The temporal elements arise because one of the superheroes has partial knowledge of the future, and he makes several comments trying to explain it.  Those comments, however, point in several different directions.  The character is called Dr. Manhattan, and in the traditions of the fifties and sixties gained his power from a nuclear accident, and so his precognitive abilities are attributed to the movement of tachyons backwards through time; during the story, something is interfering with that knowledge for a significant part of the film.  He attributes this to a tachyon surge from a supposed nuclear holocaust which he thus assumes is going to happen in a very short time, but we ultimately discover that someone has secreted a tachyon generator in his lab.  (Why did he not foresee that?)

There is not much to discuss.  Even in the director's cut there is very little said about or done with the ability.  Still, what is included raises odd questions about Dr. Manhattan, time, and consciousness, worth a brief consideration.

In some of his comments, he suggests that the future is immutable, that the disaster will happen and nothing can be done to prevent it, and that whatever he knows will happen is going to happen.  Indeed, in every case in which he claims he knows what will happen, it does happen.  At first glance it appears that Dr. Manhattan knows "the future", that what will happen has from his perspective happened already.  If this is correct, we are dealing with fixed time theory, and the future is as immutable and as knowable as the past.  It is possible for him not to know the future, but he believes that it is not possible for him to be wrong about it or to change it once he knows what it will be.

However, at one point in trying to explain his ability to another character he makes a passing comment about "parallel universes".  This then suggests that the future is not fixed, but that dimensions diverge from the present into a vast number of divergent dimensions or possibly that parallel dimensions all co-exist in their own version of space but are linked temporally to our own.  Taken thus, we have a character more like Muad'Dib, who can see all possible futures and by his own actions in the present can determine which will occur.  This view is inconsistent with Dr. Manhattan's fatalism, but that fatalism is itself inconsistent with his comment about parallel universes.  If we believe that all parallel universes are completely identical to this one, in what sense do they have independent existence?  If he sees them as possible alternate futures, in what sense is the future predestined?

There is insufficient information in the film to know whether time is treated consistently; there is sufficient information to suggest that Dr. Manhattan does not understand it as well as he thinks he does, and does not treat it consistently himself.  Although it will not be possible to reach any solid conclusions concerning how time works in this story, there are aspects to explore, warranting at least a short series.

It should again be mentioned that in addition to graphic comic book violence this film earns its "R" rating with a significant amount of foul language, sexual situations, nudity, and sexual acts.  I suspect Bob Waliszewski would give it zero capes out of a possible five for "family friendliness".

One of the oddest issues raised is the question of what Dr. Manhattan knows, that is, how his consciousness relates to reality.

The clearest example of this peculiarity arises when Dr. Manhattan, also called Jon, and Laurie Jupiter, also known as Silk Spectre, are conversing, and Dr. Manhattan tells her what is going to be said in the conversation ahead.  He says that she is going to tell him about her affair with Daniel.  "You know about my affair with Daniel?" she asks.  "Not yet," he replies.  Then further into the conversation she says, "I'm sorry I slept with Daniel."  (She probably is not sorry she slept with Daniel, but she probably is sorry about the consequences, so it's a fair statement.)  With unfeigned surprise Dr. Manhattan reacts, "You slept with Daniel?"  Yet we cannot grasp how he can know what he is going to learn in the future and not know it already.  That is, if he knows right now that in five minutes Laurie is going to tell him that she slept with Daniel, how can he not know now that she slept with Daniel and is going to tell him so?

Let's make a clear distinction.  If the teacher announces that next week we will learn quadratic equations, I know that next week I will know something about quadratic equations but I don't know what I will know.  If I check the syllabus I can see that the reign of Elizabeth I will be covered in the fourth week of the semester, but I don't know anything about the reign of Elizabeth I until that time comes.  But unless we have stepped into the world of Bill Clinton such that "an affair" and "slept with" are not euphemisms for the same thing (and there is no evidence that they were doing any sleeping together) it does not seem credible that someone could know that he was soon going to know that his wife had an affair and be surprised to learn that she slept with the person with whom he knew he was going to know she'd had the affair.

