Time Travel Without Mind-Bending Paradoxes?

Time Travel Without Mind-Bending Paradoxes Is Possible, Mathematical Modeling Suggests

Becky Ferreira

The new research builds on a 2019 study, co-authored by Costa, which concluded that “three parties can interact in such a way to be all both in the future and in the past of each other, while being free to perform arbitrary local operations”—in other words, without paradoxes.

“All previous attempts to study the motion of objects through these time loops have run into these paradoxes because the dominant paradigm in physics is you give a system an initial state, and then from that initial state, you calculate the full history of the system,” explained Tobar.

“If I throw a ball, I can calculate where and when it will be at any time,” he added. “But in these time loops, that just leads to a paradox.”

The 2019 study identified one logical process that allowed for time travel in CTCs without invoking the kinds of causal laws that lead to famous paradoxes. In the new research, Tobar and Costa broaden the scope of those initial findings, ultimately outlining multiple new processes and bolstering the hypothesis that paradox-free time travel may be consistent with fundamental cosmic laws.

Time Travel Without Mind-Bending Paradoxes Is Possible, Mathematical Modeling Suggests

Becky Ferreira

It seems to me that any form of time travel into the past that is free of possible paradoxes must be rather impotent: the time traveler must not be able to interact in any way with the past. This means absolutely no physical effects or for that matter any psychical effects; any such effects at all could possibly create a paradox due to the "butterfly effect" where such even micro effects could eventually spread so as to create a paradox. So it would be observation only, a useful function but still gravely limited. The time traveler would not be allowed to introduce anything from the future; he could not add anything or prevent anything either negative or positive. It would be a form of time travel useful only for historical research and possibly for the criminal justice system. The criminal justice application admittedly could be transforming of society since it would make available absolute certainty of whether a suspect is guilty or innocent. Another implication of there being something like this is that it would have to be a complicated mechanism.

It seems to me that any form of time travel into the past that is free of possible paradoxes must be rather impotent: the time traveler must not be able to interact in any way with the past. This means absolutely no physical effects or for that matter any psychical effects; any such effects at all could possibly create a paradox due to the "butterfly effect" where such even micro effects could eventually spread so as to create a paradox. So it would be observation only, a useful function but still gravely limited. The time traveler would not be allowed to introduce anything from the future; he could not add anything or prevent anything either negative or positive. It would be a form of time travel useful only for historical research and possibly for the criminal justice system. The criminal justice application admittedly could be transforming of society since it would make available absolute certainty of whether a suspect is guilty or innocent. Another implication of there being something like this is that it would have to be a complicated mechanism.

I'd agree but the paper - AFAICTell - suggest[s] time will self correct. But this also seems strange to me unless there is a separate timeline.

Of course I don't believe time travel or precognition so it's all science fantasy to me...though if we are in a Simulation/Dream and someone can hop onto a branching timeline I'd accept that...

I'd agree but the paper - AFAICTell - suggest[s] time will self correct. But this also seems strange to me unless there is a separate timeline.

Of course I don't believe time travel or precognition so it's all science fantasy to me...though if we are in a Simulation/Dream and someone can hop onto a branching timeline I'd accept that...

Issues like the causality problem and the free will problem are very bothersome, but much evidence for precognition has been accumulated in parapsychology. 

See the survey article at https://www.frontiersin.org/articles/10....00907/full :

Despite reasons for skepticism, researchers have pursued this topic, and a large database of studies conducted under controlled laboratory conditions now exist. This work roughly spans from the 1930's (e.g., Rhine, 1938) up to this day (Bem, 2011; Mossbridge et al., 2014; Rabeyron, 2014). The accumulated evidence includes significant meta-analyses of forced-choice guessing experiments (Honorton and Ferrari, 1989), presentiment experiments (Mossbridge et al., 2012), and recent replications from Bem (2011, discussed below; Bem et al., 2014).

