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Single Idea 21559

[catalogued under 6. Mathematics / C. Sources of Mathematics / 10. Constructivism / d. Predicativism]

Full Idea

We need rules for deciding what norms are predicative and what are not, unless we adopt the view (which has much to recommend it) that no norms are predicative. ...[146] A predative propositional function is one which determines a class.

Gist of Idea

We need rules for deciding which norms are predicative (unless none of them are)


Bertrand Russell (Difficulties of Transfinite Numbers and Types [1905], p.141)

A Reaction

He is referring to his 'no class' theory, which he favoured at that time.

Book Reference

Russell,Bertrand: 'Essays in Analysis', ed/tr. Lackey,Douglas [George Braziller 1973], p.141

Related Idea

Idea 21558 'Predicative' norms are those which define a class [Russell]