Wednesday, May 24, 2017

Donkey Brain!

Denying or Negating the Antecedent is a formal fallacy that has the following argumentative structure:
  1. If P, then Q.
  2. Not P.
  3. Therefore, not Q
This fallacy is often confused for the valid argument Modus Tollens which has the following structure:
  1. If P, Then Q.
  2. Not Q.
  3. Therefore, not P. 
The comedy show It's Always Sunny in Philadelphia presents an excellent example of Denying or Negating the Antecedent in the following clip:


If we reconstruct the argument it goes:

  1. If one has donkey brains, then they make foolish decisions.
  2. Frank does not have a donkey brain.
  3. Therefore, he does not make foolish decisions. 





Tuesday, May 16, 2017

Did doctors really believe this?

Here is a great example of the Appeal to Inappropriate Authority, a fallacy in which one relies on some "putative" expert who shouldn't really be relied upon.

An ad from the 1950's for Camel Cigarettes. The ad copy says, "Mored Doctors smoke Camels than any other cigarette!"
Picture of a doctor holding a cigarette with a pack of Camels on his desk. The caption reads, "More Doctors Smokle Camels than any other cigarette!"

Note that this ad does not claim that doctors recommend smoking. Instead, it implies that Camel cigarettes are healthier than other cigarettes because more doctors smoke them. While the ad isn't explicit, there is a clear Appeal to Authority in the claim that Camel cigarettes are preferred by doctors.

These ads were fairly common back in the 1950's until the a number of scientific studies started to be released that began to draw a clear connection between smoking and lung cancer. In addition, the FTC began to step up its regulations on tobacco advertising, essentially making ads like this illegal because they implied that some cigarettes were healthier than others or that cigarettes themselves did not pose any health risks. Much of this was dramatized on the TV show Mad Men, particularly the premiere episode "Smoke Gets In Your Eyes," which is a nice transition to this second example sent to me by a student:

Picture of a Physician holding a pack of Lucky Strikes. The caption reads, "20,679 Physicians say 'Luckies are less irritating' 'It's toasted' Your Throat Protection against irritation against cough.