Single Idea 15000

[catalogued under 5. Theory of Logic / A. Overview of Logic / 1. Overview of Logic]

Full Idea

I cannot legislate-true 'It is raining' and I cannot legislate true 'It is not raining', so if I cannot legislate either true then I cannot legislate-true the disjunction 'it is raining or it is not raining'.

Gist of Idea

'It is raining' and 'it is not raining' can't be legislated, so we can't legislate 'p or ¬p'

Source

Theodore Sider (Writing the Book of the World [2011], 06.5)

Book Reference

Sider,Theodore: 'Writing the Book of the World' [OUP 2011], p.104


A Reaction

This strikes me as a very simple and very persuasive argument against the idea that logic is a mere convention. I take disjunction to be an abstract summary of how the world works. Sider seems sympathetic.

Related Idea

Idea 15027 If truths are necessary 'by convention', that seems to make them contingent [Sider]