[未归类] 逻辑错误分类举例与解释 [复制链接]

Hasty Generalization

eg:

Listen carefully: You can’t speak French. Petey Bellows can’t speak French. I must therefore conclude that nobody at the University of Minnesota can speak French.”

explanation:

I hid my exasperation. “Polly, it’s a fallacy. The generalization is reached too hastily. There are too few instances to support such a conclusion.”

Post Hoc

eg

“Next comes Post Hoc. Listen to this: Let’s not take Bill on our picnic. Every time we take him out with us, it rains.”

explanation

“it’s a fallacy. Eula Becker doesn’t cause the rain. She has no connection with the rain. You are guilty of Post Hoc if you blame Eula Becker.”

False Analogy.

Here is an example:

Students should be allowed to look at their textbooks during examinations. After all, surgeons have X-rays to guide them during an operation, lawyers have briefs to guide them during a trial, carpenters have blueprints to guide them when they are building a house. Why, then, shouldn’t students be allowed to look at their textbooks during an examination?”

explanation

“the argument is all wrong. Doctors, lawyers, and carpenters aren’t taking a test to see how much they have learned, but students are. The situations are altogether different, and you can’t make an analogy between them.”

“Listen closely,” I said. “A man applies for a job. When the boss asks him what his qualifications are, he replies that he has a wife and six children at home, the wife is a helpless cripple, the children have nothing to eat, no clothes to wear, no shoes on their feet, there are no beds in the house, no coal in the cellar, and winter is coming.”

explanation: “The man never answered the boss’s question about his qualifications. Instead he appealed to the boss’s sympathy. He committed the fallacy of Ad Misericordiam. Do you understand?”

Dicto Simpliciter
eg:

“Dicto Simpliciter means an argument based on an unqualified generalization. For example: Exercise is good. Therefore everybody should exercise.”

explanation

“the argument is a fallacy. Exercise is good is an unqualified generalization. For instance, if you have heart disease, exercise is bad, not good. Many people are ordered by their doctors not to exercise. You must qualify the generalization. You must say exercise is usually good, or exercise is good for most people. Otherwise you have committed a Dicto Simpliciter. Do you see?”

Hypothesis Contrary to Fact.

eg:

“Listen: If Madame Curie had not happened to leave a photographic plate in a drawer with a chunk of pitchblende, the world today would not know about radium.”

explanation

“I would like to point out that statement is a fallacy. Maybe Madame Curie would have discovered radium at some later date. Maybe somebody else would have discovered it. Maybe any number of things would have happened. You can’t start with a hypothesis that is not true and then draw any supportable conclusions from it.”

“Two men are having a debate. The first one gets up and says, ‘My opponent is a notorious liar. You can’t believe a word that he is going to say.’ ... Now, Polly, think. Think hard. What’s wrong?”

“It’s not fair,” she said with indignation. “It’s not a bit fair. What chance has the second man got if the first man calls him a liar before he even begins talking?”

“Right!” I cried exultantly. “One hundred per cent right. It’s not fair. The first man has poisoned the well before anybody could drink from it. He has hamstrung his opponent before he could even start ... Polly, I’m proud of you.”

Contradictory Premises:

eg；

If God can do anything, can He make a stone so heavy that He won’t be able to lift it?”

explanation

“But if He can do anything, He can lift the stone,” I pointed out.

“Yeah,” she said thoughtfully. “Well, then I guess He can’t make the stone.”

“But He can do anything,” I reminded her.

She scratched her pretty, empty head. “I’m all confused,” she admitted.

“Of course you are. Because when the premises of an argument contradict each other, there can be no argument. If there is an irresistible force, there can be no immovable object. If there is an immovable object, there can be no irresistible force. Get it?”