Exam 6: Logical Fallaciesii

All analogies are weak.

The following is a weak analogy: A battleship is made of metal, and it floats. An aluminum canoe is made of metal, and it floats. A hammer is made of metal; so, it probably floats, too.

In the fallacy of appeal to ignorance, the arguer falsely accuses another arguer of being ignorant.

"Every time I drink a bunch of beer, I feel really hung over the next morning. The drinking must be causing the hangover." In this example, identify the fallacy and the most relevant reason for the fallacy.

"Legislators in Texas want to make it a criminal offense for citizens not using seat belts when they drive. Mark my words: If they get away with this, it won't be long before they ban beer drinking and cigarette smoking. Then they will restrict our intake of cholesterol, perhaps setting up cholesterol testing sites along major highways. We must not let this infringement of our liberties start, or there will be no stopping it." Identify the fallacy that applies to this example.

"ABC News reported that the mayor of Toledo was killed in a plane crash today. Given the credibility of the source, the story is probably true." This statement illustrates the fallacy of inappropriate appeal to authority. Identify the most relevant reason for the fallacy.

"The Brazilian soccer team has three top, match-winning players. Therefore, the entire Brazilian team must be a top, match-winning team." Identify the fallacy that applies to this example.

An arguer is guilty of the fallacy of composition when he or she assumes, without good reason, that what is true of the parts is also true of the whole.

"Most Hollywood movie stars believe in reincarnation. I know because I read it in a British tabloid." Identify the fallacy that applies to this example.

"Professor Gene Poole, the distinguished microbiologist, has argued that using animals in medical and scientific experiments is morally wrong. Given Professor Poole's impressive credentials, we should conclude that using animals in medical and scientific experiments is morally wrong." Identify the fallacy that applies to this example.

"Your accusation that I am a verbose windbag is completely unfounded. I've never uttered a sentence in my life that contained more than twelve words." Identify the fallacy that applies to this example.

Every argument that jumps to a conclusion is a hasty generalization.

If an arguer asks a question that contains an assumption, then he commits the fallacy of loaded question, even if the assumption is entirely reasonable.

"Wierdthings.com reported that 100-foot-tall aliens from the future landed in the Grand Canyon today. I guess we're not alone in the universe." This statement illustrates the fallacy of inappropriate appeal to authority. Identify the most relevant reason for the fallacy.

"An extensive, diligent search of the zoo failed to find any trace of the missing gorilla. Therefore, the gorilla probably isn't in the zoo. It must have escaped." Identify the fallacy that applies to this example.

"Kids play too many video games. That's why there's so much juvenile crime today." Identify the fallacy that applies to this example.

"Conspiracy theorists suggest that 9/11 was an inside government job. The government secretly landed those planes, took off all the passengers, and then hid the planes. Then they took remote-controlled planes and flew those planes into the towers. But days before, they had managed to sneak in explosives into the towers, without anyone seeing, and then performed a controlled detonation on the buildings after the remote-controlled planes hit the towers. And, even though thousands of people would've had to have been involved in the conspiracy to pull this off, they all kept quiet and didn't object. Given the track record of the federal government, that sounds like a plausible scenario to me." Identify the fallacy that applies to this example.

"A couple of weeks ago, I received a chain letter that said bad luck would come my way if I did not send the letter to at least 10 people I knew. I mumbled something about superstitious nonsense and threw the letter away. Bad move! The very next day I was attacked by a Rottweiler, got dumped by my girlfriend, and was fired from my job. Once is enough. You can bet that next time I get a chain letter, I will do exactly what it says." Identify the fallacy that applies to this example.

An argument that only presents you with two options is always fallacious.

If a person cites a source in support of a conclusion and there is good reason to believe that the source has been cited incorrectly, then the person commits the fallacy of inappropriate appeal to authority.