Should we subsidize or tax research into time travel?

Treat this as a balanced budget question, so it's not about fiscal policy.  Alternatively, imagine yourself as a benevolent philanthropist: should you support this area of research if you can do so as a free lunch?  Or should you try to hinder it?

I believe no one understands the underlying science much at all.  But there is some chance that the old science fiction movies are correct and that by time-traveling you alter the course of history, thereby obliterating the universe we used to have.  I'll count that as a net negative, while noting there is some chance we end up with a better universe.

On the plus side, the human race will die out anyway.  Time travel seems to yield a fairly safe haven.  As disaster approaches, keep going back in time a few days, or decades, and that asteroid will never hit you.  This is especially appealing if you are transporting back a body (upload?) which is programmed to be more or less immortal and you can take the technology with you, so as to keep on going back as time progresses.

On one side: immortal life for many of the last humans and thus immortality for the human race.  And with time they may learn how to thwart the asteriod.  On the other side: some probability of swapping universes.

So should we subsidize or tax research into time travel?


I don't really see why immortality is a benefit. Also all this death-avoiding time travel would make the earth rather crowded, no?

Interesting question. I say we should subsidize, because if its feasible at all, it'll be accomplished by someone. So it'd be better be done by someone [somewhat] accountable.

By the way, you should read Charles Stross' novella "Palimpsest". It deals with a time travelling agency (the Stasis), which manages mankind history, in order to make it last as long as physically possible (each particular point in time can only be reached once).

I know you're just being cute, and I understand the point of your question, but the fact that you ask questions like this says something terrible about the way modern people think about the world.

Few scientists think time travel will "destroy" our current timeline, but rather act as a path to a parallel timeline already in existence because the time travel to it is fait accompli.

That said, time travel is impossible. Existence itself is predicated on the stability of space-time. Hawking was right the first time, and warped his thinking only to satisfy pop science. The transporter and replicator are also impossible because of Heissenberg Uncertainty.

This is sort of like asking a midieval king how much he should subsidize the efforts of the alchemists to create gold from baser metals.

Probably a greater likelihood, with developments in nanoscience and materials science, in creating artificial gold than in taking a time travel trip.

Won't Glenn Beck and Ron Paul be pissed. We can then talk about fiat gold.

If time-travel were possible and humans discover how to do it, the odds are greater that it has already been discovered, so to speak, in the future than that we'd discover it in the near-term present, regardless of subsidies. Therefore, the time-travelers are already here if they are going to ever be here. So instead of subsidies we should offer a huge prize for a time-traveler to tell us how it works. Even if some *future* time-traveler isn't in the present now to hear about the prize directly, if we make the prize big enough it will be discovered in the historical record and someone will claim it.

The question then is: what do you get the time-traveler who has everything? Perhaps Obama should hold a press conference and say: "Time-travelers, tell me what you want." Imagine how stupid other countries will feel if that works!

I imagine information from the future could have a massively distorting effect on markets if it was not widely available. But maybe time travel would be similar to HFT in the sense that markets would more rapidly adjust to their equilibrium prices.

It has implications for stronger forms of the EMH. And it came up earlier this week when there was a line in a nytimes article about a positive ESP result saying that ESP could help people beat the market -- could it really?

The movement of stuff to different coordinates shouldn't matter so much as movement of information. So what is the current thinking on private information? Does economics even work?

We do subsidize research into time travel. That is, theoretical physicists have been studying for some time now the possibility of closed timelike curves in general relativity and quantum gravity -- that's where the idea of wormhole time machines first came from. In the U.S., the (admittedly very tiny) funding for such research generally comes from the National Science Foundation or the Department of Energy. (Also admittedly, Kip Thorne was told by the NSF that he shouldn't use any of his grant money on his work on closed timelike curves.)

Even if you could build a time machine, you can't change the past. In most models you can't even travel to a point earlier than the moment you first built the time machine -- but if you maintain it, future people can travel to you. In the most ambitious proposals, you could create a new branch of the wave function where the past was different.

Rules for time travelers

Read the news, look out the window, consider the state of the world. There is only one possible conclusion: No one has ever or will ever invent time travel.

A recent TV program featuring Stephen Hawking's views seemed to say that worm-hole time travel to the past is impossible because of paradoxes. As for travelling to the future, it's already proven to work if your notion of the future is a time that does not yet exist. This contrasts with a notion of the future that does exist "concurrent" with the present. To visit the future that does not yet exist, just travel fast and/or orbit a high mass object and return to rest at a distant future date.

"If time travel were possible, then someone from the future would have visited us already."

Most theories of time travel that involve actual physics do not allow the time traveler to go back before the time machine was made. So this could just mean that no one has made a time travel machine yet.

Furthermore it presupposes that /we/ will invent time travel. Maybe it gets invented in a different galaxy and they never bother to visit us, and we die out before we can invent it ourselves?

"Most theories of time travel that involve actual physics do not allow the time traveler to go back before the time machine was made."

And also, economic theory demonstrates that real interest rates would fall to zero if time travel existed. (Because time travelers would attempt to travel back several centuries and set up trust accounts for themselves, reaping the miracle of compound interest.) So if real interest rates ever fall to zero and stay there, that will demonstrate that a time travel machine has just been invented. So at present, we can say . . . never mind.

I refuse to watch any movie or TV show that involves time travel, and I feel the same way about this ridiculous post.

People of the 21st century: I cannot visit you, but I can send you this message. Quit eating sushi.

MarkCh: Time travel which can go back to a time before the first time machine was invented AND which can change the past is hardly the only "real" time travel. Time machines which can only travel back to the time the first time machine was invented are still pretty cool, and even if you can't change the past, that doesn't mean you can't go there.

