愛因斯坦vs.牛頓
EINSTEIN & NEWTON: GENIUS COMPARED

 - 論才智與氣質，這兩位科學巨人都很相似。
- The two scientific giants were alike in intellect and temperament

作者╱萊特曼 ( Alan Lightman )
譯者╱王道還

 如何才能衡量阿爾伯特‧愛因斯坦的天才？
How can we measure the genius of Albert Einstein?

　　在許多方面，這都是不可能的任務。要是我們回溯過去幾個世紀，曆數一個個科學大師的成就，例如馬克士威、波茲曼、達爾文、巴斯德、拉瓦錫，一直到牛頓，我們才找到堪與愛因斯坦比肩的人物。牛頓之前，可能一個都沒有。

　　In many ways, the task is not possible. If we journey back through the centuries, passing such towering figures as James Clerk Maxwell, Ludwig Boltzmann, Charles Darwin, Louis Pasteur, Antoine Lavoisier, we must travel all the way to Isaac Newton before finding another human being of comparable scientific achievement. And before Newton, there might be none.

　　愛因斯坦與牛頓的才智，使他們無論進入什麼研究領域，都能綱舉目張，照耀四方。牛頓發明微積分，提出力學與運動定律，以及萬有引力理論。愛因斯坦不僅奠定了現代物理學兩棟摩天大廈（狹義相對論與量子力學）的基礎，還提出了新的重力理論。

　　Both Einstein and Newton had intellects that carried them to every known continent of their subjects and beyond. Newton invented the calculus, formulated the laws of mechanics and motion, proposed a universal theory of gravitation. Einstein laid the foundations for the two skyscrapers of modern physics, special relativity and quantum mechanics, and created a new theory of gravity.

　　但是，除了這些具體成就，他們都徹底改變了科學思維。他們都發展出一套世界觀，現在已經冠上了他們的名 字。「牛頓宇宙」指的是一切都有絕對值的宇宙，「愛因斯坦宇宙」則一切都是相對值。在牛頓宇宙裡，時間無情地流逝，從現在到永恆，速度永遠不變。因果緊密 相隨，如上帝戒命。有果必有因，毫無例外。掌握過去，就能預測未來。在愛因斯坦宇宙中，時間沒有絕對值。時間流逝的速度，視觀察者而定。此外，根據量子力 學，次原子世界在本質上就有不確定性，令人根本無法根據過去預測未來。「確定」非得用「機率」取代不可。愛因斯坦對量子力學雖然有所保留，仍然是它的奠基 者（請參閱〈遠見，還是反動？〉一文）。

　　But beyond these particular achievements, both scientists radically changed thinking in science. Both developed worldviews. Today we refer to the 「Newtonian」 universe and the 「Einsteinian」 universe—the first being a world of absolutes, the second a world of relativities. In the Newtonian universe, time flows inexorably, always at the same rate, now and forever. Causality is as strict as a commandment of God. Without exception, every effect has a cause. The future is completely predictable from the past. In the Einsteinian universe, time is not absolute. The rate of temporal flow depends on the observer. Furthermore, according to the new quantum physics, which Einstein helped to establish despite reservations, the intrinsic uncertainties of nature at the subatomic level prevent forecasting the future from the past. Certainties must be replaced by probabilities.

　　這些觀念的重要性，不侷限於科學。它們是哲學，是一首交響曲中的主旋律，是不同的世界觀。

　　These ideas are larger than scientific theories. They are philosophies, they are symphonic themes, they are different ways of being in the world.

　　牛頓與愛因斯坦的主業是理論物理學。他們與其他理論物理學家一樣，在25歲左右完成一生最偉大的成就。 他們都做過實驗，但是牛頓比愛因斯坦高明，他發現了陽光是不同色光混合而成的，此外還有別的發現。牛頓發明了他需要的數學。愛因斯坦則沒有，他需要的數學 已經由黎曼與高斯發明了。愛因斯坦有超卓的直覺，他跟著直覺進行研究，採用當時很少人懂的非歐幾何，發展重力的幾何理論。

　　Both Newton and Einstein were principally theoretical physicists. Like many theoretical physicists, they did their greatest work in their mid-twenties. Both tried their hand at experiments. Newton, the far greater experimentalist, discovered among other things that white light is composed of a mixture of colors. Newton invented mathematics that he needed. Einstein did not, but his brilliant intuition led him to study and adopt the obscure non-Euclidean geometry of Riemann and Gauss for his geometric theory of gravity.

