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Single Idea 9652

[filed under theme 14. Science / C. Induction / 5. Paradoxes of Induction / a. Grue problem ]

Full Idea

Some beliefs are just unreasonable in a strong sense. Think of the man who, for no special reason, expects unexamined emeralds to be grue.

Gist of Idea

To just expect unexamined emeralds to be grue would be totally unreasonable

Source

David Lewis (On the Plurality of Worlds [1986], 1.4)

Book Ref

Lewis,David: 'On the Plurality of Worlds' [Blackwell 2001], p.38

A Reaction

This is a nice converse way of seeing the point that 'grue' is such an totally artificial predicate. I still say that the most illuminating point is that grue is not a colour, so seeing a grue thing is no confirmation at all.

The 20 ideas with the same theme [problem of a predicate which changes over time]:

17646 Goodman showed that every sound inductive argument has an unsound one of the same form [Goodman, by Putnam]
18749 Goodman argued that the confirmation relation can never be formalised [Goodman, by Horsten/Pettigrew]
17655 Grue and green won't be in the same world, as that would block induction entirely [Goodman]
16933 Grue is a puzzle because the notions of similarity and kind are dubious in science [Quine]
17675 Unlike 'green', the 'grue' predicate involves a time and a change [Armstrong]
17683 Science suggests that the predicate 'grue' is not a genuine single universal [Armstrong]
5485 Emeralds are naturally green, and only an external force could turn them blue [Ellis]
15887 'Grue' introduces a new causal hypothesis - that emeralds can change colour [Harré]
15888 The grue problem shows that natural kinds are central to science [Harré]
15096 'Grue' only has causal features because of its relation to green [Shoemaker]
8556 Grueness is not, unlike green and blue, associated with causal potential [Shoemaker]
9652 To just expect unexamined emeralds to be grue would be totally unreasonable [Lewis]
4783 Observing lots of green x can confirm 'all x are green' or 'all x are grue', where 'grue' is arbitrary [Mautner, by PG]
3760 Predictions are bound to be arbitrary if they depend on the language used [Bernecker/Dretske]
14989 Problem predicates in induction don't reflect the structure of nature [Sider]
14997 Two applications of 'grue' do not guarantee a similarity between two things [Sider]
6738 Any conclusion can be drawn from an induction, if we use grue-like predicates [Bird]
6739 Several months of observing beech trees supports the deciduous and evergreen hypotheses [Bird]
6799 We normally learn natural kinds from laws, but Goodman shows laws require prior natural kinds [Bird]
7296 'Grue' is not a colour [Milsted]