Time travelling is impossible.

[HexHammer]

How can something in layman's terms be incoherent? It's like insulting yourself to say that you can't understand my teachings. What exactly don't you understand? Or is this just bloated HexHyperbole meant to irritate me.

/FACEPALM!!!

[GreatandWiseTrixie]

How can something in layman's terms be incoherent?

Or is this just bloated HexHyperbole meant to irritate me.

When everything you post is word salad in layman's terms.

It seems to be working.

There seems to be an aversion to salad and nutritious things. The cultural aversion to nutrition is not limited to just food, but to words as well.

How can something in layman's terms be incoherent? It's like insulting yourself to say that you can't understand my teachings. What exactly don't you understand? Or is this just bloated HexHyperbole meant to irritate me.

/FACEPALM!!!

As I suspected, its not that you can't understand, it's that you dont want to. If you actually wanted to understand something you would send me a quote of something needed to be clarified. As such, this discussion is over, it's a waste of energy for me to humor the likes of you any further.

[thedoc]

As such, this discussion is over, it's a waste of energy for me to humor the likes of you any further.

Promise? Or are you just teasing us again.

[HexHammer]

How can something in layman's terms be incoherent? It's like insulting yourself to say that you can't understand my teachings. What exactly don't you understand? Or is this just bloated HexHyperbole meant to irritate me.

/FACEPALM!!!

As I suspected, its not that you can't understand, it's that you dont want to. If you actually wanted to understand something you would send me a quote of something needed to be clarified. As such, this discussion is over, it's a waste of energy for me to humor the likes of you any further.

No, the simple truth is that you are a mental case, so you babble and rave, because of your mental state, simple as that!

[GreatandWiseTrixie]

As I suspected, its not that you can't understand, it's that you dont want to. If you actually wanted to understand something you would send me a quote of something needed to be clarified. As such, this discussion is over, it's a waste of energy for me to humor the likes of you any further.

No, the simple truth is that you are a mental case, and babble and rave, because of mental state, simple as that!

You seem like a character in a movie, one of those old fat british guys with a monocle and pipe, a scholar, who just says "preposterous" to anything he doesn't want to hear.

[mesoraven]

So back on topic,

I agree a little with OP. If Hitler had originally lived then some one came back and killed him then we "the us of the current time period) would not see a change. Because for us it hasn't happened yet. So we create the future.

The then predetermined future known by the traveller would exist only in his head. Unless you accept the alternate universe/timeline theory in which case he has gone from his timeline in the future to a convergent point in the past. And then jumped into a new timeline future.

If you stick to one time line then he has not altered the past but rather altered the future.

In time travel I'd say the perception of time, of what is the past the present and the future is relative. The past has already happened the present is non existing and the future has not yet been written. Only someone who leaves the stream of time yet stays within the space will perceive the difference.

But as space and time are connected and intertwined in a way we cannot yet fully understand......

[David Handeye]

So back on topic,

I agree a little with OP. If Hitler had originally lived then some one came back and killed him then we "the us of the current time period) would not see a change. Because for us it hasn't happened yet. So we create the future.

The then predetermined future known by the traveller would exist only in his head. Unless you accept the alternate universe/timeline theory in which case he has gone from his timeline in the future to a convergent point in the past. And then jumped into a new timeline future.

If you stick to one time line then he has not altered the past but rather altered the future.

In time travel I'd say the perception of time, of what is the past the present and the future is relative. The past has already happened the present is non existing and the future has not yet been written. Only someone who leaves the stream of time yet stays within the space will perceive the difference.

But as space and time are connected and intertwined in a way we cannot yet fully understand......

I agree. Thanks for your contribution.

[Lawrence Crocker]

The old shooting your grandfather paradox is no problem for forward time travel, either the pedestrian variety we regularly engage in or discontinuous leaps into the future. For the past, the three solutions I know of are (1) branching worlds, whether under quantum many worlds or some other mechanism, (2) time travel with no effects on the past -- crudely you can watch but cannot touch, (3) time travel to the past simply cannot change anything about the past that would eventuate in the particular time travel not taking place. To the time traveler circumstances would just always conspire to keep her from killing her grandfather! On reflection, she will realize that they must so conspire, or she would not have been there to get into the time machine. As I recall this solution to the paradox is due to David Lewis. It is a shame that the only way we have to talk to him about the issue would itself require time travel.

