Theory:Doctor Who television discontinuity and plot holes/An Unearthly Child


 * When Susan says "I like walking through the dark" neither Ian nor Barbara seem bothered about the thought of a teenage girl walking alone at night.
 * However, this was 1963, a more innocent time.


 * Why does Susan ask Barbara for a book about the French Revolution and then leave it in the classroom (as revealed when Ace finds the book in Remembrance of the Daleks)?
 * As far as she is concerned at this point she will be at school the next day.
 * When last seen, Susan is reading the book and stating "that's not right" in response to what she was reading. Perhaps she thought the book was unsuitable and abandoned it. Or she might have sped-read the book right then and there; later, the Doctor would be shown on several occasions to have this ability. It could also have been a different printing of the book as this is a chunky brown book while the version in Remembrance of the Daleks is sleek and black with gold lettering.''


 * At the end of episode one the caveman shadow is seen to extend much further than it really should. ''That depends on the angle of the light source.
 * We see Horg leave to go and capture the travellers at the end of episode three, but at the beginning of episode four he is back with other members of the tribe, waiting for the rest to come back.
 * Whatever happens to the Doctor's bag? It's recovered by his fellow travellers after he gets captured, yet they clearly lose access to it when they too are caught. But why did they not ask for it back? The Doctors matches were in it, thus it would make their fire-making much easier. Not to mention leaving it in the tribe's possession could prove disastrous to history.
 * The bag presumably was never recovered. Although the implements within it could potentially have changed history, the odds of them ever being found are remote.


 * Susan's claim to have made up the name TARDIS is not supported by later stories that indicate that it's a term in widespread use on Gallifrey.
 * Some names catch on quite quickly. Presumably she thought of it on their planet and others heard it and liked it. The true origins of the term TARDIS and how the Doctor came by this one are still very unclear.


 * Susan states that 5 dimensions have to be used to solve a simple math equation, with the fourth, Time, and the fifth, Space, in addition to the length, width, and height that she was given. However, space is not the fifth dimension according to physics, but is made up of the first three.
 * Susan is not referring to Space in that sense (length, width, height), but more as a hypothetical construct much like Time is. There are multiple dimensions of Space just as there are multiple dimensions of Time. She needed to go at least to the fifth dimension to solve the problem to her satisfaction.


 * The door closes behind the travellers as they leave - how did it know to do this, and why doesn't it do it in other stories?
 * It sometimes does. The TARDIS, as later shown, is semi-sentient.


 * The Cavemen at the end of episode 4 are different to the ones in the rest of the story.
 * How did the cavemen beat the travellers to the TARDIS in Episode 3 - and how did they know where it was in the first place?
 * They live there, and know the quickest route to get somewhere. They knew where it was from description of where one of their tribe had originally grabbed the Doctor.
 * The travellers were slowed down by having to care for the injured Za and then carry him. The cavemen were led by Kal, who had seen the TARDIS materialise.


 * How do the cavemen see inside the cave during the night (while orb is not shining) if they don't have fire?
 * Moonlight and natural phosphorescence in some rocks, plus vision that has adapted to having little light.


 * It is scientifically impossible for an object to be bigger on the inside.
 * Dimensional transcendentalism is a scientifically plausible hypothetical construct which contends that the "inside" of the TARDIS is actually in a different dimension that the "outside" - i.e., when you pass through the opening of the police box exterior, you cross a dimensional threshold to a completely different dimension, which could certainly be much larger.