前文提到的第三部分，共15小节，目录如下：

Efficiency and Economic Institutions

Definitions of 'Economic Efficiency' and 'Waste'

Goverment Regulation with Constraints Omitted

Equal Efficiency of Politico-Economic System / Institutions

Property Rights and Transaction Costs

The Scope of Transaction Costs

The Coase Theorm as Applied to Economic Institutions

Transaction Costs as Determinants of Institutions

A Firm Compared to a Communist State

Choice and Competition as Determinants of Transaction Costs

The Extent of Choice

The Right to Buy and Sell

Information Costs of Chaning Institutions

Costs of Resistance by Privileged Group

We Summarize

这21页、15节的文字，其实蕴含了几条主线，相互交织、互相支持，最终形成了作者的结论。怎么读起来比较舒服呢？读了几遍之后，我认为最后一个小节，We Summarize，其实应该最先读，是主干，反而前面的14节都是对这一部分的论据支持、展开以及推论了 —— 因此将以总结这一部分为主，结合前面的内容，进行解读。

首先是第1个观点，可以称之为“经济学版的存在即合理”。开篇第一句：

In the domain of economic analysis, the formation or modification of economic institutions can be explained only within the framework of theory of choice.

也就是说，只有通过选择理论的分析框架，才能去解读经济制度的形成与变迁。那选择理论的分析框架是什么呢？

This dictates that the institutions observed or the changes predicted for them must be consistent with the constrained maximization and Pareto condition.

用数学的视角来说，就是约束条件下的最优化问题。而现实生活中在做出选择时，哪怕没有经过精确的计算，但仍然是进行了这样的优化。

这样就带来了一个看似不合理的合理结论：

An apparently 'inefficient' institution can continue operating only if its existence has not been explained with in a framework of choice saving economic waste persists because specific costs of operating or changing institutional arrangements have been overlooked.

也就是说：

- 现实永远已经是最优解，不存在“无效率的”情况；如果真的发现了所谓的“无效率”， 那么

- 说明对约束条件的识别不够。

以上总结，对应着就是前四节的详细展开。

因此，这就带出了第二个主线，约束都是什么？会形成什么样的社会存在？

Because economic institutions cannot be conceived as existing in a one-man economy

也就是鲁滨逊一人的世界，不需要经济学也没有社会 —— 颇有社会契约论的味道；而但凡多出来另外一个人，各种互动就带来了：

we identified transaction costs, broadly defined, as the primary constraints in determining institutional arrangements.

这背后的理论基础是科斯定律：

This view was supported by an expansion of the Coase Theorem.

而根据科斯定律，结合张五常自己的佃农理论中的分析，在特殊情况下，如果交易成本为零，会带来什么呢？

In particular, we argued that, if all transaction costs are zero, resources will be allocated to yield the highest value to society, regardless of the nature of property rights or of institutional arrangements.

Thus, in the absence of transaction costs institutions, no choices are random and indeterminate.

也就是说，没有交易成本，社会的形态是“不定型”的，在The Coase Theorm as Applied to Economic Institutions 一节中提到了两个极端：

At one end of the spectrum, with private property rights, maximization of the resource value in the absense of transaction costs would lead to the state of resource use described by Coase. Yet, at the other end of the spectrum - a state of 'common' property rights where no individual can exclude another from the use of productive resource - maximization behavior would produce the same effect. 

但回到现实来，只要有人类互动，交易成本是无处不在的 —— 人类毕竟不是三体人：

- 我们无法直接脑电波沟通，

- 更何况还有谎言、欺骗等的存在。

所以，要得出有意义的知识，需要再往前推导一步：

- 存在交易成本会怎样呢？会带来什么呢？

还是科斯的洞见，这会形成经济组织，来取代社会的资源配置作用 —— 也就是公司的起源：

When transaction costs arise, institutions emerge to reduce them.

