A new time-travel paradox? (similar to the Grandfather paradox)

[AUSloth]

Originally Posted by Darwinsbulldog

Well, you can theoretically build a time machine according to Paul Davies, as he argues that Einsteinian relativity allows it. It is just impractical. You need to form a cylinder of about 3000 neutron stars spinning at 2/3rds C. An admittedly huge task, which may be impossible. [Your "house-keeping rule, AUSloth?]

Sounds like a great after hours project , let's get cracking
The "house keeping" was phrased post time machine invention to stay in tune with the OP but if constructing one is impossible that's essentially the same thing. Before and after get confused when it is invented anyway

But what of quantum-tunnelling? This phenomenon appears to be FTL, thus breaking the causality rule? [Effect before cause].

To my knowledge it appears FTL but like all quantum level effects only Dippy Chopra can get it to apply on anything of scale.

If we did morph into a different individual after killing an ancestor, it would have to be FTL so that our universe would not "notice" it?

I don't think it a matter of morphing more a case of reaching a split in the road and following a different path. The time line where you lived prior to clocking gramps is already sans your presence while you do the deed and you never go back it continues as an alternate without you. Your off on another (at this point) closely related time line.
As an aside I think this multiple-parallel time line idea would make some neat Sci-Fi If you could tie a universal property related to gravity that exists across the barriers that separate the time lines you could call it dark energy/matter and explain the universe

[cjhimaa]

Your right AUSloth did mention it before, but if A retains the memory of B the he would be in the shit, because he would know who the dead man is and who killed him, even if he got back to the future, there would be still no B and he would be still wanted for the murder of the man in the past.

chris

[GenericBox]

Okay, so just to clarify - I was talking from the theory that there is only a single timeline, and our travellers A, B (and/or) C, went back in time on this single stream, therefore providing an environment for the grandfather paradox to be true.

But I've been thinking again..

Even on a single-timeframe, what if there is no paradox?

To suggest that killing a grandfather would result in a paradox, would suggest that we as humans are "connected" in some way to time.

I mean, just because his grandfather is killed - the atoms that make up his body in the new time could not simply cease to exist.

His atoms are now there, in the past, regardless of what events happen in his past.

Even his memories should remain in tact of the life he led before killing his grandfather - because our memories are not linked to time itself but are only the result of chemical reactions and pulses in our brain.

Regardless of whether he is born or not, his brain structure and by extension that brain chemistry/electrical circuits are present at this moment.

When he goes back to the future, sure - the future might not know who he is, or even remember sending him back in time to begin with - but his atoms would still exist (provided thats how the technology works).

So basically, what I'm trying to say, is that even if time-travellers went back in time on the same, singular timeline and changed something, it would not affect them (in terms of their physical makeup of atoms), even if the world they return to remembers sending completely different atoms back in time.

Then that begs the question. If they change something - and the future world sends C and D back in time. What happens to C and D when A and B return?

Would their time travel machine continuously return E and F and G and H until one pair of time-travellers managed to not change anything?

[Darwinsbulldog]

What makes people assume that memories would survive time-travel? If the "many worlds" interpretation is correct, quantum interactions could reverse causality. Humans are quantum interactors also. Admittedly, humans and other macro objects 'vote" as a quantum "block". But surely there is "no arrow of time" at the quantum level? But there is an arrow of time to gravitation. So perhaps "quantum gravity" is just a deepity?


But our universe is just an "opinion" of many possible realities. The particles in this universe merely agree with each other. In other universes, the particles there would reach an agreement also. Of course, this might mean that time travel is still impossible, because in violating our own time line, we leave this universe to join another.

This explains why Paul Davies' time machine is both theoretically possible but practically impossible. It is not a time travel machine, but an alternate universe travel machine.

[AUSloth]

@ DB - yep i'm pretty sure i live in an opinionated universe

[Xeno]

Originally Posted by AUSloth

@ DB - yep i'm pretty sure i live in an opinionated universe

No, not in my opinion.

[Darwinsbulldog]

Originally Posted by AUSloth

@ DB - yep i'm pretty sure i live in an opinionated universe

Are u mocking my fact-free bullshit?

[AUSloth]

Originally Posted by Darwinsbulldog

Are u mocking my fact-free bullshit?

That could be one opinion I guess

[nibble]

What if A has sex with B's grandfathe has a child, they both return to the present (A and child), then B kills his grandfather as well as As.

I'm starting to think that time travel is bullshit.

[Aldaron]

When he goes back to the future, sure - the future might not know who he is, or even remember sending him back in time to begin with

+1

This has always been my answer to the GP - you go back and kill your grandfather. You (and anyone with you) retain the memory of your grandfather's murder, because the neural connections that form that memory don't magically vanish when you return to your own time...except your own time is now completely different. In it, you remember your past (which included your grandfather), but nobody else does (except those who were "out of time" when you changed the timeline; ie: your chrononautical companions) because, for them, your grandfather died seventy years ago and you never existed...though you do look suspiciously like some old "Wanted!" posters from the 1930s...