I disagree to some extent considering my definition of free will is the freedom of choice. And time travel is one of those things that can have freedom of choice give you dire consequences.
Endgame is the only movie that fixes this problem. when they time travel, the past they're seeking becomes their future. Which means they haven't been in the place of their past selves it's a different timeline entirely
The idea is sort of tied to fatalism. If events are predetermined to happen, since the future exists and is essentially set in stone, then is it really your choice, or has it always been "fated" to happen that way?
I guess so, never paid much attention to philosophical stuff. But a future that has already happened sounds exactly like determinism and we'd be pretty powerless to stop events from occurring, if they'd already occurred. But it's possible that I might be stupid. Glad you enjoyed it though.
wow its funny that at the same as this video was released I also was thinking about time travel, coincidance? I THINK NOT! Anyways very epic video as always! Keep up the great work! ♥
I mean, a good way to make the bootstrap paradox at least consistent is to - in the book's chronology - write the book using a future copy of the book as reference, send it to your past self, use the book, then use it for the reference, instead of reuse it hoping it continuously stays the same rather than decaying and turning into the grandfather paradox. Also, the idea of free will is already an incoherent concept for several reasons without bringing time travel into it to see directly how immutable it is... And, honestly, I think you have more control over things when you're deterministic than when you're random. Events being both determined by systems followed since earlier initial states (determinism) and spontaneous/unpredictable initial states (random) are still technically out of your control though. The thing you're supposed to do to make the most of such a reality is embrace causality
The problem with the first point is that while it resolves the issue with the logical consistency of the Bootstrap Paradox, all of a sudden, we don't have a "choice" as we'd have with our common ideas of free will. (But I noticed that you don't mind determinism and free will coexisting so maybe this isn't a problem for you which is ok) Now, maybe this doesn't align with the way you see philosophy, but some people believe that predetermined events essentially mean acting is pointless; events are guided by "fate" (I believe the idea is called fatalism). The reason I bring up time travel is that it implies the future already exists in stone, events are predetermined, and then fatalism suggests there's a futility to acting. Of course, you can believe differently, that's fine. The video was meant to portray a perspective I thought was interesting.
@@jasonmayo I'm not a compatibilist, actually, but even though activity is predetermined, action isn't really futile - it's causal. As long as we're conscious and care about something, we may as well do something with that care and make our lives worth living while we live them, since my theory of consciousness has it looping through beings in incrementally-diverging parallel universes and mathematical structures. And my understanding of reality is that everything is already set in stone, even to a high hypercosmological level, especially in this universe since it's a mathematical structure. But perhaps our ignorance of the future makes things way less complicated for us. If we had could affect the past and have access to the future, we would probably be in a timeline iteration where all of us are either sure or helpless about what we're going to do, so the timeline doesn't iterate any more. (It's that theory where interaction with past and future events iterates the timeline until it falls into a stable time loop - and maybe a scenario like the double-bind/grandfather paradox would coalesce into a superpositional timeline, if it's possible)
probably the most coherent form of time travel (at least as coherence relates to our existing biased understanding of reality and free will) is where you can only travel to the past, and every time you do you create a new timeline-essentially you are custom-crafting a brand new universe from a previous snapshot of our current universe + another you (or possibly you are only transferring your consciousness over to yourself from the past? That would mean you can only go as far back as your age). I don't know if it would even be acceptable to allow you to return to your original timeline, at least not bringing anything new in with you, including memory and experience, otherwise things srart to smell paradoxical
Oh do you mean like Groundhog Day/Primer type of time travel? That's also interesting to think about and potentially an oversight on the video, but I think they run into similar issues. In Primer, anyone can go back into time as far back as the machine was created. But I think it reads as a type of "multiversey" type of time travel because there would be versions of characters that "were the original". That is, you couldn't trace back the timeline infinitely far back, so not a Bootstrappy time travel. The interesting thing, though, is that in Primer, there seems to be only one time line. But, because the past always seems to happen the same way if the time travelers don't alter anything, then you run into the same issue of "free will" where life kind of seems like a movie. But since time travel is not an ability unique to our characters, that is anyone could use the time machine, then you could generalize the problem, in a sense. That is, if I go back in time and everything happens the same way, that means nobody had "free will". But if you go back and everything happens the same way, then I never had any "free will". (Of course, depending on how the time traveler decides to do things). Groundhog Day is an interesting one because it's like Primer but for one person. So everyone else has "no free will" while the main character (idk never watched it) is the only one that can ever act freely, because we know everything else happens the same way if he doesn't intervene (ok I lied, I saw that one clip where he explains everything in detail as it happens). Meaning he's essentially the only character with free will that we couldn't immediately dismiss. Sorry I just woke up, so I might sound a little confused.
