转帖 常见谬误

雅思基本逻辑避免常见错误
作者： 来源：新东方 2011-09-05
　　要了解基本逻辑错误一定不能错过一篇英文小品文Love Is A Fallacy（作者Max Shulman），这里仅列举出十种最常见的逻辑错误。
　　1.草率前提 （Dicto Simpliciter）
　　例如：Women are on average not as strong as men and less able to perform well politically. Therefore, women can't pull their weight in government work.
　　点评：虽然女性确实在政界担任较少工作，但这不意味着女性群体中所有的人都是这样。
　　2.过度概化 （Hasty Generalization）
　　例如：McDonald's and KFC offer foods with little nutrition, and thus we cannot expect any fast food restaurant to provide us with nutritious foods.
　　点评：两个个例不足以推出一个真理。
　　3.因果颠倒 （Post Hoc）
　　例如：Most young criminals watch violent movies before they commit their crimes; obviously, violent movies lead to juvenile delinquency.
　　点评：甲事情发生在乙事情之前，这并不代表着先发生的甲事情就是后发生的乙事情的原因。
　　4.矛盾前提 （Contradictory Premises）
　　例如：If God can do everything, can he make a stone so heavy that he can't carry?
　　点评：前提条件中就有相互矛盾的地方，结论当然是错误的。
　　5.感性论证 （Ad Misericordiam）
　　例如：Think of all the poor, starving African children! How could rich countries be so cruel as not to help them?
　　点评：抒情是不能当作论证的。
　　6.错误类比 （False Analogy）
　　例如：Young children are like flowers——flowers should stay away from terrible weather to grow, so children need to get rid of everything negative.
　　点评：孩子和花朵的区别太大。成长的过程也太复杂。最好不要用这两者来类比。
　　7.虚假假设 （Hypothesis Contrary to Fact）
　　例如：If TV were not invented, today people would never have such wonderful entertainment brought by TV.
　　点评：因为电视已经被发明了，对于过去的否定假设后所得出的结论都是逻辑上的错误结论。
　　8.无关转移 （Red Herring）
　　例如：Many people say we need to exploit the outer space, a point which I believe is wrong, because there are so many poor people on Earth who hardly make ends meet.
　　点评：有一个问题没解决并不代表着另一个问题不值得解决。
　　9.从众错误 （Bandwagon）
　　例如：Everyone says it is justified to learn a second language so we must learn one.
　　点评：人人都说，或者大多数都说，这并不意味着该观点正确。
　　10.滑坡谬误 （Slippery slope）
　　例如：If we don't care about the environment, the world will die in 50 years.
　　点评：从环境问题到世界灭亡，中间有无数环节未提供论证。