least, placing the onus and presumption where they are means that the prosecution must present some evidence, while the defense needn't present any if the prosecution fails to shoulder its burden.... http://www.fallacyfiles.org/archive052013.html#05132013 I haven't read all of Charles Wheelan's new book Naked Statistics yet, so I can't give a full review of it or an unqualified recommendation. However, from what I have read, it's very clearly written and the explanations are easy to understand. Wheelan is also the author of a previous book called Naked Economics, which I also haven't read, but I suppose that explains the odd title.... http://www.fallacyfiles.org/archive052013.html#05112013 Pie charts are one of the most common and useful types of statistical graph. Often, the "pie" is simply a circle that has been divided into slice-shaped wedges, but sometimes a third dimension is introduced by slanting the pie away from the viewer, so that its edge can be seen.... http://www.fallacyfiles.org/archive052013.html#05052013 Ted Grant emails the following question.... http://www.fallacyfiles.org/archive042013.html#04262013 An ad in yesterday's New York Times for the new documentary War on Whistleblowers includes the blurb: "UNPRECEDENTED!"-Tom Devine, THE GUARDIAN.... http://www.fallacyfiles.org/archive042013.html#04202013 A headline from a San Francisco Chronicle article is about a man who supposedly "stopped eating food". Of course, it's possible to stop eating--for awhile. However, the headline is one of those misleading tabloid headlines aimed at tricking you into reading the article by suggesting something surprising but false. No, the man in question, Rob Rhinehart, is not a "breatharian". He did not stop consuming food, though he did stop "eating" it--he's drinking it, instead. Rhinehart created a beverage in his kitchen that supposedly supplies all of the protein, fat, carbohydrates, vitamins and minerals that the human body needs. Oddly enough, he calls this stuff "soylent", though this soylent isn't people.... http://www.fallacyfiles.org/archive042013.html#04172013 Bar graphs are useful for visually comparing quantities when the heights of the bars are proportional to the quantities they represent. However, if a bar chart is truncated--that is, the bottom part of the chart, including the zero baseline, is removed--the heights of the bars will no longer be in proportion to the quantities they represent, with the effect of exaggerating the differences between those quantities. We've seen examples of this type of chart before and it seems to be one of the most common types of misleading graph, if not the most. As an example, see the graph to the right.... http://www.fallacyfiles.org/archive042013.html#04042013 The new book Math on Trial: How Numbers Get Used and Abused in the Courtroom, by mathematician Leila Schneps and her daughter, looks very interesting. I haven't read it yet, but judging from the chapter titles and the Amazon "Look Inside!" feature, it deals primarily with probability theory and statistics, which makes sense given its subject matter. The first chapter concerns the tragic case of Sally Clark, and a later one the Lucia de Berk case, both of which I've alluded to previously. There's also a chapter on the Amanda Knox case that's been back in the news recently. Statistical fallacies that play a role in these cases include the so-called "prosecutor's" fallacy--which needs a more accurate name, since not only prosecutors commit it--and the mistake of multiplying non-independent probabilities--which is more a definition than a name. This book may also answer the question "where's the harm?", since it shows that fallacious reasoning can put innocent people in prison or leave the guilty free to commit more crimes.... http://www.fallacyfiles.org/archive042013.html#04032013 Will the puzzle you solve before you solve the puzzle you solve after you solve this one be harder than the puzzle you solve after you solved the puzzle you solved before you solved this one? http://www.fallacyfiles.org/archive042013.html#04012013 One-armed man applauds the kindness of strangers http://www.fallacyfiles.org/archive032013.html#03302013 Longtime readers of this weblog may remember Spinsanity, which was the best and most objective of the media watchdog sites several years ago, and whose stories I often pointed readers to. Brendan Nyhan, who was one of the three watchdogs of that site, has an article in the Columbia Journalism Review about factchecker Glenn Kessler turning into a pundit. I've criticized the tendency of factchecking to turn into punditry myself, but I do have a quibble with the following comment.... http://www.fallacyfiles.org/archive032013.html#03242013 Since I've recently begun posting examples of misleading charts and graphs, this is the first entry in a short series on the most common ways in which such graphics can mislead. Take a look at the line graph to your right, which is taken from the President's enhanced State of the Union address from earlier this year.... http://www.fallacyfiles.org/archive032013.html#03212013