We have here a considerably older John Conner and a considerably younger Kyle Reese.  Former veterinary assistant Kate Brewster is chief medic of Conner's unit, and also apparently pregnant, so she is present but not in the fighting.  Cyberdyne awkwardly re-enters the picture as a weapons developer.

It might be said that the key element in this film is the question of predestination.  That is, SkyNet is trying to find and kill Kyle Reese before he travels to the past, and is still trying to find and kill John Conner by luring him into a trap to face a T-800 unprepared.  If Skynet kills Kyle Reese, he won't be able to travel back to become John Conner's father; if it kills John Conner, he won't be able to send Reese back to become his father.

Meanwhile, the other side of the program plays as well:  if the resistance manages to destroy SkyNet before SkyNet sends a T-800 back to the past, the events that lead to John's birth are undone just as surely as they would be by the death of Kyle Reese.  Yet the film flirts with the possibilities of all of these events occurring, of the war ending before anyone was sent to the past, of Kyle being captured and killed, of John losing his life to the fight.  We are given to feel that something that cannot happen might happen anyway, and when it does not happen, we feel the relief that things have gone as necessary.

Before we begin looking at the issues involved, we should recognize that this is not the original history of the world.  You are already aware that John Conner is not Sarah Conner's original child, but the child of the man that her child sent back to protect her.  In addition to the fact that John Conner exists, he acts based on the recognition that Kyle is his father, and this means that Kyle must already (from a sequential perspective) have altered the past.  Fixed time theorists will argue that this is a simple predestination paradox, that Kyle is destined to leave for the past because he has already arrived there; however, the events of Terminator 2 cannot be reconciled with a fixed time scenario (where would the idea that Cyberdyne brought Skynet on line in 1997 have originated if it had not happened in some undone version of history?).  Thus we are looking at the modified timeline in which all the events of the previous movies have happened and been resolved.

This film also is the first to have been set in the future.  We had murky glimpses of that war-torn future in previous films, but the three previous films were all set in the year they were released.  This shift, though, is necessary, because the third film ended with a history-crushing spectacular, and it would not be possible for the world of this film to be like our world in the year it was released.

It might also be necessary to mention The Sarah Conner Chronicles.  When this series was launched, its creators stated specifically that it was diverging from the universe of the movies, and that the events of Terminator 3 never happened in the world they were presenting.  It thus follows that those stories are not part of the world of this film, either.

With that foundation laid, we can look at the temporal issues the film raises.

There is an interesting aspect of the film that is not readily apparent to the viewer, and that is the order in which events in the film series occur.  That is, from our perspective, SkyNet first attempts to kill Sarah Conner because she is John Conner's mother, then attempts to kill John himself when he is a boy, then attempts to kill all of John's lieutenants and incidentally him with them, and then after all of this attempts to kill Kyle Reese, John's father.  Thus the attempt on Kyle Reese is the last effort (known to us) SkyNet makes to eliminate the Conner threat.

However, this is not the sequence of events as experienced by SkyNet in the final history of the world.  It cannot be.  Moments after SkyNet attempts to kill Sarah Conner (by sending the T-800 to the past) Kyle Reese, now an adult, leaves from 2029 never to return.  Thus we know that the events portrayed in this fourth film occur before that departure in the first, confirmed by the date of 2018 suggested in the opening.  In sequential terms, Kyle Reese cannot be targeted as John Conner's father until he has already become John Conner's father, and he cannot become John Conner's father until after Sarah Conner is targeted as John's mother, and thus until after (in atemporal sequential terms) he has been sent back to protect her, after SkyNet attacks her to destroy her unborn child.

It is thus again clear that the events of this film are in a timeline derived from the events of the first film, and not in the original history of the world; it is the more clear here.  What is not clear is which history of the world this might be.  It is not so obvious whether the events of the second and third films have already occurred, and their occurrence or non-occurrence is significant.

