Single Idea 2252

[catalogued under 6. Mathematics / A. Nature of Mathematics / 1. Mathematics]

Full Idea

Surely whether I am asleep or awake, two plus three makes five, and a square does not have more than four sides.

Gist of Idea

Surely maths is true even if I am dreaming?

Source

René Descartes (Meditations [1641], §1.20)

Book Reference

Descartes,René: 'Discourse on Method/The Meditations', ed/tr. Sutcliffe,F.E. [Penguin 1968], p.98