more from B Russell/AN Whitehead

Single Idea 9359

[catalogued under 5. Theory of Logic / B. Logical Consequence / 7. Strict Implication]

Full Idea

In Mr Russell's idea of implication, if twenty random sentences from a newspaper were put in a hat, and two of them drawn at random, one will certainly imply the other, and it is an even bet the implication will be mutual.

Gist of Idea

Russell's implication means that random sentences imply one another


comment on B Russell/AN Whitehead (Principia Mathematica [1913]) by C.I. Lewis - A Pragmatic Conception of the A Priori p.366

Book Reference

Peirce,James,Dewey etc: 'Pragmatism - The Classic Writings', ed/tr. Thayer,H.S. [Hackett 1982], p.366

A Reaction

This sort of lament leads modern logicians to suggest 'relevance' as an important criterion. It certainly seems odd that so-called 'classical logic' should contain a principle so at variance with everyday reasoning.