Informal Logical Fallacies Informal Logical Fallacies n Persuasive

Informal Logical Fallacies

Informal Logical Fallacies n Persuasive, but irrational rhetorical device n Question of the Day: q Have you heard someone give an argument that sounded good in the moment but you realized later that the reasoning was flawed?

n You shouldn’t accept the city counselor’s argument in favor of legalized gambling. After all, he’s a godless communist. n Ad Hominem Fallacy -attacking the person rather than the argument

n The business consultant recommended that we switch to voice mail for receiving and sending internal messages. She claims this change will make our operations more efficient. I can’t believe this woman. She thinks every problem in the world has an electronic solution. Computers and telephones cannot improve the economy or morale at work. I think we should reject her recommendation. n Straw Man Fallacy -Misrepresenting the other argument to make it unacceptable

n Two students were arguing about cars. The first student said, “I can prove to you that Fords are faster than Chevys. My cousin Bill owns a Ford, and he told me that he has beaten every Chevy that he has ever raced on the highway. ” The second student asked, “How do you know your cousin is telling you the truth. ” The first replied, “Someone who drives the fastest car wouldn’t have to lie. ” n Circular Reasoning -the conclusion is assumed true at the start of the argument

n It’s perfectly all right to run red lights; everybody in town does it. n Two Wrongs Fallacy -Defending wrongdoing by pointing to other similar wrongdoing that went unchallenged

n The defense lawyer makes a good plausible argument about why the guy’s finger prints were in the room. So since you can’t prove that his story is wrong, it must be right. n Argument from Ignorance -The statement is true because it has not been proven to be false.

n We cannot allow marijuana to be legalized. If we do, then sooner or later everyone will become addicted to crack cocaine, and after that, the crime rate will surely rise. n Slippery Slope Fallacy -Incorrectly assumes multiple false alternatives that result in something bad happening

n I can’t believe you’re thinking about going to UNO. My brother went to UNL and he hated their history program. n Appealing to Unqualified Authority Not an expert in the field, or no agreement among experts in the field

n You say I’m not making sense. Give me a break. You’re the one who failed the first ethics exam. n Red Herring -the introduction of irrelevant material into the argument

n You don’t really believe that “joker” do you? Don’t you know his uncle was caught selling illegal pornography? I wouldn’t accept anything he says. n Guilt by Association -Attempt made to discredit opponent by linking him/her to a group that has already been discredited

n I can’t believe that you won’t lie for me and give me an alibi; you know I didn’t do it. If you won’t lie for me then you aren’t my friend. n False Dilemma -Offering only two alternatives, & one is clearly unacceptable

n If you are right and only people that feel pain have the right to live, then when I’m under anesthetic having surgery, the doctor could chop my head off and there would be nothing wrong with that. n Taking the argument to the absurd. Disproof a a proposition by showing that it leads to absurd or untenable conclusion