Single Idea 14117

[catalogued under 6. Mathematics / B. Foundations for Mathematics / 5. Definitions of Number / c. Fregean numbers]

Full Idea

Numbers are to be regarded as properties of classes.

Gist of Idea

Numbers are properties of classes

Source

Bertrand Russell (The Principles of Mathematics [1903], §109)

Book Reference

Russell,Bertrand: 'Principles of Mathematics' [Routledge 1992], p.113

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A Reaction

If properties are then defined extensionally as classes, you end up with numbers as classes of classes.