Confession: I have no clue what function a conductor plays in an orchestra.

As a kid, I just assumed it was aesthetic. Like, someone for an audience of non-musicians to project themselves on to.

As an adult, I recognize that this is almost certainly not the case. Presumably the conductor plays a role that is necessary and helpful to the rest of the orchestra... but I'll be damned if I can't quite figure out what that is. Surely its not just timing? Can't the players just... listen to one another to work that out?