Hell, I don't think the idea of time travel changing the past actually makes coherent sense. Change is a concept that only makes sense in a particular timeline. At time t_1, things are one way, and at time t_2, things are another way. By that conception of change, changing the past is impossible by definition. So either there is a single unchanging timeline (so you can go back and be your own grandpa, if and only if you were your own grandpa in the first place) or time branches, and all "changing the past" does is move from one reality to another. (Or some weird combination of the two involving quantum entanglement.)

Subsidizing time travel research is unnecessary - if time travel is possible, it has already successfully paid for itself, therefore any funds provided to today's researchers seeking funding who haven't already discovered how to make time travel work (let's call them rent-seekers) will only delay real progress in the field because of the misallocation of resources.

On the other hand, taxing subsidized time travel research makes more sense since it minimizes the misallocation of resources. Meanwhile, unsubsidized time travel research should not be taxed, since that would impede progress. This is why any successful time travel research programs will have been kept secret - to avoid taxation.

But don't take my word for it - here's a noted expert on the topic of how time works....

As someone from the future who recently developed time travel, I do have to say it would have been much easier with large subsidies.

If time travel had any chance of working, we could decide whether to subsidize it after knowing that it would work.

Subsidize, of course. Bring the benefits of technological innovation back to early humans so that thousands of generations can live longer, better lives. Sure you'll be "killing" the people who lived in the Universe we already had, but you'll be creating a greater number of better lives.

If you view time as another dimension across which one can travel, there's no reason to necessarily believe that time travel would extend a human life. It may be useful in the "avoid an asteriod" scenario, but it seems more obvious to just change your location within the dimensions of space. I imagine if we've invented time travel, we could probably get to another planet just as easily. Or send Bruce Willis to detonate a nuclear warhead in the center of the asteroid.

Discussions of time travel ultimately break down into fun conversations about paradoxes and 'solutions' proposed by science fiction writers.

There's a good reason for that. There is no evidence that time travel is possible, and lots of reasons to believe that it isn't. Government should not be in the business of funding pseudo-science or cool-sounding science fiction ideas.

Why not fund anti-gravity boots and hyperspace travel? Answer: Because 'it's a cool idea to think about' isn't sufficient justification for spending taxpayer money. Otherwise, you might as well also fund research into ESP, ghosts, the search for Noah's ark, and Yeti expeditions.

Time travel is not science. It's wrapped in scientific language, just like the technobabble on Star Trek. It's true that a lot of math that describes the universe does not really have an arrow of time, indicating that time might go in both directions. But there's that pesky causality thing that gets in the way, and entropy, and the fact that you have to invent all kinds of special rules for it just to have it make logical sense ("You can't change the past", "Every change you make spawns a new universe", "You can never meet yourself in the past", etc). There's no evidence for any of this, or for any real world phenomenon that would enforce these rules.

Some of these 'theories' require scaling quantum effects up to macro levels, or taking literally speculative ideas like the many-worlds interpretation of quantum behavior. But those aren't scientific theories, they aren't testable or falsifiable, and probably just highlight the fact that our current models are wrong or incomplete. And there's already plenty of research being funded for studying those models. The Large Hadron Collider, for example.

i find it hard to believe that rational people seriously consider this at all. time travel is about as likely as jesus christ coming back to earth in the next 50 years.

Time travel already exists... in a parallele universe. We just happenned to live in the wrong one where it will never be invented, that's why it hasn't yet and will not be...

A subsidy of time travel is as beneficial as many other subsidies. In some ways, due primarily to the impossibility of the task, the subsidy may provide even more benefits than the typical subsidy: Think of all the long term jobs created in a traditionally high paying field with somewhat limited employment opportunities.

@David, I agree with you:
"... it's incoherent to talk about changing the past. I know that bad fiction does, but you shouldn't. The key thing to realize about time travel is that whatever time travelers did in the past has already happened. We are temporally downstream from all the actions of time travelers in our past, if there be any. It's not like there are two versions of 1963, the one "before" you time traveled to it, and the one "after". There just is one way that 1963 went, and either it has time travelers or not..."

I have been trying to explain this to people for YEARS, and they just can't get it. They make up special rules for time travel based on what they've seen on Star Trek, Back to the Future, etc. but a universe with time travel would still follow the same logic as our real universe (where time travel seemingly doesn't exist). They are unable to view time travel OBJECTIVELY. In their thoughts they see themselves going back in time- anything they plan to do in the past seems to be in their future, but in reality it would take place in the past- and from the perspective of the future, whatever they did in the past is already done- it happened one way, it cannot happen a different way. It sounds confusing, but it's really more simple than the made up rules of time travel and alternate time lines of the sci fi universe.

What's SUPER WEIRD, David, is that when I try and explain this to people- THE EXAMPLE I USE IS ALWAYS 1963!!!!! I always use the scenario of time travelling to stop the Kennedy assassination. Also it's the year I was born. Why did you use that year, David?!?!?!

Create a wormhole, jump in one end go back in time ten years, the other end of the wormhole will drop you ten light years from earth.
Race back to earth at near lightspeed, you'll arrive in ten years, just seconds after you jumped through the wormhole the first time. Too late to stop yourself or otherwise change history during those ten years.
It's a property of spacetime. Yes, you can travel back in time as far as you want via wormhole but only to a point in spacetime that cannot cause any causality issues at the point of origin.
This also means you still won't be able to go dinosaur hunting, or encounter killer cyborgs from the future with unlikely accents.
That is all...

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