Âé¶¹´«Ã½

Letter: Many types of infinity are lurking out there (1)

Published 17 September 2025

From Guy Cox, Sydney, Australia

Your article on infinity deals with very large and very abstruse concepts of it. But what about smaller, everyday infinities?

The number pi is something we use often enough, but it can only be expressed accurately with an infinite series of digits. This doesn’t make it large – we all know that 4 is a larger number(9 August, p 28). What are the ultrafinitists going to do about this? Are they going to redefine pi with a fixed number of decimal places?

Issue no. 3561 published 20 September 2025

Sign up to our weekly newsletter

Receive a weekly dose of discovery in your inbox. We'll also keep you up to date with Âé¶¹´«Ã½ events and special offers.

Sign up
Piano Exit Overlay Banner Mobile Piano Exit Overlay Banner Desktop