We seem to have a problem of atemporal consciousness.  That is, Dr. Manhattan's ability to know and not to know do not fall in temporal sequence.  The most plausible explanation for this seems to be that when he uses his ability to know the future, he knows it only as long as he is using that ability, and when he ceases to use it he cannot remember what he knew, but only what he decided to do based on that knowledge.  The universe is thus more like an external memory device--perhaps several external memory devices--accessed by a decision to seek information about the future or the past and retained as long as the connection is maintained, but lost thereafter.  In this way he can access the information that he will be told about the affair, convey that information to Laurie, then by disconnecting from that database lose all knowledge that he had accessed it.

It still seems strange that he would not remember having said it; but then, if precognitive memory is like an external memory device, speech is clearly like an output device, akin to text appearing on your screen.  The computer does not remember text flow that has left the screen unless it is stored in a cache file or internal memory space; whether Jon remembers what he said depends on whether he chose to store that information in immediately accessible memory.

Such a memory seems at first glance impractical.  Memory is necessary to our survival.  Even mice retain enough memory to learn how to find food and avoid dangers.  The notion of selective memory of this sort is counter-intuitive:  if he said it, why would he not remember it?  It raises the question of whether such a memory could evolve naturally, even given the unnatural environmental factors which stimulated its supposed evolution.  That, though, raises the much more complicated question of what we mean by asking whether the ability could have been created under those conditions.

We determined that Dr. Manhattan's consciousness was atemporal, and concluded that there was a separation between what he knew when he accessed the future and what he knew when he was not using that ability.  Thus it was possible for him to tell Laurie that she was going to tell him about the affair she had with Daniel and still be surprised a moment later when she told him of it.  The question arises whether a creature could evolve whose memory worked thus, that it could know information for a moment that it did not remember a moment later unless it made the conscious decision to do so.  We now face that question, asking whether it could occur naturally.

To avoid confusion at the outset, let us be clear that we do not mean whether a particle field such as altered Jon would or could have the effects that the field had on someone caught in it.  What we mean is whether such an ability could in any way be found in a creature given any environmental forces.  The probability of any given accident having this result is not at issue; part of the concept of evolution is that improbable accidents occur alongside probable ones, and useful ones are retained by future generations.

The problem is whether a memory requiring specific commands to remember information has useful survival value.  That is, since Jon tells Laurie that she will tell him about her affair in a few minutes and when she does a few minutes later he is genuinely surprised, it must be that he did not store the information in the statement he made to her in a memory file accessible to him when he is not "knowing the future", and therefore things happen to him and he says things but he does not retain memories of them unless he chooses to remember them.  It would be comparable to a consciousness in which you could not remember anything that occurred yesterday except for those events which at the time you decided to remember.

The first problem with imagining the evolution of such a feature is that it necessitates consciousness; that is, something has to understand and make decisions concerning what ought and ought not be remembered.  That further involves value judgments concerning what ought and ought not be remembered, and value judgments of that sort require experience against which to weigh the relative value of potential memories.  By definition, memory in this circumstance is a positive choice--Jon does not choose what not to remember, but what to remember--and thus at the starting point he must have a basis for making those affirmative decisions.  An infant could not make them, because regardless of what evolutionary advances there were in consciousness and intellect it would lack experience.

It thus follows that as an evolutionary characteristic, this type of memory is a survival disadvantage; the children born with it would be less survivable and so the trait would be excised from the population fairly quickly.  Jon does not suffer that disadvantage (there are disadvantages to this type of memory concerning social interactions which he does suffer) because he did not have the ability until after he had acquired the experience.  He thus has the experience on which to base such decisions, and can use the memory effectively, choosing what information to retain and what to forget.

