投资界的费曼法则:不要欺骗自己

Forget the 'Dimon principle.' Investors should follow the Feynman principle.

别管什么“戴蒙法则”(Dimon principle)，投资者应当牢记的是费曼法则(Feynman principle)。

When J.P. Morgan Chase's chief executive, James Dimon, disclosed a $2 billion trading loss during a hastily organized conference call on Thursday, he said: 'This trading may not violate the Volcker rule, but it violates the Dimon principle.'

Associated Press罗伯特•密立根（图中人物）和理查德•费曼都认为：对所谓“专家”的结论偏听偏信是一种自欺行为。摩根大通(J.P. Morgan Chase)首席执行长杰米•戴蒙(James Dimon)在5月10日召开紧急电话会议，披露该公司发生了20亿美元的交易损失。他说，“这笔交易也许没违反沃尔克法则(Volker Rule)，但违反了戴蒙法则。”

Mr. Dimon didn't say what the Dimon principle is, and a spokesman for the U.S.'s largest bank by assets didn't respond to requests for comment.

戴蒙当时并未对戴蒙法则进行解释，摩根大通的一位发言人也未对置评请求作出回应。

The Feynman principle, however, is simple: 'You must not fool yourself-and you are the easiest person to fool,' as the Nobel Prize-winning physicist Richard Feynman put it.

费曼法则却不难理解，就是诺贝尔奖得主、物理学家理查德•费曼(Richard Feynman)明确指出的，“不要欺骗自己，你自己正是最容易被欺骗的人。”

Asked on April 13 whether J.P. Morgan's trading operation posed significant risks to the bank, Mr. Dimon called it a 'tempest in a teapot.' The bank's chief financial officer insisted the London-based division was merely 'protecting that balance sheet,' adding that J.P. Morgan was 'very comfortable with the positions we have.'

回想4月13日被问及摩根大通交易业务是否对整个银行构成巨大风险时，戴蒙曾回应称这是“小题大做”。摩根大通的首席财务长也坚称该行位于伦敦的交易部门只是在“保护资产负债表”，并补充称“摩根大通对当前的头寸很满意”。

J.P. Morgan's moguls, in letting a complex risk run wild and denying any potential for error until too late, are a reminder one of the biggest dangers in finance is self-deception.

事到临头之前，摩根大通的大佬们这种放任复杂风险失控、矢口否认存在出错可能性的做法无疑提醒了我们：金融领域最大的危险之一就是自欺欺人。

For investors, the bigger the commitment, the more certain they become that they must have been right to make it-and the harder it becomes to let go.

作为投资者，对某项投资付出越多，就越相信自己能够成功，对失败也就越难以释怀。

The literal meaning of the word 'invest'-from the Latin vestire, to clothe or dress-is to wrap oneself up in something. Experiments at racetracks and elsewhere have shown that people who bet on an outcome become up to three times more confident that it will occur than people who didn't put up any money.

从字面来看，英语中的“invest”（投资）一词源自拉丁语中的“vestire”，后者是“穿戴”的意思，即把自己包裹起来。在赛马场和其它场所进行的实验表明，相比没有押注的人，对某一结果押了注的人相信该结果会出现的程度可高出三倍之多。

Not trying to disprove your own beliefs is an especially dangerous deception. In a commencement address he gave to students at the California Institute of Technology in 1974, Mr. Feynman urged his listeners to avoid what he called 'cargo cult' thinking, after Pacific islanders who believed they could make airplanes land, full of food and clothing, by standing alongside makeshift runways, as they had during World War II.

PBS/Everett Collection罗伯特•密立根和理查德•费曼（图中人物）都认为：对所谓“专家”的结论偏听偏信是一种自欺行为。从不试着反驳自己的信念是一种尤其危险的自欺行为。1974年费曼在加州理工学院(California Institute of Technology)的毕业典礼致词上呼吁听众避免被他称为“草包族”(cargo cult)的思想，就像一些太平洋岛民那样，二次世界大战结束后他们还以为守在临时跑道旁边就可以等来满载物资的飞机。

You also can fool yourself by placing too much faith in the findings of supposed experts. Mr. Feynman recounted the story of an influential formula for measuring the charge of an electron that was devised by the pioneering physicist Robert Millikan. The result was slightly wrong, but it took many researchers years to prove it wrong-since Millikan's successors assumed that he had to be right. They adjusted the value, but not enough; deference made them too timid to believe the evidence of their own eyes.

