Past, Present and Future

[--Pete]

Hi,

Why would "instantaneous" be necessary.

Because the special theory of relativity cannot handle accelerations. That's why Einstein went on to develop the general theory, because the special theory was incomplete. Only by reducing the period of acceleration to zero can you stay completely within the special theory. So, either the twin paradox requires the general theory (contradicting the quoted statement) or it requires infinite accelerations (contradicting physical reality).

I thought the Hafele-Keating experiment verified the relativistic effects of velocity.

There is no question about relativistic effects, either special or general. The details may turn out to need refinement, but within experimental error, both theories are well supported. The question is simply whether the special theory could explain the twin paradox. And the answer is 'no'.

Consider a simplified version of the paradox:
Two travelers, each in his own spaceship (i.e., 'reference frame') pass each other at a high relative velocity. By mutual arrangement, they synchronize their (perfect) clocks at the moment of closest approach. After some time, which has aged more? The question is indeterminate. Each 'sees' the other's clock running slow by the same amount. Since a universal 'now' does not exist, there is no way of comparing their relative ages that all observers would agree on. Only by bringing the two back together can we compare their ages in their local 'now'. Since they are moving apart, the only way to bring them back together is for one or both to accelerate. Unlike velocity, acceleration can be measured locally -- i.e., within the reference frame. If both accelerate by the same amount and in opposite directions, then when they pass each other, both will have experienced the same elapsed time. If one accelerates more than the other, then that one will experience a smaller elapsed time. It is the difference in the accelerations, not the velocity itself, that leads to the difference in elapsed time. Note that looking at it from this point of view, it doesn't matter if the accelerations are infinite or small. By assuming they are infinite, all the calculations can be done in special relativity.

--Pete

[Jester]

He details it in the chapter "The Experiment". Generally, he has a detailed journal of his (and later others) dreams, where he notes everything remembered from them. When he reviews the real world experiences to what was recorded in journal, and critically notes whether the event was "predictable" based upon logic, probability and reason, or probable based on current events.

Yeah, that's what I thought. Fascinating though this process may be to go through, it is essentially a machine for self-delusion, and has no scientific reliability. There are no priors. There is no threshold of significance. There is no solid definition of what constitutes a hit or a miss, and no objective method of tallying them up and comparing them to what chance alone would produce. It isn't falsifiable.

Now, it's not fair to hold someone writing in 1927 personally to standards devised in the 1930s. But it is fair to ask whether his test holds up enough to convince us today. I don't think, from your descriptions, that this is even possible, given its experimental design. It is fatally flawed - retroactively "predicting" the future with information from the past does not demonstrate precognition.

I can give you a real life example, which still has me baffled to explain... A good friend told me about a weird dream he had, meeting a woman named Mary Hastings, who was terribly worried because she had discovered she had cancer. He described her to me in great detail. In his dream he remembers telling her not to worry because her cancer would go into remission, and she would be fine. He didn't know any Mary Hastings. About a month later, a different friend of his set him up on a blind date and the woman's daughter was the Mary Hastings from his dream, and the rest of the dream unfolded. I witnessed the before and after, and I have no explanation for this event.

If I had a nickel for every anecdote of this type I've heard from perfectly intelligent people, I could buy a round for the lurkers at Atma's.

I can't speak to your good friend's memory, or the accuracy of his dreams. I can't speak to the timing of events, or to any of the details, since I wasn't there, and even if I was, I'd be far from a perfect observer.

However, even so, this is not beyond belief. As Richard Feynman never tired of pointing out, the thing that would be weird is if we never had coincidences. There are millions of people out there we bump into, thousands of whose names we learn. If we're primed to look for something, a name, a concept, we find it with a regularity that appears to defy chance, but is simply the normal result of chance, plus our left-brain's pattern solving ability.

Mary Hastings is not an uncommon name. Cancer is not uncommon in women, and when it strikes early, it will usually go into remission with treatment, even if it returns some time later. Remarkable that both things coincided, but certainly not beyond the bounds of chance.

Now think of all the dreams that never did come true, the people met who never showed up in life, the situations that turned out to be just dreams. Where do they tally against the improbability of this event? They can't even be counted, because they are not distinct. We may not be able to explain any given coincidence, but if we treat each one as an example of the impossible, we are denying the obvious result of probability - that in the long run the unlikely happens exactly in proportion to its unlikeliness, no more, no less.

-Jester

[kandrathe]

But it is fair to ask whether his test holds up enough to convince us today. I don't think, from your descriptions, that this is even possible, given its experimental design. It is fatally flawed - retroactively "predicting" the future with information from the past does not demonstrate precognition.

Then again, you've not read it, and have dismissed it, based upon hearsay (mine), without giving the author fair treatment. You've asked me to summarize his approach, which I may have done or may have misinterpreted.

If I had a nickel for every anecdote of this type I've heard from perfectly intelligent people, I could buy a round for the lurkers at Atma's.

