"Well, you're certainly that," the Doctor said with a small, teasing grin. "But, I don't know how you can open yourself up for one without potentially opening yourself up for the other. Unless you're significantly better at negotiating emotions than I am."

He nodded to the world outside of the mouth of the cave. "It's different out there, now. In a few millenia, when I'm created, well, they'll have set up standards. Emotions are verymuch a not-to-do, but I started in on them early. I learned why they emphasized indifference. It's better than heartache."

He looked back at Jack. "I know, I know, you're not going to. It's habit. For me."