@@jasonmayo those are good points. I'm not sure though if choosing the same path in the same circumstances is necessarily contradictory with free will. After all if you ask someone after they made their decision they would say they evaluated all options and came to the conclusion that one was superior, so why should they choose any different in any other timeline? If people made different decisions every time you went back you could still argue there is no free will and every choice we make is really random. Although, making the same decisions every time implies determinism, which certainly is at odds with how we usually think of free will. I am not sure if any result after travelling to the past would really be indicative of free will, so it might just be an untestable hypothesis.
Good point, I guess it comes down to what you'd consider to be free will. Because, like you said, it could come down to "They're the same person, of course they'll make the same choice again" but it could also be like "Oh, if the future exists, then things already have a predetermined path" which I believe some people would consider to at least toe the line between free will. But like I said, this is just a poor philosophy take that I felt like making, it's more so supposed to be food for thought, which I'm glad made you bring up some interesting points :)
@@jasonmayo Well, adding my 2 cents to the discussion, like in Groundhog, if you could send your consciousness to the past with the new experiences/memories you have, I don't think any non godly being could make the same decisions to have the same outcome as once did because the butterfly effect. I also would argue that free will exists for everyone even on this scenario because as the butterfly effect grows, every being on the universe will make decisions slightly different from before because of their new enviroment being different physically or like 1 second after or later that what it was before. If quantum fluctuations are a thing and things REALLY random exists, then at the very fundamental level, we don't have determinism.
Sorry, not trying to argue, just clarifying a few points. I believe your points are valid, I'm just explaining "the other side". I don't actually have a solid take on the topic, but I have considered both possibilities. That's a very good point. I guess I was stuck on the idea that if you did nothing, everything would happen the same way. But, like you said, everyone does make different decisions if the main character interacts with them differently. But the main point of philosophy is that an alternate future has already happened in some capacity, which leaves room for the whole question. First, you could imagine that if the main character did everything the same, it would be kind of like watching movie, although like previously discussed in the comment chain, this can be seen as free will, or can be seen as predetermined events happening, that's the philosophy part. Groundhog Day is unique in the fact that the main character can alter the trajectory of the timeline. But this alteration happens in a very predictable manner. The same alteration results in the same outcome, kind of like a bunch of slightly different takes of the same movie. I believe the main point is "Does the future already existing mean that events are predetermined?" To some people that's yes. To others that's no. It's also related to the "fate/destiny" trope in other parts of fiction, where characters have to "break" what the future predicts for them. Do they have the free will to determine their own future or is everything set in stone? I'm using a similar line of thinking for time travel in this video. Also, you could still technically have quantum mechanics with determinism, think of it like a random seed in a video game. Boot up the game with the same starting conditions and we'd have the same random events happen. But we can't really verify that in our universe experimentally, because rebooting the universe would destroy any information gained from that experiment; it'd be impossible to test if quantum mechanics really existed as a random seed.
The thing is all outcomes of all possible futures past and present exist, it's still free will as our subjective stream of consciousness still gets to choose the path it takes even if infinite other versions of you choose different outcomes. Saying it's not freewill is like saying you can predict the future because you know a coin will land on either heads or tails. Sure you know that both outcomes do occur in two seperate timelines but which one it lands on for your individual stream of consciousness is still indeterminate to you as you cannot guess for certain which you will experience. Just because all outcomes happens doesn't mean you don't have freewill.
