So the butterfly effect, the idea is that some systems are sufficiently unpredictable that a small perturbation, the small change in their initial conditions and result in vastly different outcomes you have, whether whether it's complicated and maybe whether butterfly flaps its wings or not can be the thing that makes the difference as to whether or not there's a tornado and there's nothing technically wrong with this.

是以，蝴蝶效應的想法是，一些系統是充分不可預測的，一個小的擾動，其初始條件的小變化，並導致巨大的不同的結果，你有，無論它是否複雜，也許蝴蝶是否拍打它的翅膀，可以是使差異的事情，是否有一個龍捲風，這在技術上沒有錯。

Like the whole point of complex, nonlinear chaotic systems is that small changes in the initial conditions can result in big changes in the final state.

就像複雜的非線性混沌系統的全部意義在於，初始條件的微小變化會導致最終狀態的巨大變化。

You look at a chaotic pendulum.

你看一個混亂的鐘擺。

Small changes in where the different pendulums are initially placed, results in very different patterns After a while.

不同的擺件最初放置位置的微小變化，在一段時間後導致了非常不同的模式。

The idea is very true that small changes in initial conditions can result in big changes in the final state.

這個想法非常正確，初始條件的微小變化可以導致最終狀態的巨大變化。

However, I don't like the butterfly effect.

然而，我不喜歡蝴蝶效應。

There are two main reasons why I don't like the butterfly effect.

我不喜歡蝴蝶效應的主要原因有兩個。

The first one is simply that it's talking about whether and whether it's complicated and there's tons of amazing chaotic systems that have really high sensitivity to initial conditions that are way simpler than the weather.

第一個簡單的是，它在談論是否以及是否複雜，有大量驚人的混沌系統，對初始條件有非常高的敏感性，比天氣要簡單得多。

A double pendulum, for example, or three planets orbiting each other.

例如，一個雙擺，或三顆行星相互繞行。

These are all chaotic systems, but they're also very simple and they help explain what is it about?

這些都是混亂的系統，但它們也非常簡單，它們有助於解釋它是怎麼回事？

A system that makes it chaotic rather than just being busy and having lots of stuff going on, you can have a chaotic system that is very simple and very straightforward, it doesn't have to be busy and complex to be chaotic.

一個讓它變得混亂的系統，而不僅僅是忙碌和有很多事情要做，你可以有一個混亂的系統，它是非常簡單和非常直接的，它不一定要忙碌和複雜才是混亂的。

Yeah.

是的。

Mhm.

嗯。

The second reason is really the one that I care the most about.

第二個原因確實是我最關心的一個原因。

It's that the butterfly effect is normally described as if the butterfly is causing the tornado, this doesn't really jive with our normal notion of causality, right?

這是蝴蝶效應通常被描述為如果蝴蝶導致龍捲風，這與我們正常的因果關係概念並不一致，對嗎？

Like butterflies don't cause tornadoes me blowing isn't going to cause a tornado in Kansas, you blow it again, isn't gonna stop the tornado.

就像蝴蝶不會引起龍捲風，我吹是不會在堪薩斯州引起龍捲風的，你再吹，也不會阻止龍捲風。

So how do you talk about causality and the butterfly effect?

那麼，你是如何談論因果關係和蝴蝶效應的呢？

They're a couple used always to think about this one is called the probability of necessity.

他們是一對夫婦，總是用來思考這個叫作必然性概率的問題。

How likely as a result will still happen if the cause didn't happen.

如果原因沒有發生，作為結果的可能性有多大，仍然會發生。

So, if you have a giant flood, can you say climate change caused it?

那麼，如果你有一場巨大的洪水，你能說是氣候變化造成的嗎？

Given that we have climate change, 100 year flood is far more likely to happen.

鑑於我們有氣候變化，100年一遇的洪水發生的可能性要大得多。

In fact, a 500 year flood is far more likely to happen.

事實上，500年一遇的洪水發生的可能性要大得多。

Climate change on its own is not sufficient to cause it because you need a bunch of other factors to align.

氣候變化本身並不足以導致它，因為你需要一堆其他因素的配合。

But climate change is necessary to cause it because these other factors, even if they had aligned without climate change, they maybe wouldn't have resulted in such a bad flood.

但氣候變化是導致它的必要條件，因為這些其他因素，即使沒有氣候變化，它們也是一致的，也許不會導致如此嚴重的洪水。

So climate change is a necessary cause, but not a sufficient cause of the flood in a perfectly deterministic butterfly effect situation of course, is the butterfly has to flap its wings in order for the effect, the final tornado to happen.

