The grandpa paradox

[Albert Mond]

Originally Posted by Steppenwolf

I've heard it's possible to the past , but not to the future .

You're constantly traveling into the future. If you travel from the present to the past, the present becomes both the future and the past, as it's already happened.

[Steppenwolf]

true , true ... but where is the future of the past? It's right now?

[Godslayer Jillian]

Originally Posted by Underwater Ophelia

That was a joke, right?

You don't see why that's true?

[Albert Mond]

Originally Posted by Godslayer Jillian

You don't see why that's true?

It's not. It's an assumption that if it were possible to build a time machine, people would certainly go back in time and use it. It also assumes that human kind will undoubtedly be around long enough to build such a thing, and because they haven't built it and come back, it's impossible.

[Godslayer Jillian]

If it's not used, then what makes it a time machine?
And the number of permutations possible by the construction and use of a time machine by anything will invariably lead to a discovery of it by anything that's capable of using it.

[Underwater Ophelia]

Originally Posted by Godslayer Jillian

You don't see why that's true?

I know what you're saying. You're saying that if a time machine exists in one time, it should exist in all times. I get that. We might just not know it, so it doesn't really exist to us.

Also for some reason I thought you meant that about ALL things. Like, if a lightbulb doesn't exist, it never will.

[schoolsucksletsanarky]

Um... I was just joking, just so you all know.

[Albert Mond]

Originally Posted by Underwater Ophelia

I know what you're saying. You're saying that if a time machine exists in one time, it should exist in all times. I get that. We might just not know it, so it doesn't really exist to us.

It seems like it would only exist in all times if it were used more than once.

[Steppenwolf]

what if every posibility exist in every single piece of time?
For example , we are living now in a present which is also running the future and the past at the same time , in background . Perhaps it's necesary for keep things in order .
The fact that we don't see it doesn't mean it doesn't exist . Perhaps every single thing of every single possible universe is "written" and "stored" in every single moment of history .
Therefore , a time travel machine will exist everywhere even if for us doesn't exist or even if actually we never used it , not even though about it .

[Albert Mond]

Originally Posted by Steppenwolf

what if every posibility exist in every single piece of time?
For example , we are living now in a present which is also running the future and the past at the same time , in background . Perhaps it's necesary for keep things in order .
The fact that we don't see it doesn't mean it doesn't exist . Perhaps every single thing of every single possible universe is "written" and "stored" in every single moment of history .
Therefore , a time travel machine will exist everywhere even if for us doesn't exist or even if actually we never used it , not even though about it .

It would exist everywhere only in that sense, though. It would impossible to discover it without having it.

[Beneath the Shadows]

Several possibilities:

A causality loop: You kill your grandfather, preventing your father/mother from being born, preventing you from being born, which prevents you from going back in time and killing your grandfather, which prevents you from ceasing to exist, which enables you to go back in time where you kill your grandfather. Beyond that loop, the time-line progresses normally.

A branch: The death of your grandfather results in the creation of two separate but parallel time-lines, the one from which you came from and the one where your grandfather is dead. Both time-lines progress normally.

Predestination paradox:

Originally Posted by Tam Li Hua

...the wound doesn't kill or seriously injure your grandpa, and it ends up being the wound he told you about when you were a little kid.

The time-line continues to progress normally.

Temporal balloon goes pop: The very act of traveling through time tears the space-time continuum, resulting in the annihilation of past, present, and future.