Judging Outside Your Expertise 如何在你专业领域之外辨别是非 作者：David Friedman @ 2015-6-9

译者：Who视之      校对：小聂

来源：Ideas，http://daviddfriedman.blogspot.com/2015/06/judging-outside-your-expertise.html

I have just been involved in a lengthy exchange on Facebook over my criticism of the claim that warming on the scale projected by the IPCC for 2100 can be expected to have large net negative consequences. The response I got was that the person I was arguing with was not interested in my arguments. He does not know enough to judge for himself whether the conclusion is true, so prefers to believe what the experts say.

政府间气候变化专门委员会（IPCC）宣称，按照他们预测的气候变暖速度，到2100年，会产生大规模的恶性后果。我对此种言论有所指摘，为此我一直在Facebook上和人没完没了地辩论。我得到的反馈是，和我争论的那个人对我的论点并没有兴趣，他懂的东西有限，没法判断结论是否正确，所以宁可相信专家的说法。

Accepting the views of experts on a question you are not competent to answer for yourself, assuming that you can figure out who they are and what they believe, is often a sensible policy, but one can sometimes do better. Sometimes one can look at arguments and evaluate them not on the basis of the science but of internal evidence, what they themselves say. Here are three examples:

假设你能找出谁是专家，理清他们的思路，那么在你不懂的问题上接受专家的看法，通常是个不错的选择。但有时你可以做得比这更好。有时候，可以无须依靠科学知识基础，而只借助内在证据——即他们自己是的说法——，便可对不同论点作出评估。这里有三个例子：

The widely cited 97% figure is based mostly on Cook et. al. 2013, which is webbed. It is often reported as the percentage of climate scientists who believe that humans are the main cause of warming and that warming will have very bad effects.

广为引用的那个数字97%，基本是来自库克（Cook）等人2013年发表的研究，可以在网上找到。引用者经常会说，97%的气候科学家认为，人类是引发气候变暖的元凶，而且变暖会带来非常糟糕的后果。

Simply reading the article tells you that the second half is false. The article is about causes of warming and offers no evidence on consequences. Anyone who says it does is either ignorant or dishonest, and other things he says can be evaluated on that basis.

只要去读读那篇文章，就会发现，上面那句话的后半部分是错的。那文章讲的是变暖的原因，并未提供变暖会带来什么后果的证据。如果某人据此认为变暖会有恶果，要么是无知，要么是不够诚实。此人的其他言论，可以据此而加以判断。

If you read the article carefully you discover that the 97% figure, which is a count of article abstracts not scientists, is the percentage of abstracts which say or imply that humans are a cause of warming (“contribute to” in the language of one example).

如果你仔细读读那篇文章，就会发现，所谓97%计算的是论文摘要的数量，而不是所涉及科学家的人数。并且统计的是认为或者暗示人类是气候变暖的原因“之一”的摘要比例（有一个摘要里用的说法是“亦有贡献”）。

The corresponding figure for humans as the principal cause, which is not given in the article but can be calculated from its webbed data, is 1.6%. That tells you that anyone who reports the 97% figure as the number of articles holding that humans are the main cause of warming is either ignorant or dishonest.

至于有多少比例的论文把人类认作是气候变暖主要原因，那篇文章里没有直接给出数字，但在其提供的网上数据中可以算出，是1.6%。这就告诉你了，如果有人说，认为人类是暖化元凶的文章占了97%，此人要么无知要么不诚实。

One person who has done so, in print, is John Cook, the lead author of the article. John Cook runs skepticalscience.com, which is a major source for arguments for one side of the global warming dispute, so knowing that he is willing to lie in print about his own work is a reason not to believe things on that site without checking them.[ My old blog post giving details ]

某人就这么做了，还发表了，他就是上述论文的主要作者约翰·库克。他有个网站，skepticalscience.com，是全球变暖大争论中，一方论据的主要来源。所以，如果知道此人白纸黑字地对他自己的研究扯谎，就有理由不再相信那个网站的其他内容，根本不需要进一步核查。[我的一篇旧博文给出了相关细节]

One of the economists who has been active in estimating consequences of warming is William Nordhaus. He is, among other things, the original source for the 2° limit. A few years ago, he published an article in the New York Review of Books attacking a Wall Street Journal piece that argued that climate was not a catastrophic threat that required an immediate response.

