我們生活在虛擬世界中嗎？| 諾獎得主Wilczek專欄_風聞

Frank Wilczek

弗蘭克·維爾切克是麻省理工學院物理學教授、量子色動力學的奠基人之一。因在夸克粒子理論（強作用）方面所取得的成就，他在2004年獲得了諾貝爾物理學獎。

撰文 | Frank Wilczek (麻省理工學院教授、2004年諾貝爾獎得主）

翻譯 | 胡風、梁丁當

責編**| 隋幸迅**

來源：蔻享學術

我們生活在虛擬世界中嗎？

Are We Living in a Simulated World?

多半不是。但這個想法足夠瘋狂，以至於有必要認真討論一下。

Probably not, but the idea is just crazy enough to be worth taking seriously.

《黑客帝國》這部電影為我們開了一個巨大的腦洞：我們生活的現實世界只不過是由一台超強計算機所創造出來的虛擬世界。這個想法足夠瘋狂，以至於我們有必要認真討論一下。但在此之前，我們需要區別兩個不同的問題。

在《黑客帝國》中，強大的計算機創造出了一個虛擬世界。

第一個是：有沒有可能存在這樣一個包羅萬象的精神世界，它是由抽象的數據形成的，而不是像表面上看上去那樣建立在物質的基礎上？

第二個問題則是：我們真實經歷的這個世界——由物理學定律和宇宙學事實所描述的世界——是不是這樣的一個虛擬世界？

The idea that the world we experience is an illusion being fed to us by powerful computers,  popularized by the “Matrix” movies, is just crazy enough to be worth taking seriously. But if we’re going to be serious, it is important to distinguish between two very different questions. First: Could there be a richly experienced mental world that is not made of matter, as it appears to be, but of abstract data? And second: Is the world we actually experience—the universe as described by the laws of physics and the facts of cosmology—such a world?

對於前者，答案無疑是肯定的。事實上人在處於異相睡眠時會做夢。我們每天大約有一兩個小時的時間，完全沉浸在大腦產生的虛幻感知中。在夢裏，我們所看到的物體其實是大腦中不同形式的電信號。虛擬現實與此類似。虛擬現實技術通過各種數據流創造出我們所感知到的一切。可是夢會醒，而目前的虛擬現實技術還不能夠提供包羅萬象的體驗。在大部分的時間裏，我們仍然生活在一個共同的現實世界，在飲食人生中漸漸老去。但是很多專家認為，總有一天我們能夠實現基於電子線路的人工心靈——它可以模擬人的思考過程，包括人的自我意識。這種存活在程序裏的人工心靈，雖然嵌在物理真實裏，卻又能夠超脱其外。

The answer to the first question is pretty surely yes. In fact, humans occupy self-generated mind worlds for an hour or two each day, when we dream during REM sleep. The objects we see in dreams are just patterns of electrical excitation in our brains. Analogously, virtual reality tunes us into data streams that we perceive as objects.

Dreams are transient, and at present virtual reality is not an all-encompassing experience. We humans still live the bulk of our lives in a shared reality, where we do things like eat, drink and get older. But many experts think that one day it will be possible to build artificial minds, wholly based on electronic circuitry, that will simulate human thought processes, including self awareness. Such artificial minds, inhabiting programmed worlds, could well be oblivious to physical reality, despite being embedded within it.

對於第二個問題——即我們所感知到的世界是不是由這些抽象的數據創造出來的，最佳的答案是：不是的。首先，如果我們所經歷的物理世界真是由計算機模擬出來的，它就會帶來一個更根本的問題，即這台計算機本身又是由什麼構成的呢？撇開這些細節不談，就描述我們這個世界的物理學來説，它在很多方面都不像是一個高效的世界模擬器的產物。比如，我們對物理定律最精確的表述是建立在時空是平滑連續的這個思想上的。可如果我們要在模擬中使用連續數字而不是0和1，保持精確性的難度就會高很多。

To our second question—is our own perceived world manufactured, in fact, from such abstract data—the best answer is pretty surely no. First of all, the idea that the physical world we experience is a computer simulation begs a basic question: What is the computer made of?

Leaving that detail aside, there are many aspects of physics in our world that do not look like the product of an efficient world simulator. For example, our most accurate formulation of the laws of physics depends on the idea that space and time are smooth and continuous. When you work with continuous numbers, instead of 0 and 1, it becomes much more difficult, in a simulation, to maintain precision.

更一般地講，我們的世界包含了很多隱藏的複雜性。比如我們可以根據基本定律計算質子的性質，但這些計算是極其複雜的。如果用如此難以計算的成分來構建一個模擬的世界，這實在是一個很糟糕的策略。

More generally, our world contains a lot of hidden complexity. We can calculate aproton’s  properties based on fundamental laws, but those calculations are extremely complicated. It would be a poor strategy to build a simulated world out of such hard-to-compute ingredients.

《黑客帝國》關中於超強計算機創造虛擬世界的這個幻想其實並不新鮮。它不過是唯心主義哲學觀念在計算機時代的改良版，認為所謂的物質現實的核心是精神而非物質。

The basic “Matrix” fantasy isn’t new. It is a computer-age variation on the philosophical notion of idealism, according to which so-called physical reality is at base mental, not material.

18世紀的哲學家伯克利大主教就曾説過：世界是上帝心理活動的映射。但是塞繆爾·約翰遜（Samuel Johnson）並不贊成這個理論。正如他的傳記作家詹姆斯·博斯韋爾（James Boswell）所描述的：“我們站在那兒，談論着伯克利大主教的物質不存在、萬物皆是我們感知的詭辯……我永遠都忘不了約翰遜當時情緒激昂的樣子。他狠狠地往一塊大石頭上踢了一腳，收回腳後，他説道，‘就這樣，我便能駁倒他。’ ”那一腳真是勝過千言萬語。想象一個虛擬的世界當然是可能的。但如果我們的世界真的是虛擬的，那創造它的心靈——天曉得它是由什麼構成的——的工作方式實在是太神秘了。

According to the 18th-century philosopher Bishop Berkeley, the world reflects activity in the mind of God. But Samuel Johnson was not impressed with this theory, as astory told by his biographer James Boswell relates:

“We stood talking for some time together of Bishop Berkeley’s ingenious sophistry to prove the nonexistence of matter and that everything in the universe is merely ideal.… I never shall forget the alacrity with which Johnson answered, striking his foot with mighty force against a large stone, till he rebounded from it—‘I refute it thus.’”

That kick is worth a thousand words. It is quite possible to imagine a simulate world. But if ours is such a world, then the mind that creates it, made of God knows what, works in very mysterious ways.

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