A Time Machine, A Warehouse Store Membership, and 50 bucks...

[Alpha_Geek]

I went to Costco last night as I wanted to go there to stock up on spices and I realized something. All it would take to get to be super duper mega ultra rich without hurting anyone would be a Time Machine, a Costco membership, and 50 bucks. With 50 Bucks you could buy a bunch of spices like cinnamon, caraway, etc.. and then take it to 1600's Europe and trade it for Gold, then take the gold back to now which is 800 bucks a ounce, sell it, buy even more spice and then repeat the cycle. When the place you are trading runs out of gold, you then travel a few years later and trade more spices for gold....

You could even sell those rubes in the past Aluminum foil and they trade large amounts of gold for sheets of the stuff. (not to much to screw up the timeline though.)

I like this time travel wealth generating scheme better than betting on sporting games using an almanac.

While you're there, take a video camera and shoot the goings on in a kitchen where those spices are going, because nobody really knows how measurements of time, quantity, and such were done during that period, other than a few vague things in extant cookbooks.

The surviving cookbooks were more decorative than working documents, and I suspect cooks working for nobility guarded their methods and recipes to some degree. Job security, ya know!

 

[Samurai8472]

Go back to the late 1800's

Slowly integrate the idea of tv and news

By the early 1900's you'll have CNN covering the second World War.

Yes the idea is flawed but it would interesting to advance television.

 

[Lapis Exilis]

I'm not really sure what you're saying here. Subjectively speaking, you can't change the past. Whatever you experience in the past will be the same history you know, because as a quantum observer you're constrained to observe the already-measured quantum state you're part of. It's not that your history continues to exist while you create and experience a different history (like Nero in the Star Trek movie) -- that's fiction. You're compelled to experience the same history you originally came from. Any other histories that may exist are beyond your perception and are functionally irrelevant. In terms of what you experience as a time traveller, the past cannot be altered.

The explanation is given in the 2005 paper Quantum Theory Looks at Time Travel by Greenberger & Svozil.

No offense, but I just read this paper and you are somewhat misrepresenting what it says. The authors clearly state their assumptions, which preclude certain possibilities in order to advance a specific time travel model of their creation.

That is, they are not saying that their model is the definitive word on theoretical time travel, merely a particular model arrived at by their interpretation of quantum physics, ignoring a possibly deterministic universe (which they say they reject on psychological grounds, because they don't like the idea), and ignoring relativistic models of time travel (because those are outside the scope of their model).

It's a good model and it makes sense in terms of quantum theory, but it's a bit presumptive to act as if it was somehow the final word on an entirely theoretical area of physics. Relativistic models tend to have little to say on whether the past can be changed, instead only showing that travel to the past is possible. Since we can hardly claim to understand all the nuances of the fabric of the universe at this point, it's a little soon to close the book on the issue based on an extremely brief paper by two physicists. I'm sure they're very good, but they don't represent the entirety of scholarly thought on the subject.

 

[Christopher]

^I resent your tone. I never presented it as the "final word" -- I'd have to be grossly ignorant to think science worked that way, so I'm deeply insulted that you'd accuse me of such a thing. I merely offered it as an illustration of my point. I could also give you a relativistic analysis that arrives at the same conclusion; if you're curious, just search for "Novikov."

Geez, I try to participate in a friendly discussion and inevitably someone takes it too seriously and slaps me in the face. Honestly, sometimes I really loathe the Internet.

 

[Davros]

Make sure your time machine can move through space as well as time. Locations like the earth move.

 

[sojourner]

^I resent your tone. I never presented it as the "final word" -- I'd have to be grossly ignorant to think science worked that way, so I'm deeply insulted that you'd accuse me of such a thing. I merely offered it as an illustration of my point. I could also give you a relativistic analysis that arrives at the same conclusion; if you're curious, just search for "Novikov."

Geez, I try to participate in a friendly discussion and inevitably someone takes it too seriously and slaps me in the face. Honestly, sometimes I really loathe the Internet.