Sounds great! :D The world must be filled with miraculously lucky coincidences. I guess, whatever it takes to preserve your opinion of how the world works.

[Jester]

Then again, you've not read it, and have dismissed it, based upon hearsay (mine), without giving the author fair treatment. You've asked me to summarize his approach, which I may have done or may have misinterpreted.

Okay. I remain open to the possibility that this man, eighty years ago, discovered a method for predicting the future. I also remain open to Russell's teapot. Doesn't mean I'm going looking for it.

I don't see how this method could even in theory provide the evidence I'd be looking for. Unless the method is so vastly different from what you describe as to bear almost no resemblance, I feel quite content resting upon your "hearsay".

If you are in fact so utterly unreliable as to have completely misrepresented him, then that's just a risk I'll have to take. Maybe I'll read his book someday, and marvel at not only your failure, but the failure of every internet source I could track down, to describe what he did with even vague accuracy. All I can say is that I doubt it.

The world must be filled with miraculously lucky coincidences. I guess, whatever it takes to preserve your opinion of how the world works.

The world *is* filled with miraculously lucky coincidences. This is the point. People win the lottery twice in one day. People are hit by lightning dozens of times in a lifetime. Lincoln had a secretary named Kennedy, and Kennedy had a secretary named Lincoln. Events with staggeringly low probability happen to someone, at some time. If they didn't, then *that* would be suspicious.

Conspiracy theories, parapsychology, and other outright crankery revolves around this kind of argument from incredulity: things couldn't *possibly* have happened by chance, therefore <insert wild theorizing>. There's no need to postulate fantastical theories when a perfectly ordinary explanation of coincidence will do.

But, just in case you're still holding to this, here's the question: Is this repeatable? Can this method generate solid predictions, ex ante, which can then be checked against future events? Or is it just fishing for coincidences?

-Jester

[--Pete]

Hi,

I remain open to the possibility that this man, eighty years ago, discovered a method for predicting the future. I also remain open to Russell's teapot.

I don't. Asimov, in one of his many essays, discussed degrees of belief. He put it in terms of his reaction to a colleague's claim to have a jar of a certain compound, and gave three examples. The first example was that of a common material, which he would accept without proof. The second was of a rare material, which he would want to see and would want to test before he used any. The third was of a material so rare that hardly a pound of it exists in the Earth's crust at any one time. This he rejected, a priori. The point of the essay isn't one of 'open' versus 'closed' mind. It is about allocation of resources, specifically our limited lifetime. If we squander our time trying to disprove what is almost certainly true or to prove what is almost certainly false, we lose the opportunity to study and learn what is truly interesting.

So, there is no teapot, there is no prescience, there are no aliens in Area 51. I might be wrong, but I'm not unsure. At least, not enough to waste my time checking it out.

Lincoln had a secretary named Kennedy, and Kennedy had a secretary named Lincoln.

Oh, noes! You don't believe? But the facts are overwhelming!!!!1!! :P

Conspiracy theories, parapsychology, and other outright crankery revolves around this kind of argument from incredulity: things couldn't *possibly* have happened by chance, therefore <insert wild theorizing>.

Yes. The combination of finding patterns where none exist and the lack of understanding of how probability works leads to mystic conclusions. It's amusing to ponder that the common expression, "one in a million", when applied to humans means that it occurs about 6,000 times in our living population -- hardly 'impossible'.

--Pete

[Jim]

Déjà Vu (2006 film, time travel to the past)

Hi, :)

IF you haven't seen Deja Vu rent it, it is a Must see movie, I didn't get it till my 3rd view:w00t:

edit::w00t: Your favorite Time travel film ???

Warning! This synopsis contains spoilers.
http://www.imdb.com/title/tt0453467/synopsis

See plot summary for non-spoiler summarized description.
http://www.imdb.com/title/tt0453467/plotsummary

"The end of the film may be confusing to some people, but it is all laid out if one cares to look carefully."

DEJA VU Part 6 VIDEO
http://www.youtube.com/watch?v=T6XPC4XUoIw...feature=related
With a team led by scientist Dr. Alexander Denny, they investigate the events leading up to the explosion by using a new program called "Snow White", which enables them to look into the past (4 days, 6 hours, 3 minutes, 45 seconds, 14.5 nanoseconds) in detail. The system is limited in that they can only see past events once; there is no fast forwarding or rewinding, although they can record what they see.
===============
DEJA VU Part 7 VIDEO
http://www.youtube.com/watch?v=zeKx9mBMkmE...feature=related
Doug eventually discovers that "Snow White" is actually a time window, and is also capable of sending inanimate objects into the past. Despite Denny's protests against tampering with the past, Doug has the team send a note back in time to inform his past self of the time and place to meet and stop the ferry bomber.

See all 12 youtube videos !!!

[--Pete]

Hi,

edit::w00t: Your favorite Time travel film ???

