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撰文 | Frank Wilczek
翻譯 | 胡風(fēng)、梁丁當
來(lái)源：蔻享學(xué)術(shù)
中文版
自 1950 年以來(lái)，基礎性物理研究對技術(shù)的貢獻幾乎為零。這是因為物理學(xué)家太過(guò)沉溺于對美的追求嗎？
如果一項研究的思想與實(shí)踐脫節，但想法特別漂亮，那么物理學(xué)家應該為這樣的研究感到內疚嗎？又應該如何評價(jià)這類(lèi)工作？在現實(shí)生活中，科學(xué)家常常會(huì )遇到這樣的問(wèn)題。一方面是盡情展開(kāi)想象的翅膀所帶來(lái)的愉悅與可能的榮耀；另一方面是朝著(zhù)既定目標穩步前進(jìn)而得到的實(shí)際回報。在兩者之間，我們必須進(jìn)行權衡。
在基礎性物理研究的前沿領(lǐng)域，這兩者的沖突尤其突出?；A性物理研究旨在解析那些無(wú)法用既有定律解釋的物理現象，它們只能通過(guò)發(fā)現新的定律來(lái)理解。一直到20世紀初，基礎性物理研究本身也是最重要的應用物理學(xué)之一。通過(guò)揭示原子和光的量子秘密，物理學(xué)為化學(xué)、材料科學(xué)和工程學(xué)奠定了基礎。
1929年，物理學(xué)家保羅·狄拉克 (Paul Dirac) 宣稱(chēng)：“對于大部分的物理與整個(gè)化學(xué)，它們的數學(xué)理論所依照的基本物理定律，我們都已知曉?！蔽覀儗@些基本定律的驗證已經(jīng)遠遠超過(guò)了實(shí)際應用所要求的精準度，以至于我們放寬了對“實(shí)際應用”的定義。印證這項成功的是一個(gè)頗具諷刺意味的事實(shí) ：20世紀50年代之后，基礎性物理研究領(lǐng)域的發(fā)現對技術(shù)幾乎沒(méi)有任何貢獻。
在基礎性物理研究中仍然存在一些重要而“不實(shí)際”的問(wèn)題，比如宇宙的大部分質(zhì)量源于一種所謂的“暗物質(zhì)”——一種不是電子、光子、夸克、膠子或中微子的物質(zhì)。盡管研究人員費盡了心力去探索暗物質(zhì)這類(lèi)問(wèn)題，研究的進(jìn)展依然緩慢。那么，一個(gè)雄心勃勃的理論物理學(xué)家又能做什么呢？
千百年來(lái)數學(xué)家一直面對著(zhù)一個(gè)類(lèi)似的問(wèn)題 ：到底是選擇純粹性的研究還是應用性的工作？在G · H · 哈迪 (G.H. Hardy) 于1940年出版的《數學(xué)家的道歉》(A Mathematician's Apology) 一書(shū)中，他為純粹的研究提供了一個(gè)硬核的理由 ：“可是一個(gè)普通的應用數學(xué)家的立腳點(diǎn)，在某種程度上，是不是有點(diǎn)可憐？‘想象的’宇宙要遠比這個(gè)笨拙構建的‘真實(shí)’宇宙美麗得多?！?/p>
而 另 一 方 面， 約 翰 · 馮 · 諾 依 曼 (John von Neumann) 在 他1947年 的 文 章《 數 學(xué) 家 》(The Mathematician) 中譴責了這種純粹性 ：“當一門(mén)數學(xué)學(xué)科遠離了它的經(jīng)驗來(lái)源時(shí)……它將面臨嚴重的危險。它變得越來(lái)越美學(xué)化，到了這個(gè)地步，我覺(jué)得唯一的補救辦法就是回到原點(diǎn)，即重新或多或少地結合一些實(shí)際的想法?！?/p>
我認為馮 · 諾依曼在這個(gè)爭論中占了上風(fēng)。在他的職業(yè)生涯中，他利用數學(xué)天賦成為了博弈論和計算機科學(xué)的先驅?zhuān)瑥亩诩兛茖W(xué)與實(shí)用技術(shù)方面都留下了巨大的科學(xué)遺產(chǎn)。
簡(jiǎn)單來(lái)說(shuō)，一些科學(xué)家更注重于理想的美，另一些則更看重經(jīng)驗真理。我自己的方法是 ：遵循哥白尼、伽利略和開(kāi)普勒的偉大傳統，把美作為真理的向導。這種研究方法在純粹的基礎性物理研究中已經(jīng)變得比較困難與緩慢了，因為我們已經(jīng)了解了太多。但這種知識積累所帶來(lái)的“詛咒”也有好的一面，它讓我們有信心在想象與現實(shí)之間建立起一座橋梁。
所以，不！我不會(huì )因為有一個(gè)漂亮的主意而感到內疚。但我不能，也不愿忘記我心中的英雄理查德·費曼 (Richard Feynman) 含蓄的警示 ：“不管你的理論有多美，也不管你有多聰明，如果它與實(shí)驗不符，那就是錯的?！?/p>
英文版
ILLUSTRATION: TOMASZ WALENTA
Since the 1950s, fundamental physical research has made little contribution to technology. Arephysicists too focused on beauty?