One of the key questions is whether John recognizes the T-800 model 101 when it is abruptly revealed during the climactic battles of the film (and kudos to the creators of this film for finding so convincing a double for Arnold Schwartzenegger).  If this is the history which arises from the events of the first film only, then John has never seen a T-800 before this moment, and it has an element of surprise from its human appearance (the reason for the design).  If he knows what it is on sight, though, that means that the events at least of the second movie have also already occurred.  That scene is inconclusive.  Certainly John is surprised when the T-800 appears from behind the door; but the information Marcus Wright downloaded from SkyNet and sent to him said Kyle Reese was there, so his surprise could be simply that he was expecting someone else.

Significantly, John recognizes the design plans of the T-800 early in the film.  Far more significantly, he recognizes the nuclear power cells for the T-800, which he never saw until Terminator 3.  Thus this must be the history flowing from that.

One other factor is suggestive.  When Marcus Wright meets SkyNet, the computer says that he has accomplished what SkyNet's best machines never could.  That, though, opens another problem concerning SkyNet's knowledge of the past and the future.

We have established that the events of the first film must have happened, because Kyle Reese cannot be targeted as John Conner's father until (sequentially) he has become John Conner's father.  We also noted that John recognized T-800 power cells which he had not seen until the third film.  This brought us to a puzzle, something SkyNet says to Marcus Wright, which suggests that SkyNet knows of those events.

To quote Skynet:

Our best machines had failed time and again to complete a mission....You did what SkyNet has failed to do for so many years. You killed John Conner.

We also know, significantly, that all Terminators sent to the past were destroyed in the past without communicating directly with SkyNet.  Further, General Brewster, head of the team which oversaw and launched the Skynet project, is unaware of the attacks of those machines, so it is not in the programming.

We have postulated the existence of histories in which each of Skynet's terminators is unchallenged and so reports its mission to SkyNet later.  However, the original third terminator would have been destroyed in the first attack, and so would never have contacted SkyNet (and the T-X was not sent until its T-800 adversary was there to destroy it), so it cannot be the source of this information.  Further, the first terminator that could have reported was in a timeline in which Kyle Reese was not present, and this cannot be that timeline.  That means we must postulate that the T-1000 that killed Sarah but not John survived to report to Skynet not less than seven years later.  However, the terminat.html#third">previous reconstruction of this timeline concludes that that machine was destroyed before it found John.  In brief, the T-1000 is powerful and relentless, and if not destroyed it would still be searching for John Conner decades later.  To kill Sarah, it would have to reveal its presence to authorities:  there is video tape of it passing through the bars, at least, so while they do not know what they face, they know it is not human, and they know that it purposefully killed Sarah (what, did you think she would survive without help?), and they know that she believed a machine had been sent from the future to kill her.  The T-1000 cannot accomplish that portion of its mission without revealing its presence, and once it has both revealed that it is not human and killed numerous persons in a secure facility, it becomes the hunted.  The probability of it contacting SkyNet seven years later in this timeline is minimal.

We determined that the T-X might have left a message on the network.  This is speculative, and any such message probably contains little information.  If SkyNet knew in advance that its machines will fail, it probably would not send them, and thus would undo that knowledge.

All of this pushes us to the inevitable conclusion that SkyNet does not know about the machines it has not yet sent to the past; yet its statement to Marcus Wright implies that it has sent machines to kill John Conner, which have failed.

The best construction (without stating that SkyNet could not have said that) is that SkyNet has already sent other machines, perhaps hydras, T-600's, and hunter/killers, which failed to kill John in its own present.  Thus the statement to Wright is irrelevant to the question of which history this is.  SkyNet has been attempting to kill John Conner since SkyNet was born; it has not yet attempted to kill him before that moment, and is not aware that it is going to do so.

There is one huge unanswered question in Terminator Salvation:  why does SkyNet want to kill Kyle Reese?