I mean... that makes free will kinda meaningless. If we could choose deliberately and voluntarily, we'd probably eventually get to choosing the most ideal timebranch for ourselves every single time. Or there would be some system set in stone that we don't have access to. Otherwise, it would be totally random...
I'm not saying this because I think you're wrong; I believe you have a valid viewpoint. I'm saying this because I feel like you've quickly dismissed another viewpoint which I'd still consider valid too. From the perspective of somebody only looking at one timeline, I'd agree with you. But I don't think it's so obviously definitive when you consider all timelines as a whole. If everything that can happen happens, then you introduce a sense of fatalism into the problem. Things are fated to play out in every possible way, so is there a point in acting if there's gonna be a different timeline where you act the other choice? Use the apple example I provided. If I choose to pick up the apple, then from my perspective, the other me had no choice but to not pick up the apple, since all possible choices happen. But the same applies from the perspective of me not picking up the apple. They'd have "chosen" to not pick up the apple, which essentially means I'd appear to have no choice but to pick up the apple. Because there has to be a situation where at least somebody makes the other choice if the other choice is possible. And in the case for infinite parallel timelines, with an infinite amount of yous picking up the apple and not picking it up, they'd still have to follow some form of ratio based on the probability of you picking up the apple. Which introduces the same idea as I've mentioned, but on an infinitely larger scale.
@@FireyDeath4 It's like if I gave you the choice to go down two paths which each have a 50% chance of having another. Then told you somewhere out there in the infinite multiverse there's a version of you which chose to go down the other path for one reason or another. That version of you while equally real as you is not your subjective experience of reality and might as well be an entirely different person as theoretically I could put you in the same room. Until you make your choice those in the future are not you. Simply outlining every possibility doesn't remove freewill, it still gives you a choice. You're also conflating every possible outcome with every choice for example if I told you down each path there's a 50% chance of an additional path that remains out of your control but each outcome of there being an extra path or not still happens. Given infinite possibilities you're bound to choose one way or another for some reason not out of compulsion but simply because it's possible even if unlikely it still will happen infinite times.
@@jasonmayo There's a reality in which you're me, you were born to my parents, you lived my life, picked up my interests and did everything I did. But here you are not me because your subjective view is from your life. Are you still me then? It's similar to superposition the only truth is your own subjective reality when measured now. It's like the Library of Babel, it does contain every single possible piece of literature but it doesn't mean we can use it to cure cancer or unravel the universes greatest mysteries or look at the news from a month from now. Simply the fact that it exists doesn't mean it impacts our own subjective reality. It's not out of compulsion that we end up on all possibilities we're the monkey at the typewriter with the infinite lives we live one was bound to choose slightly differently in one are.
@@jasonmayo Imagine someone threw a ball to you and you decide to not try and catch it because all possibilities happen even in which you don't try it will land in your hand. It exists out there in infinite realities where you succeeded and caught it despite not attempting to however a greater infinite of realities exist where you don't catch the ball because you didn't try, that's fatalism. You're still governed by probability because it's your subjective reality, all other outcomes can be disregarded just as when we finally define something in a state of superposition we don't continue to account for the other positions despite them actually existing as well in other realities. The Future Exists in a state of Superposition to you but it's still governed by probability and likelihood so you still get to interact with it and have freewill by changing probabilities.
That would raise some additional issues because a person travelling back in time would also be "reversed" if entropy is reversed. And while that could be fine, it would at least impose some very interesting writing constraints, like a person comes from the future but doesn't understand why.
