I am interested in alternate history but I find it ridiculous when the writers ignore the butterfly effect and have FDR in a TL that diverged during the Civil War twenty years before Roosevelt was born. Do the writers realize the conception of FDR would not happen in the exact same way in happened in our world? Even if say the divergence happened on May 1st and a man named John Smith was conceived that night-suppose Smith’s father read the newspaper that night instead of procreating with his wife-everything changes! Thus how strong do you think the butterfly effect is once one thing changes?
You do realize that your “Butterfly Effect” is speculation because no one has been able to test it yet?
Science fiction short story-yes.
Crappy movie made from short story-yes.
Scientific theory-not so much.
Qin, I think Restaurant At The End Of the Universe sums it up well.
“One of the major problems encountered in time travel is not that of becoming your own father or mother. There is no problem in becoming your own father or mother that a broad-minded and well-adjusted family can’t cope with. There is no problem with changing the course of history—the course of history does not change because it all fits together like a jigsaw. All the important changes have happened before the things they were supposed to change and it all sorts itself out in the end.”
Huh?? Yeah, that’s what I think too.
It seems to me that one has to dramatically discount the butterfly effect if they’re going to think about alternate history at all. Otherwise the answer to every question is “how the hell could I possibly know?”
Hmmm? No, it’s testable enough, and well confirmed. Scientists have been playing with deterministic chaos for a long time. In some types of systems small changes tend to snowball into larger ones, which is why we can’t predict the exact weather a year in advance.
Where the OP goes wrong is twofold. First, in ignoring the fact that people write about alternate universes like that because without making assumptions that “except for X, history goes the same until the birth of FDR”, they can’t tell the story they want to. And second, just as random chance would tend to cause changes in the timeline, being random it also might not cause changes. If we are talking about Many Worlds Interpretation style parallel universes there ought to be one where just that happened, in among all the multitudes of universes where it didn’t.
Would this thread play better in Cafe Society? Or is there a consensus that this could be a Great Debate?
[ /Mod question ]
Where was it moved in the other timelines? 
My choice: IMHO
I’d consider it GD material. The question doesn’t just apply to fiction; alternate universes are a genuine scientific concept, as is chaos theory.
It happens because it makes for a good story, not because it’s realistic.
This part of the OP’s question is interesting, and I am not aware of anyone having done a competent back-of-the-envelope calculation that gets to the heart of the question (anyone?). Here are my thoughts:
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The answer is going to be strongly dependent on how big a deviation in initial conditions we are talking about. When you say “once one thing changes” are we talking “one H20 molecule in Nepal is displaced by 4 nm?” Or are we talking “the entire course of US history has been altered dramatically?”
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The answer is going to strongly depend on how far in the future after “once one thing changes” you want to look.
A more general answer to your question might be a couple of examples stated in the following form:
*Given X deviation in initial conditions, it will take Y days before Z is affected. *
For example, given what I know about weather prediction (basically nothing), I would guess that a deviation in temperature of 1 degree over one square kilometer would cause something like total unpredictability of local weather for the entire globe after only (total guess) 10 days. Total unpredictability of local weather would obviously have the effects of changing enough about daily life that it is clear that the exact sperm impregnating any woman after 10 days would be totally uncertain. Therefore everyone born after 9months+10 days would have been randomized. Therefore at a total minimum, world history would begin to be drastically altered after only 9months+10 days+years-until-relevant after the weather variation was introduced. This is just a silly example, but you get the point.
I’ve often wondered about this sort of thing, embarrassingly enough, as it relates to my theoretical status as a time-traveling sports bettor. Let’s call this “The Tannen Paradox.” Say I’m somehow transported 10 years into the past. I have some money and decide to grow it by betting on sporting events of which I already know the outcomes. Even if I do my best to be unobtrusive and non-impactful, how long do I have before the consequences of my mere presence begin to ripple outward to the extent that they change the outcomes of the very sporting events I intend to wager on? My guess is “not bloody long.”
You are talking about the changing of the present to affect the unwritten future. The aspect he is talking about hasn’t been tested-the changing of the written past to affect the present.
A butterfly can affect a particular hurricane, but have little effect on long-term climate change. Similarly, perhaps the general trajectory of 21st-century geopolitics doesn’t depend on 20th-century details. Hari Seldon developed sophisticated mathematics to predict as much as 1000 years into the future. He posts in these forums; perhaps he’ll show up and elucidate.
On the other hand, IIRC, Hari Seldon’s predictions were upset by a man nicknamed “The Mule.” Perhaps our own 21st century is similarly at the mercy of … whom? … Sarah Palin? :dubious: :smack:
And isn’t it convenient how, after Michael Dorn joined the cast of Deep Space Nine, an alternate version of Worf appeared in the Mirror Universe episodes? What up with that?!