　　他們都是藝術家，追求簡單、優雅與數學美。他們與藝術家一樣，寧願單獨工作。牛頓一旦著手研究一個問 題，會幾個月不與外界接觸，好專心致志。愛因斯坦從未指導過研究生，也很少教學。兩人都是獨行俠。牛頓更孤獨；他似乎明顯表現出反社會傾向。牛頓過世時， 伏爾泰評論道：「牛頓十分長壽，一生既無熱情又無弱點；他從未接近過任何女性。」牛頓甚至有個獨身方案：「保持獨身的秘訣，不是與難以自制的思慮掙扎，而 是分心旁鶩，例如找事做、找書讀或專注別的事。」

　　Both were artists. Both devoted themselves to simplicity, elegance and mathematical beauty. Like artists, both preferred to work in isolation. Newton sequestered himself for months at a time when he was at work on a project. Einstein never had any graduate students and rarely taught. Both were loners. Newton was the greater loner. He seems to have been practically antisocial, and, as Voltaire noted at Newton's death, 「in the course of such a long life [Newton] had neither passion nor weakness; he never went near any woman.」 Newton even formulated a plan to preserve his celibacy: 「The way to chastity,」 he wrote, 「is not to struggle with incontinent thoughts but to avert the thoughts by some employment, or by reading, or meditating on other things.」

　　愛因斯坦到了晚年，參與過許多社會活動，例如支持人權聯盟，在世界各地發表許多演講，討論政治、哲學與 教育，協助創辦耶路撒冷希伯來大學。愛因斯坦一生中有許多女友。但是，在最私密的層次上，他似乎與牛頓一樣孤獨。1931年，愛因斯坦52歲，發表了一篇 文章。他寫道：
　　我沒有與其他人、其他人類社群建立直接接觸的需求，可是我又非常關心社會正義與社會責任，因而這種熱情一直顯得怪異。我是個道地的孤獨旅客，從未對我的國家、我的家、我的朋友，甚至我最接近的家人交過心。

　　In later life, Einstein involved himself with many social causes, such as supporting the League for Human Rights, giving numerous lectures around the world on politics and philosophy and education, helping to found the Hebrew University of Jerusalem. Einstein had many romantic relationships in his life. But at the most personal level, he seems to have been as solitary as Newton. In an essay published in 1931, at the age of 52, Einstein wrote:
　　My passionate sense of social justice and social responsibility has always contrasted oddly with my pronounced lack of need for direct contact with other human beings and human communities. I am truly a 「lone traveler」 and have never belonged to my country, my home, my friends, or even my immediate family with my whole heart.

　　牛頓與愛因斯坦都極力維護自己的獨立性。他們都醉心於自己的孤獨。

　　Both Newton and Einstein fiercely guarded their independence. Both worshipped their solitude.

　　牛頓與愛因斯坦都給世人留下了深厚的遺澤。牛頓之前的許多世紀裡，西方人深信有些領域的知識，人心無從 掌握，而牛頓征服了這個觀念。在牛頓之前，大部份思想家都相信人心只配理解上帝想教人類理解的事物。亞當與夏娃被逐出伊甸園，正因為他們吃了知識樹的果 子，那可是上帝的知識。普羅米修司將取火技術傳給凡人，洩漏了神祇的秘密，宙斯就以鐵鍊將他縛在岩石上。在密爾頓的《失樂園》中，亞當向天使拉斐爾詢問天 體力學的問題，拉斐爾含糊以對，只透露了一些模糊的線索，然後他說道：「其餘的，創世者英明，都藏了起來，不讓人與天使知曉。」牛頓的《原理》 （1687）一問世，將這些限制與禁忌全給掃到一邊，成為科學史的里程碑。牛頓以精確的數學語言，將人類知道的自然世界全都收服，無論鍾擺、彈簧、彗星， 還是行星繞日軌道，如在指掌中。牛頓之後，精神界與物質界的分野更為清晰；物質界是人類能夠通曉的領域。

