April 27, 2026
Math wars, but make it nerdy
"Why not just use Lean?"
Old-school math nerd calls Lean a ‘cult’ and the internet shows up with popcorn
TLDR: A veteran researcher called out the hype around the Lean proof system, arguing that people were formalizing math on computers decades before it existed. Commenters turned it into a culture clash between old-school tools and the “just use Lean” crowd, debating whether Lean is real math, programmer candy, or just the loudest fandom.
An old veteran of digital math tools just lobbed a grenade at modern favorite Lean, basically saying: “Why is everyone acting like this shiny new thing invented formal math?” He calls Lean’s current hype a bit cult-like and reminds everyone that people were teaching computers math back in the 1960s. Cue the comments section instantly turning into a mix of history lesson, fandom war, and stand-up comedy.
One top commenter cheers, “We need more of this,” begging people to stop saying “just use Lean” like it’s the only religion in town. Another chimes in with a simple “Good post! +1,” the internet equivalent of slow clapping from the back row. Others jump in to explain that what people really love is not Lean the language, but its mega-library of theorems, Mathlib, whose creators are apparently very practical and not at all culty.
Then comes the spiciest take: one user claims that type theory and Lean are more interesting “to people who like computers than to people who like math,” which is basically calling Lean fans keyboard nerds rather than real mathematicians. Meanwhile, another commenter recommends a programming book on Lean, turning the thread into half fan club, half support group for people who never finished it. The whole thing reads like: old guard vs new hype, but with surprisingly polite snark.
Key Points
- •The article argues Lean’s prominence should be contextualized within a 60-year history of formalized mathematics.
- •AUTOMATH (1968) enabled significant formalizations, including Jutting’s 1977 work on Landau’s Foundations of Analysis and Dedekind completeness.
- •Boyer–Moore’s computational logic evolved into ACL2, achieving deep mathematical formalizations and focusing on hardware verification.
- •Edinburgh LCF introduced ML as a metalanguage, influencing the development of HOL, Coq/Rocq, Isabelle, and Nuprl.
- •John Harrison’s HOL Light work includes formalizing real numbers and proving the prime number theorem via Cauchy’s integral formula; by 2014 many advanced results were formalized.