Free will is an illusion, but it is also still free will, you make decisions based on your brain being a decision-making machine. But it's still just a machine bound by physics, so the same exact input results in the same outcome. However, it takes in all its input, meaning that even knowledge of this process can affect the outcomes such as choosing to do something illogical to prove your sense of free will to yourself. If we could get knowledge from the future, then it would cause paradoxes as once it becomes input you can do any number of things to circumvent the future if that is your goal. i.e. you learn you are going to sleep with your mother and kill your father so instead you promptly drown yourself in the river to avoid it. No way that could lead to the described future. My solution to this paradox: The future doesn't exist yet. Yes, it's all deterministic, but the universe is like a massive universe sized computer running calculations to find out what happens, and the whole system is mathematically chaotic, so it needs to happen one step at a time to find out how it ends. Every single thing effects every single other thing in one giant butterfly effect. It has to play out in order, you can't skip to a later point.
Thats also, I believe, why we experience a "present moment" even though relativity tells us time can move differently depending on the reference frame. But what we experience is the universe actively calculating what happens next with every particle.
Yeah I suppose I made that point very poorly. If we operate under the assumption of "everything has a cause and effect" then the big band would be an outlier, and effect without cause. So, under the assumption of cause and effect, you'd have to mathematically "extend the timeline" infinitely outwards to have a cause and effect for everything. But that leads to the issue described in the video. Also, I'm pretty sure it's technically ambiguous if time existed before the big bang, since events that occurred around that time are muddy, at best. It could be that spacetime was how it is today, got "scrunched up" for some reason, and started the big bang. That'd likely be mathematically plausible in some sense and not really possible to test, given how little we know about the laws of physics during that period.
Free will is the problem. Give up the illusion. Or not. Depending on what happens.
Fair point, free will is overrated, I'd suppose. Or am I saying that because this action was predetermined due to a fundamental lack of free will?
I disagree to some extent considering my definition of free will is the freedom of choice. And time travel is one of those things that can have freedom of choice give you dire consequences.
Endgame is the only movie that fixes this problem. when they time travel, the past they're seeking becomes their future. Which means they haven't been in the place of their past selves it's a different timeline entirely
just because someone knows youll make a choice doesnt mean you didnt choose to do it
The idea is sort of tied to fatalism. If events are predetermined to happen, since the future exists and is essentially set in stone, then is it really your choice, or has it always been "fated" to happen that way?
@@jasonmayo thats true even if theres no time travel
This sounds to me like some form of popularization of fatalism? Regardless of whether it's a subliminal message or not, it's a pretty good video.
I guess so, never paid much attention to philosophical stuff. But a future that has already happened sounds exactly like determinism and we'd be pretty powerless to stop events from occurring, if they'd already occurred. But it's possible that I might be stupid.
Glad you enjoyed it though.
Mechanical hands are the ruler of everything...
Ok, I just searched up your comment. Not sure if it's a song reference or just a major coincidence. But I guess it doesn't matter.
Do you like how i dance? Ive got zirconium pants
LOVE OF THE S*N
@@jevilcatfan123 came back again to make it clear that he never said he would be the man (if thats what youre referencing)
@BeeOnAScreen Weak & strong & wet & dry & right & wrong & live & die & sane & gone & love & not & all the &'s that we forgot
wow its funny that at the same as this video was released I also was thinking about time travel, coincidance? I THINK NOT!
Anyways very epic video as always!
Keep up the great work! ♥
Glad you liked it! Also, it would be a huge coincidence if you happened to be thinking about poetry next...
@jasonmayo How did you know...?
@@komi8362 wait really?
@@jasonmayo yeah
Well shoot, I guess that means we're the same person then
I mean, a good way to make the bootstrap paradox at least consistent is to - in the book's chronology - write the book using a future copy of the book as reference, send it to your past self, use the book, then use it for the reference, instead of reuse it hoping it continuously stays the same rather than decaying and turning into the grandfather paradox.
