Logical Fallacies

How do we define a fallacy? A logical fallacy is an argument that contains a mistake in reasoning. There are many types of fallacies that fall under two main groups: fallacies of relevance or fallacies of insufficient evidence. A fallacy of relevance occurs because the premises are logically irrelevant to the conclusion. A fallacy of insufficient evidence occurs because the premises, although logically relevant, fails to support the conclusion. I have chosen to touch on 3 fallacies of relevance and 2 fallacies of insufficient evidence. (Critical Thinking Ð'- A Students Introduction, 140)

Fallacies of Relevance

Ad Hominem or Attacking the Person

This type of fallacy is the most familiar of all of the fallacies, also being the most used. With this type of fallacy we tend to attack the person instead of their argument. We could care less about how relevant the information is. It is all about being negative about he person himself. There are 2 sub fallacies that fall under Ad Hominem: abusive and circumstantial. In an abusive Ad Hominem, the person is attacked by a personal quality, which is used as the evidence against them. A circumstantial ad hominem is an irrelevant personal circumstance that surrounds the opponent, which is used as the evidence against the opponent. (Argumentum ad Hominem, www.fallacyfiles.org) An insult is considered to be fallacious if it is made in a manner as to insult the opponent's argument, and to encourage the audience to give it less weight that it merits. The argument is not judged on its material, rather it is judged on the arguer. (www.adamsmith.org/logicalfallacies.php) A perfect example is John Kerry. Back when he was in the Army, he protested against the Vietnam War, but yet he joined the military. Doesn't really make much since considering he knew what was going on with that war.

Tu Quoque or Look Who's Talking

This fallacy is normally utilized when a person rejects another person's stance on a subject because that person does not practice what they preach. Its kind of like saying, "Why should I not surf the web at work, you do itÐ'..." (Critical Thinking-A Students Introduction, 145) In other words a person attempts to defend themselves by turning the situation around onto the accuser. (Tu Quoque, www.fallacyfiles.org) This fallacy is often times used to undermine an accusation to discredit the accuser. It is to make the accuser look bad in order to make themselves look like they didn't do anything wrong. (www.adamsmith.org/logicalfallacies.php)

Two Wrongs Make a Right

It is similar to the look who's talking fallacy. This is achieved by the arguer attempting to justify a wrongful action by claiming that some other action was just as bad, if not worse. Using the same example from Tu Quoque, but it would change slightly. "Don't get mad at me for surfing the web on a work computer when half the company does it. Some even go to porn sites!" We try to justify what is wrong with an excuse. We turn the wrong around to make us look innocent. We justify our actions by saying, "Well if they do it, I can too." (Critical Thinking-A Student's Introduction, 146)

Fallacies of Insufficient Evidence

Inappropriate Appeal to Authority

This fallacy attempts to convince the listener by appealing to the expert. Individuals try to come out of their ordinary element into a completely different. (Critical Thinking Ð'- A Student's Introduction, 162-163) They try to explain something that they know absolutely nothing about to begin with. I have seen this most recently in my company. The CEO of my company, not IT oriented, tried to accuse the IT department of remote controlling the CFO's laptop computer without his permission. He thought he knew what he was talking about by automatically assuming that we remote controlled it. When in fact the laptop had a WIRELESS keyboard and mouse attached to it. Well we all know that these devices can pick up other frequencies from the outside. The CEO tried to say that it was not possible. He was trying to argue about an IT issue that he knew absolutely nothing about. What,