He didn't accuse you of anything. I think you need to reread his post a little more objectively. It's one of the more coherent and reasoned posts I have seen on this board.

 

[Myasishchev]

Incidentally, in MW I don't think you'd be prevented from "changing" the past according to your own subjective, one-universe view of history. You simply wouldn't be changing your past--just as you cannot really change your future, at least inasmuch as "you" are the collection of quantum states that in sequence produce the "present" moment of consciousness, and literally nothing else. You can determine to a degree what universe several collections of quantum states that are very similar to you will experience, but that's not quite, philosophically, the same thing.

I'm not really sure what you're saying here. Subjectively speaking, you can't change the past. Whatever you experience in the past will be the same history you know, because as a quantum observer you're constrained to observe the already-measured quantum state you're part of. It's not that your history continues to exist while you create and experience a different history (like Nero in the Star Trek movie) -- that's fiction. You're compelled to experience the same history you originally came from. Any other histories that may exist are beyond your perception and are functionally irrelevant. In terms of what you experience as a time traveller, the past cannot be altered.

The explanation is given in the 2005 paper Quantum Theory Looks at Time Travel by Greenberger & Svozil.

My understanding, through David Deutsch's descriptions of MWI, is that the multiverse is most profitably thought of as arranged as an interrelated stack of quantum states, each capable of being described by an energy state and a position in four or greater dimensional space, with gross reality as experienced by any particular human observer understood as a superposition of those states decohering, through interaction with other states, based on a determination that seems subjectively probabalistic to an observer.

If I get this right, that means that any possible event occurs somewhere/when in the multiverse. It is not possible to change your own history, or any history, or ultimate any thing, because all possible events have already occurred, arranged as a stack of coordinates in spacetime. Time travel is hence a misnomer--it could only be accomplished by traveling into another universe that, since there is no flow of time, already exists in a four-dimensional sense.

If human time travel is physically possible, then as a possible collection of quantum states, it exists, in a larger or smaller percentage of possible universes.

This is how I understand the MWI. Interestingly, in my view, it reconciles free will with the certain determinism of classical mechanics and random determinism of quantum mechanics.

Now your paper there is interesting but I think it ignores an aspect of the many-worlds interpretation that is vital--in their thought experiment, the past is fixed and the future is not because the many quantum states that make them up have already been measured and determined. So of course any attempt to beam a photon into the past can do nothing to upset these measurements from their subjective point of view.

In MWI, someone somewhere else (most precisely the particles of a human being in superposition with our own scientist, decohered by interference with other particles, including the particles of the other scientist in the other universe) is measuring a nearly-identical photon that had existed in superposition with ours, and also finding that their photons cannot change the past from their subjective point of view.

So you still cannot kill your grandfather (a collection of quantum superpositions which following many measurements decohered into the entity that passed his DNA along to you in the usual way), but you could, assuming a magical ability to appropriately manipulate energy and matter in a rather disparate universe, kill a person identical to him in gross terms--identical features, DNA, and personal history up to the point of his unfortunate demise--but very different in quantum terms, inasmuch as once he ceases to live, he will be a very different collection of quantum states than if he had continued to breathe.

MWI in the past and future is a better explanation than the objective collapse interpretation that I think that paper essentially espouses, for at least two good reasons.

Firstly, it avoids the common sensical problem of "where did the other possibilities go?" that MWI arose to resolve, particularly as a result of double-slit experiments demonstrating interference patterns in real and "phantom" photons. In the linked paper, superpositions disappear, "objectively collapsing." Under MWI, they "decohere," subjectively collapsing. And I think this makes more sense.

Secondly, it avoids the non-common sensical problem of attempting to impose an arrow of time on the universe, when none such seems to actually exist, and only appears to as a result of the human conscious moment's perception of past and future. Time makes much more sense as a type of position of any given particle or collection thereof.