Your Lockhart is typical religious cleric, like all mathematicians.
Mathematicians like to reassure themselves that foundational questions are resolved by some mumbo-jumbo about "Axioms" but in reality successful mathematics requires familiarity with a large collection of "elementary" concepts and underlying linguistic and notational conventions. These are often unwritten, but are part of the training of young people in the subject. For example, an entire essay could be written on the use, implicit and explicit, of ordering and brackets in mathematical statements and equations. -- Norman J Wildberger, Associate Professor in Mathematics.