VarlosZ, if you haven’t already read Replay, by Ken Grimwood, I highly recommend it. The main character in the novel does exactly what you talk about.
I think most writers are assuming that there is an inertia pulling the altered timeline along and shaping it similar to our universe.
Of course it could also assume an infinite number of universes and the writer is simply choosing one that has similar events but is different in various ways.
How much did the timeline diverge? The birth of the exact FDR is kind of ridiculous, because even if his mother and father married and had a son just as in our timeline, there’s no reason to assume the son has the same genetic mix as our FDR. But someone named FDR may have born on the same day as the one we know, but not the same person. Even if by coincidence he has the same DNA as FDR, if he doesn’t contract polio, he may bever become president. Not every butterfly affects a hurricane, so many things will seem superficially the same. And some things just average out. The number of people born in the next 10 years may be about the same. But in the details, each of those people could be somewhat different.
There is also the matter of how this divergence occurred. If this is about an alternate universe among the infinite universes that contain every combination of everything, then it could be a universe which differs from our is some tiny way. A butterfly could flap it’s wings one more time in that universe than in ours, and nothing else detectable to humans has to change at all.
This isn’t really a productive way to look at it, as it assumes a certain relationship between ‘size of change’ and ‘predictability of output’ that isn’t necessarily there.
In chaotic systems, and especially large scale systems that feed back on themselves, change can be completely unpredictable. Sometimes an input can look like it’s causing linear change, until it reaches some threshold when suddenly the entire system reacts.
A couple of real examples: Take the Butterfly effect. How might that work? Well, imagine a hot, clear muggy summer day. The relative humidity is close to 100%. The air is saturated with moisture, but clouds haven’t formed. Along comes a butterfly flapping its wings. It creates a tiny vortex that lofts a dust particle into the air, whcih acts as a cloud seed, which causes a cloud to form. Eventually the cloud turns into a big thunderstorm, which pours rain down on a village. Had the butterfly not flapped its wings at exactly that time, perhaps some other disturbance would have caused a cloud to form in a slightly different place, causing a different village to be flooded. And maybe in that other village, the flood would have killed a person who went on to become the assassin of a politician, which triggers WWIII.
This isn’t random behavior. The system is deterministic in that we know what causes clouds, and how they are seeded, and all the rest. But it’s wholly unpredictable because it’s highly sensitive to initial conditions, and because the effects cascade because of feedback.
Another example from economics. Let’s say you decide to raise the price of a product through fiat by passing a law. We know what a supply and demand curve looks like, and how prices affect demand. So we raise the price by 5%, and observe the result. The demand drops by X. Now we’ve modeled the price elasticity of demand. So now we can predict what the next price change will do, so we pass a law to increase it another 5%. And sure enough demand drops by X again, confirming our model. Yay! So we raise it another 5% - and suddenly everything goes to hell, because we finally pushed the price above the level where some other alternative is cheaper, so demand vanishes, and demand for the alternative spikes through the roof.
This cascades down the supply chains of both products, causing major shifts in demand and price shifts for thousands of goods that share the same raw materials. The entire system’s behavior changes based on a tiny input. And the point where the shift happens may be completely unknowable without perfect knowledge.
Unfortunately, we can’t really say how sensitive the past would be to changes from a time traveler, because the system itself is unknowable in that way. Suffice it to say that the future is a random walk, that there’s no force we know of that pushes everything in one ‘right’ direction, and because we don’t actually have time travel or the ability to see all the paths not taken, we have no idea just how much change is caused by small changes of even a nanometer’s distance. But we can certainly do thought experiments like the cloud example which suggest it’s certainly possible that tiny changes can have large, lasting effects in exactly the right circumstances.
Yes, that’s a pretty common problem with alternate histories, but some stories do it right - in one novel, the timeline splits in the mid-1940s into 20 alternatives - people born before the date of the split have duplicates in each timeline, but folks born after the date are unique, because even the tiniest changes has a strong chance of causing a difference in the circumstances of conception. By the 1980’s the president of the US in one universe is someone who is of no consequence at all in all the others, simply due to the accumulation of chance effects.
One novel that did a really bad job on the other hand, had the European theatre of WWII aborted very early (by a revolution in Germany before the invasion of Poland), but in the 1980s, people with the same names and characterstics still get born and end up married to the same people and in pretty much the same jobs - bleah.
(I’ll give Mirror Mirror a bye on this issue - it’s not really an alternate history in which the consequences of changes to historical events is explored - it’s a “what if” story: “What if Kirk, Spock and the rest are all on the Enterprise, but everybody is evil?”
Or the means of travel between alternate universes constrains you to travel to worlds that have some resemblance to our world - you can’t travel to a world where Kirk died as a kid and the Enterprise was destroyed by a computer that Kirk would have out-talked; you have to end up in a world where the Enterprise crew have the same look and names as the real Enterprise, even if they’re bearded, slutty or evil.