鑽石舞台

所謂的天才，並不只是一粒種子剛好落在了適合他生長的土壤，更在於他堅守住自己種子的特性，即使在萬物都在狂歡般地瞻仰世界，他依然願意在黑暗潮濕里，滿懷激情地扎着根，編織着夢想。

與您分享愛因斯坦1918年在紀念麥克斯.普朗克60歲生日演講會上的演講——《探索的動機》。

在科學的廟堂里有許多房舍，住在裡面的人真是各式各樣，而引導他們到那裡去的動機也實在各不相同。有許多人所以愛好科學，是因為科學給他們以超乎常人的智力上的快感，科學是他們自己的特殊娛樂，他們在這種娛樂中尋求生動活潑的經驗和對他們自己雄心壯志的滿足；

在這座廟堂里，另外還有許多人所以把他們的腦力產物奉獻在祭壇上，為的是純粹功利的目的。如果上帝有位天使跑來把所有屬於這兩類的人都趕出廟堂，那麼聚集在那裡的人就會大大減少，但是，仍然還有一些人留在裡面，其中有古人，也有今人。我們的普朗克就是其中之一，這也就是我們所以愛戴他的原因。我很明白，我們剛才在想象隨便驅逐可許多卓越的人物，他們對建築科學廟堂有過很大的也許是主要的貢獻；在許多情況下，我們的天使也會覺得難於作出決定。但有一點我可以肯定，如果廟堂里只有被驅逐的那兩類人，那末這座廟堂決不會存在，正如只有蔓草就不成其為森林一樣。因為，對於這些人來說，只要有機會，人類活動的任何領域都會去干；他們究竟成為工程師、官吏、商人還是科學家，完全取決於環境。現在讓我們再來看看那些為天使所寵愛的人吧。

他們大多數是相當怪癖、沉默寡言和孤獨的人，但儘管有這些共同特點，實際上他們彼此之間很不一樣，不象被趕走的那許多人那樣彼此相似。究竟是什麼把他們引到這座廟堂里來的呢?這是一個難題，不能籠統地用一句話來回答。

首先我同意叔本華(Schopenhauer)所說的，把人們引向藝術和科學的最強烈的動機之一，是要逃避日常生活中令人厭惡的粗俗和使人絕望的沉悶，是要擺脫人們自己反覆無常的欲望的桎梏。一個修養有素的人總是渴望逃避個人生活而進入客觀知覺和思維的世界；這種願望好比城市裡的人渴望逃避喧囂擁擠的環境，而到高山上去享受幽靜的生活，在那裡透過清寂而純潔的空氣，可以自由地眺望，陶醉於那似乎是為永恆而設計的寧靜景色。除了這種消極的動機以外，還有一種積極的動機。人們總想以最適當的方式畫出一幅簡化的和易領悟的世界圖像；於是他就試圖用他的這種世界體系(cosmos)來代替經驗的世界，並來征服它。這就是畫家、詩人、思辨哲學家和自然科學家所做的，他們都按自己的方式去做。各人把世界體系及其構成作為他的感情生活的支點，以便由此找到他在個人經驗的狹小範圍里所不能找到的寧靜和安定。理論物理學家的世界圖像在所有這些可能的圖像中占有什麼地位呢？它在描述各種關係時要求儘可能達到最高的標準的嚴格精密性，這樣的標準只有用數學語言才能達到。另一方面，物理學家對於他的主題必須極其嚴格地加以控制：他必須滿足於描述我們的經驗領域裡的最簡單事件。

企圖以理論物理學家所要求的精密性和邏輯上的完備性來重現一切比較複雜的事件，這不是人類智力所能及的。高度的純粹性、明晰性和確定性要以完整性為代價。但是當人們畏縮而膽怯地不去管一切不可捉摸和比較複雜的東西時，那末能吸引我們去認識自然界的這一渺小部分的究竟又是什麼呢？難道這種謹小慎微的努力結果也夠得上宇宙理論的美名嗎？