We think there is an obvious answer.  Kyle Reese is John Conner's father.  SkyNet failed to kill John's mother, and failed to kill John as a boy, and failed to kill John and Kate on Judgment Day, and it is quite reasonable that he would attempt to kill John's father.  As John says, "Kill Kyle Reese.  Reset the future.  No John Conner."  That, though, brings up two other questions:  how does Skynet know that Kyle Reese is John's father, and why doesn't it just kill him as soon as he has been captured?

It certainly is not common knowledge that Reese is Conner's father.  Resistance command does not know it.  It is not sufficient that Kyle Reese is John Conner's father; for SkyNet to act on that information, it must know this.  It does not appear that anyone knows but for John himself and his wife, Kate.  It is not something SkyNet might have overheard.

Already we can do partial matches of genetic profiles, and thus identify two people as blood relatives.  We can recognize a relationship as close as parent/child or full sibling; however, we are not yet able to distinguish who is who in these relationships.  Were we to test these two men, our logical conclusion would be that Kyle, the younger, was the son of John, the elder, or possibly his younger brother.  We could not distinguish father from son.

Perhaps technology will advance sufficiently that it becomes possible to identify which is the "source" sample and which the "derivative".  This, however, begs the question.  How would SkyNet have acquired DNA samples of both John Conner and Kyle Reese, known their identities, and not already have killed either of them?

A similar question could be raised concerning the facial recognition software by which SkyNet identifies Kyle Reese.  Although it probably has trillions of images from surveillance cameras, how does it know that this image is that of Kyle Reese, and of the correct Kyle Reese?  The page How Many of Me says that there are sixty-seven people in the United States named Kyle Reese, one thousand one hundred seventy named John Conner, and one hundred eighty-one named Sarah Conner.

If we assume that following the destruction of any of its machines SkyNet downloads all audio files and video images and does a forensic sweep of the area, it would gradually build identity files on resistance fighters opposing it successfully.  It might use this data to identify the genetic connection between the young Kyle Reese and the older John Conner.  Not being inherently constrained by the perception that Kyle is the younger, it might consider the possibility that Kyle somehow became John's father, and that he must have done so by traveling to the past from some time yet in the future.  Kyle then becomes a viable target.

Why, though, does it not merely kill Kyle Reese at its first opportunity?  Certainly for the bait to work Conner must believe that Kyle is still alive; but that does not mean Kyle must be alive, only that his death is not known.  Kyle could be killed as soon as he is hidden and Conner is on the premises.

Perhaps the simpler answer is that SkyNet is not attempting to kill John Conner's father.  It determined only that the Conners were searching for Kyle Reese, and without knowing his significance it decided to find him first and use him as bait.  Kyle becomes, to SkyNet, the inexplicably useful bait in the trap.  Killing him would be incidental; keeping him alive long enough to attract John is important.

This construction is useful, because if SkyNet is not attempting to kill John Conner's father but attempting to kill John Conner by using something John wants as bait, it does not need to know that Kyle is John's father.  Thus we can accept that it does not know what it has until it gets that information by interfacing with Marcus Wright, and so it does not take action when it can.

Why is Kyle's name at the top of the assassination list?  As with all the other data the resistance captured on that raid, it was planted to trap Conner and destroy the resistance.  Skynet already knew the Conners were trying to find this person, and while it seeks him it puts out the notion that it already has him.

There is another plausible explanation, though.

SkyNet did not know Kyle Reese was John Conner's father, but only that he was someone Conner wanted to find.  Certainly Skynet finds out the connection when it downloads the data from Marcus Wright during their direct interface; there is no evident way for it to have known before that.

Yet there might be a different reason for SkyNet to have hesitated, and it has to do with Niven's Law.

One of the great paradoxes in time travel discussions, commonly called a grandfather paradox (although there are actually two distinct anomalies under that name), asks what happens if a time traveler kills his own grandfather before his father is conceived.  In such grand terms it becomes the basis for great debates.  However, the popular interpretation of Niven's Law assumes that once a change has been made in the past it remains changed, even if the cause in the future is thereby undone.  Applied to our current story, it means that once John Conner is born in the past, that cannot be prevented by killing Kyle Reese in the future.