Looking at it then from an evolutionary perspective, the trait probably could be gained by some sort of mutation or disease process, such that the victim has memories only when they are intentionally and specifically formed, but such an ability would be a survival disadvantage for any offspring born with it, and thus would be limited to a single individual.  It would be problematic even for most adults, comparable to degenerative diseases such as Alzheimer's and senile dementia but distinct in its function.  A tremendous amount of mental effort would have to be allocated to making the decisions whether to retain or forget each incident (and note that it would be difficult to make a rule to "forget incidents like these" without remembering the model incidents chosen to be forgotten).  It would not be impossible to have such a condition or trait if gained at an adult stage.

There is another complication, though, in that Jon speaks at one point of being aware of parallel universes, as if this were a complication in his knowledge of the future.  Exactly what he means by this is difficult to ascertain based on the limited information, but there are several possibilities.

It might refer to distinct separate universes whose similarity to each other is entirely coincidental, and that he can see all of them but cannot always be certain which he sees.  Thus there would be a universe (or many such universes) in which after the American Revolutionary War America rejected English and adopted German as its official language, later entering World War I on the side of the Germans, and following that war saw the rise of English Facism leading to a second world war in which England attempted to claim and then conquer Europe, and America stood with its German allies against this; and Jon could tell that that was not this universe.  Yet there would also be a world in which the Prime Minister had the chicken instead of the beef at the banquet, and was hospitalized because the chicken was tainted, disrupting the British government, and Jon would not know whether that was this world's future or some other--unless he knew which world was our own future, in which case the existence of other universes is merely interesting and not relevant to his ability to see the future, and should not have been mentioned.  It would have no bearing on his ability to know "the future", and would be like someone saying that they neglected to mention having stopped at the store because they had seen so many television shows that they couldn't keep clear what was real.

It might mean that Jon sees all possible futures, like Maud'Dib, knowing everything that might happen and what actions will lead to each possible future.  As with the Atriedes model, he would be able to steer the future by his own actions in the present, to the degree that his actions were able to do this.  That is more on the lines of what Ozymandias is doing, predicting (in his case by superior intellect and sufficient information) all possible futures and taking steps to create the one he considers preferable.  This, though, would mean that Jon does not know what is going to happen, but only everything that might happen and what choices would lead to which outcomes.  While that certainly does constitute knowing the future, no one who knew the future in that way would ever consider it immutable.  The very essence of the knowledge is that the future is mutable, and the decisions made by those alive now will form it.

It might be that, as with Cris Johnson in Next and Agatha and the twins in Minority Report, Jon knows not "the future" but rather "the most probable future based on the present".  As Johnson indicates, knowing the future changes it, and thus moment by moment Jon's knowledge would change as he learns what will happen and then what will happen because he knows what would have happened, and then what will happen because he knows that.  Thus again the future is not fixed, exactly, but is not entirely mutable either, as at any given moment there is a most probable future, but as knowledge of that most probable future reaches Jon it changes.  He would not think it can be changed by his choices, but it is obviously changed by his knowledge through his choices, even if he thinks that his own actions are fated because he will act based on his knowledge.  On the other hand, this kind of foreknowledge would have nothing to do with tachyons carrying information from the future (rather a weak notion in itself--even if they do come from the future, why should they be encoded with information about the future if they were not manipulated by an intelligence?).  Jon could be wrong about the means by which he knows the future, but the fact that the tachyon generator interferes with the ability suggests that tachyons do have something to do with it.

There is yet one more possible understanding of parallel futures that needs to be considered.  It relates to the twentieth century's most famous feline.

We have discussed three concepts of parallel dimensions, and found each of them wanting in connection with the explanation of Dr. Manhattan's precognitive abilities.  Those versions assume that there is ultimately only one future, and although Dr. Manhattan sees many possibilities he knows that only one will become the reality.  There is yet another alternative, in which he perceives all possible futures and knows that all of them will become realities, and thus that what he does in the present will not "alter the future" because everything that might happen will happen.  This reminds us of Schrödinger's Cat, the beast that is both alive and dead depending on which of an infinite number of parallel universes happens to be the one in which we are living.  Suddenly the notion that the future cannot be changed means not that a specific chain of events will happen but that all chains of events will happen to everyone, and in one sense all of us will experience them.  In that sense, Jon cannot prevent the nuclear war, nor can he fail to prevent it, because he will in one universe act to prevent it successfully and in another universe fail to act (and in another universe attempt unsuccessfully to do so, and many other combinations, each interacting with all the many different choices made by Ozymandias, President Nixon, and everyone else whose choices impact the future).  Seeing all possible futures as existing, he cannot change that; he can only choose one to experience consciously.

