more from this thinker     |     more from this text

Single Idea 15890

[filed under theme 14. Science / C. Induction / 5. Paradoxes of Induction / b. Raven paradox ]

Full Idea

Non-black non-ravens have no role to play in assessing the plausibility of 'All ravens are black' because their existence is not among the existential presuppositions of that statement.

Gist of Idea

Non-black non-ravens just aren't part of the presuppositions of 'all ravens are black'

Source

Rom Harré (Laws of Nature [1993], 5)

Book Ref

Harré,Rom: 'Laws of Nature' [Duckworth 1993], p.111

A Reaction

[He cites Strawson for the 'presupposition' approach]

The 16 ideas with the same theme [problem irrelevant evidence for a general law]:

19000 Read 'all ravens are black' as about ravens, not as about an implication [Belnap]
17674 The raven paradox has three disjuncts, confirmed by confirming any one of them [Armstrong]
15889 It is because ravens are birds that their species and their colour might be connected [Harré]
15890 Non-black non-ravens just aren't part of the presuppositions of 'all ravens are black' [Harré]
15284 Contraposition may be equivalent in truth, but not true in nature, because of irrelevant predicates [Harré/Madden]
15285 The items put forward by the contraposition belong within different natural clusters [Harré/Madden]
15287 The possibility that all ravens are black is a law depends on a mechanism producing the blackness [Harré/Madden]
16832 If something in ravens makes them black, it may be essential (definitive of ravens) [Lipton]
16836 My shoes are not white because they lack some black essence of ravens [Lipton]
16831 A theory may explain the blackness of a raven, but say nothing about the whiteness of shoes [Lipton]
16833 We can't turn non-black non-ravens into ravens, to test the theory [Lipton]
16834 To pick a suitable contrast to ravens, we need a hypothesis about their genes [Lipton]
18993 If sentences point to different evidence, they must have different subject-matter [Yablo]
19003 Most people say nonblack nonravens do confirm 'all ravens are black', but only a tiny bit [Yablo]
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]
7006 Observing irrelevant items supports both 'all x are y' and 'all x are non-y', revealing its absurdity [Schofield,J]