If at this point you are thinking that this is absurd, you are in ample company; John Conner obviously believes that the death of his father before he becomes his father would be fatal to him, even if that death happened in the future.  Yet this challenges our fundamental notions about causality and time travel:  would the death of Kyle Reese in the future matter to the birth of John Conner in the past, or not?  More fundamentally, if the cause in the future of an effect in the past is undone, does that undo the effect as well?

Strict replacement theory would say yes, and Conner is working on that basis.  Niven's Law provides a potential escape, but leads to this absurdity.  If we think Kyle's survival matters, we do not believe Niven.

This is not the only place where this problem arises.  If John Conner dies, he will never send Kyle Reese to the past; probably SkyNet will never send any terminator to the past if John dies here in the future, because he will have ceased to be a problem.  Similarly, if the resistance wins the war here, now, then no one will be sent to the past and it will all be undone.  These are the issues that the film raises.  Without anyone traveling in time during this portion of the story, time travel threatens the history and future of the world.  Any one of these changes could create an infinity loop, bringing about the end of time.

Fortunately that does not happen.  Those who must survive--John, Kyle, Kate, and Skynet itself--all do.  That, though, raises a perennial question about the entire Terminator series:  is it fixed time?.

Over the course of the story we are several times confronted with the possibility that a change would occur in the future that would undo events in the past.  We noted that although these raise significant issues, everything ultimately works as it must.  That then raises the question, in what sense must it?  Is John Conner wrong when he says at the end that we make our own fate?  Is time fixed such that we cannot change the past, or the future, that even were we to travel to the past we would do, do, do what we did, did, did before, before, before?

If it is fixed time, then it becomes a somewhat less interesting story.  Kyle and John have to survive, not because we need them to and not because of plot immunity but because of something far more fundamental:  having lived in the future they really can't be killed in the past.  John then does not need to rescue Kyle to save his life, because Kyle was never in any danger.  Rather, John needs to rescue Kyle because that is what John is fated to do.  He thinks he is risking his life to save his father's life, but neither his nor his father's lives are ever at risk.  Of course the fact that it makes an unbearably dull story doesn't mean it's not the intended story.  It just makes it dull.

Distinguishing fixed time from replacement theory stories is not easy.  The final stable history of an N-jump will be completely self-supporting and internally consistent, just like a fixed time timeline.  They can be distinguished only if there is evidence of a different original history which cannot be explained under fixed time.  Terminator gave us a predestination paradox, which some fixed time theorists insist is plausible and others reject as impossible; no certainty can be obtained there.  Terminator 2:  Judgment Day gave us a grandfather paradox, postponing judgment day a few years, and thus when it arrived behind schedule in Terminator 3:  Rise of the Machines it forced the understanding that history had been altered.  Yet there are those who reject the third film as "not canon", who would insist that the first two must stand on their own, and as such are fixed time stories.  The first manages to survive only if you are willing to accept the validity of the uncaused cause in the predestination paradox; the second only if you conclude that Sarah's destruction of Cyberdyne was too late and Skynet went live that year anyway.  But the question is whether there are any hints in the fourth film, apart from the obvious predestination paradoxes, that there was a different history originally.

The problem is that given a particular resolved fact set the two theories are unfalsifiable and indistinguishable in their final histories.  That is, the final replacement theory timeline will have only those traces of previous histories that we call predestination paradox, and fixed time accepts predestination paradox as a viable event in history.  Thus if a film has a perfect temporal resolution, either theory will explain it.

This was disrupted in the Terminator series, because the acts of Sarah Conner at the end of Terminator 2:  Judgment Day were calculated to prevent that apocalypse, and Terminator 3:  Rise of the Machines gave us a story in which judgment day was delayed seven years.  However, Terminator Salvation has no time travel within itself, and creates no anomalies that are not resolvable by both theories.

