Travelling back in time with today's knowledge

What would happen if you travelled back in time and presented a scientist of the past, say Newton or the like, with a modern science book?

Would our civilization today be more advanced since what we know now, they would know then? Or would you simply be burned at the stake for being a lunatic? Or perhaps they’d gain your trust once the material in the book began showing positive results…

The more I look at it the more I’m starting to think this question doesn’t belong in GQ but who knows… Any theories?

I don’t know if it would have as big of an impact as we’d like to think. Plenty of great scientists, artists, and philosophers were well ahead of their time, but it took years, decades, or even centuries for their ideas to take off.

Take steam power for example. The greeks understood the concept of steam power and one scientist used it to make a little toy. However, it never went beyond that. Stalls in innovation such as this suggest that some things take time to absorb.

Just because something is light-years ahead of everything else doesn’t mean it will stick. The book Guns, Germs, and Steel points out how in spite of being technologically advanced for its day, China lagged behind other nations and eventually became susceptible to european colonization attempts.

Short answer: Nobody knows. SF writers have played around with various possibilities. They fall, roughly, into the following categories:

  1. Changing the past is impossible. If you go back in time, you will find that nothing you do will really change anything. If you try to stop Booth from shooting Lincoln, some unforeseen circumstance will prevent you. So go as a tourist and don’t worry. (See Robert Heinlein’s Time Enough For Love.)

  2. Changing the past is possible. Either
    (a) Doing so will threaten your own existence (if you go back in time before your birth), or
    (b) It won’t, because what you’re doing is creating a new timeline, leaving your timeline of origin unaffected, or
    © It won’t threaten your own existence, but will in fact change your own timeline without causing any paradox, because the physics and logic of time travel [waves hands], as in the Back to the Future movies, or
    (d) You will create a paradox that will destroy the universe, so don’t try, or
    (e) If you visit the past and try to change something, the “time-space forces” will snap you back to the present (killing you in the process) to avoid a paradox, which you can’t have in a “well-ordered universe” (see L. Sprague de Camp’s short story, “A Gun for Dinosaur”), or
    (f) Past-changing time travel, while possible under the laws of physics, will never be discovered in any given universe of discourse, because there are so many people with good reasons to want to change the past that eventually, the process will produce a universe where time travel is never discovered and therefore that universe will be altered (by time travel) no further (see Larry Niven’s essay, “The Theory and Practice of Time Travel”).

  3. Time travel is impossible. (This is included purely for the sake of completeness – I’ve never read an SF story based on that assumption.)

BrainGlutton, You’re leaving out the enormous number of stories that fall into the general category of “alternate history,” in which a change is made (or assumed) and the past and a new history results, exactly what the OP asks.

Unfortunately, that’s as far as any answer can be taken: fiction. Once you change the past, any answer you feel like giving is equally valid, including ones that seem extremely unlikely or even impossible. Nothing an author dreams up can be as extremely unlikely or impossible as real history has been.

That means that this thread, like the million earlier threads on alternate histories, belongs in GD. I’ll ask a mod to move it.

That’s because those do not necessarily involve a “Connecticut Yankee” time traveler to make the change; they simply assume things went differently at a given point-of-divergence, e.g., Napoleon won at Waterloo.

You also gotta consider what you’re giving Newton or whoever. For example, if you handed him every document from the Manhatten Project, it won’t make much difference…he doesn’t read modern English, and even if you translate it for him, he doesn’t have the technology to start cranking out A-bombs.


Yep, you’re right. I believe it’s IMHO territory.




What about:
1(b) - Going back in time is actually fulfilling the timeline. Say if you went back in time to kill Hitler, you didn’t succeed because something stopped you (maybe you were killed, or couldn’t go through with it after all)… but according to your history before you went, you were always there, you just never knew about it.

This is different than 1(a), because you were always actually there. You think you’re going back to change something, but you’re actually fulfilling it.

The exact scenario the OP asks about was covered by Asimov in “The Red Queen’s Race”, probably the best time-travel story he wrote (which is somewhat faint praise). A crazy scientist invents time tracel, and comes to the conclusion that, had the ancient Greeks had modern scientific knowledge, most of the unpleasentness of history would never have occured, and so he goes to great lengths to send a few textbooks back to ancient Greece. Of course, were he successful, the timeline which lead to us would never have come to pass, so cooperation with him could be seen as suicidal or even genocidal. The translator he hired to translate the texts into ancient Greek, though, goes along with it, because he realizes that our timeline is exactly the one in which the books were sent back, accounting for ideas emerging seemingly out of nowhere, like Democritus’ concept of the “atom” and Pythagoras’ apparent heliocentrism. So this Greek scholar was “running as fast as he could just to stay in one place”.