我認為，是夠得上的；因為，作為理論物理學結構基礎的普遍定律，應當對任何自然現象都有效。有了它們，就有可能藉助於單純的演繹得出一切自然過程(包括生命)的描述，也就是說得出關於這些過程的理論，只要這種演繹過程並不太多地超出人類理智能力。因此，物理學家放棄他的世界體系的完整性，倒不是一個什麼根本原則性的問題。物理學家的最高使命是要得到那些普遍的基本定律，由此世界體系就能用單純的演繹法建立起來。要通向這些定律，沒有邏輯的道路，只有通過那種以對經驗的共鳴的理解為依據的直覺，才能得到這些定律。

由於有這種方法論上的不確定性，人們可以假定，會有許多個同樣站得住腳的理論物理體系；這個看法在理論上無疑是正確的。但是，物理學的發展表明，在某一時期，在所有可想到的構造中，總有一個顯得比別的都高明得多。凡是真正深入研究過這問題的人，都不會否認唯一地決定理論體系的，實際上是現象世界，儘管在現象和它們的理論原理之間並沒有邏輯的橋樑；這就是萊布尼茲(Leibnitz)非常中肯地表述過的「先定的和諧」。物理學家往往責備研究認識論者沒有給予足夠的注意。我認為，幾年前馬赫和普朗克之間所進行的論戰的根源就在於此。渴望看到這種先定的和諧，是無窮的毅力和耐心的源泉。我們看到，普朗克就是因此而專心致志於這門科學中的最普遍的問題，而不是使自己分心於比較愉快的和容易達到的目標上去。我常常聽到同事們試圖把他的這種態度歸因於非凡的意志力和修養，但我認為這是錯誤的。促使人們去做這種工作的精神狀態是同信仰宗教的人或談戀愛的人的精神狀態相類似的；他們每天的努力並非來自深思熟慮的意向或計劃，而是直接來自激情。

我們敬愛的普朗克就坐在這裡，內心在笑我像孩子一樣提着第歐根尼的燈籠鬧着玩。我們對他的愛戴不需要作老生常談的說明。祝願他對科學的熱愛繼續照亮他未來的道路，並引導他去解決今天物理學的最重要的問題。這問題是他自己提出來的，並且為了解決這問題他已經做了很多工作。祝他成功地把量子論同電動力學、力學統一於一個單一的邏輯體系里。

當太多人越來越熱衷於追逐短暫目標和純粹利益的時候，這個世界總還有一些人保持着對科學對人類長遠利益宗教式甚至戀愛式的熱愛。一個人的才華和精力，究竟要以怎樣的一種方式燃燒呢？對於普通人，我們探索生活的動機，是什麼？

INthe temple of science are many mansions, and various indeed are they that dwell therein and the motives that have led them thither. Many take to science out of a joyful sense of superior intellectual power; science is their own special sport to which they look for vivid experience and the satisfaction of ambition; many others are to be found in the temple who have offered the products of their brains on this altar for purely utilitarian purposes. Were an angel of the Lord to come and drive all the people belonging to these two categories out of the temple, the assemblage would be seriously depleted, but there would still be some men, of both present and past times, left inside. Our Planck is one of them, and that is why we love him.