Thus this film could be understood as a fixed time story, or as a replacement theory story.  The characters within it act as if it is a replacement theory story, that the past can be changed with devastating results for them.  They might be mistaken.  We cannot know just as they cannot know.  Terminator has its share of fixed time theory fans, but also has replacement theory fans.  Individually some of the films work under either theory, but for the series as a series, fixed time fails.

There is a more glaring issue with this movie.

The biggest problem in the Terminator series might be the birth of not John Conner but Kyle Reese.

The film Terminator Salvation is just a bit vague about the age of Kyle Reese during this week or so in 2018, and that amplifies the problem.  We take him for a boy, not much more than twenty, but certainly at least fifteen.  If he is twenty, he was born in 1998; if he is fifteen, he was not born until 2003.  That puts his birth inside the the uncertain period created by the shift in judgment day.  The earliest date we can easily imagine for him means he was born the year after the hardware version of SkyNet would have gone live in 1997; the latest puts him the year before the software version went live in 2004.  This matters.

There are a few events in history that change everything.  We know for example that the British lost a million men in World War One, and the French, Germans, and Russians each increasingly more.  That is millions of men whose heredity was eliminated from the gene pool.  Had World War One not happened, almost nobody native to those countries today would ever have been born, the impact on the gene pool would have been that significant.

Judgment day is a similar event.  It begins with a defense computer system becoming sentient, and within a very few hours the major population centers of the United States and of most of the world are obliterated in a nuclear attack.  Very few people who would have been born otherwise will be born following this event.  Part of that is because some mothers and some fathers are dead; part of it is because the general upheaval of society means that people who would have met now won't; part of it is simply that everyone's lives have changed so drastically that even the unplanned children are not the same children.

The problem is that Kyle Reese must exist after both the 1997 hardware launch and the 2004 software launch, and yet his birth falls between the two.  If SkyNet does not go live until 2004, Kyle's parents are living in the peaceful pre-apocalyptic world of California.  When that date shifts to 1997, if they both survive at all their lives are in that post-apocalyptic upheaval.  Yet somehow Kyle must be born within those years in both histories.

We could solve the problem by making him older or younger.  Younger is the better solution, because then we do not have to worry about whether he has memories of the pre-apocalyptic world; yet it is easier to make him twenty-two than to make him fourteen, and not easy to do that.  The Kyle Reese who meets Sarah Conner does not know the 2004 date, so as we mentioned he must know this history based on what John Conner told him, and not based on his own experience. 

Although it seems implausible, in order for this Kyle Reese to exist in both histories he must have been born after the 2004 date. That means he cannot be older than fourteen now, despite his looks.  Even this is difficult, since it means that Kyle's parents in one history survived seven years of the war against the machines and in the other they had him shortly after the disaster struck.  He becomes the greatest improbability in the film.

There is, however, another potential solution to this problem.

When SkyNet goes live in 1997 (the date he gives Sarah Conner when he becomes John's father), Kyle's parents gave birth to him during the war, sometime after judgment day; when SkyNet goes live in 2004, however, they gave birth to him before judgment day.  Somehow despite the upheaval caused by a nuclear war, the same boy was born with the same name at the same time, and that quite near a major strike zone.  The probability of any person being born in that area during those years under both histories is slim in the extreme; that it would be the one person who matters is pushing improbabilities to Hitchhiker proportions.

Yet the probability can be raised significantly if we allow the possibility that it is not quite the same Kyle Reese.

There are people in the world who know what they are going to name their children long before they are in a position to have any.  Their son will be named for their father, or their daughter for their grandmother, or a child for their best friend.  It almost does not matter whether their spouse likes the name; that is the name.  Thus if Ralph Reese is such a man, or Rhoda Reese is such a woman, it might not matter whether Ralph met Rhoda.  Whether before the war or after, if Rhoda is an unwed mother of a boy she will name him Kyle Reese, or if Ralph fathers a son he will name him Kyle Reese.  Someone will be born named Kyle Reese.  In this case, since Kyle mentions his father but not his mother, we can guess that his father is the connection that matters.  As long as the man fathered a boy, we have a Kyle.

