And so I thought well, okay, go ahead And he said a shaman told me that my grandmother is still alive because of quantum mechanics Is this right?

於是我想，好吧，說吧 他說，一個巫師告訴我，我的祖母還活著，是因為量子力學的緣故，是這樣嗎？

I had to pause for a moment and try to understand and after thinking about this for a while I came to the conclusion.

我不得不停頓片刻，試著去理解，在思考了一會兒之後，我得出了結論。

It's not entirely wrong But the thing is it's got nothing to do with quantum mechanics.

但問題是，這與量子力學毫無關係。

It's actually got something to do with Einstein's theory of special relativity It's all about the reality of time It's all about the question whether the present moment this now which we experience ourselves Whether this is of fundamental importance There are a lot of things like those big existential questions about afterlife that physics can actually tell us something about My name is Sabine Hossenfelder I'm a physicist and research fellow at the Frankfurt Institute for Advanced Studies And I have a book that's called existential physics a scientist's guide to life's biggest questions Before Einstein, time was this universal parameter We all shared the same moment of time the same moment of now that we could all agree on But then Einstein came and he said well, it's not that simple And the major reason for this is that the speed of light is finite And nothing can go faster than the speed of light It's the same for all observers and This sounds like a really innocent assumption, but it has a truly Fundamental consequence which is fairly easy to understand actually if you ask yourself Whether you know if the screen in front of you is actually there right now Naively would say yes, of course.

這跟愛因斯坦的狹義相對論有關 這跟時間的現實性有關 這跟當下這個我們親身經歷的 "現在 "是否具有根本重要性有關在愛因斯坦之前，時間是一個普遍存在的參數 我們共享同一個時間點，同一個我們都能認同的時間點 但後來愛因斯坦出現了，他說事情沒那麼簡單 主要原因是光速是有限的，沒有什麼能比光速更快

It's there I mean, I'm holding it my hand or I see it directly in front of me But we just learned that the speed of light is finite and nothing can go faster than the speed of light So everything that you experience everything that you see You see it as it was a tiny little amount of time in the past So, how do you know that anything exists right now?

但我們剛剛知道，光速是有限的，沒有任何東西的速度能超過光速，所以你所經歷的一切，你所看到的一切，都是在過去的一小段時間裡看到的，那麼，你怎麼知道任何東西現在就存在呢？

What do you even mean by now?

你說現在是什麼意思？

so this is the problem that comes up in Einstein's theory of special relativity and Einstein tried to construct A notion of now in this new theory and he failed So imagine you're looking straight ahead and there's a train going through to your line of sight say from the left to the right And on the train, there's your friend.

這就是愛因斯坦狹義相對論中出現的問題 愛因斯坦試圖在這個新理論中構建一個 "現在 "的概念，但他失敗了 想象一下，你正直視前方，有一列火車從你的視線中穿過 比如說從左向右，火車上有你的朋友

So let's call her Alice Now, let's also imagine that at the exact moment that Alice who's standing in the middle of the train is looking straight at you There are light flashes going off on both ends of the train And the question is did these light flashes happen at the same time?

那麼我們就叫她愛麗絲吧！現在，讓我們再想象一下，就在站在火車中間的愛麗絲直視著你的那一刻，火車的兩端都有燈光閃爍，問題是這些燈光閃爍是同時發生的嗎？

Now if you want to answer this question looking at the train, that's pretty straightforward There are those light flashes going off.

現在，如果你想通過火車來回答這個問題，那就非常簡單了。

They both come from sources that are the same distance from you So, of course you see them at the same time But how does the same thing look from Alice's perspective?

它們都來自與你距離相同的信號源，所以你當然能同時看到它們，但從愛麗絲的角度看，同樣的事情又是怎樣的呢？

The light flashes go off, but while the light travels towards her She's moving towards one of the light sources and away from the other So the one path of the light is shorter and the other one is longer So from Alice's perspective the light flash from the front of the train arrives earlier than the one from the back So she would say no, they did not happen at the same time And now the important point is that this is relativity Neither of them is right and neither of them is wrong.

是以，從愛麗絲的角度來看，火車前方的閃光比後方的閃光來得早，所以她會說不對，它們不是同時發生的，現在重要的一點是，這是相對論。

They both have an equally valid perspective And what do we conclude from this?

他們的觀點都同樣正確，那麼我們能從中得出什麼結論呢？

Well, we conclude from this that there is no Unambiguous notion to define what happens now.

