Jack meets Dogen & Dogen's son at David's audition for the Williams Conservatory

Jack goes to the Williams Conservatory t o find David. Once he's inside, he hears David performing "Fantaisie-Impromptu in C-Sharp Minor," the same piece of music Jack found in David's room (it's also the same piece young Daniel Faraday performed in the season 5 episode "The Variable"). Jack is clearly moved by David's performance.

A young Asian boy, who we can assume is Dogen's son, tells Jack that David is really good then walks away. As Jack is leaving the room, Dogen stops him and says that their sons are too young to have this kind of pressure. When he asks Jack how long David has been playing, Jack has to admit that he doesn't know, which is reminiscent of Michael's answers about Walt during the custody meeting in the season 2 episode "Adrift."

That's a fun little cross the new timeline, but what does that mean for the island's fate if Dogen never went there?