Predestination

[_Keno_]

As I see it, there are two types of predestination, one religious and one non-religious:

1. God knows the future, therefore it has already been determined that you do X.
2. All actions have a cause and effect, and the chain of all events within the universe, including all human decisions, was inevitable from the moment of the Big Bang.

Do you agree with either of these?

Follow up question for 2:
Assume someone successfully creates a perfect model of the universe, then fast forwards the model (aka looks into the future). What does it imply if the person can purposely defy the model's outcome?

 

[Sucumbio]

2.

Also i think a model replica is still going to adhere to the fatalistic reality of its surroundings ergo the real universe. Therefore any changes are technically not real changes just what was always fated to be. The only way to break free of fate is to separate oneself from space-time.

Edit: I'm getting deja vu... Either you're familiar or this subject is... Or both!

 

[SleuthMechanism]

i have a kind of different belief/theory related to 2. where basically i think most things are variable but some particular moments and meetings between individuals are just meant to happen one way or another. Basically the circumstances leading to such a thing are not set in stone but regardless of what variables end up happen said event will happen in some form.

 

[Sucumbio]

Kinda like dr. Who and so called fixed points vs flexible points. Some things just always happen even if you try to change it other things are variable

 

[FalKoopa]

I believe in 2 as well.

As for the follow up question, I think it creates a paradox, because the perfect model of the universe would also predict that person's actions, and would also predict that he would defy the model's outcome, which means that the original outcome was wrong in the first place.

 

[Sehnsucht]

Scenario 1 reminds me of Calvinism, a variant of Christianity in whose theology one's metaphysical fate is locked in from the beginning (i.e. one's salvation or damnation is predestined). Most denominations of Christianity, to my knowledge, will advocate Free Will (mostly because Salvation through God (and Christ) must be freely chosen or rejected in such cases).

This seems to conflict with the quality of omniscience -- absolute knowledge of all things from any perspective. Perhaps one way to reconcile this conflict would be to say that God knows all the choices that you will have (or already have) freely made. I'm not sure what other religions hold to theological predestination.

But I digress.

Scenario 2 is the definition of Determinism -- the idea that everything is invariably the result of of what came before (which was in turn the cause of what came before, and so on until the beginning of time).

If a leaf falls from a branch, then it could have done nothing but fall from the branch, since all the factors in the system at play in that moment -- the gust of wind, the weakening of the leaf's stem, etc. -- were the culmination of all the causes and effects that came before it. Causality determines the outcome (hence determinism).

Determinism doesn't necessarily mean that everything is predestined -- it only means that everything that happens (or has happened) was the inevitable outcome of what came before. It could be that determinism applies, but the future it not yet set in stone; it will be determined through antecedent causes.

Predestination seems to concern not choices, but the nature of time itself. Which is to say, whether a given timeline comprises the whole of time, or if "time" is decided one moment at a time. By elucidating the way time works (or is "shaped" overall), you'd be able to infer whether predestination applies.

Being non-religious, and also considering how causality works (it's a complex chain of dominoes), I do lean toward Determinism as being applicable. Though I'm not yet sure what philosophical camp I fall into (Compatibilist or Incompatibilist variants of Determinism).

As for the bonus scenario you posit under Determinism, if the model is a perfect replica of the universe's timeline, then we have a situation of Turtles Going All The Way Down.

You'd have an infinite regress, wherein the replica's timeline accounts for the architect creating the model (leading to a replica-within-a-replica). In other words, within the "timeline" of the replica, the architect's creation and viewing of the replica is included. And within that nested replica's timeline is the moment of the architect creating and viewing the perfect universal replica (leading to a replica-within-a-replica-within-a-replica).

Not only could the architect not defy their determined outcome by viewing the replica's timeline, but the infinite regress of timeline replicas would account for whatever action the architect will have already made. It would necessarily be the case that the architect never does anything to contradict the replica's timeline -- and the determinist cause would be that the architect has foreseen what they do in the future (in a case of non-linear causality).

Also, the thing with turtles is that they might go up as well as down. If we have an infinite regress, can the architect ever be sure that their own universe is not a perfect replica being observed by some identical version of himself "higher up" the nested replica chain?