　　Isaac Newton and Albert Einstein left profound legacies. Newton conquered the notion that some areas of knowledge were inaccessible to the human mind, an idea ingrained in Western culture for centuries. In much thinking before Newton, humankind was entitled to comprehend only what God deigned to reveal. Adam and Eve were banished from Eden for eating from the tree of knowledge, God's knowledge. Zeus chained Prometheus to a rock for giving fire, the secret of the gods, to mortal man. When Adam, in John Milton's Paradise Lost, questioned the angel Raphael about celestial mechanics, Raphael offered some vague hints and then said that 「the rest from Man or Angel the great Architect did wisely to conceal.」 All these limitations and forbidden regions were swept aside with Newton's monumental work The Principia (1687). There, in precise, mathematical terms, Newton surveyed all phenomena of the known physical world, from pendulums to springs to comets to the grand trajectories of planets. After Newton, the division between the spiritual and physical was more clear. And the physical world was knowable by human beings.

　　狹義相對論的公設既不尋常，乍看又荒謬。可是愛因斯坦以狹義相對論證明了：即使仔細觀察外在世界，也無 法揭露自然的最終本相。有時科學家必須從內心出發，先發明假說與邏輯體系，然後再以實驗驗證。舉個例子吧，我們自出生以來，所有經驗都明白告訴我們時間以 恆定速率流逝，然而這個信念並不真。現在，現代物理學終於跨進了超越人類知覺與經驗的領域，我們已經知道：我們以常識理解這個世界，不免會犯錯。愛因斯坦 推翻了流行了幾個世紀的想法；在科學中，實證研究與經驗並不佔首要地位。他也反駁了牛頓的名言，「我不做假設」。牛頓的意思是，他不是個安樂椅上的哲學 家，例如亞里斯多德，而是個科學家，只以人觀察得到的事實立論。

　　Einstein, with his extraordinary and seemingly absurd postulates of special relativity, demonstrated that the great truths of nature cannot be arrived at merely by close observation of the external world. Rather scientists must sometimes begin within their own minds, inventing hypotheses and logical systems that only later can be tested against experiment. For example, all of our experience since birth screams at us that time flows at a uniform rate, and yet this belief is not true. Modern physics has at last advanced to an understanding of nature beyond human sense perception and experience, teaching us that our commonsense grasp of the world can be mistaken. In this legacy, Einstein overturned centuries of thought about the supremacy of empirical study and experience. He also contradicted Newton's famous dictum hypotheses non fingo (「I frame no hypotheses」), by which the British scientist meant that he was not an armchair philosopher, like Aristotle, but a scientist who based his theories on observable facts.

　　愛因斯坦在自傳中，這樣描述他悖離牛頓的地方：牛頓，原諒我；你發現了一條路，在你的時代裡，即使具有 最高才智與創造力的人，都不可能超越。你所創造的概念，直到現在仍然是物理學的指導方針，雖然我們知道，它們必須用其他的概念替代。替代概念必須來自遠離 直接經驗的領域。

　　In his autobiography, Einstein expressed his departure from Newton in this way: 「Newton, forgive me; you found the only way which, in your age, was just about possible for a man of highest thought and creative power. The concepts, which you created, are even today still guiding our thinking in physics, although we now know that they will have to be replaced by others farther removed from the sphere of immediate experience.」

　　1931年，牛頓《光學》的現代英語文本問世，愛因斯坦在導論中這麼描述牛頓：「對他來說，自然是一本 攤開的書……他集實驗家、理論家、儀器技師於一身。此外，他還是高明的作家。他站在我們面前，有說服力、有自信，但是孤單。」要是牛頓能藉時光機旅行來到 現在，也許會以同樣的話描述愛因斯坦。

　　In an introduction to a 1931 edition of Newton's Opticks, Einstein wrote of Newton, 「Nature to him was an open book. . . . In one person he combined the experimenter, the theorist, the mechanic, and, not least, the artist in exposition. He stands before us strong, certain, and alone.」 If Newton could reappear in the future, in a forbidden trick of time travel, he would probably say similar words about Einstein.