
Pop culture loves the 'butterfly effect' and gets it wrong - smacktoward
http://archive.boston.com/bostonglobe/ideas/articles/2008/06/08/the_meaning_of_the_butterfly/?page=full
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anyfoo
The actual Butterfly Effect sometimes gets me thinking. Unlike what's popular
in time travel fiction, it seems to me that even the tiniest change would
cause a _completely_ different world, with completely different people
inhabiting it, about a generation or so deeper.

As a stupid example, consider the change being a tree branch falling in the
Serengeti. A small animal, which would otherwise have just continued eating,
scuttles away. It crosses a nearby road, causing a nearly imperceptible
slowdown for a woman on here way to the airport. She arrives just a few
seconds later, but it's enough for the pattern of people in the hall to change
and her to not see a sandwich shop she would have seen at a glance. She
arrives meeting her husband, sleeps with him just like in the original
timeline--but because she's slightly more hungry, did slightly different
things on the plane, and so has slightly different discussions, they sleep
with each other a tiny bit earlier or later, in an ever so slightly different
position, but completely enough to either not cause conception of the child
they would have conceived originally, or the conception of a different child
(different sperm, different combination of genetic material, and so on).

And now it's obvious. The child is essentially a completely different person,
with completely different thoughts, actions, being not exactly where the
original child would habe been throughout its life at practically _all_
moments (even if they go to the same school, they're unlikely to stand in the
same spot in the hallway at all times). Blocking other people's view, or
slowing them down, or causing them to go somewhere else. Causing many many
"tree branches" of its own, many of which result in people meeting or not
meeting other people, or having different offspring regardless, and so on.

Now, consider that this was just looking at one consequence of the falling
tree branch. There are many more. The point is, it can be the tiniest things
that ripple through time to entirely change who is populating earth a few
decades later.

In media, even when the change is "prevent World War II", today's world almost
always gets portrayed with the same characters and same personalities, that
somehow still all met. I don't blame the writers, though, it certainly makes
for a more entertaining story.

~~~
baddox
How could we estimate how resilient the timeline is to small changes? If no
small animal had been in the vicinity of the falling tree, perhaps that event
would be _much_ more insulated from humans.

~~~
breuleux
Think of it this way: if you take a single particle in the world changing
course, when it eventually collides with another, it will be with a different
particle that it would originally have collided with. Once that happens, two
particles now have a different course. Eventually, it'll be four, then eight,
and so on, until pretty much every particle's course is shifted. This global
shift is almost certain to happen eventually, and relatively quickly.

At a macroscopic scale, though, that won't look like much at all. Air
currents, temperature, and so on don't really depend on what specific
microstate the atmosphere is in. It's like shifting every object in a room at
random by a tenth of a millimeter, for all intents and purposes it doesn't
change anything. Usually. From time to time, some microscopic details can
snowball into macroscopic effects. Well, pretty much any small change anywhere
in the world is going to shuffle _all_ of these, everywhere in the world, a
few years down the road.

This means that, perhaps counter-intuitively, the more time passes, the more
likely a small change is to have an effect. First it will shift everything a
tenth of a millimeter, but eventually one of these shifts will snowball into a
one-millimeter shift... which will propagate everywhere, setting the stage for
a ten-millimeter shift, and so on. You'd be unlikely to notice, though,
because the proximal cause for a big change will almost always be a medium-
sized change, not a tiny one. Furthermore, it could take a very long time for
the effects to really ramp up: large scale natural processes are very robust.
Still, if a process has any kind of sensitivity to noise, it's just a matter
of time before it shifts.

~~~
kosievdmerwe
One simple way it can snowball is by affecting who gets cancer due to some
radiation being or not being absorbed.

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dcanelhas
The butterfly effect movie doesn't get this concept wrong IMO, since it's all
about the unpredictable results of past actions. It does however have some
logical plot holes large enough to fit a tornado through.

~~~
cortesoft
Yeah, I feel like pop culture in general gets that idea right (that a small
change can have a large effect, and it is unpredictable).

Jurassic Park also has gets that concept correct.

I feel like pop culture uses the butterfly effect as shorthand for "don't
change anything in the past because you have no idea how big a change it would
cause in seemingly unrelated things"

~~~
thwarted
_I feel like pop culture uses the butterfly effect as shorthand for "don't
change anything in the past because you have no idea how big a change it would
cause in seemingly unrelated things"_

This is the plot of Ray Bradbury's "A Sound of Thunder".

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roel_v
What caught my eye in this article was this sentence:

"This is a founding idea of chaos theory, whose advocates sometimes say Lorenz
helped dispel the Newtonian idea of a wholly predictable universe."

Maybe someone more well-versed in physics than myself can comment: is it
really so that 'metaphysical determinism' (so to say) is specific to Newtonian
physics, and so, that it's no longer the state of the art in our understanding
of nature? In other words, is there no room for Laplace's demon beyond
classical mechanics? That would take the concept of the nature of 'randomness'
beyond what I so far understood it to be.

