The Lesson Restated
第25章
课后温习

Economics, as we have now seen again and again, is a science of recognizing secondary consequences. It is also a science of seeing general consequences. It is the science of tracing the effects of some proposed or existing policy not only on some special interest in the short run, but on the general interest in the long run.

正如我们反复认识到的，经济学是一门认识种种续发后果的科学，同时还是一门分析总体后果的科学。它研究的是某些现行政策或者政策建议的后果，不仅仅限于比较短的时期某些特殊利益集团，而且是在长期内对整体的后果。

This is the lesson that has been the special concern of this book. We stated it first in skeleton form, and then put flesh and skin on it through more than a score of practical applications.

这便是本书所特别关注的教训。我们首先给出了其骨架结构，然后以各种实际应用的例子，使之有血有肉。

But in the course of specific illustration we have found hints of other general lessons; and we should do well to state these lessons to ourselves more clearly.

就在对个例的阐述中，我们也发现了其他一些更为普遍的教训的线索；我们应该就这些教训作出更好更清楚的说明。

In seeing that economics is a science of tracing consequences, we must have become aware that, like logic and mathematics, it is a science of recognizing inevitable implications.

在认识到经济学是一门探究各种后果的科学时，我们必须懂得，就象逻辑学和数学一样，经济学是认识那些必然结果的科学。

We may illustrate this by an elementary equation in algebra. Suppose we say that if x = then x + y = 12. The “solution” to this equation is that y equals 7; but this is so precisely because the calculation tells us in effect that)? equals 7. It does not make that assertion directly, but it inevitably implies it.

我们用个简单的代数方程来说明这一点。假设x=5，且x+y=12。这个方程“解”是y=7。答案之所以确切无疑，是因为这个方程式事实上告诉了我们y等于7。它并没有直接地给出这一结果，但它却必然蕴含了这个结果。

What is true of this elementary equation is true of the most complicated and abstruse equations encountered in mathematics. The answer already lies in the statement of the problem. It must, it is true, be “worked out.” The result, it is true, may sometimes come to the man who works out the equation as a stunning surprise. He may even have a sense of discovering something entirely new—a thrill like that of “some watcher of the skies, when a new planet swims into his ken.” His sense of discovery may be justified by the theoretical or practical consequences of his answer. Yet the answer was already contained in the formulation of the problem. It was merely not recognized at once. For mathematics reminds us that inevitable implications are not necessarily obvious implications.

这个简单的方程式所蕴含的道理就是数学中其它最复杂、最深奥的方程式也要遵循的。答案已经蕴含于问题的陈述之中。因此，必须把它“解出来”。的确，出现的结果有的时候出乎解题的人的意料，甚至有一种感觉，好象发祥了某种全新的东西——那种兴奋战栗，就象“天文观测者猛然发现一颗新行星游入了他的视野”。对其答案进行理论的和实际的分析所得到的结果而言，他的这种创造感也名至实归。然而，答案的确早已蕴含在问题的陈述里了，只不过并非一目了然。数学的研究告诉我们：必然的结果未必是显然的结果。

All this is equally true of economics. In this respect economics might be compared also to engineering. When an engineer has a problem, he must first determine all the facts bearing on that problem. If he designs a bridge to span two points, he must first know the exact distance between these two points, their precise topographical nature, the maximum load his bridge will be designed to carry, the tensile and compressive strength of the steel or other material of which the bridge is to be built, and the stresses and strains to which it may be subjected. Much of this factual research has already been done for him by others. His predecessors, also, have already evolved elaborate mathematical equations by which, knowing the strength of his materials and the stresses to which they will be subjected, he can determine the necessary diameter, shape, number and structure of his towers, cables and girders.

所有这些对于经济学来说同样适用。在这方面，经济学也可以拿工程来比喻。工程师处理问题的时候，必须先确定对那个问题有影响的所有事实。如果他要设计一座桥梁来连接两地，就必须先知道这两个点之间的精确距离、两点附近确实的地形特性、桥梁所要承受的最大载荷、建桥用的钢材或其他材料的抗张和抗压强度，以及桥梁应该具有的应力和应变等等。这些参数方面的实际研究已经由其他人完成了。他的前辈们早已推出了复杂精确的数学方程式，从这些方程式出发，根据他已经掌握了的材料的强度和桥梁应当达到的应力，他就能确定索塔、斜拉索、主梁的必要直径、形状、数量和结构。

In the same way the economist, assigned a practical problem, must know both the essential facts of that problem and the valid deductions to be drawn from those facts. The deductive side of economics is no less important than the factual. One can say of it what Santayana says of logic (and what could be equally well said of mathematics), that it “traces the radiation of truth,” so that “when one term of a logical system is known to describe a fact, the whole system attaching to that term becomes, as it were, incandescent.”

同样，当一个经济学家确定了自己所要分析的问题时，他必须用类似的方法了解与其问题有关的基本事实，以及从这些事实中可以得出的有根据的推论。在经济学分析中，演绎推理与了解事实是同等重要的。我们可以引用桑塔雅纳论述逻辑学的话来讲经济学（它同样适用于数学），即它是“探寻真理之光的辐射”，因此，“当人们懂得了逻辑体系中的一个词，并用它来描述事实时，与这个词联系在一起的整个逻辑体系就会豁然明朗”。{脚注:桑塔雅纳，《真理的境界》George Santayana, The Realm of Truth (1938), p. 16.}

Now few people recognize the necessary implications of the economic statements they are constantly making. When they say that the way to economic salvation is to increase credit, it is just as if they said that the way to economic salvation is to increase debt: these are different names for the same thing seen from opposite sides. When they say that the way to prosperity is to increase farm prices, it is like saying that the way to prosperity is to make food dearer for the city worker. When they say that the way to national wealth is to pay out governmental subsidies, they are in effect saying that the way to national wealth is to increase taxes. When they make it a main objective to increase exports, most of them do not realize that they necessarily make it a main objective ultimately to increase imports. When they say, under nearly all conditions, that the way to recovery is to increase wage rates, they have found only another way of saying that the way to recovery is to increase costs of production.

