If Skynet sees humanity as a threat to it's existence, why did it send a robot back to kill Sarah Connor in the first film, and then John Connor in the second and third film? Why not just send a robot all the way back and kill adam and eve, thus destoying every single instance of humanity, ever? (Of course assuming that you believe that Adam and Eve were the first humans).
After much speculation the only answer I could come up with, was this one: John Connor is simply the leader of the human resistance, and thus, Skynet's biggest threat. However, without humanity in the first place, Skynet wouldn't exist because not even Dyson or Cyberdyne would have existed for Skynet to be created.
This idea came to me from a Stephen Hawking documentary I watched on "Time Travel", called "The Mad Scientist" experiment. The idea is that the scientist creates a "wormhole" that looks just 1 minute into the past. On one side of the wormhole, the scientist assembles a gun, and then walks around the wormhole while waiting to see himself assembling the gun. Then he shoots himself through the wormhole. This of course is known as a paradox… because, how could the scientist shoot a former version of himself and still exist to tell the tale?
This is just one possible explanation I have for her question… I'm just wondering if anyone else has any other explanations or opinions?