Gaping plot hole: the time travellers each experience a to them linear time narrative, but somehow David sees his present self in a 10 year old home movie?! That should not have been in David's "original" history at all, since it's only AFTER seeing this home video that he travels back to that birthday party. Of course: had he not seen himself in the video, he never would have built the time machine in the first place...
There is simply no getting around the fact that a circular causality (causal nexus) like this never, ever works when the time traveller's personal timeline is linear (or immutable). The only way they could have swung it would have been by going fully mutable (as in: there is only one timeline, which everyone shares), but even then a circular causality would still be considered a paradox.
Shout by Andreas StenlundVIP 6BlockedParentSpoilers2015-05-22T21:46:10Z
Gaping plot hole: the time travellers each experience a to them linear time narrative, but somehow David sees his present self in a 10 year old home movie?! That should not have been in David's "original" history at all, since it's only AFTER seeing this home video that he travels back to that birthday party. Of course: had he not seen himself in the video, he never would have built the time machine in the first place...
There is simply no getting around the fact that a circular causality (causal nexus) like this never, ever works when the time traveller's personal timeline is linear (or immutable). The only way they could have swung it would have been by going fully mutable (as in: there is only one timeline, which everyone shares), but even then a circular causality would still be considered a paradox.