I've been pondering the rules time outlined in Doctor Who and how the Doctor says he can't change history or violate the rules of time. Key episodes on my mind are: 4th Doctor: Pyramids of Mars - When the Doctor shows Sarah Jane what the world of 1980 would look like, if he didn't stop Sutekh in 1912. 5th Doctor: Earthshock/Time Flight - Adric dies while being on board a freighter that is on a collision course to Earth. The Doctor tells Nyssa and Tegan he cannot change their history and that there are rules that can't be broken with the Tardis. 6th Doctor: Mindwrap/The Ultimate Foe - Peri dies but is later restored by the magic of the Time Lords. We know the Time Lords have more power and control over the changing events of history, than the Doctor himself. Just something to think about. 9th Doctor: Father's Day - The Doctor and Rose go back and see Pete die twice. On the second time, Rose intervenes to save Pete. Thus crossing her own timeline; as her and the Doctor's previous selves were also present to witness Pete be struck by a car. Time fights back with time wraiths. Who tried to correct the paradox of a man being alive, who shouldn't be. 10th Doctor: Fires of Pompeii - The Doctor and Donna are present during the hours before Mt. Vesuvius blows. Donna tries hinting to the people what is going to happen and the Doctor chastises her for attempting to alter history. When the volcano blows, the Doctor is set to leave, but Donna begs him just to save someone. The Doctor relents and saves the family who he spent the episode with. 10th Doctor: Waters of Mars - The Doctor encounters astronauts of a doomed Martian expedition and becomes apart of the events. He decides to save the 3 of them and bring them to Earth. After all hell breaks lose on Mars. The head director rebels against the Doctor's gift of life and commits suicide as a way to monkey wrench his intentions. The Doctor changed the personal history of one woman and her family, and in a way, history fought back. 11th Doctor: Angels Take Manhattan - Amy and Rory are zapped by a weeping angel and sent back to 1938 New York. Because a previous paradox, the Doctor said he was unable to go to that same year in NYC again. Otherwise it would destroy the city. Seeing Rory and Amy's gravestone, seemingly solidified the two's fate as dead. Something the Doctor could not change. 12th Doctor: Dark Water - Danny Pink dies and Clara threatens the Doctor to have him change history. It was all an illusion of course, but the Doctor is willing to take Clara to "hell" and attempt a rescue. 12th Doctor: Face the Raven/Hell Bent - Clara dies and the Doctor uses the machines on Galifrey to extract her at the moment of her death, to save her. However, his attempts through this episode are only partially successful. The result leaves Clara functionally immortal but without a pulse. The Doctor admits by episode's end that he broke every single rule and became "the Hybrid". Clara and the Doctor couldn't continue to travel together anymore, because they would continue to cause chaos protecting each other. Well, that took forever. Now, common reasons/excuses the Doctor gives for not changing history and or saving people from death are: Fixed points in time can't be changed. Can't cross his own time line. Changing history can lead to chaotic effects on the universe. Paradoxes and unraveling, etc. What do you think? Or rather, could someone simply the rules Doctor Who (the IP) plays fast and loose with frequently?