有位经济学家，名叫William Nordhaus，一直在忙于估算气候变暖的后果。他是那个“2摄氏度极限”理论的始作俑者。几年前，他在《纽约书评》上写了篇文章，和《华尔街日报》的一篇文章叫板，后者认为，气候不是一个需要马上应对的、会带来灾难的威胁。

In it, he gave his figure for the cost of waiting fifty years instead of taking the optimal steps now—$4.1 trillion dollars—and commented that “Wars have been started over smaller sums.” What he did not mention was that that sum, spread out over the rest of the century and the entire world, came to about one twentieth of one percent of world GNP. He was attacking the WSJ authors for an argument which his own research, as he reported it, supported.

William Nordhaus认为，如果等50年而不是立即采取最佳应对办法，成本会达到4.1万亿美元。他说，人类曾为了比这少的钱开战。他没提的是，这笔钱如果在本世纪余下的时间里均摊给全世界，大概也就是全球GNP的0.05%。他批判《华尔街日报》的观点，而他自己发表的研究实际上却是在支持它。

In a recent Facebook exchange on the consequences of AGW for agriculture, someone linked to an EPA piece on the subject. Reading it carefully, I noticed that the positive effects of warming and CO2 fertilization were facts, with numbers: “The yields for some crops, like wheat and soybeans, could increase by 30% or more under a doubling of CO2 concentrations. The yields for other crops, such as corn, exhibit a much smaller response (less than 10% increase).”

最近在Facebook上，还为了人为全球暖化理论（ Anthropogenic Global Warming ）对农业的影响和人吵了一架。有个人发了个环保局（EPA）文章的链接。我把这文章仔细读了读，发现气候暖化和二氧化碳的增肥带来的正面效应是事实，而且有具体数字：“如果二氧化碳浓度翻倍，小麦和大豆这类作物的收成会增加30%以上，对玉米等其他作物，收成增长较小（小于10%）”。

The negative effects were vague and speculative: “some factors may counteract these potential increases in yield. For example, if temperature exceeds a crop's optimal level or if sufficient water and nutrients are not available, yield increases may be reduced or reversed.” The same pattern held through the article.

有关负面影响的陈述则是含混不清且推测性的：“某些因素可能抵消这些可能的收成增长，比如气温高过了作物成长的最佳温度，或者水和营养素供应不足，这样收成增加可能会减少，甚至减产”。这种模式充斥全文。

A careful reader might also notice that the piece referred to the negative effects of extreme weather without any attempt to distinguish between extreme weather that AGW made more likely (hot summers), less likely (cold winters), or would have an uncertain effect on (droughts, floods, hurricanes). It was reasonably clear that the article was designed to make it sound as though the effects of AGW would be negative without offering any good reason to believe it was true.

仔细的读者还会发现，那篇文章说到极端天气的不利影响时，并未试图区分人为全球暖化会令这些极端天气更频繁（如炎热的夏天），更少见（如严冬），或者影响不确定（如干旱、洪水和龙卷风）。很清楚，这文章目的是把人为全球暖化的影响弄得听上去非常糟糕，而并没有提供好的理由来对此理论的真伪进行判断。

One telling sentence: “Overall, climate change could make it more difficult to grow crops, raise animals, and catch fish in the same ways and same places as we have done in the past.” With most of a century to adjust, it is quite unlikely that farmers will continue to do everything in the same ways and the same places as in the past.

有句话将此意图暴露的特别明显：“总而言之，气候变化可能会让我们一直以来在祖祖辈辈劳作的地方，按照同样的方式来种植作物，饲养牲畜，捕捞鱼虾，变得更加困难”。我们还有近一个世纪的时间来应对，农民们怎么可能会按祖祖辈辈的方式，在同样的地方，做同样的事情呢？

These are three examples of arguments for one side of the climate controversy by a source taken seriously by supporters of that side. Each can be evaluated on internal evidence, what it itself says, without requiring any expert knowledge of the subject. In each case, doing so gives you good reasons not to trust either the source or the conclusion.

这三个例子来自气候大辩论中某一方很认真依靠的资料。每个都可以用资料的内在证据来进行评估，不需要对这个题目有什么专业知识。这些例子让你有很好理由不去相信这些资料来源和结论。

Readers may reasonably suspect that I too am biased. But nothing I have said here depends on your trusting me. In each case, you can look at the evidence and evaluate it for yourself. And all of it is evidence provided by the people whose work I am criticizing.

读者有理由认为，我是有偏见的。但我说的一切是否正确，不需要凭借你对我的信任。你只要研究一下证据，自己评估一下。所有这些证据都是我正在批判的对手们自己提供的。

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