Character Analysis
Jacob Kahn is the temperamental genius sculptor whom the Rabbi hires to mentor Asher. He's best friends with Picasso (no big deal or anything), has survived a bunch of pogroms in Europe, and is regarded as the greatest living sculptor alive—he's kind of a triple threat, in other words.
He becomes a father figure for Asher, nurturing his talent while Rivkeh and Aryeh are living in Vienna. He tells Asher that he must choose between Judaism and a career as a painter, because the two are pretty much mutually exclusive:
'Listen to me, Asher Lev. As an artist you are responsible to no one and to nothing, except to yourself and the truth as you see it. Do you understand? An artist is responsible to his art. Anything else is propaganda.' (218.2)
Heavy stuff, right? Jacob Kahn's nurturing guidance is what enables Asher to grow as an artist, but it also contributes to Asher's emotional distance from his family, highlighting the brutal choice he must make between his religion and his passion.
Jacob Kahn's Timeline