Also, the idea of free will is already an incoherent concept for several reasons without bringing time travel into it to see directly how immutable it is... And, honestly, I think you have more control over things when you're deterministic than when you're random. Events being both determined by systems followed since earlier initial states (determinism) and spontaneous/unpredictable initial states (random) are still technically out of your control though. The thing you're supposed to do to make the most of such a reality is embrace causality
The problem with the first point is that while it resolves the issue with the logical consistency of the Bootstrap Paradox, all of a sudden, we don't have a "choice" as we'd have with our common ideas of free will. (But I noticed that you don't mind determinism and free will coexisting so maybe this isn't a problem for you which is ok)
Now, maybe this doesn't align with the way you see philosophy, but some people believe that predetermined events essentially mean acting is pointless; events are guided by "fate" (I believe the idea is called fatalism). The reason I bring up time travel is that it implies the future already exists in stone, events are predetermined, and then fatalism suggests there's a futility to acting. Of course, you can believe differently, that's fine. The video was meant to portray a perspective I thought was interesting.
@@jasonmayo I'm not a compatibilist, actually, but even though activity is predetermined, action isn't really futile - it's causal. As long as we're conscious and care about something, we may as well do something with that care and make our lives worth living while we live them, since my theory of consciousness has it looping through beings in incrementally-diverging parallel universes and mathematical structures. And my understanding of reality is that everything is already set in stone, even to a high hypercosmological level, especially in this universe since it's a mathematical structure. But perhaps our ignorance of the future makes things way less complicated for us. If we had could affect the past and have access to the future, we would probably be in a timeline iteration where all of us are either sure or helpless about what we're going to do, so the timeline doesn't iterate any more. (It's that theory where interaction with past and future events iterates the timeline until it falls into a stable time loop - and maybe a scenario like the double-bind/grandfather paradox would coalesce into a superpositional timeline, if it's possible)
probably the most coherent form of time travel (at least as coherence relates to our existing biased understanding of reality and free will) is where you can only travel to the past, and every time you do you create a new timeline-essentially you are custom-crafting a brand new universe from a previous snapshot of our current universe + another you (or possibly you are only transferring your consciousness over to yourself from the past? That would mean you can only go as far back as your age). I don't know if it would even be acceptable to allow you to return to your original timeline, at least not bringing anything new in with you, including memory and experience, otherwise things srart to smell paradoxical
Oh do you mean like Groundhog Day/Primer type of time travel? That's also interesting to think about and potentially an oversight on the video, but I think they run into similar issues. In Primer, anyone can go back into time as far back as the machine was created. But I think it reads as a type of "multiversey" type of time travel because there would be versions of characters that "were the original". That is, you couldn't trace back the timeline infinitely far back, so not a Bootstrappy time travel. The interesting thing, though, is that in Primer, there seems to be only one time line. But, because the past always seems to happen the same way if the time travelers don't alter anything, then you run into the same issue of "free will" where life kind of seems like a movie. But since time travel is not an ability unique to our characters, that is anyone could use the time machine, then you could generalize the problem, in a sense. That is, if I go back in time and everything happens the same way, that means nobody had "free will". But if you go back and everything happens the same way, then I never had any "free will". (Of course, depending on how the time traveler decides to do things).
Groundhog Day is an interesting one because it's like Primer but for one person. So everyone else has "no free will" while the main character (idk never watched it) is the only one that can ever act freely, because we know everything else happens the same way if he doesn't intervene (ok I lied, I saw that one clip where he explains everything in detail as it happens). Meaning he's essentially the only character with free will that we couldn't immediately dismiss.
Sorry I just woke up, so I might sound a little confused.
@@jasonmayo those are good points. I'm not sure though if choosing the same path in the same circumstances is necessarily contradictory with free will. After all if you ask someone after they made their decision they would say they evaluated all options and came to the conclusion that one was superior, so why should they choose any different in any other timeline? If people made different decisions every time you went back you could still argue there is no free will and every choice we make is really random. Although, making the same decisions every time implies determinism, which certainly is at odds with how we usually think of free will. I am not sure if any result after travelling to the past would really be indicative of free will, so it might just be an untestable hypothesis.
