Jack shrugged. "I'm sure there is. And even if she's from a different reality, it doesn't negate the fact that she is certain I'm her 'Uncle Jack', and that I'm going to keep holding onto that as hope I'll get home." He held the Doctor's gaze. "Impossible just means you haven't figured it out yet. Emphasis on the 'yet', Doctor. You will, eventually. One way or another."