That raises serious issues about that notion of reality.  If we assume that Jon has the ability consciously to select the universe he will experience, and thus to experience that universe exclusively, how can he exist in any universe in which he would have to have selected otherwise than to be present?  We might stretch our imagination to suppose that Schrödinger's cat is alive in one universe and dead in another, but if Jon gets to choose which universe he would experience, what version of him would choose to experience the one in which he dies?

In discussing Next, we confronted the problem of how Frank can foresee a future which cannot possibly happen.  We have a similar problem here.  If Jon can see a means of preventing nuclear war and he believes this to be the best of all possible futures and so chooses to act so as to prevent the war, how can there also be a version of the universe in which he does not see the means, or does not believe it to be the best choice, or does not act?  We thus find that Jon, being who he is, can only exist in one of the seemingly infinite futures; but if he cannot exist in any of the others, they cannot exist without him.  The only universe that can exist is the one he chooses; the cat is either alive or dead, not both and not neither.

(That, incidentally, was Schrödinger's point; that the man credited with best explaining the concept did so as part of an effort to demonstrate its patent absurd impossibility does not speak well for the idea.)

Parallel universes of this sort are not consistent with fixed futures as a temporal concept any more than the types previously discussed; they are competing theories in physics.  In consequence, either Jon sees the only future that will be, or he sees the future that is most likely to be derived from the present, or he sees what futures might come based on his choices in the present, or he sees nothing of value, the future history of thousands of universes which might exist but have no relevance to ours.

His power is intriguing, but in the end it fails to explain itself in a coherent fashion that would work in reality.

Fixed time stories often include incidents which cause themselves, known as a predestination paradox.  Although here it is subtler we find evidence of such uncaused causes in Watchmen.  The most blatant occurs in a conversation previously discussed for a different reason.

Our earlier discussion noted that Jon told Laurie that she was going to tell him, later in the conversation, about her affair with Daniel.  In response to her direct question about whether he knew about the affair, he says, "Not yet."  A few minutes later, true to his prediction, she tells him about it, and he responds as if this is new information for him.

What is peculiar, though, is the way she broaches the subject.  She does not say, "I slept with Daniel; I'm sorry."  She says, "I'm sorry I slept with Daniel."  Her phrasing and delivery are those of someone apologizing for doing something of which the offended party is aware.  It says that she would not be saying this if it were not something he already knew.  However, the only reason she thinks he knows it is that he mentioned it already.  She would not have said what she did had he not mentioned the affair first.  Yet he insists that he is ignorant of that.  He knows that she is going to tell him because she doees; but she tells him only because she thinks he knows, which she thinks solely because he mentioned that she will tell him.

Put more clearly, if she did not mention the affair, he would not be able to predict that she would tell him, but if he did not mention it she would not think he knew and so she would not mention it.  Her comment is caused by his, and his by hers, in a causal loop in which neither statement will be made unless the other is made.  Ultimately, her confession is its own cause, and an event which will only happen if it happens will never happen.

Replacement theory offers a solution.  In the original, very different, conversation Jon does not predict the confession.  Something absent from the conversation we see induces her to confess.  He then gains knowledge of the confession, and makes his prediction, altering the conversation to the new form in which her confession presumes his knowledge.  This altered version is sufficiently similar that it does not alter what he predicts.

Most of Jon's predictions can be explained this way, creating an original history in which he foresees nothing, and gradually altering it as the future forms and morphs in response to his foresight.