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归纳法问题

从一个普遍概念的已被观察到之事例所具有的特性,推论出该概念的尚未被观察到之事例,关於证明此一推论为合理的问题。举例来说,如果我曾见过的翡翠都是绿色的,若说我过去的观察并不全然导出(或演绎上蕴含)所有翡翠都是绿色的话,我有何资格推论所有翡翠都是绿色?我们能推论说从部分人口样本的特性就是全部人口的特性吗?一位品管工程师检视由特定制造程序生产出的一组一百枚灯泡样本,发现其中五枚有瑕疵,可能会结论说同一程序过去及将来生产的所有灯泡有5%的瑕疵品。为证明工程师的推论合理,必须满足下述两个判准:(一)样本的取得是随机的(亦即一百个灯泡一组的每一组被选来检视的机率相同),(二)样本的数量要够大(就数学精确计算来说)。亦请参阅statistics。

induction, problem of

Problem of justifying the inference from the characteristics of observed instances of a general concept to unobserved instances of the same concept. For example, if all emeralds I have ever seen have been green, what entitles me to draw the inference that all emeralds are green, given that my past observations do not strictly entail (or deductively imply) that all emeralds are green? May we infer that the characteristics of a sample taken from a population are characteristics of the entire population? A quality-control engineer who looks at a sample of 100 lightbulbs produced by a particular manufacturing process and finds that five are defective may conclude that 5% of all bulbs that have been and will be produced by the process are defective. For the engineer's inference to be justified, two criteria that must be met are (1) that the sample be random (i.e., every subset of 100 bulbs has an equal chance of being selected for examination), and (2) that the sample be sufficiently large (in a mathematically precise sense). See also statistics.