是以，氣候變化是一個必要的原因，但不是洪水的充分原因，當然，在一個完全決定性的蝴蝶效應的情況下，是蝴蝶必須扇動它的翅膀，以使效果，最後的龍捲風發生。

However, there's plenty of other little things, little changes that also could cause a tornado to happen or not happen.

然而，還有很多其他的小事情，小變化也可能導致龍捲風發生或不發生。

Regardless of whether not the butterfly flaps its wings with a nonlinear system, a small change to a butterfly over there or butterfly over there or butterfly over there could also result in the tornado happening or not happening.

不管非線性系統的蝴蝶是否扇動翅膀，那邊的蝴蝶或那邊的蝴蝶或那邊的蝴蝶的一個小變化也可能導致龍捲風發生或不發生。

And so the butterfly is not necessary to cause the tornado.

是以，蝴蝶沒有必要引起龍捲風。

And the other factor is called the probability of sufficiency is the butterfly sufficient to cause the tornado.

而另一個因素被稱為充分的概率，就是足以引起龍捲風的蝴蝶。

If I pull a leaf off of a tree, I'm definitely sufficient cause for the leaf leaving the tree, but I'm not a necessary cause because all these leaves are gonna leave the trees soon anyway.

如果我從樹上拔下一片葉子，我肯定是葉子離開樹的充分原因，但我不是必要原因，因為所有這些葉子反正很快就會離開樹。

We don't go around worrying that every single time a butterfly flapped its wings it's gonna cause a tornado and that has to do with the sufficiency of a butterfly being able to cause a tornado.

我們不會到處擔心每一次蝴蝶扇動翅膀都會引起龍捲風，這與蝴蝶能夠引起龍捲風的充分性有關。

Mhm.

嗯。

In short, butterflies are not necessary to cause tornadoes because tornadoes happen without butterflies and butterflies flapping their wings are not sufficient to cause tornadoes because if a butterfly flaps its wings, we don't all start freaking out about the tornado that's about to happen.

簡而言之，蝴蝶不是引起龍捲風的必要條件，因為龍捲風的發生不需要蝴蝶，蝴蝶拍打翅膀也不足以引起龍捲風，因為如果蝴蝶拍打翅膀，我們不會都開始為即將發生的龍捲風而感到恐慌。

The other way to understand the causality.

另一種理解因果關係的方式。

The butterfly effect is to think about the kind of stability of the fine tune nature, right?

蝴蝶效應是要考慮到微調性質的那種穩定性，對嗎？

Like everything else in the world has to be so perfectly set up in order for a situation to arise where butterfly flaps its wings and that is the tipping point for the tornado.

就像世界上的其他一切都必須是如此完美的設置，以便出現蝴蝶扇動翅膀的情況，這就是龍捲風的轉捩點。

This is an incredibly fine tune scenario and any slight change in any of the other parameters, right?

這是一個令人難以置信的微調方案，其他任何參數的任何輕微變化，對嗎？

Like a different butterfly flapping its wings, a leaf falling off a tree three seconds earlier.

就像一隻不同的蝴蝶在拍打翅膀，一片樹葉在三秒鐘前從樹上掉下來。

All of those things are likely to change whether or not the butterfly wings actually cause a tornado or not and most of them probably mean that the butterfly wings don't cause the tornado.

所有這些事情都有可能改變蝴蝶翅膀是否真的導致龍捲風，而其中大部分可能意味著蝴蝶翅膀不會導致龍捲風。

So in my mind, the problem is that the butterfly effect misses the entire point of chaos.

所以在我看來，問題在於蝴蝶效應忽略了混沌的全部意義。

Chaos is about nonlinear systems that are sensitive to their initial conditions and that are very hard to predict.

混沌是關於非線性系統，對其初始條件很敏感，而且很難預測。

The butterfly effect.

蝴蝶效應。

Kind of makes it seem like we can predict that if the butterfly flaps its wings, a tornado is going to happen now.

這有點像我們可以預測，如果蝴蝶扇動翅膀，現在就會發生龍捲風。

Behind chaos is that things are very hard to predict predictability is one of the things that you lose in a chaotic system, Even if it's deterministic, you can't predict because you can't actually know the initial conditions with enough sensitivity to make a useful prediction.