There is a question of the survival of this Kyle.  After all, we've accepted that he might have a different mother, and thus that he will be a very different person.  He might be genetically very different even with the same mother, given the upheaval of the world.  Yet he has the same father, the father who taught him to survive, and thus even a somewhat different Kyle has a good chance of surviving.

There is the question of whether John Conner would choose this person to protect his mother.  However, that only matters the first time through.  John knows that Kyle Reese is his father, and even if he does not see his best warrior in the boy this will be his pick.

There is the question of whether Sarah Conner will fall in love with this Kyle Reese.  It seems, though, that Sarah was ready to fall in love with someone (we noted that she must have gotten pregnant right around this time without Kyle's arrival), and any Kyle Reese is going to admire the John Conner, leader of the resistance who risked his life to save an unknown boy (himself), and the mother who prepared that boy for his place in life.  Sarah is very likely to fall for her rescuer, whatever changes we make in his DNA, as long as he succeeds in rescuing her.

It is more difficult assessing whether he will succeed and also die; but at this point we are so deep into the nature/nurture debate that we cannot begin to predict the answer.  He is Kyle Reese, son of that same man who taught him to survive, trained by John Conner in John's full expectation that this man would save his mother's life and become his father.

It also changes who Sarah Conner's child is, because if Kyle Reese has a different mother, he is a different father, and John a different son; but as long as he is a son (a fifty-one percent chance) he will still be John Conner, trained by Sarah Conner to save the world from SkyNet.

So perhaps the birth of Kyle Reese is not so improbable after all.

It is difficult to know what to say in summary of this series on Terminator.  It began by reconstructing an original timeline for what many claim is a fixed time film.  It then tracked the changes made to history as the events of the original Terminator shifted judgment day forward to 1997, and then Terminator 2:  Judgment Day pushed them back again to 2004.  An infinity loop based on a grandfather paradox was avoided by assuming that John lied to his mother, and that brought us back to something resembling the original history and date.

That brought us to Terminator 3:  Rise of the Machines, where we had to work our way through a few potential anomalies.  If in the original history they were not being chased by a machine, how did John and Kate get together?  If in the second history they were not assisted by a terminator, how did they escape from one?  And how did those names get listed as John's lieutenants if they were already executed?

Thus half of our examination addressed the first three films before we reached the new one, Terminator Salvation.  We discussed the sequence of events from SkyNet's perspective, and the suggestion in Marcus Wright's conversation that SkyNet already knew about assassination attempts it had not yet made.  We asked whether SkyNet knew that Reese was Conner's father, and whether that mattered, and whether the fact that everything worked meant this was actually a fixed time story.  Finally, we considered how entirely improbable it was that Kyle Reese could be born both before the late Skynet launch date and after the early one, and whether there was an alternate solution if we allow the possibility of a slightly different Kyle Reese.

We are thus faced with the fact that it is extremely difficult to reach the moment that is the beginning of Terminator Salvation; however, most of those difficulties fall in the previous films.  If we accept that all of the events of the first three Terminator movies (and the alternate histories they demand) have happened, that we have reached the starting point for this film, then the events portrayed are not impossible, not even terribly improbable, and they fit comfortably into the existing story without disrupting anything that has become necessary.

The possibility also exists for future franchise films.  I have long liked the notion of the resistance sending someone back to the past to plant a weakness in SkyNet's programming that they can access in the future; it would put them on the offensive and have SkyNet sending something back to stop them.  If SkyNet can act between the moment the resistance sends their man back and the moment they can take advantage of the weakness, the chase is on sometime in 2004 while the resistance in the future has to hold its position long enough for their trick to take effect.

Unfortunately, it would have to be after the death of John Conner, so the only character known to us who could be in it would be an aging Kate Brewster Conner, and maybe John Conner's child.

The series is probably not over as long as it continues to make enough money.  I expect we'll see a fifth movie of some sort.