Well, he might simply see no reason to believe it. For instance, try to explain Relativity to Newton and he might reject it on the basis that Newtonian physics explains everything adequately and is simpler. 17th Century scientific instruments were not accurate enough to show that the Newtonian laws aren’t quite correct, so why should he believe they were *not *correct? Just because someone claiming to be from the future (clearly a crackpot) showed him a book?

I have dreams about going back in time and bringing my laptop into my General Science class, opening it up and bringing up a chat room, thereby ensuring a date with Lynn, the hot chick I never was able to get give me the time of day.

Yeah, right. This was the early 60’s, before the friggin’ microchip (as we know it today) , fer Chrissakes.

So why didn’t I (the real-time me) know that before opening the friggin’ laptop in the dream, and looking like a dipwad when the damn thing wouldn’t work???

I don’t think I want y’all to answer that question.

[Archie Bunker ] Let’s just leave it rectorical there, all right? [/Archie Bunker]



Well, you have to consider the obvious that the book you show him is going to have all these fancy photos and glossy paper and printing techniques he has never seen before. It is also going to have the date and a whole bunch of supporting info that it really is from the future. It isn’t like you are just throwing him equations carved into a stone tablet.

That ain’t a bet I’d want to make. In Newton’s day, “A Wizard did it” was one possible explanation. They were killing witches during his lifetime, weren’t they? And other than the fancy printing and nice paper, why should he accept it any differently than we accept Heinlein’s “Future History”?

What items would you take with you, were you able to go back five or ten thousand years ago? Only what you can carry with you, however.

Well, no, it’ll probably never happen. Er, it probably never happened? I get confused with these time traveler verb tenses.

Here’s some things I might try; don’t know if they’d work… I’d like to see what Ben Franklin would say if I just demonstrated some binary math to him; give him some ideas about how it might be worked into some various mechanical ideas, nothing outlandish like trying to show him how to build an electrical flip-flop circuit (not that I know how to build one myself, other than knowing what one does). …And Ben, we might be able to work up some cool military encryption with it too, maybe.

…Maybe try to argue with these guys a little about the benefits of standardized parts for manufacturing… …and sanitation… …look, guys, you don’t have to take my word for it, see for yourselves…

…Might have to give up on this, but maybe go out drinking with… who?.. and ask him or her what it would really mean if there really, truly were an absolute speed limit in the universe, like, say, the speed of light…

'Course, I probably would wind up in a local asylum, or with my throat cut.

I don’t see the difference. When Lazarus Long, starting from about 4000 AD, travels back to Missouri in 1917 to visit his old family, he’s not changing anything and he knows it – knows, also, that if he does anything to leave a trace in such historical records as still survive 2000 years later, he could find that trace with a little library research, and it would be the same whether he went to library before making the time-trip or after.

BTW, check out these earlier IMHO threads:

What would you do with a time machine?

What would you do if you could visit the future and change it?

I once read a short story (in the old Omni magazine) about a scientist who travels back and visits Newton to give him an electronic calculator, to save time. Newton is skeptical and wonders if he’s an emissary from the Devil. The scientist demonstrates by dividing one randomly-chosen long number by another. Unfortunately, the result is “666” – well, you can guess Newton’s reaction.

Since we’re recounting stories, I remember a very short story where a time-traveller goes back to ancient Rome with penicil… penecill… pinecil… antibiotics ( :wink: ). The world becomes so overpopulated that the governments pool their rapidly declining resources, builds another time machine, and sends somebody back in time to assassinate the original time traveller as he steps out of the original machine.

Chronos writes:

L. Sprague de Camp wrote a story with a similar premise, but very different results: “Aristotle and the Gun”. A Brookhavebn scientist goes back in time to correct Aristyotle’s outlook somewhat, hoping to prevent its having a strangehold that restricted European scientific development for a long time. Unfortunately, it has the effect opposite the intended one of pushing scientific development forwatrd, and he returns to an alternate timeline in which Columbus didn’t sail, and Brookhaven is now located in one of a handful of Amerindian megastates that’s just beginning to interact with Europe in the 20th century.