好吧，我們由此得出結論，沒有一個明確的概念來定義現在發生的事情。

It depends on the observer So they're both right and If you follow this logic to its conclusion Then the outcome is that every moment could be now for someone and that includes all moments in your past and It also includes all moments in your future So this impossibility to define one notion of now that we all agree on is called the relativity of simultaneity and it's super important because it tells us that fundamentally this Experience of now that we all share is meaningless So the mathematical framework that Einstein came up with to make sense of this absence of now and the finiteness of the speed of light and the relativity of Simultaneity is that he combined space with time to one common entity which is called space-time and More specifically because the present moment has no fundamental significance this entire space-time Exists in the present moment and it's become known as the block universe In the block universe the past the present and the future exist in the same way There's just no way that you can single out one particular time as special So the past in which your grandma is still alive exists the same way as this present moment Now there's another way to look at this idea that people who have sadly deceased Do in some sense still exist and it's because of the way that all the fundamental laws of nature that we know work They don't destroy information.

這取決於觀察者 所以他們都是對的 如果你按照這個邏輯得出結論 那麼結果就是 每個時刻對某人來說都可能是現在 這包括你過去的所有時刻 也包括你未來的所有時刻愛因斯坦想出了一個數學框架來解釋這種 "現在 "的缺失、光速的有限性和同時性的相對性，他把空間和時間合併為一個共同的實體，稱為空間-時間。更具體地說，因為當下沒有根本意義，所以整個空間--時間就存在於當下，而當下又被稱為 "時間"。更具體地說，因為當下沒有根本意義，所以整個時空都存在於當下，這就是所謂的積木宇宙 在積木宇宙中，過去、現在和未來都以同樣的方

The only thing that they do is that they Rearrange the matter and radiation and everything that's in the universe They just give you the rules for how to put them in different places with different velocities but you can apply those rules forward and backward and this means if you had a really really good computer you can in principle always Find out what happened earlier.

他們所做的唯一一件事就是重新排列宇宙中的物質、輻射和萬事萬物，他們只是給了你如何以不同的速度把它們放在不同地方的規則，但你可以把這些規則向前和向後應用，這意味著如果你有一臺非常非常好的計算機，你原則上總能找出之前發生了什麼。

So in this sense information cannot get destroyed it can however become for practical purposes impossible to retrieve.

是以，從這個意義上說，資訊是不會被銷燬的，但實際上它可能變得無法檢索。

There are two cases that Physicists have considered where information might get destroyed that have so far not been resolved One of them is information that falls into a black hole we don't actually know what happens with it and the other one is the Mysterious measurement process in quantum mechanics, which is also an unresolved problem So if someone you knew dies then of course we all know that you can no longer communicate with this person and that's because the information that made up their personality it disperses into very subtle correlations in the remains of their body which become entangled with all the particles around them and slowly slowly they spread into Radiation that disperses throughout the solar system and eventually throughout the entire universe But this is a very anthropomorphic thing.

物理學家曾考慮過兩種資訊可能被破壞的情況，但至今尚未解決。一種情況是資訊落入黑洞，我們實際上並不知道會發生什麼；另一種情況是量子力學中的神祕測量過程、如果你認識的某個人死了，我們當然都知道你無法再與這個人交流，這是因為構成他人格的資訊在他身體的殘骸中分散成非常微妙的相關性，這些相關性與周圍的所有粒子糾纏在一起，慢慢地，慢慢地，它們擴散成輻射，散佈到整個太陽系，最終散佈到整個宇宙。

It's very tied to our own existence and Who knows what's going to happen in a billion years or something to the nature of humans?

這與我們的生存息息相關，誰知道十億年後人類的本性會發生什麼變化呢？

Maybe there'll be some cosmic consciousnesses, which will also be spread out and this information will become accessible again So, I know it sounds crazy but for all we know about the fundamental laws of nature about Einstein's theories and about the way that our Current theories work.

所以，我知道這聽起來很瘋狂，但就我們所知，愛因斯坦的理論和我們目前的理論都是關於自然界的基本規律的。

It seems that our existence actually transcends the passage of time there is something timeless about the information that makes up us and everything else in the universe and I think that's a really deep spiritual insight that we get directly from studying the foundations of physics and I have to admit that I Personally find it really hard to make intuitive sense of it It's one way to look at the maths and say okay.

我們的存在似乎超越了時間的流逝，構成我們和宇宙萬物的資訊具有永恆性，我認為這是我們直接從物理學基礎研究中獲得的深刻的精神洞察力，我不得不承認，我個人覺得很難直觀地理解這一點。

This is how it works These are the conclusions that we draw from our observations and the mathematics describes it correctly It's another thing entirely to make sense of this in your everyday life But as a physicist, I trust the process of knowledge discovery that comes from using the scientific method And so I take this seriously Get smarter faster with videos from the world's biggest thinkers and To learn even more from the world's biggest thinkers get big think plus for your business

這就是它的工作原理 這些是我們通過觀察得出的結論，數學對其進行了正確的描述 在日常生活中如何理解這些完全是另一回事，但作為一名物理學家，我相信通過使用科學方法來發現知識的過程，是以我對此非常重視 通過觀看世界頂級思想家的視頻更快地變得聰明，並從世界頂級思想家那裡學習更多知識，為您的企業獲取 big think plus。