Ad Hominem (Latin: “against the man”): When Ad Hominem is used a claim is rejected based on an irrelevant fact about the author presenting the claim.
Example:
Fred: “I believe that your level of education affects what jobs you will be able to acquire.”
Bill: “Of course you would say that; you’re a teacher!”
Fred: “But what about all the data and arguments I showed you proving how an education affects your employment and earning potential?”
Bill: “Your evidence doesn’t count because you’re a teacher. You just want to keep your job, and besides, you have to say education is important or you would get in trouble with the State Office of Education.”
Why?
Ad Hominem is a fallacy because the character, circumstances, and actions of a person do not (in most cases) have a bearing on the truth or falsity of a claim.
Appeal to Fear: A claim (often a hidden threat) is presented and then another claim is presented that may have nothing to do with the previous claim, yet the arguer links the two as if they depend on one another.
Example:
“Hey, I really think you should give me a promotion and a raise; it’s important to me. Why don’t you think about that while I go visit my Dad, who’s one of the CEO’s of this company.”
Why?
Threats do not serve as legitimate evidence in arguments; they merely serve to intimidate.
Appeal to Belief: An idea is declared true because many people believe it.
Appeal to Tradition: A way of doing things is declared to be “right” or “better” because it is the way things have been done for many years.
Appeal to Novelty: Something or a way of doing things is declared to be “better” or “correct” because it is new.
Appeal to False Authority: A person who is not a legitimate expert on a subject makes certain claims about the subject and then uses their “authority” as their evidence.
Bandwagon: The bandwagon is a fallacy in which a threat of rejection by one’s peers is substituted for real evidence in an argument.
Example:
Larry: “Hey, I know you’ve often said you believe that 4+4 = 8, but we don’t believe that in our group, so you can’t join.”
Hubert: “Oh, uh, I was just joking; I don’t actually believe that.”
Larry: “Good answer. You can join.”
Why?
A threat of rejection may never serve as evidence in a logical argument. A threat is a form of intimidation, not evidence.
Begging the Question: A fallacy where the premise of the argument already assumes the conclusion is true.
Example:
Teacher: “How do I know you’re telling the truth?”
Student: “Well, my friend Bob can vouch for my character.”
Teacher: “How do I know that Bob is honest?”
Student: “Well, I can vouch for Bob!”
Why?
Assuming that a conclusion is true can never serve as evidence that the conclusion is true.
Biased Sample: This fallacy occurs when a person draws a conclusion about a population based on a sample that is biased or prejudiced in some manner.
Example:
A poll is taken in Florida, Louisiana, and Texas, where it is found that about 50% of all those polled have sustained some kind of personal property loss due to hurricanes. So, the pollsters conclude that 50% of all Americans have sustained personal property loss due to hurricanes.
Why?
The statistics gained from a biased sample will not truly be representative of the group that is being sampled.
Burden of Proof: This fallacy is used when the burden of proof is placed on the wrong side of the argument, or when a lack of evidence to support one side of an argument is taken as evidence for the other side.
Example:
Wilma: “I think some people have psychic powers.”
Juliet: “What’s your proof?”
Wilma: “No one has been able to prove that people do not have psychic powers, so, that must mean that psychic powers exist!”
Why?
Just because one side of an argument cannot provide sufficient evidence does not mean the other side is automatically true.
False Dilemma: A false dilemma is a fallacy used when a person reasons that if there are two claims made, then one must be true and the other false (when, in actuality, they could both end up being false or true).
Example:
Either 2+3 = 6 or 2+3 = 23
It is not the case that 2+3 = 6
Therefore, 2+3 = 23
Why?
Claims have to be proved by evidence. Just because an opposing claim is proved wrong does not automatically mean that the other claim (without evidence) is true.
Guilt by Association: This fallacy occurs when a person rejects a claim because he/she dislikes the people who accept the claim.
Example:
Boris: “I think that it is important to have a strong military.”
Calvin: “You know, Stalin and Hitler were also in favor of having strong militaries; they were terrible dictators who were responsible for the deaths of millions of people.”
Boris: “Oh! Then having a strong military must be a bad idea.”
Why?
Just because you may not like the people who make certain claims does not automatically make their claims untrue.
Poisoning the Well: This fallacy involves trying to discreditwhat a person might later claim by presenting unfavorable information about that person.
Example:
Phyllis: “I heard your sister’s fiancé is arrogant and dishonest; when you meet him, you better be careful not to believe a thing he says.”
Yvette: “That’s good to know; I won’t believe one word he says.”
Why?
Just because you are given unpleasant information about someone doesn’t make that person’s future claims false.
Post Hoc (“Post hoc, ergo propter hoc” = “after, therefore because of it”): This fallacy occurs when it is assumed that one event caused another simply because the former event happened first.
Example:
George takes his car into the repair shop for a tune-up. A week later, his battery dies. He blames the repair shop for shoddy workmanship.
Or
Manny begins wearing red socks to his soccer games and his team wins three games in a row. Manny believes his lucky socks are the reason.
Why?
Just because one event follows another event does not mean that the first event caused the second to occur.
Red Herring: This is a fallacy in which an irrelevant topic is presented in an argument in order to divert attention from the original issue.
Example:
Harvey: “This new plan to build a city office building is very popular and the office building is needed.”
Lloyd: “Yeah, but there are so many different plans on the ballot this year that it’s getting out of control. That’s why we shouldn’t vote for it.”
Why?
Subjects and topics that have no direct bearing on the argument are not sufficient evidence, or even relevant evidence, for rejecting the claim.
Slippery Slope: This fallacy is one in which a person asserts that some event must inevitably follow from another, without any argument or evidence to explain the inevitability of the second event.
Example:
Daphne: “You should never give anybody a break or listen to their excuses.”
Cleo: “Why not?”
Daphne: “Because if you do, then you will be taken advantage of and people will just walk all over you!”
Why?
Just because one event occurs does not automatically mean that another event must always follow.
Straw Man: This fallacy occurs when a person simply ignores the actual argument of their opponent and instead substitutes a distorted, exaggerated, or misrepresented version of their opponent’s argument.
Example:
Tom: “I don’t think that we should buy an alarm system; we just don’t have the money right now.”
Pam: “I can’t understand why you don’t care about protecting our children and home!”
Why?
This type of reasoning is fallacious because attacking a distorted version of a claim does not serve as a valid attack on the actual claim.
Two Wrongs Make a Right: This fallacy takes place when person A justifies an action against person B by asserting that person B would do the same thing, even though the action is not actually necessary to prevent person B from acting against person A in the same manner.
Example:
Ronald: “Hey, where did you get that pencil?”
Barney: “I borrowed it from Mike without telling him.”
Ronald: “Are you going to give it back?”
Barney: “Probably not. I mean, if he borrowed one from me he probably wouldn’t give it back.”
Why?
This reasoning is false because an action that is wrong is wrong even if another person would do it if they were in your place.