 

[_Keno_]

Determinism doesn't necessarily mean that everything is predestined -- it only means that everything that happens (or has happened) was the inevitable outcome of what came before. It could be that determinism applies, but the future it not yet set in stone; it will be determined through antecedent causes.
Predestination seems to concern not choices, but the nature of time itself. Which is to say, whether a given timeline comprises the whole of time, or if "time" is decided one moment at a time. By elucidating the way time works (or is "shaped" overall), you'd be able to infer whether predestination applies.

Maybe I'm just confused by definitions, but if an event is wholly inevitable, then is it not predestined? At least, in a universe where no mysticism exists, all matter down to even quarks behaves by laws (although not all are known, and it has been shown that humans will likely never actually be able to predict such causal chains without affecting the outcome).

As for the bonus scenario you posit under Determinism, if the model is a perfect replica of the universe's timeline, then we have a situation of Turtles Going All The Way Down.

You'd have an infinite regress, wherein the replica's timeline accounts for the architect creating the model (leading to a replica-within-a-replica). In other words, within the "timeline" of the replica, the architect's creation and viewing of the replica is included. And within that nested replica's timeline is the moment of the architect creating and viewing the perfect universal replica (leading to a replica-within-a-replica-within-a-replica).

Not only could the architect not defy their determined outcome by viewing the replica's timeline, but the infinite regress of timeline replicas would account for whatever action the architect will have already made. It would necessarily be the case that the architect never does anything to contradict the replica's timeline -- and the determinist cause would be that the architect has foreseen what they do in the future (in a case of non-linear causality).

Also, the thing with turtles is that they might go up as well as down. If we have an infinite regress, can the architect ever be sure that their own universe is not a perfect replica being observed by some identical version of himself "higher up" the nested replica chain?

Although I'm fairly certain you know more than me, I still don't fully understand.

To me, the difference between this replica paradox and Turtles is the application of human choice. This meaning, it is not possible for the model the account for a human's decision to absolutely defy the outcome. Even if there is an infinite chain of architects, and maybe a single architect is watching himself and waiting for a way to contradict, time will still pass and there will be events occurring that can be contradicted.

 

[Sehnsucht]

Maybe I'm just confused by definitions, but if an event is wholly inevitable, then is it not predestined? At least, in a universe where no mysticism exists, all matter down to even quarks behaves by laws (although not all are known, and it has been shown that humans will likely never actually be able to predict such causal chains without affecting the outcome).

It probably is an issue of definitions. What does one mean by predestination? Is it:

A) That the future is already decided, because it already exists beyond my subjective present?

or

B) That the outcome of a given event will inevitably be the result of its causal antecedents (i.e. what came before)?

In A), then indeed, everything is predestined, because "destiny" (i.e. the future, or your future) already exists further along the timeline of the universe.

In B), the causal frames of destiny aren't necessarily "set in stone". But I do suppose that, if the outcomes of events are inevitable, then there will only be one "way" that the future will be manifested anyway.

To return to an earlier example, if, in the timeline of a leaf, the future isn't yet decided -- the timeline is being built one "frame" of animation at a time -- but causal antecedents make the leaf's fall inevitable, then the future of the leaf's timeline will inexorably be to fall from the branch. In this respect, you could say that the leaf's fall was "predestined", for there would have been no other possible outcome.

I read your OP thinking you were using the A) definition. I was simply thinking of a scenario in which something can be deterministic without being predestined. But I will concede that the answer will depend on one's definition of predestined.

Although I'm fairly certain you know more than me, I still don't fully understand.

To me, the difference between this replica paradox and Turtles is the application of human choice. This meaning, it is not possible for the model the account for a human's decision to absolutely defy the outcome. Even if there is an infinite chain of architects, and maybe a single architect is watching himself and waiting for a way to contradict, time will still pass and there will be events occurring that can be contradicted.

If we suppose that the model of the universe is 1:1 in its accuracy -- all particles in all of their proper positions at all points in time, all events unfolding identically, etc. -- then the model necessarily will account for any and all human decisions past, present, or future. If it did not account for such, then the model would not be a perfectly accurate, 1:1 representation of the timeline of our universe (which, unless I've misread, is meant to be the premise of your hypothetical).

The model will show me what I do in my future. If the model is a flawless rendition of my future, then I can't contradict it -- because this future will already have accounted for my desire to contradict any future I witness (supposing such desires arise).