Actually, I can't think of a great time travel film. Terminator was good as an action movie, as were the sequels. But the time travel shtick in it is pretty weak. Back to the Future was a fun film, the sequels sucked, but again, the time travel was almost incidental to the story. Bill & Ted's Excellent Adventure is one of the best comedies of the 'stupid is funny' type. But, again, the time travel is secondary to the humor. Perhaps the best where time travel is central to the story is Timecop. While I consider Jean-Claude Van Damme to be a mediocre actor, at best, he does an adequate job in this film. The concepts were good (if somewhat clichéd in the SF world) and the production was adequate. All the other time travel movies I've seen were schlock.

Recently (OK, recently to me, say the last twenty years) time travel has become a staple of TV. Both Lost and Heroes use it freely. Doctor Who is effectively based on it. It crops up frequently in the Stargate universe and in the Star Trek one as well. IMHO, none use the concept well, though the jury is still out on Lost (but they're losing points weekly). FlashForward, though not strictly time travel, does fit into the main topic in that one of its central questions is to what degree the future is fixed. I'm hoping they don't end it (and Lost) with some lame "and then they all woke up" ending.

Time travel in literature, like magic, has to have rules. The author must work out those rules, stick to them, and somehow convey them to the reader. Arbitrarily throwing in time travel in a "and then a miracle occurs" fashion is an admission of incompetence.

It's not a movie, but my favorite time travel story is RAH's —All You Zombies—. Once again, the old master shows how it should be done -- with cynicism and flair. <_<

--Pete

[Jester]

Your favorite Time travel film ???

I've never gotten around to seeing it, but I've heard Primer is worth watching for a time travel movie that takes the concept seriously, rather than just being a handwaving plot device to drive the action/comedy/drama.

-Jester

[LavCat]

edit::w00t: Your favorite Time travel film ???

The Invisible Boy

[kandrathe]

The Invisible Boy

Star Trek: Save the Whales.

[--Pete]

Hi,

The Invisible Boy

Time travel? I haven't seen it since the early '60s, but I don't remember any time travel in it.

--Pete

[Jim]

Hi Pete...Hi Magi :wub:

Did you see the movie Deja Vu?

If YES, what did you think about the movie's premise for time travel?

Pete said: Time travel in literature, like magic, has to have rules. The author must work out those rules, stick to them, and somehow convey them to the reader. Arbitrarily throwing in time travel in a "and then a miracle occurs" fashion is an admission of incompetence.

[--Pete]

Hi,

Did you see the movie Deja Vu?

Not yet, but I added it to my NetFlix queue after reading your post. Popped it up to the #1 slot, so we'll see it sometime next week (we average about 2 a week and have one at home).

I'll let you know what I think of it. At the very least, it's got Denzel Washington in it, and he can always be depended on for a fantastic performance. He's one of the best actors alive, IMO. If you like movies with a twist, try Fallen. Great story, great performance. Totally off topic.:)

--Pete

[LavCat]

Hi,
Time travel? I haven't seen it since the early '60s, but I don't remember any time travel in it.

--Pete

That's how they got Robby the Robot back to the 1950's.

[--Pete]

Hi,

That's how they got Robby the Robot back to the 1950's.

Oh, OK. Don't remember that, but then again, don't remember much about that whole movie.:)

--Pete

[--Pete]

Hi,

I've never gotten around to seeing it, but I've heard Primer is worth watching for a time travel movie that takes the concept seriously, rather than just being a handwaving plot device to drive the action/comedy/drama.

I just finished the first half of that dog and don't have the intestinal fortitude to watch the second half. The acting is awful, the dialog banal. The production values are non-existent, it looks like a high school film project. The technobable is mostly muttered. Judging from the total ignorance in the part that's understandable, that muttering is to disguise the writer's total lack of knowledge.

(Aside: in every field of human endeavor, there are thousands of grad students very familiar with that field and, usually, desperate for money. A few hundred bucks for a day of their time to, at least, get the terminology right would be money well spent.)

Truly, the time travel isn't "a handwaving plot device to drive the action/comedy/drama" since the movie is innocent of any such properties. Perhaps the second half of the movie redeems it, but I, for one, prefer my entertainment to be entertaining. I was raised a Catholic, but I've long since abandoned the concept that we have to pay for pleasure with suffering.

--Pete

[LavCat]

Madame Eva shared something profound tonight: "The future holds much death and uncertainty, not unlike the past."

[--Pete]

Hi,

Madame Eva shared something profound tonight: "The future holds much death and uncertainty, not unlike the past."

In ancient times, comets were believed to foretell disaster and misfortune. And they were always right. Every time a comet showed up, misery followed. Of course, every time a comet did not show up, misery still followed. :whistling:

--Pete

[Jim]

Madame Eva shared something profound tonight: "The future holds much death and uncertainty, not unlike the past."

Hi, :)

Madame Eva ?

[ Google Results 1 - 10 of about 1,150,000 for Madame Eva]

[LavCat]

Hi, :)

Madame Eva ?

[ Google Results 1 - 10 of about 1,150,000 for Madame Eva]

You must not hang out much in Darkshire.