In response to Resequencing, Hesus asked:

Previously, you seemed to ignore that John and Kate's first kiss were as young teens and that if the terminator in the second film hadn't shown up and killed his foster parents and sent John into hiding (or deeper hiding?) then they would have fallen in love and married (according to the reprogrammed terminator in part 3 who said they were married in his timeline and that he had killed John before being reprogramed and sent into the past to protect Kate from the female terminator). Yes?

This is a complicated question, but a brief recap of the timelines of the series should help.

1. In the original history, nothing arrives from the future.  Sarah Conner has a child, General Brewster launches Skynet around 2004, and Sarah's child is a problem for Skynet.  Kyle Reese and Kate Brewster are irrelevant; this history ends in 2029 when Skynet sends a T-800 back to kill Sarah.


2. This T-800 is not the one in Terminator.  It kills Sarah after she gives birth.  The child still becomes Skynet's problem, which still goes online in 2004.  Kyle is born and joins the resistance; Kate is irrelevant.  Skynet sends the T-800, and the Conner child sends Kyle to save Sarah.


3. Kyle displaces the original father, and John Conner is born.  Kyle gives Sarah information, but the T-800 is destroyed in Cyberdyne's factory, giving them hardware.  SkyNet launches sooner, and the T-800 improves; Kyle has revised information.  A sawtooth snap stabilizes when Cyberdyne cannot learn more from the latest parts than from the last set.  Skynet goes live in 1997; some version of Kyle is sent to protect Sarah.  Kyle knows Sarah's child as John.  John makes out with Kate in 1997, but after that she's irrelevant.


4. That history ends when Skynet sends a T-1000 to kill young John in Terminator 2.  Everything is the same until 1997 including the party with Kate; the T-1000 never catches John, but kills Sarah and is destroyed when the bombs fall in 1997.  Kate probably dies in the attack; she is still irrelevant, Kyle is still sent, and the T-1000 departs.  John then sends the T-800 back ostensibly to protect himself, actually to protect Sarah.


5. The arrival of the T-800 saves Sarah, but she uses information from the future to alter the future.  This succeeds in postponing judgment day back to 2004, but erases the information.  John lies, programming the T-800 with the now incorrect history of Cyberdyne's involvement.  Thus she destroys Cyberdyne because if she didn't Skynet would go live in 1997, and this delays it until 2004.
   
   John meets Kate through his motorcycle accident when he breaks into her clinic.  No terminator arrives, but they breakfast together, and as the virus infects the Internet and cell phones and credit card systems crash, John panics and persuades Kate to take him to Mexico.  The bombs fall that day, putting them together.  They become Skynet's big problem.  Skynet sends a T-800 back to 2004 to kill Kate and others.


6. The mission of that T-800 is thwarted because John recognizes it.  It kills General Brewster before being destroyed when the bombs fall.  History stabilizes when Skynet sends the same machine on the same mission; just before doing so it kills John Conner with a T-800.  Kate captures that T-800 and reprograms it, sending it back to protect her father from the other T-800.


7. General Brewster is still killed.  Kyle is born, Kate and John escape, and history runs smoothly to the moment when Skynet was to have sent the T-800 to kill Kate.  Being now aware that another T-800 will be sent, Skynet upgrades to a T-X anti-terminator terminator, sending it on the same mission.  It encounters the T-800 which Kate sends moments later (sent in a previous timeline and so already having arrived in the revised past), which protects John and Kate as they flee to the underground shelter together.
   
   Terminator Salvation happens in this history, which continues through the sending of all the travelers from the future including the sending of the T-800 which established the final history.

Thus Kate needs to meet John at thirteen in 1997 after the histories created by the T-800 and Kyle Reese are formed--the third point above--but she does not need to meet him again until after the resolution of the events of Terminator 2, in the fifth point above.  That 2004 meeting at the veterinary clinic is fairly stable, since travelers from the future have not yet interfered sufficiently to change it, and under all remaining histories they survive together.