[JadeNB]

> Mathematics, at its core, is about tangible and easily perceptible stuff like counting things and measuring space.

I think that it depends on what you mean by 'core'. This is certainly the historical core of mathematics—where things started, and so around which all later developments have accreted—and I suspect it characterises a large part of most 'users'' interactions with mathematics, but I think that there are many mathematicians who would not describe your characterisation as the core of what they do professionally.

(It happens that I can't substantiate that even by a flimsy appeal to my own work, because there is a reasonable sense in which counting things is at the heart of my work (even though it's not combinatorics); but there are other fields that I think don't have that sort of connection informing their everyday work, even though it is of course always there historically.)

[bluetomcat]

> but I think that there are many mathematicians who would not describe your characterisation as the core of what they do professionally.

Those mathematicians are certainly doing something much more intellectually-challenging than counting things and measuring space, but I would argue that those basic activities represent the basic problems upon which most of the low-level math abstractions are built. "Serious" math is about operating at much higher abstraction levels, but it is not disconnected from those low-level foundations.