more from this thinker     |     more from this text


Single Idea 22285

[filed under theme 2. Reason / D. Definition / 8. Impredicative Definition ]

Full Idea

The circularity in a definition where the property being defined is used in the definition is now known as 'impredicativity'. ...Some cases ('the tallest man in the room') are unproblematic, as they pick him out, and don't conjure him into existence.

Gist of Idea

Impredicative definitions are circular, but fine for picking out, rather than creating something

Source

Michael Potter (The Rise of Analytic Philosophy 1879-1930 [2020], 07 'Impred')

Book Ref

Potter,Michael: 'The Rise of Anaytic Philosophy 1879-1930' [Routledge 2020], p.50


A Reaction

[part summary]


The 9 ideas with the same theme [definition that doesn't introduce a new concept]:

A defined name should not appear in the definition [Hobbes]
Predicative definitions are acceptable in mathematics if they distinguish objects, rather than creating them? [Zermelo, by Lavine]
Impredicative Definitions refer to the totality to which the object itself belongs [Gödel]
Impredicative definitions are wrong, because they change the set that is being defined? [Bostock]
'Impredictative' definitions fix a class in terms of the greater class to which it belongs [Linsky,B]
Impredicative definitions quantify over the thing being defined [George/Velleman]
Impredicative definitions are circular, but fine for picking out, rather than creating something [Potter]
An 'impredicative' definition seems circular, because it uses the term being defined [Friend]
Predicative definitions only refer to entities outside the defined collection [Horsten]