轻率概括.ppt

Hasty Generalization (Converse Accident) 轻率概括 2017-1-14 Hasty generalization ? Hasty generalization is a fallacy that affects inductive generalizations . The fallacy occurs when there is a reasonable likelihood that the sample is not representative of the group. ? Such a likelihood may arise if the sample is either too small or not randomly selected. ?归纳概括轻率概括?样本很有可能不具有代表性?样本数量太小样本不是随机选取 2017-1-14 Example ⑴? After only one year the alternator went out in 'Grady's new Chevrolet. Mrs. Dod-son's Oldsmobile developed a transmission problem after six months. The obvious conclusion is that cars made by General Motors are just a pile of junk these days. ? In the argument a conclusion about a whole group is drawn from premises that mention only a few instances. Because such small , atypical samples are not sufficient to sup-port a general conclusion, each mits a hasty generalization. 2017-1-14 typical drawing Hasty generalization Generalization Specfic case(s) (not representative) General rule 2017-1-14 Attention Ⅰ? The mere fact that a sample is small, however, does not necessarily mean that it is atypical. On the other hand, the mere fact that a sample is large does not guarantee that it is typical. In the case of small samples, various factors may intervene that render such a sample typical of the larger group. 2017-1-14 Examples ⑵? Ten milligrams of substance Z was fed to four mice, and within two minutes all four went into shock and died. Probably substance Z, in this amount, is fatal to mice in general. ? In the second argument the fact that the mice died in only two minutes suggests the existence of a causal connection between eating substance Z and death. If there is such a connection, it would hold for other mice as well. 2017-1-14 Examples ⑶? On three separate occasions I drank a bottle of Figowitz beer and found it flat and bitter. Probably I would find every bottle of Figowitz beer flat and bitter. ? In