现在，很少有人能够真正懂得，他们不断提出的各种经济主张会有什么样的必然结果。当他们说，拯救经济的方式就是增加信贷，就等于是说，加重债务就能拯救经济。二者是同一事物，从不同侧面去看，便有了含义不同的名称。当他们说，繁荣之道是提高农产品的价格，就等于是说，让城市劳工购买的食物价格变贵就能迈向繁荣。当他们说，增加国家财富的方法是政府提供补贴，就等于是说，加重税负就能增进国家的财富。当他们主张以增加出口为主要目标的时候，大多数人并没有意识到，应该相应制定一个扩大进口的目标。当他们说，任何情况下，刺激经济复苏的方法是提高工资率，就等于拐弯抹角表示，只有提高生产成本才能促使经济复苏。

It does not necessarily follow, because each of these propositions, like a coin, has its reverse side, or because the equivalent proposition, or the other name for the remedy, sounds much less attractive, that the original proposal is under all conditions unsound. There may be times when an increase in debt is a minor consideration as against the gains achieved with the borrowed funds; when a government subsidy is unavoidable to achieve a certain military purpose; when a given industry can afford an increase in production costs, and so on. But we ought to make sure in each case that both sides of the coin have been considered, that all the implications of a proposal have been studied. And this is seldom done.

上述种种说法都象硬币一样有其相反的一面，可能因为我们观察的角度不同，或是为了说得更全面一些而换了一种说法，现在它们听起来似乎不如原来有吸引力。当然，这不一定表示，那些主张在所有的情况下都站不住脚。有些时候，借来的资金可以产生很大的收益，加重债务也许算不得什么；有些时候，为达到军事目的，政府在个别情况下进行补贴也是不可避免的；而且，有的时候，个别产业也负担得起生产成本的增加；诸如此类。不过，不管是哪一种状况，我们都务必要同时考虑硬币的两面，去探讨经济政策提案所蕴含的的所有结果。事实上，人们很少能做到这一点。

2

The analysis of our illustrations has taught us another incidental lesson. This is that, when we study the effects of various proposals, not merely on special groups in the short run, but on all groups in the long run, the conclusions we arrive at usually correspond with those of unsophisticated common sense. It would not occur to anyone unacquainted with the prevailing economic half-literacy that it is good to have windows broken and cities destroyed; that it is anything but waste to create needless public projects; that it is dangerous to let idle hordes of men return to work; that machines which increase the production of wealth and economize human effort are to be dreaded; that obstructions to free production and free consumption increase wealth; that a nation grows richer by forcing other nations to take its goods for less than they cost to produce; that saving is stupid or wicked and that squandering brings prosperity.

我们对例证所作的分析，从另一方面给了我们一点附带的启发。那就是说，当我们不仅仅从短期的某一集团的利益出发，而同样研究了各种各样的建议对所有集团长期利益的影响时，我们所得到的结论通产符合那些最简单的常识。不了解当今流行经济观点的“半文盲”们也根本不会想到，橱窗被砸破、城市毁于战火是件好事；或者兴建一些并不需要的公共工程不算纯粹浪费；或者政府裁撤冗员让闲人重回劳动市场非常危险；或者添置能增进财富创造、让工作更省 力的机器会令人不寒而栗；或者对自由生产和自由消费设置障碍就可以增加财富；或者迫使其它国家以低于生产成本的价格，购买我们的产品，可以让我们变得更加富裕；或者储蓄是既愚蠢又邪恶的行为以及挥霍享用才能带来繁荣。

“What is prudence in the conduct of every private family,” said Adam Smith’s strong common sense in reply to the sophists of his time, “can scarce be folly in that of a great kingdom.” But lesser men get lost in complications. They do not reexamine their reasoning even when they emerge with conclusions that are palpably absurd. The reader, depending upon his own beliefs, may or may not accept the aphorism of Bacon that “A little philosophy inclineth men’s minds to atheism, but depth in philosophy bringeth men’s minds about to religion.” It is certainly true, however, that a little economics can easily lead to the paradoxical and preposterous conclusions we have just rehearsed, but that depth in economics brings men back to common sense. For depth in economics consists in looking for all the consequences of a policy instead of merely resting one’s gaze on those immediately visible.

亚当·斯密用极其普通的常识，回应当时的诡辩家说：“在每一个家庭的管理中是精明的举措，用于一个大国的管理，很少会是错的。”但不智者就在复杂关系中迷失了。即使他们得出来的结论看上去就很荒唐，他们也不会重新检查自己的推导过程。哲学家培根说：“稍微懂点哲学的人会倾向于无神论，而深究哲理则会使人的思想更接近宗教。”依读者本身的信仰而定，可能接受，也可能不接受这句箴言。不过，下面这句话却千真万确：懂得一点点经济学很容易引导人们得出自相矛盾的十分荒谬的结论，而真正理解经济学则会使人的思想重新回到常识。因为通达的经济学在于向人们揭示一项经济政策的全部后果，而不是仅仅引导人们把目光停留在那些显而易见的现象上。

（未完待续）