All Topics
All Topics
Technology
Technology
Design
Design
Programming
Programming
Science
Science
News
News
Gaming
Gaming
Entertainment
Entertainment
Business
Business
Finance
Finance
Sports
Sports
Health
Health
Food
Food
Travel
Travel
Art
Art
Music
Music
Books
Books
Education
Education
Politics
Politics
Personal
Personal
No algorithm. No AI slop. No ads. Just RSS. Pro-human. Indie writers. Real journalism. Open web. Chronological. Hand toasted.

A critique of Lean and the culture of formal mathematics communities

By

ibobev

1mo ago· 9 min readenOpinion

Summary

The article discusses the author's perspective on the modern formal mathematics community, particularly the pressure to justify not using the Lean proof assistant. The author acknowledges Lean's technical merits—great language, good tools, large library, and enthusiastic community with astounding recent accomplishments—but expresses discomfort with what they perceive as cultism, insularity, and conformity in the dependent-typed world. The piece draws on the author's 40-year history with formal mathematics, including work on AUTOMATH, LCF, HOL system, and HOL Light, to provide historical context and critique of current trends in the field.

Key quotes

· 3 pulled
I have been told that when proposing to formalise mathematics these days, you have to explain why you are not using Lean.
And that reminds me why I left the dependent-typed world 40 years ago: its cultism, insularity and conformity.
Lean is a great language with good tools, a large library and a huge, enthusiastic user community that has lately accomplished astounding things.
Snippet from the RSS feed
23 Apr 2026

You might also wanna read