Since Richard Posner’s surprise retirement from the U.S. Court of Appeals for the Seventh Circuit in 2017, he’s focused much of his energy on making the justice system more accessible and responsive to pro se litigants.

That impulse has informed the 80-year-old polymath’s latest move: Posner is entering the world of litigation finance. But he’s not taking a position with one of the giants of the nascent industry. Instead, he’s signed on to serve as an adviser to Legalist, a San Francisco start-up founded by two Harvard undergrads in 2016.