The model wouldn't show my near-future self freaking out, trying to do anything to contradict the model's timeline, and so on and so forth. By virtue of seeing the model's future, I would see that any attempts of contradicting the timeline are futile from the very start. The most probable future is that Sehnsucht-A looks at Sehnsucht-B's future in the model, and understanding the fatalism of the situation, slumps in his chair in resignation (and Sehnsucht-B slumps resigned in his chair upon seeing Sehnsucht-C's future, and so it goes all the way down).

This is all a prime example of predestination -- the act of seeing what the future of the model holds is what cements the future of my own universe. This phenomenon is called a causal loop, though it can also be referred to as a predestination paradox. This effect arises when you have non-linear temporal systems (e.g. the act of trying to see the future of my timeline determines that very future, one in which my past self tried to see the future of my timeline).

Now, if you propose a scenario where the model is NOT a faithful 1:1 representation of our universe's entire timeline, then there could be room agency. If I see Sehnsucht-B (in the model) zig at future Moment X, then perhaps Sehnsucht-A (me) could indeed zag at Moment X.

But a perfect model of the universe's entire timeline will have accounted for every choice I will ever make, including the impulse of wanting to change my predestined fate, and the subsequent resignation when I realize that I cannot, and all of this as a direct result of viewing the model's representation of the (perfectly replicated) future.

In other words, human choice would be included in the model's contents, which means that whatever choice I ever make will be represented -- including the choices I end up making as a result of observing the model's contents in the first place.

This may be a bit twisty and convoluted to understand. I hope I'm making some measure of sense. XS

If I had to compress all of this in simple terms, I'd say that your scenario, due to the non-linearity involved, will necessarily cause a predestination paradox, meaning that human agency will not be possible. There will be no choices to make, because they will already all have been made (for a predestination paradox makes no distinction between past, present, or future; it's all happening at once).

 

[KACHOW!!!]

In my mind I think the same answer about both of _Keno_ 's questions: You can't prove that it does or doesn't exist, so you may as well asume it doesn't exist because if you asume it does exist it might get in your way of having a more happy/ fullfilled life, and you don't really stand to gain from asuming either is true.

 

[Claire Diviner]

Here's something to consider:

When we look to the heavens at celestial bodies, such as a planet or a star, we are looking at an event that happened years in the past because of how time, light, and distance work. While it doesn't exactly tell us what the future holds for us or for other celestial objects as far as predestination is concerned, perhaps there is some relation between now and the future, where the choices we would make years from now has already occurred and we simply don't and won't know until we come to that point, whether by design of a higher being, or simply by chance?

To put it in perspective, if someone who is, say, 5 light-years away, observed our planet, they'd see events that had already occurred 5 years ago.

 

[Sehnsucht]

Here's something to consider:

When we look to the heavens at celestial bodies, such as a planet or a star, we are looking at an event that happened years in the past because of how time, light, and distance work. While it doesn't exactly tell us what the future holds for us or for other celestial objects as far as predestination is concerned, perhaps there is some relation between now and the future, where the choices we would make years from now has already occurred and we simply don't and won't know until we come to that point, whether by design of a higher being, or simply by chance?

To put it in perspective, if someone who is, say, 5 light-years away, observed our planet, they'd see events that had already occurred 5 years ago.

I'm not sure I quite grasp your point.

The lightspeed-delay effect is a past-present relation, so it can tell us nothing about the future of any observer involved in the situation. You acknowledge as much, yet you then posit that perhaps this delay effect can inform us about predestination, because reason? Your pondering on whether our lives are preordained by some force, whether intentional or not, reads as a non-sequitur coming off deliberations of Cosmic Light Buffering.

Unless, perhaps, you're trying to extrapolate on the past-present relation of Cosmic Light Buffering. Much as light from distant objects show the trajectory of our past, perhaps we currently have a similar present-future relation, in which the light that springs from Earth is technically its past.

Or something. That doesn't seem to make much sense, given the relativity of the observer. All light is an image of the past, whether that past be microseconds or millennia away. Maybe you could expand or reword your idea, Claire, in a way that more clearly shows the relation between talks of light-years and talks of predestination.

