In his long career as a scholar and conductor, Joshua Rifkin has done a lot: arranged for Judy Collins, performed in the first-ever marathon of "Vexations," helped lead the ragtime revival and, perhaps most importantly, totally upended the conventional wisdom about Bach's choral music. This is a conversation about all of that, and more: rich, insightful, and scandalous stories about one of the most fascinating lives a music scholar can lead. (Including: getting tipsy with John Cage, playing i...