When it comes to modern/living polymaths, it's worth mentioning Noam Chomsky. He did groundbreaking work in formal language theory that is fundamental to lots

When it comes to modern/living polymaths, it's worth mentioning Noam Chomsky. He did groundbreaking work in formal language theory that is fundamental to lots of theory of computation. He basically (re)invented modern linguistics. Then there's the media analysis work of Manufacturing Consent. Then there's the unending political criticism. It's pretty staggering.