He's just distinguishing between pure and applied maths. Pure math -> "level one". Start with axioms and apply logic. Applied math -> "level two". Take some p

He's just distinguishing between pure and applied maths. Pure math -> "level one". Start with axioms and apply logic. Applied math -> "level two". Take some pure math, and find an analogous system in the real world. The question in applied math is whether (or better yet when) the analogy is a good one.