A paradox of induction (1). Suppose that someone notes that all emeralds that have ever been observed are green, and argues inductively to conclude that all emeralds are green. Now suppose we define grue as the property of being green up to time t (say, the beginning of the year 2050) and blue thereafter. All our inductive evidence supports the conclusion that all emeralds are grue just as well as it supports the conclusion that all emeralds are green, therefore we have no grounds for preferring either conclusion. Many people (though not Goodman) interpret this as a refutation of induction. Also called the grue paradox. Compare Hempel's paradox. [Named after the US philosopher Nelson Goodman (1906–98) who published it in an article in the Journal of Philosophy in 1946 and expanded it in 1955 in his book Fact, Fiction, and Forecast (pp. 74–5)]
Subjects: Psychology — Philosophy.