I am quite aware that we have just now lightheartedly expelled in imagination many excellent men who are largely, perhaps chiefly, responsible for the buildings of the temple of science; and in many cases our angel would find it a pretty ticklish job to decide. But of one thing I feel sure: if the types we have just expelled were the only types there were, the temple would never have come to be, any more than a forest can grow which consists of nothing but creepers. For these people any sphere of human activity will do, if it comes to a point; whether they become engineers, officers, tradesmen, or scientists depends on circumstances. Now let us have another look at those who have found favor with the angel. Most of them are somewhat odd, uncommunicative, solitary fellows, really less like each other, in spite of these common characteristics, than the hosts of the rejected. What has brought them to the temple? That is a difficult question and no single answer will cover it. To begin with, I believe with Schopenhauer that one of the strongest motives that leads men to art and science is escape from everyday life with its painful crudity and hopeless dreariness, from the fetters of one's own ever shifting desires. A finely tempered nature longs to escape from personal life into the world of objective perception and thought; this desire may be compared with the townsman's irresistible longing to escape from his noisy, cramped surroundings into the silence of high mountains, where the eye ranges freely through the still, pure air and fondly traces out the restful contours apparently built for eternity.

With this negative motive there goes a positive one. Man tries to make for himself in the fashion that suits him best a simplified and intelligible picture of the world; he then tries to some extent to substitute this cosmos of his for the world of experience, and thus to overcome it. This is what the painter, the poet, the speculative philosopher, and the natural scientist do, each in his own fashion. Each makes this cosmos and its construction the pivot of his emotional life, in order to find in this way the peace and security which he cannot find in tbe narrow whirlpool of personal experience.

What place does the theoretical physicist's picture of the world occupy among all these possible pictures? It demands the highest possible standard of rigorous precision in the description of relations, such as only the use of mathematical language can give. In regard to his subject matter, on the other hand, the physicist has to limit himself very severely: he must content himself with describing the most simple events which can be brought within the domain of our experience; all events of a more complex order are beyond the power of the human intellect to reconstruct with the subtle accuracy and logical perfection which the theoretical physicist demands. Supreme purity, clarity, and certainty at the cost of completeness. But what can be the attraction of getting to know such a tiny section of nature thoroughly, while one leaves everything subtler and more complex shyly and timidly alone? Does the product of such a modest effort deserve to be called by the proud name of a theory of the universe?

In my belief the name is justified; for the general laws on which the structure of theoretical physics is based claim to be valid for any natural phenomenon whatsoever. With them, it ought to be possible to arrive at the description, that is to say, the theory, of every natural process, including life, by means of pure deduction, if that process of deduction were not far beyond the capacity of the human intellect. The physicist's renunciation of completeness for his cosmos is therefore not a matter of fundamental principle.

The supreme task of the physicist is to arrive at those universal elementary laws from which the cosmos can be built up by pure deduction. There is no logical path to these laws; only intuition, resting on sympathetic understanding of experience, can reach them. In this methodological uncertainty, one might suppose that there were any number of possible systems of theoretical physics all equally well justified; and this opinion is no doubt correct, theoretically. But the development of physics has shown that at any given moment, out of all conceivable constructions, a single one has always proved itself decidedly superior to all the rest. Nobody who has really gone deeply into the matter will deny that in practice the world of phenomena uniquely determines the theoretical system, in spite of the fact that there is no logical bridge between phenomena and their theoretical principles; this is what Leibnitz described so happily as a "pre-established harmony." Physicists often accuse epistemologists of not paying sufficient attention to this fact. Here, it seems to me, lie the roots of the controversy carried on some years ago between Mach and Planck.

The longing to behold this pre-established harmony is the source of the inexhaustible patience and perseverance with which Planck has devoted himself, as we see, to the most general problems of our science, refusing to let himself be diverted to more grateful and more easily attained ends. I have often heard colleagues try to attribute this attitude of his to extraordinary will-power and discipline -- wrongly, in my opinion. The state of mind which enables a man to do work of this kind is akin to that of the religious worshiper or the lover; the daily effort comes from no deliberate intention or program, but straight from the heart. There he sits, our beloved Planck, and smiles inside himself at my childish playing-about with the lantern of Diogenes. Our affection for him needs no threadbare explanation. May the love of science continue to illumine his path in the future and lead him to the solution of the most important problem in present-day physics, which he has himself posed and done so much to solve. May he succeed in uniting quantum theory with electrodynamics and mechanics in a single logical system.