And speaking of relativity, here's something else to consider. For a photon, there exists no time. The faster you travel, the slower apparent time becomes -- and if you're going maximally fast, then time would become maximally dilated. So while it took five years for light from Jim's position to reach me, for the stream of photons, it took no time at all.

 

[Claire Diviner]

I'm not sure I quite grasp your point.

The lightspeed-delay effect is a past-present relation, so it can tell us nothing about the future of any observer involved in the situation. You acknowledge as much, yet you then posit that perhaps this delay effect can inform us about predestination, because reason? Your pondering on whether our lives are preordained by some force, whether intentional or not, reads as a non-sequitur coming off deliberations of Cosmic Light Buffering.

Unless, perhaps, you're trying to extrapolate on the past-present relation of Cosmic Light Buffering. Much as light from distant objects show the trajectory of our past, perhaps we currently have a similar present-future relation, in which the light that springs from Earth is technically its past.

Or something. That doesn't seem to make much sense, given the relativity of the observer. All light is an image of the past, whether that past be microseconds or millennia away. Maybe you could expand or reword your idea, Claire, in a way that more clearly shows the relation between talks of light-years and talks of predestination.

And speaking of relativity, here's something else to consider. For a photon, there exists no time. The faster you travel, the slower apparent time becomes -- and if you're going maximally fast, then time would become maximally dilated. So while it took five years for light from Jim's position to reach me, for the stream of photons, it took no time at all.

Before I debate further, do you mind defining "Cosmic Light Buffering"? You capitalize the term, and because I've never heard of such a thing before, I had assumed it was a recent thing, but upon searching everywhere for a reference, I found nothing.

What I'm trying to say is that while no known method exist for us to achieve precognition to know whether events are preordained or not, similar principles would apply if we were able to accomplish a form of foresight. For instance, if we were to see an event that plays out in the future, we can very well try and stop it, but for all we know, our attempt to do so could have been what caused the event in the first place, or our attempts would simply fail and whatever caused the event would simply happen regardless, or we can simply choose to do nothing with the future event happening anyway because of our choice to do naught in the way of change.

Of course, these are merely theories that assume things that go against the principle of antecedence can be reached, but they are theories that are seen with some level of viability (retrocasuality in this case). A theory also suggests that such precognition and the ability to change "fate", if you will, could alter the present while the present can be made to alter the past. Assuming such a feat is possible, the end result could be the same; never knowing if predestination really is a thing, or if the future can be altered by a number of variables. Of course, there're also things, such as the Grandfather Paradox and the like to consider, but then there's also the whole multiple timeline/universe theory as well. Just some food for thought to get the brain going, I suppose.

 

[Sehnsucht]

Before I debate further, do you mind defining "Cosmic Light Buffering"? You capitalize the term, and because I've never heard of such a thing before, I had assumed it was a recent thing, but upon searching everywhere for a reference, I found nothing.

It's a term I whipped up on the spot. I couldn't recall if there was a technical term for the relation between light, distance, and time, and how looking into distant space is to look further pastward.

I have the tendency to engage in word play in online discussion. The downside is that it can lead to momentary confusion. XP

What I'm trying to say is that while no known method exist for us to achieve precognition to know whether events are preordained or not, similar principles would apply if we were able to accomplish a form of foresight. For instance, if we were to see an event that plays out in the future, we can very well try and stop it, but for all we know, our attempt to do so could have been what caused the event in the first place, or our attempts would simply fail and whatever caused the event would simply happen regardless, or we can simply choose to do nothing with the future event happening anyway because of our choice to do naught in the way of change.

Of course, these are merely theories that assume things that go against the principle of antecedence can be reached, but they are theories that are seen with some level of viability (retrocasuality in this case). A theory also suggests that such precognition and the ability to change "fate", if you will, could alter the present while the present can be made to alter the past. Assuming such a feat is possible, the end result could be the same; never knowing if predestination really is a thing, or if the future can be altered by a number of variables. Of course, there're also things, such as the Grandfather Paradox and the like to consider, but then there's also the whole multiple timeline/universe theory as well. Just some food for thought to get the brain going, I suppose.

Your first paragraph describes a simple causality loop (also known as a "predestination paradox", though there is no actual contradiction at play). In short, the act of witnessing the future (or gaining foreknowledge of it) is precisely what causes that future to come to pass. This is the consequence of non-linear causation.

