You missed a dozen posts ago where we demonstrated that the only way Reese gets the photo Sarah has taken at the end of T1 is if she's impregnated by Reese first. The photo proves Reese was always John Connor's father.
No, I read that, but re-read my last paragraph and see if that makes sense. Here's a possible "chronology of events"
- Sarah Connor has a baby with some other guy. Don't know who, don't care.
- Skynet takes over and John Connor grows to become the leader of the human resistance for whatever reason
- Skynet decides to send a T-800 back in time, so Connor sends one of his best men, Kyle Reese to protect him
- Reese travels back in time and impregnates Sarah before she gets pregnant from someone else
- Reese dies, Sarah gets her picture taken and heads off to raise John
At this point, he
does not have a picture of her and the future is radically altered. John is not the man he was from a DNA perspective, but he is prepared from birth to become the leader of the resistance. Knowing it is his destiny, he makes choices that lead him to the leadership role his previous self discovered more naturally.
- In the future, this different John remains a threat, so Skynet sends a T-800 back in time.
- At this point, John knows Reese is his father, so he sends Reese back after him. Again.
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This time, John knows its his dad and he gives Reese the picture. Maybe this version of John is sentimental because of his different DNA or maybe its just that he now knows its his dad or maybe he just didn't have a picture of his mom in the initial timeline because that John didn't know what was coming.
This is the point at which we see Terminator 1. From this point on, there is no reason for anything to change. Reese has the picture, saves Sarah, dies. John is born, becomes the leader, knows Reese is the father, gives him the picture, sends him back in time with the picture. Its an endless loop from that point that has no reason to change unless something else in the timeline causes a change.
I've always thought the intent was something similar to this and I find it fairly plausible (outside of machines taking over and time travel, etc.!), but that's just my opinion. We do know from the TV show that history can be completely re-written. Hence the T3 storyline becoming null and void when Sarah avoids her death by jumping into the future.