Single Idea 14460

[catalogued under 10. Modality / E. Possible worlds / 1. Possible Worlds / a. Possible worlds]

Full Idea

Saying that the axiom of reducibility is logically necessary is what would be meant by saying that it is true in all possible worlds.

Gist of Idea

If something is true in all possible worlds then it is logically necessary

Source

Bertrand Russell (Introduction to Mathematical Philosophy [1919], XVII)

Book Reference

Russell,Bertrand: 'Introduction to Mathematical Philosophy' [George Allen and Unwin 1975], p.193


A Reaction

This striking remark is a nice bridge between Leibniz (about whom Russell wrote a book) and Kripke.