Originally Posted by
somerset fox:
“So, the Doctors only solution was to wait 40 years to send a message?? What did he and Martha do in the intervening years apart from record the easter eggs? If this was the case then a 60+ Martha would still be around as well as the Doc. In which case why didn't he deliver his own message? No, a good initial story which falls apart when given some thought. Besides, if they were in 1969, all they would have to do is go to UNIT and meet Patrick Troughtons Doctor, or wait until 1970 and meet John Pertwee's and use his Tardis to come forwards, or pass the message... Now that would have been a cracking cgi-fest/ challenge in the style of Back to the Future 2. Tennant and Pertwee...
”
Oh this one is easy. Don't forget that the Doctor only got the necessary information from Sally at the very end of the episode. At this point, the Doctor had not yet met Sally, but Sally already knew him because of the information that he communicated to her, that he originally got at this point in time.
Get it? Time isn't linear. The Doctor and Martha were never around to grow old in the 60s because the TARDIS got sent back by Sally. It's kinda like that old (and admittedly awful) show "Crime Traveeler," treated time. Sure, you can time travel, but you can't actually alter events, because in the big, non-linear perspective of time, you were always meant to time travel to that point and interact with the events. It's not a change in the past, it's the way it always was.
It's no wonder that sentence started well and went off. It's damned hard to explain, but if you can grasp the idea of non-linear time, you can see how it all, perfectly, fits together, without any major plotholes. It's just damned hard to put into words.