漏洞落在做证明的人身上
The Gap Landed on the One Who Proved It
1993 年 6 月 21 日至 23 日,Andrew Wiles 在剑桥的牛顿研究所连讲三场,宣布证明了半稳定椭圆曲线的谷山–志村猜想,从而证明费马大定理。1993 年夏末,被指定审稿的 Nick Katz 在手稿里找到一处缺口:用来把 Kolyvagin 与 Flach 的方法推广过去的那个欧拉系统并不完整。Wiles 后来在 NOVA 的访谈里说,这是“论证关键部分的一个错误,但它是那样细微,直到那一刻我完全没有看出来”。此后将近一年,他一个人试了又试,后来在 Peter Sarnak 的建议下找来自己从前的学生 Richard Taylor,两人一起改,仍然没有出路。
1994 年 9 月 19 日,Wiles 最后一次回头看自己最初的那条路(岩泽理论),同时盯着 Kolyvagin–Flach 方法为什么失败。他看到,这一次失败本身说明:最初那条路,只要吸收了从失败的方法里学到的东西,就能走通。他的原话是“忽然,完全出乎意料,我得到了这个不可思议的启示”,又说那“无法形容地美,那样简单,那样优雅”。1994 年 10 月 24 日他提交了两篇稿子,第二篇与 Taylor 合写,两篇于 1995 年 5 月刊在《数学年刊》上。
这是第十条光线,自我之美,主要是它生成的那一面。判断者在这里不能不承认的,是错误的去向。一个证明出了错,可以说是世界错了,可以说是这个方法天生不行,也可以把它当成别人的事。这里发生的是:看错了的东西落回到看的人身上:这是我宣布的证明,这一处是我没有看出来的,而这个“我”有来历(一条他自己选定的最初路线)、有边(一处他看不见的地方)、有尚未属于他的方向。然后,使他得以继续的,恰好是他认真检查那条失败的路线:失败的方法没有被丢掉,它说出了最初那条路缺的是什么。这是凿构循环:凿的是“Kolyvagin–Flach 足以替代最初的路”这个已经构成的判断,构的是被它补强之后的原路。
它不是什么:不是坚持,也不是谦逊,这两样都是对人的赞美,而这里要看的是结构,不是品格;不是“问题终于解决了”的欣慰,那属于有用与正确;也不是对一个著名结论的敬意。我们能说的只有被记录下来的东西:缺口出现的时间,一年的失败,一个具体的日期,以及他自己对那一刻的描述。这里也不比较任何人,只指向这一个动作:错误落回自己,并没有把自己压垮,而是变成了这个人看清自己最初选择的方式。
它的余项很明白:“我”在这里有了,接下来这个“我”往哪里去,不属于这一条射线,那是目的之美的问题,这篇文字没有资格替 Wiles 回答。现在值得再看一遍,是因为这个故事太容易被讲成“天才的胜利”,而被记录下来的实际是更细的东西:一处是他自己没看见的缺口,和他回头看的那一次。
NOVA: Andrew Wiles on the Proof ↗On 21–23 June 1993, Andrew Wiles gave three lectures at the Isaac Newton Institute in Cambridge announcing a proof of the Taniyama–Shimura conjecture for semistable elliptic curves, and with it Fermat's Last Theorem. In late summer 1993 the referee, Nick Katz, found a gap in the manuscript: the Euler system used to extend the method of Kolyvagin and Flach was incomplete. Wiles later told NOVA it was “an error in a crucial part of the argument, but it was something so subtle that I'd missed it completely until that point.” For nearly a year he tried to repair it alone, and then, at Peter Sarnak's suggestion, brought in his former student Richard Taylor. Together they still found no way through.
On 19 September 1994 Wiles took one last look at his original route (Iwasawa theory) while studying why the Kolyvagin–Flach method failed. He saw that the failure itself meant the original route could be made to work, once strengthened with what he had learned from the method that had failed. In his words: “Suddenly, totally unexpectedly, I had this incredible revelation,” and it was “so indescribably beautiful; it was so simple and so elegant.” On 24 October 1994 he submitted two manuscripts, the second written with Taylor; both appeared in the Annals of Mathematics in May 1995.
This is the tenth ray, the Beauty of the Self, mainly in its generative face. What a judge cannot not acknowledge here is where the error went. A proof that fails can be blamed on the world, on a method that was never going to work, or on someone else. What happens here is that the wrong seeing lands on the one who saw: this is the proof I announced, this is the place I did not see, and that “I” has an origin (a route he had himself chosen), an edge (a spot he could not see), and a direction not yet his own. Then what lets him go on is that he looks hard at the route that failed: the failed method is not thrown away, it says what the original route was missing. That is the chisel-construct cycle: the chisel is the already constructed judgment that Kolyvagin–Flach could stand in for the original route, the construct is the original route as strengthened by it.
What it is not: not perseverance and not humility, both of which are praise of a person, whereas what is to be seen here is structure, not character; not the relief of “the problem is finally solved”, which belongs to usefulness and correctness; not reverence for a famous result. We can say only what is on record: when the gap appeared, a year of failure, one specific date, and his own description of that moment. Nobody is ranked against anyone; what is pointed to is one act: the error folding back onto its maker did not crush him but became the way this person saw his own first choice clearly.
Its remainder is plain: here there is an “I”, and where that I goes next is not a question for this ray; it belongs to the beauty of purpose, and this text has no standing to answer it for Wiles. It is worth seeing again now because the story is so easily told as a genius's triumph, when what is on record is finer: a gap he had not seen himself, and the one time he looked back.
NOVA: Andrew Wiles on the Proof ↗