Howling:Crossing timelines

We know that it's dangerous, and possibly difficult, for a Time Lord to cross his own timeline. And the same is true for non-Time Lord time-travelers.

It's also dangerous, and possibly difficult, for two Time Lords to meet out of sequence. But if they're not both Time Lords, it doesn't seem to be any problem at all.

We've met time travelers in various episodes and novels who remember adventures the Doctor hasn't had yet. And we've actually watched the Doctor meeting (off the top of my head) Sarah Jane, Mel, Sam, Fitz/Kode/Kreiner, Rose, River, Amy, and Rory. And that's not even counting multi-Doctor stories, MA/PDA/BFA stories that take place in the Doctor's past, etc. It doesn't seem to take any special effort, and there are no negative consequences other than a bit of mild confusion.

So, why is it different?

I'm pretty sure we've never gotten an answer on-screen/-page/-CD, so I'm happy with either out-of-universe explanations or pure in-universe speculation. I'm curious what people can come up with, because I can't think of anything. (Especially since River is apparently part-way to being a Time Lady, or at least has a "Time Head", and is also the most out-of-order…) --173.228.85.118 05:52, August 11, 2011 (UTC)