 In this task you will see 16 different arguments.  You have to identify which of the 8 common fallacies is being used by the argument.

1. Bill purchases a new PowerMac and it works fine for months. He then buys and installs a new piece of software. The next time he starts up his Mac, it freezes. Bill concludes that the software must be the cause of the freeze.

 Post hoc ergo propter hoc (post hoc)  A occurs before B. Therefore A is the cause of B.

 We should disregard Fred's argument because he is just angry about the fact that defendant once cheated him out of $100.

 Attacking the person (ad hominem)  An arguer who uses ad hominems attacks the person instead of the argument. Whenever an arguer cannot defend his position with evidence, facts or reason, he or she may resort to attacking an opponent.

 We have no evidence of alien visitors; therefore, aliens do not exist.

 Argument from ignorance (argumentum ad ignorantiam)  A misleading argument used in reliance on people's ignorance.

 The belief in God is universal. After all, everyone believes in God.“

 Circular reasoning (one form is known as Begging the question)  Begging the Question is a fallacy in which the premises include the claim that the conclusion is true or (directly or indirectly) assume that the conclusion is true

 God must exist! If God did not exist, then all basis for morality would be lost and the world would be a horrible place!"

 Appeals to consequences (argumentum ad consequentiam)  an argument that concludes a premise (usually a belief) as either true or false based on whether the premise leads to desirable or undesirable consequences

 "You can never give anyone a break. If you do, they'll walk all over you.“

 Slippery slope (the camels nose or the thin end of the wedge)  a change in procedure, law, or action, will result in adverse consequences. (e.g., If we allow doctor assisted suicide, then eventually the government will control how we die.) It does not necessarily follow that just because we make changes that a slippery slope will occur.

 Bill: "Jill and I both support having prayer in public schools." Jill: "Hey, I never said that!" Bill: "You're not an atheist are you Jill?“

 False dilemma (false dichotomy)  A False Dilemma is a fallacy in which a person uses the following pattern of "reasoning":  Either claim X is true or claim Y is true (when X and Y could both be false). Claim Y is false. Therefore claim X is true.

 We should discount what Steve Forbes says about cutting taxes because he stands to benefit from a lower tax rate.

 Attacking the person (ad hominem)

 You live on Sunny Street. You have a gun. Nobody else on Sunny Street has a gun. There was a murder on Sunny Street last night. You were involved.

 Argument from ignorance (argumentum ad ignorantiam)

 We have to stop the tuition increase! The next thing you know, they'll be charging $40,000 a semester!“

 Slippery slope (the camels nose or the thin end of the wedge)

 "Look, you are going to have to make up your mind. Either you decide that you can afford this stereo, or you decide you are going to do without music for a while.“

 False dilemma (false dichotomy)

 "It's against the law for stores to be open on weekends, therefore it's wrong for them to do so.

 Illegitimate appeals to authority (argumentum ad verecundiam)  using the words of an "expert" or authority as the bases of the argument instead of using the logic or evidence that supports an argument.

 I don't think that there will be a nuclear war. If I believed that, I wouldn't be able to get up in the morning. I mean, how depressing."

 Appeals to consequences (argumentum ad consequentiam)

 The picture on Jim's old TV set goes out of focus. Jim goes over and strikes the TV soundly on the side and the picture goes back into focus. Jim tells his friend that hitting the TV fixed it.

 Post hoc ergo propter hoc (post hoc)

 I am going to buy a car, my accountant has a BMW and thinks that BMW’s are the best car so I will buy a BMW.

 Illegitimate appeals to authority (argumentum ad verecundiam)

 If such actions were not illegal, then they would not be prohibited by the law."

 Circular reasoning (One form is known as Begging the question)