Perhaps most central to the recent debate regarding the existence of precognition is work by Bem (2011). Bem (2011) time-reversed several classic psychology effects (e.g., studying after instead of before a test; being primed after, instead of before responding) and found evidence across nine experiments supporting precognition. Given the sound methodology and publication in a high-impact mainstream psychology journal, Journal of Personality and Social Psychology, this work has prompted the attention of psychologists...

Issues like the causality problem and the free will problem are very bothersome, but much evidence for precognition has been accumulated in parapsychology. 

See the survey article at https://www.frontiersin.org/articles/10....00907/full :

Oh I don't doubt that someone has a psychic sensory experience of an event that then happens.

I just don't think that there is a reverse arrow of causation going from Future to Present.

I recall one suggestion is that if you can peer into both the subconscious & conscious of others and gain a "God's eye" view of causation you can see events that are very likely to happen.

Oh I don't doubt that someone has a psychic sensory experience of an event that then happens.

I just don't think that there is a reverse arrow of causation going from Future to Present.

I recall one suggestion is that if you can peer into both the subconscious & conscious of others and gain a "God's eye" view of causation you can see events that are very likely to happen.

You seem to be taking the deterministic view of human consciousness - that there is no free will in a deterministic cause/effect/cause/effect world.  Free will has been discussed many times here. As far as I am concerned it exists and demonstrates that human consciousness is not subject to the laws of cause and effect - there is something ineffable and unknowable about it that allows true free will, a unique property of conscious agency not subject to clockwork determinacy. Given that, such a "God's eye" view of consciousness would not enable prediction of many human events depending on free choice of individuals. And I think some of the parapsychological experiments into precognition depended on true random number generators which are not even in principle predictable by cause and effect.

It seems to me that any form of time travel into the past that is free of possible paradoxes must be rather impotent: the time traveler must not be able to interact in any way with the past.

That's consistent with the traditional thinking on the topic, but if it ends up possible to "travel backwards" I don't see why we'd cling to this notion other than it seems rational.

Seriously, perhaps the sophistication needed to travel backwards in time makes it such that an intelligence with such a capability would be fully equipped and responsible enough to not create reality-bending paradoxes.  I have no idea what I'm talking about here of course, but I find it difficult to project limitations on things based on our current, relatively unsophisticated understanding of reality.

You seem to be taking the deterministic view of human consciousness - that there is no free will in a deterministic cause/effect/cause/effect world.  Free will has been discussed many times here. As far as I am concerned it exists and demonstrates that human consciousness is not subject to the laws of cause and effect - there is something ineffable and unknowable about it that allows true free will, a unique property of conscious agency not subject to clockwork determinacy. Given that, such a "God's eye" view of consciousness would not enable prediction of many human events depending on free choice of individuals. And I think some of the parapsychological experiments into precognition depended on true random number generators which are not even in principle predictable by cause and effect.

I don't think it's any more an argument against free will tha[n] advertising, profiling, etc.

As for random number generators that's easily just PK, or so it seems to me?

I am curious how you reconcile precognition with free will. Do you see two arrows of causation, Future -> Present and Past -> Present, coming together into a place that allows for freedom of choice?

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That's consistent with the traditional thinking on the topic, but if it ends up possible to "travel backwards" I don't see why we'd cling to this notion other than it seems rational.

Seriously, perhaps the sophistication needed to travel backwards in time makes it such that an intelligence with such a capability would be fully equipped and responsible enough to not create reality-bending paradoxes.  I have no idea what I'm talking about here of course, but I find it difficult to project limitations on things based on our current, relatively unsophisticated understanding of reality.

We could say this, but then it puts us in a challenging bind of not using logic for much of anything. For example could Physicalism be true but we simply cannot see how this is because of limitations to our brain?

I realize NDErs and mystics have talked about Time being an Illusion...I am quite skeptical of this. After all there is a "before" and "after" these experiences to start with, and more simply an illusion of change is still changing and so there is some aspect of before/after to account for in any full description of reality.