对所谓“专家”的结论偏听偏信也是一种自欺行为。费曼讲述了先驱物理学家罗伯特•密立根(Robert Millikan)推导出的电子电荷测算公式的故事。其测算结果并不十分准确，但很多研究人员过了多年才得以证明这一点，原因就在于密立根的追随者们想当然地认为密立根肯定是正确的。他们调整了数值，但没有用；对密立根的盲目推崇使他们不敢相信摆在眼前的事实。

Quantitative claptrap can have the same effect on investors. Some banks-including J.P. Morgan-use a technique called 'value at risk,' or VAR, to estimate the potential vulnerabilities of their portfolios. VAR is a short-term measure that generally assumes that past levels of risk and relationships among assets will persist, says Donald van Deventer, author of 'Advanced Financial Risk Management' and chairman of Kamakura Corp., a financial-consulting firm in Honolulu. It gives a precise, but incomplete, picture, he says.

听起来玄乎其玄的定量术语也会对投资者产生类似的效果。包括摩根大通在内的一些银行都喜欢采用一种被称为“风险价值模型”(VAR)的方法来评估其投资组合的损失风险。火奴鲁鲁财务咨询公司Kamakura Corp.董事长、著有《高级金融风险管理》(Advanced Financial Risk Management)一书的唐纳德•范•戴维特(Donald van Deventer)指出，风险价值模型是一种短期方法，通常假定过去的风险水平和资产之间的关系不变。他称，这种方法提供的结果固然精准，却不全面。

So how can investors avoid deceiving themselves?

那么，投资者该如何避免自我蒙蔽呢？

First of all, remember that 'the riskiest moment is when you are right,' as the economist Peter Bernstein was fond of saying.

首先，记住“最危险的时刻就是你正确的时刻”，这是经济学家彼得•伯恩斯坦(Peter Bernstein)常说的话。

You should set, in advance, a threshold of profit at which you must review any holding-say, a 50% gain. At that point, you must seek out the opinions of people who think you are wrong-research from short sellers betting against the stock, for example.

你应当提前设定一个盈利底线──例如50%的涨幅，要求自己一旦触及这个底线就对手中的头寸进行全面评估。到时候，你必须考虑反方的意见，例如，你持有某只股票，那就应该仔细研究一下做空这只股票的人所持的观点。

Look at the results of other people and organizations that have tried something similar to the actions you are considering. Unless other people have succeeded, there isn't any objective reason to believe that you will. (J.P. Morgan might have notedthe record of big U.S. banks trying to make money off leveraged portfolios of derivatives is abysmal.)

如果你在考虑采取某项行动，还应当先看一下其他已经采取了类似行动的投资者或机构的战绩如何。除非其他投资者取得了成功，否则你也不应当认为自己就会赢。例如，摩根大通本应该看一下其他美国大银行在衍生品杠杆投资方面的糟糕记录。

Monitor yourself for vehemence. If you find yourself tempted to ridicule anyone who tells you are wrong, you probably are wrong. Bertrand Russell warned the less evidence someone has that his ideas are right, 'the more vehemently he asserts that there is no doubt whatsoever that he is exactly right.'

时刻提防自己走向偏激。如果你发现自己开始嘲笑那些说你做错了的人，那么你也许真的做错了。伯特兰•罗素(Bertrand Russell)曾经警告世人，越是对自己的观点缺乏证据的人，越是会固执地坚称自己是绝对正确的。

Finally, try the technique that psychologist Gary Klein calls a 'pre-mortem.' Gather people whose views you respect. Ask them all to imagine looking back, a year from now, at the investment you just made-and that it has turned out to be a disaster. Have them list all the possible causes of the failure. That may well help you see how it might have been avoided.

试试被心理学家加里•克莱因(Gary Klein)称为“事前验尸”(pre-mortem)的方法吧。假设你刚做的投资在一年后惨败，召集一些你重视其观点的人，让他们设想一下从那个时候往回看你所做的投资，并列出他们认为的可能导致你投资失败的所有原因。这或许有助于你弄清楚该如何防范于未然。

Above all, remember that the smarter you are, the more easily you can fool yourself.

说到底，就是切记不要“聪明反被聪明误”。