个人交出自由决策的权力，带来了什么？

- 形成了经济组织组织

- 形成了支持经济组织的其他社会组织

- 各种组织有了集权，而个人有了想要的安稳

最终，组织的加总，就形成了社会的整体交易成本，或者张五常也曾经称之为 institutional cost.

相对应地，下一步的核心，就是要分析这个最广义的交易成本的变化。而任何分析的第一步，永远是定义，或者叫分类：

We divided transaction costs into those incurred in the operation of institutions and those incurred in adopting or changing institutions.

下面这段论断就很有意思了：

It was argued that an institution with a lower operating cost will be adopted whenever the perspective saving exceeds the cost of the effecting the change.

If the costs of changing institutions are ignored, an institution operating with higher costs than some alternative would be regarded as efficient, and we would have no explanation for its survival.

有点绕？换个角度，如果将“社会”也视为产品，看看俞军的产品价值体验公式：

用户价值 = （新体验 - 旧体验）- 替换成本

是不是一回事？所以，一切人造物的万事万物：

- 既是技术，根据《技术的本质》，

- 但也是产品。

以上内容，对应于A Firm Compared to a Communist State 之前的内容。

第3个论断，现在看来稍微有点跑题，但对于当时的中国可能很重要：

After citing the Coase thesis that a firm emerges to reduce operational (transaction) costs of the market, we suggested that the establishment of a firm is, in effect, a major step towards a form of communism.

Indeed, the Coase thesis bears some resemblance to the most sophisticated defense of the communist state.

That similarity end, however, with the demonstration that, once private property rights have been abolished, the transaction costs in the operation of communist firm are necessarily higher because of the relative lack both of institutional choice and of the competition to reduce those costs generated by the option to transfer or to buy and sell.

其实本质还是在于：

- 只要有多于一人的存在组成的社会，就会有交易成本 —— 人类不是三体人；

- 为了降低市场的交易成本而出现的组织，如果体量过大会带来的僵化；僵化会使得内部交易成本会远远大于市场交易的成本。

以上内容，对应于 A Firm Compared to a Communist State 直到 The Right to Buy and Sell 的内容，其中有很多是对以上核心内容的展开。

最后一个论断来了，对于第2个论断中的“改变的成本”，怎么进行分析呢？答案还是分类：

Major obstacles to institutional change are observed in the cost of obtaining correct Information about other institutional arrangements and the costs of persuading or forcing the privileged group to acquiesce.

这个分类很有意思：

- 首先你知不知道怎么变？这个就涉及到“见识”、“心智模式”、“认知”等各种话题；

- 其次就是，既得利益群体怎么能同意改变？

对于第一个问题，也有一个分类，就是将人类的已知未知分三种：

- known knowns，知道自己知道，这个当然就没什么了

- known unknowns，已知的未知，也就是说，知道自己的无知 —— 这个是可以挽救的

- unknown unknowns，未知的未知，也就是说，都不知道自己无知 —— 很难自我挽救，往往还沾沾自喜

这是需要建立方法论，不断破解第三层的原因 —— 无论是依靠真正的顶级专家，还是完整的学识框架，等等。

这里，我们回到作者对于当时中国的观察：

We further argued that the privileged group, the officials in China have an incentive to distort information and shape the results of the game (property rights arrangements) to their own competitive advantage. Thus communism, a system of exceptionally high transaction costs in its operation, was adopted and has survived because of the cost of changing institutions.

所以作者的结论很清楚了，还是存在有部分人扭曲了信息，带来的结果是，对于已知未知三层：

- 有人在第一层

- 有人在第二层

- 有人被欺骗和隐瞒，一直在第三层

那么站在1980的时点，改变的成本方面有变化吗？

It will now be shown that these costs, higher as they undoubtedly are, are clearly on the declining in China.

这是一个很乐观的对第三部分的总结，也就引出了全文的第四部分 —— 但是对于《经济解释》的笔记来讲，就不展开了。