On Kurt Gödel's essays, “Some Basic Theorems on the Foundations of Mathematics and their Implications” (1951) and “The Modern Development of the Foundations of Mathematics in Light of Philosophy” (1961).
Gödel is famous for some "incompleteness theorems" of direct interest only to those trying to axiomatize mathematics. What are the implications for the rest of philosophy? Gödel thought that, contra people's claims that incompleteness demonstrates some kind of relativism, he had showed that the world of mathematics even in its most abstract reaches is part of the real (though non-physical) world. Mark, Wes, Dylan, and guest Adi Habbu try to figure out these unpublished and dare I say incomplete essays.
End song: "Axiomatic" from Mark Lint & the Simulacra. Read about it.