Theory:Doctor Who television discontinuity and plot holes/Father's Day


 * If Rose can remember Jackie telling her about the blonde girl who was by her father's side when he died, that means it is impossible to change the past because the past changes would have already taken place which contradicts many events.
 * Rose's memory changed when the past changed. Previously she remembered Jackie telling her that no one was with Pete when he died.
 * Spoiler:Amy Pond still remembered the clerics and the Weeping Angel that got in her head after they were entirely removed from Time in Flesh and Stone, and the Doctor tells her that being a Time traveller changes the way you experience Time, implying that it makes their memories immune to changes in the time stream.


 * The Doctor later, in Cold Blood, states to Amy as she is trying to remember Rory that memories are not immune if one's own time stream is directly affected, which Rose's was by her father's death and her involvement in it.


 * In the church scene, the Doctor's sonic screwdriver goes off without making a noise.
 * It could have a silent setting.
 * Why would he need to use a silent setting, it makes no sense.


 * It has been shown that the sonic screwdriver changes pitch depending on the setting. It is possible that this setting is at a range of sound that cannot be detected by Human ears.


 * Or simply the production team stuffed up


 * Surely there are a number of times the Doctor has changed past events, where the Reapers should thus show up. Is the survival of Rose's father somehow more important than any of the other seemingly fixed events that the Doctor has encountered?
 * The Doctor said the Time Lords always cleared up problems like this in the past. With them gone, the timeline is much weaker.


 * The presence of two Doctors and two Roses at the scene of Pete's death was a paradox, which the Reapers could use as energy to get through.


 * The Doctor makes sure never to cross his own time-line. Rose's actions caused her past self and Doctor to have no reason to go back again, causing the paradox which let the Reapers through.


 * There are differences between changing history, preventing a change, and being part of history. Even when the change creates a paradox, it can be either constructive or destructive. This particular paradox was destructive, which is why it became a "wound" and had to be fixed. If you have any particular story in mind where you would have expected Reapers to appear; it would be more productive to discuss the issue in that discontinuity section rather than letting this be an open-ended topic here.