Good point, I guess it comes down to what you'd consider to be free will. Because, like you said, it could come down to "They're the same person, of course they'll make the same choice again" but it could also be like "Oh, if the future exists, then things already have a predetermined path" which I believe some people would consider to at least toe the line between free will. But like I said, this is just a poor philosophy take that I felt like making, it's more so supposed to be food for thought, which I'm glad made you bring up some interesting points :)
@@jasonmayo Well, adding my 2 cents to the discussion, like in Groundhog, if you could send your consciousness to the past with the new experiences/memories you have, I don't think any non godly being could make the same decisions to have the same outcome as once did because the butterfly effect. I also would argue that free will exists for everyone even on this scenario because as the butterfly effect grows, every being on the universe will make decisions slightly different from before because of their new enviroment being different physically or like 1 second after or later that what it was before. If quantum fluctuations are a thing and things REALLY random exists, then at the very fundamental level, we don't have determinism.
Sorry, not trying to argue, just clarifying a few points. I believe your points are valid, I'm just explaining "the other side". I don't actually have a solid take on the topic, but I have considered both possibilities.
That's a very good point. I guess I was stuck on the idea that if you did nothing, everything would happen the same way. But, like you said, everyone does make different decisions if the main character interacts with them differently. But the main point of philosophy is that an alternate future has already happened in some capacity, which leaves room for the whole question. First, you could imagine that if the main character did everything the same, it would be kind of like watching movie, although like previously discussed in the comment chain, this can be seen as free will, or can be seen as predetermined events happening, that's the philosophy part. Groundhog Day is unique in the fact that the main character can alter the trajectory of the timeline. But this alteration happens in a very predictable manner. The same alteration results in the same outcome, kind of like a bunch of slightly different takes of the same movie.
I believe the main point is "Does the future already existing mean that events are predetermined?" To some people that's yes. To others that's no. It's also related to the "fate/destiny" trope in other parts of fiction, where characters have to "break" what the future predicts for them. Do they have the free will to determine their own future or is everything set in stone? I'm using a similar line of thinking for time travel in this video.
Also, you could still technically have quantum mechanics with determinism, think of it like a random seed in a video game. Boot up the game with the same starting conditions and we'd have the same random events happen. But we can't really verify that in our universe experimentally, because rebooting the universe would destroy any information gained from that experiment; it'd be impossible to test if quantum mechanics really existed as a random seed.
The thing is all outcomes of all possible futures past and present exist, it's still free will as our subjective stream of consciousness still gets to choose the path it takes even if infinite other versions of you choose different outcomes. Saying it's not freewill is like saying you can predict the future because you know a coin will land on either heads or tails. Sure you know that both outcomes do occur in two seperate timelines but which one it lands on for your individual stream of consciousness is still indeterminate to you as you cannot guess for certain which you will experience. Just because all outcomes happens doesn't mean you don't have freewill.
I mean... that makes free will kinda meaningless. If we could choose deliberately and voluntarily, we'd probably eventually get to choosing the most ideal timebranch for ourselves every single time. Or there would be some system set in stone that we don't have access to. Otherwise, it would be totally random...
I'm not saying this because I think you're wrong; I believe you have a valid viewpoint. I'm saying this because I feel like you've quickly dismissed another viewpoint which I'd still consider valid too.
From the perspective of somebody only looking at one timeline, I'd agree with you. But I don't think it's so obviously definitive when you consider all timelines as a whole. If everything that can happen happens, then you introduce a sense of fatalism into the problem. Things are fated to play out in every possible way, so is there a point in acting if there's gonna be a different timeline where you act the other choice? Use the apple example I provided. If I choose to pick up the apple, then from my perspective, the other me had no choice but to not pick up the apple, since all possible choices happen. But the same applies from the perspective of me not picking up the apple. They'd have "chosen" to not pick up the apple, which essentially means I'd appear to have no choice but to pick up the apple. Because there has to be a situation where at least somebody makes the other choice if the other choice is possible.
And in the case for infinite parallel timelines, with an infinite amount of yous picking up the apple and not picking it up, they'd still have to follow some form of ratio based on the probability of you picking up the apple. Which introduces the same idea as I've mentioned, but on an infinitely larger scale.
