This is probably because Howard Marks popularized the idea under that name in "The Most Important Thing". He looks like FS's main source in the detail piece (ht

This is probably because Howard Marks popularized the idea under that name in "The Most Important Thing". He looks like FS's main source in the detail piece (https://www.fs.blog/2016/04/second-level-thinking/ https://www.fs.blog/2016/04/second-level-thinking/). I think he does mean it as an analogy to the math concept, like ~x being first order and ~x^2 being second order for x near zero; x dominates but x^2 (the "second order") gets you closer to the truth. And similarly for x^3, x^4, ..., x^n.