Should physicists feel guilty about working on ideas with no real-world consequences, just because they’re intellectually beautiful? How should such work be evaluated? These questions arise often in the life of research scientists. We have to weigh the pleasure and potential glory of imaginative flights against the more solid rewards of steady progress towards clear goals.
This dilemma has become acute at the frontier of fundamental physics. Until the early 20th century, fundamental physics—that is, the study of phenomena that can’t be explained by existing laws but require the discovery of new ones—was also the most important applied physics. By unveiling the quantum secrets of atoms and light, physics was laying the foundations for chemistry, materials science and engineering.
In 1929, the physicist Paul Dirac announced that “the underlying physical laws necessary for the mathematical theory of a large part of physics and the whole of chemistry are… completely known.” Those basic laws have now been tested with far greater accuracy than is required for practical applications—even allowing for a generous interpretation of “practical.” An ironic demonstration of this triumph is that since the 1950s discoveries in fundamental physics have contributed little if anything to technology.
There are still some big “impractical” problems in fundamental physics, such as the fact that most of the mass in the universe is made of something that is not electrons, photons, quarks, gluons or neutrinos—the so-called “dark matter.” But experimenters and observers must sweat blood to probe those problems, and progress has been slow. So, what’s an ambitious theoretical physicist to do?
Mathematicians have faced a similar choice between pure and applied work for millennia. In his 1940 book “A Mathematician’s Apology,” G.H. Hardy made a hard-core case for purity: “But is not the position of an ordinary applied mathematician in some ways a little pathetic?…‘Imaginary’ universes are so much more beautiful than this stupidly constructed ‘real’ one.”
On the other hand, John von Neumann rebuked purity in his 1947 essay “The Mathematician”: “As a mathematical discipline travels far from its empirical source…it is beset with very grave dangers. It becomes more and more purely aestheticizing,… whenever this stage is reached, the only remedy seems to me to be the rejuvenating return to the source: the re-injection of more or less directly empirical ideas.”
I think von Neumann has the better of this argument. In his own career, he used his mathematical talents to pioneer fields like game theory and computer science, leaving a titanic legacy, practical as well as intellectual.
To put it over-simply, some scientists focus on ideal beauty, others on empirical truth. My own approach, following a great tradition going back to Copernicus, Galileo and Kepler, has been to use beauty as a guide to truth. That approach has become difficult and slow in pure fundamental physics, basically because we know so much already. But that “curse” of knowledge empowers us to build bridges connecting imagination to reality with confidence.So no, I don’t feel guilty about working out pretty ideas. But I can’t and don’t want to shake off my hero Richard Feynman’s implicit challenge: “It doesn’t matter how beautiful your theory is, it doesn’t matter how smart you are. If it doesn’t agree with experiment, it’s wrong.”
Frank Wilczek
弗蘭克·維爾切克是麻省理工學(xué)院物理學(xué)教授、量子色動(dòng)力學(xué)的奠基人之一。因發(fā)現了量子色動(dòng)力學(xué)的漸近自由現象，他在2004年獲得了諾貝爾物理學(xué)獎。
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