[Hobbes' Choice]

The old shooting your grandfather paradox is no problem for forward time travel, either the pedestrian variety we regularly engage in or discontinuous leaps into the future. For the past, the three solutions I know of are (1) branching worlds, whether under quantum many worlds or some other mechanism, (2) time travel with no effects on the past -- crudely you can watch but cannot touch, (3) time travel to the past simply cannot change anything about the past that would eventuate in the particular time travel not taking place. To the time traveler circumstances would just always conspire to keep her from killing her grandfather! On reflection, she will realize that they must so conspire, or she would not have been there to get into the time machine. As I recall this solution to the paradox is due to David Lewis. It is a shame that the only way we have to talk to him about the issue would itself require time travel.

1) This would entail an entire reduplication of the Universe for each instance of time travel. This would be more than prohibitive as the energy and mass requirements would be one entire universe, and there is only one.
2) The light that has emanated from the objects of your interest, has long ago been absorbed by other objects, and can no longer stimulate your retina. A moment's thought will tell you that this "solution" is, like 1., a transgression of the laws of Thermodynamics.
3) This is just absurd, and fails a basic test on cause and effect.

[Lawrence Crocker]

1) This would entail an entire reduplication of the Universe for each instance of time travel. This would be more than prohibitive as the energy and mass requirements would be one entire universe, and there is only one.
2) The light that has emanated from the objects of your interest, has long ago been absorbed by other objects, and can no longer stimulate your retina. A moment's thought will tell you that this "solution" is, like 1., a transgression of the laws of Thermodynamics.
3) This is just absurd, and fails a basic test on cause and effect.

(1) Perhaps. The partisans of the many world interpretations of quantum mechanics, however, do not think it impossible. At the other end of the size spectrum, I believe the many universes theory is the most popular current view among cosmologists, producing a rather nice account of inflation.

(2) Your comment on (2) simply assumes that no time travel to the past is possible. But that is what is at issue.

(3) If an instance of time travel takes place, then nothing physically inconsistent with its taking place transpired in the future. The world might seem an odd one to the time traveler, but there will be no violation of classical notions of cause and effect. (Those classical notions, however, have themselves been rather beat up by quantum theory. It may not be a good strategy to base judgments of what is absurd upon them.)

[Hobbes' Choice]

1) This would entail an entire reduplication of the Universe for each instance of time travel. This would be more than prohibitive as the energy and mass requirements would be one entire universe, and there is only one.
2) The light that has emanated from the objects of your interest, has long ago been absorbed by other objects, and can no longer stimulate your retina. A moment's thought will tell you that this "solution" is, like 1., a transgression of the laws of Thermodynamics.
3) This is just absurd, and fails a basic test on cause and effect.

(1) Perhaps. The partisans of the many world interpretations of quantum mechanics, however, do not think it impossible. At the other end of the size spectrum, I believe the many universes theory is the most popular current view among cosmologists, producing a rather nice account of inflation.

(2) Your comment on (2) simply assumes that no time travel to the past is possible. But that is what is at issue.

(3) If an instance of time travel takes place, then nothing physically inconsistent with its taking place transpired in the future. The world might seem an odd one to the time traveler, but there will be no violation of classical notions of cause and effect. (Those classical notions, however, have themselves been rather beat up by quantum theory. It may not be a good strategy to base judgments of what is absurd upon them.)

1) I disagree. No one seriously offers the many universes hypothesis as an actually cosmology without their tongue in their cheek. For sure no one is advocating the breach of the First Law of Thermodynamics that time travel of this sort would entail.

2) The phrase 'time travel' is a contradiction. It is not even wrong. It just makes no sense. The past is not a place to visit. You might as well say you can't paint a sound. There is no real "issue".
3) YES - as I said absurd. So knowing that your Hitler lived until 1945, you feel compelled not to pull the trigger on Adolf minor in 1899? By what mechanism is this policed?

[Advocate]

The universe does not contain cheat codes. There are no wormholes, no time travel, no other universe to escape to, no transcendence, no quantum loophole in causality, no souls.

[commonsense]

Time travel is already widespread. It just depends on how you think of time.

Of course, it is impossible to actually exist as your current self in past times and likewise for future times.

Obviously, but for the sake of emphasis, at the moment while I am writing these words the 24th of Sept is today, and the 25th is tomorrow. On the 25th, the 25th is today.

In other words, it is always today; it is always now. Time is a continuum of now’s.

So, yesterday was now, but it no longer is. Today, yesterday is a memory of what was then now. Similarly, tomorrow is a collection of predictions, expectations, wishes, hopes, etc.

It is not uncommon for memories of previous now’s to be revised. The first European in North America had been Christopher Columbus until Leif Ericsson took his place.

In like fashion, future expectations are often updated. Just pay attention to the odds at the racetrack as the race gets closer and closer to starting time.

Time travel is possible and is a fact currently. Memories can be rewritten. Now is always changing. And the future is not fixed until it is not the future.