This was the topic of my exchange with Keno and their "perfect universal replica", as seen earlier above. If I could see a perfect model of my timeline, and then fast-forward to a point further along the model's timeline, then whatever I see would necessarily be part of my own future. The model, if it were to be perfect, would need to account for any decision I choose to make (and since this is a predestination effect, any decision I make will be the one I'll already have made).

All of this depends on the greater context, as you note. Such as whether different outcomes to a given event spawn new timelines/realities/universes, or if we have only one immutable timeline, and if so, how non-linear phenomena (e.g. time-travel) could be expressed.

You've encapsulated the spirit of the debate surrounding predestination. Do you have any current positions on whether there may or may not be predestination, and/or whether you find deterministic models more probable than totally free models, or vice-versa?

 

[Claire Diviner]

You've encapsulated the spirit of the debate surrounding predestination. Do you have any current positions on whether there may or may not be predestination, and/or whether you find deterministic models more probable than totally free models, or vice-versa?

Personally, I haven't quite made up my mind. On one hand, I do not like the idea of not being in control of my own life. On the other hand, it's not like I'll really know to actually care in the end.

As for what I believe, I feel no matter what happens, everything is pretty much set in stone as far as a single timeline/universe is concerned. While I believe we can alter things, I am one who supports the idea of a multiple timeline scenario, especially assuming time travel will become possible.

As an example of the above paragraph with the Grandfather Paradox, let's say a time machine was invented before my birth. Now let us assume I go back to a time period that predates my birth and I decide to assassinate either my grandfather or one of my own parents. According to the paradox, I should no longer exist because I'd have prevented my own birth. However, I would have created a history in which said parent/grandparent was murdered by me, an existing entity. Logic suggests that I wouldn't just simply disappear, since I'm clearly there, but instead I'll have created a different timeline where I will not be born despite the sudden existence of my future self in that point in time, if that makes sense. As far as history will be concerned, my future self appeared suddenly, spawning from thin air, and will be the only one of my kind, until some other yahoo from the future appears out of nowhere to commit a similar action.

 

[Sehnsucht]

Personally, I haven't quite made up my mind. On one hand, I do not like the idea of not being in control of my own life. On the other hand, it's not like I'll really know to actually care in the end.

As for what I believe, I feel no matter what happens, everything is pretty much set in stone as far as a single timeline/universe is concerned. While I believe we can alter things, I am one who supports the idea of a multiple timeline scenario, especially assuming time travel will become possible.

I would argue that the difference doesn't matter, practically speaking.

It might be academically interesting to know for certain one way or another, but whether our reality is predestined or determined or voluntary, it doesn't change that I have the experience of the capacity for choice. That's all that really matters, ultimately, for things that have no relevance to one's experience need not be seriously factored into one's decision-making process. If I were to definitively learn that I have no "free will", what difference would it make? I'm still going to experience making those choices, whatever they will be (or already are).

This rationale applies to other stances I hold, such as the existence or non-existence of supernatural deities, or whether my experience of reality is authentic or illusory. That God exists or not means nothing if God has zero apparent impact in my lived experience, and that my experience may not be authentic doesn't negate that my experience feels authentic. The truth of any of these matters may inform how you go about making decisions, but you're still going to be making decisions anyway. So that doesn't change.

In terms of "academic interest", total free will is impossible, since we know we are influenced, to some extent, by factors and variables our conscious self may not necessarily be aware of (external factors, biological factors, etc.). So our choices are at least partially determined. Are we biological automatons, with consciousness as simply a very complex, yet nonetheless determined process? That's harder to say, though with neurological quirks and cognitive biases abound, then if we do have free will, it can't be said that our decisions are fully informed.

Predestination from a spatio-temporal standpoint is more probable than not, as well. If the entirety of space-time exists, then all of time is laid out. There is no "present", with time being constructed one "frame" at a time; all frames of time exist simultaneously, and what we call "time" is just the experience of flipping through the frames of animation in one direction. Under relativity, there exist no privileged (see: absolute) frames of references, so there being an absolute "present moment" doesn't seem viable.

