|Grue, philosophy: Artificial predicate in a thought experiment by Nelson Goodman (N. Goodman, Fact, Fiction and Forecast, Indianapolis, 1965) to illustrate his "New riddle of induction". An object x is grue iff x has been observed before time t and is green or has been observed after t and is blue, the time t being in the future. The problem of uncertainty as to whether something is green or grue arises because the set of green objects is a subset of the set of grue objects. See also induction, projectability, predicates.|
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Grue/ChomskyVsGoodman: marginal problem - the initial question is much too vague - you can easily find a property of language "grue bleen" which is not a property of a "languange like German" - e.g. the predicate "being similar", only applied to objects rather than to qualia - Chomsky: there is no point in time t such that we can predict of objects that they will not be similar - they could be the similar if both were green - it is a property of natural languages that they behave more like German than like "grue bleen" - but language concepts such as "German" are too vague to satisfy Goodman’s criterion - we cannot explain why the learner does not acquire grue as basis for generalisation - that certainly follows from the sensory system.
Aspekte der Syntaxtheorie Frankfurt 1978
Language and Mind Cambridge 2006