[cskinner]

The article spends most of its words discussing the reality of math via Platonism vs empiricism while forgetting its own title "What is Math?"

If going for a pithy answer, I like tha following quote by G. H. Hardy:

A mathematician, like a painter or poet, is a maker of patterns. If his patterns are more permanent than theirs, it is because they are made with ideas.

I think I originally saw this quote in "A Mathematician's Lament" [0] (also known by the author's name as "Lockhart's Lament"), which has a lot to say about modern math education.

[0] (PDF) https://www.maa.org/sites/default/files/pdf/devlin/Lockharts...