A multiverse scenario may be a way out of this. But if a multiverse is just a continuity of space-times, which are all laid out in full, then the branching of outcomes into new timelines would similarly consist of a set of frames, which all exist simultaneously. At greater spatial dimensions, time (in the sense of linear progression of states) would not exist. So in this respect, a multiverse, finite or infinite, would be predestined.

Perhaps you could say that predestination concerns all the choices we will have freely made. A timeline would consist of frames in which our every choice was voluntary. Though this may get complicated if you were to gain foreknowledge of your future (voluntary) actions. If your (voluntary) present self saw your (voluntary) future, then this future would have to have already accounted for your past self's reactions and subsequent actions faced with this foreknowledge. Would you really have free will if your future was preordained?

It seems I go on and on, but I nonetheless say that even if the above is true, it doesn't change that we have to experience going through it anyway. Which is rather much a relief, since I don't have to think about my determined timeline (unless that determinism becomes directly relevant to my decision-making).

As an example of the above paragraph with the Grandfather Paradox, let's say a time machine was invented before my birth. Now let us assume I go back to a time period that predates my birth and I decide to assassinate either my grandfather or one of my own parents. According to the paradox, I should no longer exist because I'd have prevented my own birth. However, I would have created a history in which said parent/grandparent was murdered by me, an existing entity. Logic suggests that I wouldn't just simply disappear, since I'm clearly there, but instead I'll have created a different timeline where I will not be born despite the sudden existence of my future self in that point in time, if that makes sense. As far as history will be concerned, my future self appeared suddenly, spawning from thin air, and will be the only one of my kind, until some other yahoo from the future appears out of nowhere to commit a similar action.

I'm savvy on topics of temporal phenomena and paradoxes and the like (mostly through sci-fi media and layman's physics). So I understand full well the Grandfather Paradox.

There are different ideas concerning time-travel. There is the Novikov Self-Consistency Principle, which is a form of retrocausality. You can't change the past, because your time-travelling self is the one who cemented your future of origin. So in such a case, if you tried to go back and kill an ancestor of yours, the very fact that you exist in 2014 means that you failed to assassinate them in the first place. It's not that the universe is conspiring against you; it's that your time-travelling self was part of history to begin with.

Your posited scenario is standard multiversal timeline-branching, and is a solution to the Grandfather Paradox. Since paradoxes are contradictions, what might reasonably happen if timeline branching doesn't occur? It would cause a superposition of timelines, I would imagine. If you go back and kill your grandfather, then you never come to be; yet how can your grandfather have been killed by you if you never come to be? Perhaps both outcomes exist simultaneously, or repeatedly co-cause one another, or something similarly zany.

I also wonder what might reasonably happen should I perceive my own predestined future. That future will necessarily have to account for my present self's witnessing of it, and the reactions and subsequent actions that follow. If this future will have accounted for any and all impulses to avert or ensure, or do nothing faced with this knowledge, what would this future look like? Interesting stuff to think about.

 

[Claire Diviner]

I would argue that the difference doesn't matter, practically speaking.

It might be academically interesting to know for certain one way or another, but whether our reality is predestined or determined or voluntary, it doesn't change that I have the experience of the capacity for choice. That's all that really matters, ultimately, for things that have no relevance to one's experience need not be seriously factored into one's decision-making process. If I were to definitively learn that I have no "free will", what difference would it make? I'm still going to experience making those choices, whatever they will be (or already are).

This rationale applies to other stances I hold, such as the existence or non-existence of supernatural deities, or whether my experience of reality is authentic or illusory. That God exists or not means nothing if God has zero apparent impact in my lived experience, and that my experience may not be authentic doesn't negate that my experience feels authentic. The truth of any of these matters may inform how you go about making decisions, but you're still going to be making decisions anyway. So that doesn't change.

In terms of "academic interest", total free will is impossible, since we know we are influenced, to some extent, by factors and variables our conscious self may not necessarily be aware of (external factors, biological factors, etc.). So our choices are at least partially determined. Are we biological automatons, with consciousness as simply a very complex, yet nonetheless determined process? That's harder to say, though with neurological quirks and cognitive biases abound, then if we do have free will, it can't be said that our decisions are fully informed.

