[Lostie!]

I've read another theory that Bernard is a physical recreation of Arnold and the scenes of his secret chats with Dolores are actually flashbacks of Arnold. The room he's in when he's talking to Dolores is pretty identical to the room Theresa died in and people have pointed out that when Ford showed him the picture of him and Arnold, the second man actually looked like Ford's father and there was a part of the picture obscured, if Bernard was modeled after Arnold then he physically wouldn't be able to see him in the picture.

And it's been mentioned more than once that Bernard wasn't there when the first generation Hosts and Arnold were, maybe because he was only made after Arnold died because he's based on him?