混沌的背後是事物很難預測，可預測性是你在混沌系統中失去的東西之一。即使它是確定性的，你也無法預測，因為你實際上無法以足夠的敏感度知道初始條件，以做出有用的預測。

That's why I think the butterfly effect is maybe the worst example of chaos because it really places too much emphasis on causality and predictability when the whole point is unpredictability.

這就是為什麼我認為蝴蝶效應也許是最糟糕的混沌例子，因為它真的太強調因果關係和可預測性了，而整個觀點是不可預測的。

So I spent all this time talking about what I don't like about the butterfly effect.

所以我花了這麼多時間談論我不喜歡蝴蝶效應的原因。

But I feel like I need to then replace it with something.

但我覺得我需要用一些東西來取代它。

You can't just undermine something and leave a vacuum.

你不能只是破壞一些東西，留下一個真空。

So what should be used instead of the butterfly effect is a good example of chaos.

所以應該用什麼來代替蝴蝶效應，是一個很好的混沌的例子。

The best thing I've come up to replace it is that too many butterflies effect?

我想出的最好的替代方法是，太多的蝴蝶效應？

The idea being that in a chaotic system there are so many tiny, tiny little places where a slight change can change the outcome of the entire system that you can't keep track of them all.

這個想法是，在一個混亂的系統中，有許多微小的地方，一個輕微的變化就能改變整個系統的結果，你不可能把它們都記下來。

So it's too many butterflies to keep track of this.

所以說，這裡面的蝴蝶太多，記不住了。

Butterfly flaps its wings here, that butterfly flaps its wings there, this one there, the grass moves, the wind blows etcetera and you can't make predictions based on this because there's so much uncertainty of course with simple chaotic systems like a chaotic pendulum, it's not a butterfly situation is just how steady is your hand when you set the pendulum going.

蝴蝶在這裡扇動翅膀，那隻蝴蝶在那裡扇動翅膀，這隻蝴蝶在那裡扇動翅膀，草在動，風在吹等等，你不能根據這些進行預測，因為有很多不確定性，當然，對於簡單的混沌系統，如混沌鐘擺，它不是一個蝴蝶的情況，只是當你設置鐘擺時，你的手有多穩定。

So yeah, get rid of the butterfly effect, replace it with too many butterflies effect or the too many butterflies to keep track of effect and there's the end of my rant.

是以，是的，擺脫蝴蝶效應，用太多的蝴蝶效應或太多的蝴蝶來跟蹤效應取代它，這就是我的咆哮的結束。

I hope you enjoyed it.

我希望你喜歡它。

I hope there's some nice nature along the way and uh enjoy your butterflies, enjoy your tornadoes.

我希望沿途有一些漂亮的自然風光，呃享受你的蝴蝶，享受你的龍捲風。

It may not surprise you to hear that.

聽到這個消息，你可能不會感到驚訝。

I've been working through a causality textbook recently, actively engaging with material like this is one of the best ways to learn something new and that's exactly the idea behind brilliant.

我最近一直在研究一本因果關係的教科書，主動參與這樣的材料是學習新東西的最好方法之一，這正是輝煌背後的想法。

This video sponsor, brilliant, helps you learn science and math through their hands on highly visual courses.

這個視頻贊助商，精彩紛呈，通過他們手把手的高度可視化課程，幫助你學習科學和數學。

And I think you might particularly like their interactive course on the fundamentals of statistics, a key prerequisite to learning about causality and essential for analyzing results in basically every other field of science.

我想你可能會特別喜歡他們關於統計學基礎知識的互動課程，這是學習因果關係的一個關鍵前提，對於分析基本上所有其他科學領域的結果都是必不可少的。

To sign up for brilliant for free, go to brilliant dot org slash minute physics.

要免費註冊輝煌，請到輝煌點org斜線分鐘物理學。

The 1st 200 people will get 20% off an annual premium subscription with full access to all of brilliance courses and puzzles like the fundamentals of statistics course.

前200人將獲得20%的年度高級訂閱，可以完全訪問所有的輝煌課程和謎題，如統計學基礎課程。

Again, that's brilliant dot org slash minute physics.

同樣，這是輝煌的點狀組織斜線分鐘物理學。

And thanks to brilliant for their support, I wish you could find a butterfly, but I don't think it's that likely here in october in Montana.

並感謝輝煌的支持，我希望你能找到一隻蝴蝶，但我認為在蒙大拿州的十月，這是不可能的。

It is pretty though.

不過，它很好看。

Yeah.

是的。