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2 ideas
| 4783 | Observing lots of green x can confirm 'all x are green' or 'all x are grue', where 'grue' is arbitrary [Mautner, by PG] |
| Full Idea: Observing green emeralds can confirm 'all emeralds are green' or 'all emeralds are grue', where 'grue' is an arbitrary predicate meaning 'green until t and then blue'. Thus predictions are arbitrary, depending on how the property is described. | |
| From: report of Thomas Mautner (Penguin Dictionary of Philosophy [1996], p.225) by PG - Db (ideas) | |
| A reaction: This increasingly strikes me as the sort of sceptical nonsense that is concocted by philosophers who are enthralled to language instead of reality. It does draw attention to an expectation of stability in induction, both in language and in nature. |
| 4782 | 'All x are y' is equivalent to 'all non-y are non-x', so observing paper is white confirms 'ravens are black' [Mautner, by PG] |
| Full Idea: If observing a white sheet of paper confirms that 'all non-black things are non-ravens', and that is logically equivalent to 'all ravens are black' (which it is), then the latter proposition is confirmed by irrelevant observations. | |
| From: report of Thomas Mautner (Penguin Dictionary of Philosophy [1996], p.105) by PG - Db (ideas) | |
| A reaction: This seems to me more significant than the 'grue' paradox. If some observations can be totally irrelevant (except to God?), then some observations are much more relevant than others, so relevance is a crucial aspect of induction. |