~~~
rwallace
Metaphysical determinism still works in relativity. It also still works in
quantum mechanics if you accept the many-worlds interpretation.

That's quite orthogonal to the question of _practical predictability_. What
chaos theory shows is that, regardless of which model of microscopic physics
we are talking about, there are important aspects of the future that cannot be
predicted to high precision from within the universe.

~~~
jhrmnn
No, it doesn't work in quantum mechanics. Even under many-worlds, the result
of a measurement is fundamentally indeterminable until it is realized. In
many-worlds parlance—which "world" you end up in is indeterminable.

~~~
adrianN
You end up in all the worlds.

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DoreenMichele
I generally think of time travel fiction as a means to explore and develop
"what if" type thinking for purposes of enhanced decision making. So I tend to
cut them some slack for their myriad shortcomings. I find them useful for
developing pragmatic mental models.

I liked _The Butterfly Effect._ I also like _A sound of thunder_ wherein the
death of a moth alters the future.

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melling
“They expose the growing chasm between what the public expects from scientific
research - that is, a series of ever more precise answers about the world we
live in - and the realms of uncertainty into which modern science is taking
us.”

Perhaps it’s not a butterfly effect, but I like to think of the “butterfly
effect” of extra money invested in research, for example, paying off in large
future dividends.

For instance, if the transistor had been discovered 10 years earlier, would
the world be significantly different today? Imagine hundreds of other smaller
discoveries had happened sooner...

~~~
anyfoo
Of course the world would be entirely different today, but whether that
results in "large future dividends" is entirely unpredictable, and the whole
point of the butterfly effect.

Maybe some very talented people would have picked up a career based on
transistors before they were locked into something else and humanity would
have harnessed fusion power by now.

Maybe some aggressive people would have harnessed transistors for weapons
earlier and humanity would be eradicated by now.

Maybe due to a strange coincidence involving a transistor salesman on a trip
to Brazil and some records on his way back, we'd all be dancing Bossa Nova at
New Year's Eve, in honor of a decades old tradition.

"What if", is, in reality, pointless, as everything depends on everything (at
least within our Light Cone:
[https://en.wikipedia.org/wiki/Light_cone](https://en.wikipedia.org/wiki/Light_cone)
)

~~~
melling
i never said it would be predictable.

Also, I’m not trying to play what-if with the past, I’m trying to get you to
think about a different future where we make an additional investmen/effort to
learn more sooner.

~~~
anyfoo
That's noble, but a bit far away from the article, so I did not realize what
you meant. (Plus, I'd consider it likely that most people spending any time on
such rather academic concepts as the Butterfly Effect are well aware of the
payoff that science and education can bring, directly or indirectly.)

~~~
melling
“the concept that small events can have large, widespread consequences”

If the US spent 1% more on research every year, that would have a large
widespread consequence. If the top 10 ten countries did...

[https://en.m.wikipedia.org/wiki/List_of_countries_by_researc...](https://en.m.wikipedia.org/wiki/List_of_countries_by_research_and_development_spending)

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oarabbus_
I don't understand this article at all.

>A SmartMoney.com market analysis from 2007 cites Lorenz, then suggests that
hypothetical problems at Sony could affect a string of shippers, retailers,
and investors: "One butterfly, in this case a Japanese butterfly, sets off the
entire chain." Even applied to society, rather than nature, such claims merit
skepticism.

What's wrong with that? Is he blissfully unaware of, for example, the Maersk
hack and how it "butterfly effected" the entire chain?

~~~
quelltext
The author's point is that anytime the butterfly effect is used in this way
(identifying the singular cause of a chain) it insinuates that we can always
pinpoint such a butterfly if we look very hard or that there is one single
such butterfly causing the chain of effect in the first place. However Lorenz
(at least per the author) tried to make the exact opposite point. Among many
many variables if one slightly changes (e.g. flap or no flap of a butterfly's
wings somewhere) it can affect a lot, but we don't know which one.

I don't know it's wrong per say to use it as most people do but I see the
author'a point. It's often (falsely) used when there is a chain of ovents and
we know which thing caused that chain.

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rimliu
My favorite time-travel version is still _The Technicolor Time Machine_ by
Harry Harrison. It does away with this by having a single timeline. And if you
go to the past, it means you were already there "originally".

Related: [https://en.wikipedia.org/wiki/Novikov_self-
consistency_princ...](https://en.wikipedia.org/wiki/Novikov_self-
consistency_principle)

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bayesian_horse
Good news for the butterfly: Nobody affected by the storm will know WHICH
butterfly caused it.

Also there is a detail I don't understand: Lorenz talked about the pressure
differential underneath a butterfly's wing, being used in a large-scale
weather simulation. But given the computing resources and thus the limited
resolution of such simulations at the time, I wonder how big that butterfly
must have been.

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cairo_x
Billions of events happen regardless of billions and billions of previous
events having happened.

