You might not, but philosophers certainly do--I learned it in my philosophy classes on logic. I also learned there about Cantor's diagonalization proof. More

You might not, but philosophers certainly do--I learned it in my philosophy classes on logic. I also learned there about Cantor's diagonalization proof. More generally, in the early 20th century there was a huge overlap between mathematics and philosophy. You had Russell and Whitehead's Principia Mathematica, you had the Vienna Circle, you had Carnap and logical positivism... It's really not possible to cleanly categorize Goedl's proof into either math or philosophy--they weren't disjunct categories then, and they're not now, either. More importantly, if you approached any of those figures and asked whether they were separate things, they'd have thought the question nonsensical. Philosophy was, and still is, the home of logic in the academy, and the fact that logic and math frequently seem like different sides of the same coin doesn't settle the issue either way.