In layman's terms: Seeing our future choices would not impact anything other than the fact that we know for certain that we will make those choices regardless of any conscious attempt to contradict them; it's a matter of waiting and seeing how we come to that point and ultimately why.

Predestination from a spatio-temporal standpoint is more probable than not, as well. If the entirety of space-time exists, then all of time is laid out. There is no "present", with time being constructed one "frame" at a time; all frames of time exist simultaneously, and what we call "time" is just the experience of flipping through the frames of animation in one direction. Under relativity, there exist no privileged (see: absolute) frames of references, so there being an absolute "present moment" doesn't seem viable.

Damn! I know I saw something that goes over this theory. I don't remember the details, but I did find it intriguing.

A multiverse scenario may be a way out of this. But if a multiverse is just a continuity of space-times, which are all laid out in full, then the branching of outcomes into new timelines would similarly consist of a set of frames, which all exist simultaneously. At greater spatial dimensions, time (in the sense of linear progression of states) would not exist. So in this respect, a multiverse, finite or infinite, would be predestined.

A theory goes that all moments in time does exist in one simultaneous point, and that witnessing said moments depend completely on one's position in the universe, and this includes the future, despite the current lack of means to observe it the way we can the past. If this is indeed the case, then time - and by extension, the ability of precognition/predestination - is naught but things that cannot be manipulated.

If you really think about it, time, events, past, present, and future and the way we measure them are varied and abstract. After all, time on Earth is quite different than time in space. In fact, if you were standing on the ground, and I was standing on a shelf above you, my perspective of time, though impossible to notice, is different due my further distance from Earth's gravity, which actually bends time, events, and the way we perceive them (or "flow" in simplistic terms). So in theory, as stated before, you can feasibly perceive a future event should such a condition be met (if such a condition is actually possible). If the rather young history of human progress has taught us anything, it's that anything is possible, and I am a supporter of that mindset.

I would also like to point out that at the current moment, mankind is the only species that measures time the way we do, whether time actually exists or not. Time could very well be in our heads. According to a study, as we age, time seems to flow faster, and it all is thanks to the way the brains function. Below are a couple of interesting articles among many others that delve a bit into the idea:

http://www.nytimes.com/2013/07/21/opinion/sunday/fast-time-and-the-aging-mind.html?_r=0

http://ubiquity.acm.org/article.cfm?id=1455706

http://www.bbc.com/future/story/20120709-does-life-speed-up-as-you-age

There are different ideas concerning time-travel. There is the Novikov Self-Consistency Principle, which is a form of retrocausality. You can't change the past, because your time-travelling self is the one who cemented your future of origin. So in such a case, if you tried to go back and kill an ancestor of yours, the very fact that you exist in 2014 means that you failed to assassinate them in the first place. It's not that the universe is conspiring against you; it's that your time-travelling self was part of history to begin with.

Your posited scenario is standard multiversal timeline-branching, and is a solution to the Grandfather Paradox. Since paradoxes are contradictions, what might reasonably happen if timeline branching doesn't occur? It would cause a superposition of timelines, I would imagine. If you go back and kill your grandfather, then you never come to be; yet how can your grandfather have been killed by you if you never come to be? Perhaps both outcomes exist simultaneously, or repeatedly co-cause one another, or something similarly zany.

Hence the multi-timeline/multiverse theory.

I also wonder what might reasonably happen should I perceive my own predestined future. That future will necessarily have to account for my present self's witnessing of it, and the reactions and subsequent actions that follow. If this future will have accounted for any and all impulses to avert or ensure, or do nothing faced with this knowledge, what would this future look like? Interesting stuff to think about.

The future will be what it is, and that would be something we'd be forced to accept. I sometimes wonder if I really want to see what my future will be like, but then it could result in me seeing a potentially depressing future, and because it depresses me that said future will occur, I'll wind up depressed at the fact that I know how depressed I will be, and that's just really depressing.

Truth be told, I personally believe that knowing one's own future, especially one's time of death would be more frightening than it would be liberating, because then one would live life by nothing but numbers, by every tick of the clock, counting down to one's own death by the second, and goodness knows we already live by the clock enough as we already do. The last thing we need is to know exactly when we'll be out of time.

Still, it's fascinating to wonder how time works in the universe if time even is a thing, and whether manipulation of events in the past and future is possible, etc., etc.