I have a problem with the Doctor Who timeline in several episodes. For example, in the 10th Doctor episode, "Blink", the Doctor and Martha Jones were trapped in 1969 and are able to leave a message for Sally in 2007 to assist them getting back the TARDIS, which was stuck in 2007. After the problem was solved,
Sally encountered the Doctor in 2008, but at that time the Doctor didn't even know Sally, and Sally passed the Doctor the clues to escape from 1969 - in particular, the DVD Easter Egg script that Larry wrote in 2007.
In my point of view, Sally wouldn't be able to solve the problem if the Doctor didn't know about Sally before the Weeping Angel sent them back to 1969, and the Doctor can't leave a message to Sally in 1969, because the Doctor couldn't know the exact events that would happen in 2007.
Sally needed to know about all this before the Doctor was trapped, and her source of information is the Doctor, and at that time the Doctor don't know about the trouble he was going to encounter.
This complex timeline of Doctor Who is a "chicken and egg" paradox, isn't it? There are other examples of this in Doctor Who, such as:
- The 11th Doctor episode "The Big Bang" - how did the Doctor get out of the Pandorica?
- The 10th and 11th Doctor "River Song" story arc.