@@FireyDeath4 It's like if I gave you the choice to go down two paths which each have a 50% chance of having another. Then told you somewhere out there in the infinite multiverse there's a version of you which chose to go down the other path for one reason or another. That version of you while equally real as you is not your subjective experience of reality and might as well be an entirely different person as theoretically I could put you in the same room. Until you make your choice those in the future are not you. Simply outlining every possibility doesn't remove freewill, it still gives you a choice. You're also conflating every possible outcome with every choice for example if I told you down each path there's a 50% chance of an additional path that remains out of your control but each outcome of there being an extra path or not still happens. Given infinite possibilities you're bound to choose one way or another for some reason not out of compulsion but simply because it's possible even if unlikely it still will happen infinite times.
@@jasonmayo There's a reality in which you're me, you were born to my parents, you lived my life, picked up my interests and did everything I did. But here you are not me because your subjective view is from your life. Are you still me then? It's similar to superposition the only truth is your own subjective reality when measured now. It's like the Library of Babel, it does contain every single possible piece of literature but it doesn't mean we can use it to cure cancer or unravel the universes greatest mysteries or look at the news from a month from now. Simply the fact that it exists doesn't mean it impacts our own subjective reality. It's not out of compulsion that we end up on all possibilities we're the monkey at the typewriter with the infinite lives we live one was bound to choose slightly differently in one are.
@@jasonmayo Imagine someone threw a ball to you and you decide to not try and catch it because all possibilities happen even in which you don't try it will land in your hand. It exists out there in infinite realities where you succeeded and caught it despite not attempting to however a greater infinite of realities exist where you don't catch the ball because you didn't try, that's fatalism. You're still governed by probability because it's your subjective reality, all other outcomes can be disregarded just as when we finally define something in a state of superposition we don't continue to account for the other positions despite them actually existing as well in other realities. The Future Exists in a state of Superposition to you but it's still governed by probability and likelihood so you still get to interact with it and have freewill by changing probabilities.
The entropy problem would be solved if the act of time travel reverses said entropy.
That would raise some additional issues because a person travelling back in time would also be "reversed" if entropy is reversed. And while that could be fine, it would at least impose some very interesting writing constraints, like a person comes from the future but doesn't understand why.
Free will is an illusion, but it is also still free will, you make decisions based on your brain being a decision-making machine. But it's still just a machine bound by physics, so the same exact input results in the same outcome. However, it takes in all its input, meaning that even knowledge of this process can affect the outcomes such as choosing to do something illogical to prove your sense of free will to yourself.
If we could get knowledge from the future, then it would cause paradoxes as once it becomes input you can do any number of things to circumvent the future if that is your goal. i.e. you learn you are going to sleep with your mother and kill your father so instead you promptly drown yourself in the river to avoid it. No way that could lead to the described future.
My solution to this paradox: The future doesn't exist yet.
Yes, it's all deterministic, but the universe is like a massive universe sized computer running calculations to find out what happens, and the whole system is mathematically chaotic, so it needs to happen one step at a time to find out how it ends.
Every single thing effects every single other thing in one giant butterfly effect. It has to play out in order, you can't skip to a later point.
Thats also, I believe, why we experience a "present moment" even though relativity tells us time can move differently depending on the reference frame. But what we experience is the universe actively calculating what happens next with every particle.
Time is not fundamental thus you cannot infinitely extend time backwards
Yeah I suppose I made that point very poorly. If we operate under the assumption of "everything has a cause and effect" then the big band would be an outlier, and effect without cause. So, under the assumption of cause and effect, you'd have to mathematically "extend the timeline" infinitely outwards to have a cause and effect for everything. But that leads to the issue described in the video.
Also, I'm pretty sure it's technically ambiguous if time existed before the big bang, since events that occurred around that time are muddy, at best. It could be that spacetime was how it is today, got "scrunched up" for some reason, and started the big bang. That'd likely be mathematically plausible in some sense and not really possible to test, given how little we know about the laws of physics during that period.
how long does it go if you cant infinitely extend it