Grandfather Paradox Resolved?

[DrmDoc]

The host of this MinutePhysics YouTube video says that if time travel were possible something called Quantum Supposition suggests that one could kill his or her grandfather from an earlier time and not vanish from existence as a consequence. To those of you who are more knowledgeable than I on the relevant theoretical physics, what are your thoughts? Are the host's assertions valid?

[Raider5678]

The host of this MinutePhysics YouTube video says that if time travel were possible something called Quantum Supposition suggests that one could kill his or her grandfather from an earlier time and not vanish from existence as a consequence. To those of you who are more knowledgeable than I on the relevant theoretical physics, what are your thoughts? Are the host's assertions valid?

Well, I probably know less then you. My thoughts is that if time travel into the past were possible, then killing one's grandfather wouldn't matter because you would already be feeling the affects, meaning you already did it, so it never happened kind of, it's just....... it's tough to explain.

[fiveworlds]

then killing one's grandfather wouldn't matter because you would already be feeling the affects, meaning you already did it

 

I'd be leaning more towards traveling into the past would really put you in a parallel universe in which you appeared from the future. This means that even if you killed your own grandfather in that universe you cannot kill your own grandfather from your own universe.

[DrmDoc]

 

I'd be leaning more towards traveling into the past would really put you in a parallel universe in which you appeared from the future. This means that even if you killed your own grandfather in that universe you cannot kill your own grandfather from your own universe.

 

This host mentioned that as an alternative; however, he specifically suggested that Quantum Supposition supposed his continued existence even if the grandfather killed belonged to his universe--kind of a twist on Shroedinger's Cat with granddad being both alive and dead.

Edited May 16, 2016 by DrmDoc

[swansont]

The host of this MinutePhysics YouTube video says that if time travel were possible something called Quantum Supposition suggests that one could kill his or her grandfather from an earlier time and not vanish from existence as a consequence. To those of you who are more knowledgeable than I on the relevant theoretical physics, what are your thoughts? Are the host's assertions valid?

 

 

It's quantum superposition. In general, the concept is presented correctly, but it's not like you're going to get a rigorous workup in a short video.

[DrmDoc]

 

 

It's quantum superposition. In general, the concept is presented correctly, but it's not like you're going to get a rigorous workup in a short video.

 

My bad, these old eyes and ears sometimes see and hear what I think rather than what is presented...so...is what the host said plausible with time travel a reality?

Edited May 16, 2016 by DrmDoc

[swansont]

 

My bad, these old eyes and ears sometimes see and hear what I think rather than what is presented...so...is what the host said plausible with time travel a reality?

 

 

Like I said, there is a concept of superposition, but it tends not to hold at the scale of macroscopic objects. However, it's as plausible as the many-worlds scenario he (ironically) dismissed as being uninteresting, since one could view it as a variation on that idea.