Logical Fallacies

Bad Logic or Propaganda? Logic is the process of drawing a conclusion from one or more premises or statement of fact, which, by itself, is neither logical or illogical (although it can be true or false).

 

      Premise 1: All men are mortal.                  Premise 1: A=B

      Premise 2: Socrates is a man.                   Premise 2: B=C

      Conclusion: Socrates is mortal.                 Conclusion: A=C

 

As an example of how logic can be abused, consider the following argument widely propagated on the Internet. One way of testing the logic of an argument like this is to translate the basic terms and see if the conclusion still makes sense.

 

Example 1

Premise 1: Hillary Clinton supports gun-control legislation.

Premise 2: All fascist regimes of the twentieth century have passed gun-control legislation.

Conclusion: Hillary Clinton is a fascist.

 

As you can see, the premises may be correct, but the conclusion does not necessarily follow.

 

Example 2

Premise 1: All Christians believe in God.

Premise 2: All Muslims believe in God.

Conclusion: All Christians are Muslims.

 

Example 3

Premise 1: Nothing is better than eternal happiness.

Premise 2: Eating a sandwich is better than nothing.

Conclusion: Eating a sandwich is better than eternal happiness.

 

A message can be illogical without being propagandistic -- we all make logical mistakes. The difference is that propagandists deliberately manipulate logic in order to promote their cause.

 

Unwarranted Extrapolation

This is the tendency to make huge predictions about the future on the basis of a few small facts, which can create a common logical fallacy. It uses prior knowledge to form an educated guess;however, the educated part of the guess is often twisted to create propaganda.

 

Stuart Chase, an American economist, points out, "it is easy to see the persuasiveness in this type of argument. By pushing one's case to the limit... one forces the opposition into a weaker position. The whole future is lined up against him. Driven to the defensive, he finds it hard to disprove something which has not yet happened. Extrapolation is what scientists call such predictions, with the warning that they must be used with caution." (1952)

 

This logical sleight of hand often provides the basis for an effective fear-appeal.

Consider the following examples:

• If Congress passes legislation limiting the availability of automatic weapons, America will slide down a slippery slope which will ultimately result in the banning of all guns, the destruction of the Constitution, and a totalitarian police state.

• The introduction of communication tools, such as the Internet, cell phones, texting, email, etc., will lead to a radical decentralization of government, greater political participation, and a rebirth of community.

 

 

Twisting Statics and Data from Studies

It is often stated by people that, "Numbers don't lie", meaning that you cannot argue against statistical evidence. People always love to quote studies and use numbers and figures in their argument, because any good argument is supported with evidence; however, many people also attempt to leave out or twist the data to fit their argument instead of adjusting their argument to the data.

 

Argument: David Horowitz: "Teachers are overpaid and underworked. They are not required to be at their job more than 6 hours and 20 minutes a day. When you add to that teachers only work nine months out of the year, and then calculate teachers pay on the basis of the eight-hour day and 11 and a half-month year that the rest of us work, the pay for a seventh-grade teacher in New York city is between $60 and $70 an hour. This amounts to an average salary of well over $100,000 a year."

 

Analysis: Questionable use of good statistics. The good statistics involve 'They are not required to be at their job more than 6 hours and 20 minutes a day'. What is ignored is (1) the fact that teachers salaries must last the entire year, (2) the fact that teachers spend quite a bit of time at home working to prepare lessons and grade homework. This is an egregious example of twisting statistics.

 

Check Yourself, Before you Wreck Yourself...

When a communicator attempts to convince you that a particular action will lead to disaster or utopia, it wise to ask the following questions:

• Is there enough data to support the speaker's predictions about the future?

• Can I think of other ways that things might turn out?

• If there are many different ways that things could turn out, why is the speaker painting such an extreme picture?