CardsofSTL wrote: ↑April 7 22, 7:59 pmAdmiralKird wrote: ↑April 7 22, 2:15 pmThat explanation doesn't fit how time travel works in Star Trek. If a timeline has an event where people in the year 2500 visit 2000 AD, and a change occurs to the timeline in 2100, preventing the people from 2500 ever existing, the year 2000 events had already occurred on that branch of time where the alteration takes place and they still must exist for that alteration to take place. The people from 2500 still technically exist on an overwritten branch of the timeline to influence the current one. This stuff also happens in things like E^2 in Enterprise and how the Xindi think there is more than one Earth ship in the Expanse even though the alternate Enterprise was wiped out. Sela's existence in TNG - even though the events of the Klingon-Federation war never took place now, Tasha Yar's daughter is able to exist.
Sure but we're not just talking about time travel.
That's not how it works in Star Trek. Paradoxes in Star Trek are avoided because they use multiple branches. The grandfather paradox is avoided because you can go back and kill your own grandfather, you just are no longer born on this timeline in the future. Just because you altered an earlier point, doesn't mean it overrides your existence when you're back in time.
Look at it this way:
A. Dave is born in 2000.
B. Dave heads back in time from 2040
C. Dave appears in time in 1950
D. Dave kills his grandfather.
E. Dave jumps forward in time to 2040
F. Dave arrives in 2040.
On this timelline, A and B never take place. But C, D, E, and F all take place.
If you want to talk JJ Kelvin stuff, that is a prime example of this. Vulcan is destroyed in ST2009, yet Spock still has the ship he went back in time with from the Vulcan Science Academy in his timeline. There is no paradox, the ship jumps timelines. Just because Vulcan is destroyed, doesn't override its existence when it appears in Kirk's time.
A. Vulcan builds the fish science ship thing with the red matter.
B. Spock follows Nero back in time in the science ship from the 24th Century
C. Spock and the science vessel appear in the 23rd Century.
D. Nero destroys Vulcan
E. The Science ship is destroyed by young Spock to destroy Nero.
F. Old Spock vows to rebuild Vulcan in some way.
Once again. A and B no longer occur, but C, D, E F occur.
Now with Picard S2 and TNG. The events of Picard traveling back to 1893 happened on the same branch, prior to where the timeline is altered. It doesn't matter if, lets say... Earth and all the Federation is blown up in the 23rd century before Picard is born. The events of 1893 where the Enterprise D, Picard, etc arrived in the past still took place because they (1) occurred on the same branch as the alteration and (2) prior on the timeline to when the alteration takes place. Just because the Federation is destroyed, does not override the existence of the Enterprise D in Mark Twain's time.
Without the Picard streaming show we have:
A. The Enterprise D finds Data's Head in the future.
B. The Enterprise goes back in time from the 24th Century
C. The Enterprise arrives back in the 19th century.
D. Picard meets Guinan.
E. The Enterprise departs the 19th century.
F. Enterprise D arrives back in the 24th Century
But wait! There's interference on the timeline, well now we have:
A. The Enterprise D finds Data's Head in the future.
B. The Enterprise goes back in time from the 24th Century
C. The Enterprise arrives back in the 19th century.
D. Picard meets Guinan.
E. The Enterprise departs the 19th century.
F. The Federation in the 23rd Century is destroyed.
G. Enterprise D arrives back in the 24th Century
A, B, and G no longer occur because F overrides them because they take place after the alteration, but C, D, E still occur.
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I don't know how to explain this any better, if you don't get it reread it until you like it. There isn't an alt-version. There are some writers of errant episodes who write things that are different than this but they're usually just stingers of "ain't it cool!?" that have little bearing on anything and can be handwaved away. Examples of this would be things like the Borg sending a signal to the Delta Quadrant during the events of Regeneration or Annorax's final scene with his wife in Year of Hell Pt 2.