宋圭武：科斯定理需要纠正和完善

科斯定理需要纠正和完善。关于科斯定理存在众多争论。一个是存在不存在科斯定理，或者科斯定理算不算是一个定理，有不同争论。另外，若有科斯定理，到底科斯定理的真正含义是什么，也有不同争论。目前，主流的看法是认为科斯定理应当是存在的，并且一些学者将科斯定理主要归结为两种情况：第一，在交易费用为零的情况下，不管权利如何进行初始配置，最终自愿交易都会导致资源配置成本最小化或收益最大化；第二，在交易费用不为零的情况下，不同的权利配置界定会带来不同的资源配置效果，所以产权制度的设置是优化资源配置的基础。

对于第一种情况，科斯认为，如果交易成本为零，无论权利如何初始界定，当事人都可以通过交易实现资源的最优配置。

经济学有一个最后通牒博弈案例，可以看成是一种交易费用为零的一种资源配置，但其自愿交易的结果并不符合科斯定理第一种情况。因为实际情况是当对方提出的份额少于30%时，人们倾向于拒绝，这就与科斯定理第一种情况有矛盾。

如何解决这个矛盾，笔者认为，这里应扩展科斯定理中的成本和收益概念。科斯定理中的成本和收益，主要考虑的是物质成本或物质收益，并没有考虑精神成本和精神收益。而在最后通牒博弈中，当事人（不管是决定分配的还是接受分配的）实际考虑的是物质成本、物质收益和精神成本、精神收益的总和，是按照物质成本加精神成本总和最小化和物质收益加精神收益总和最大化来决定资源配置策略的。

同时，在最后通牒博弈中，我们也看到，从群体角度看，在交易成本为零的情况下，资源配置结果与权利的初始界定（分配比例）是有密切关系的，并不是没有关系，其中权利的初始界定一定要考虑公平因素。若不公平，会引起不同程度的社会对抗。对一个人而言，若当不公平所导致的负效用大于一个人生命的正效用时，这个人甚至可能会用牺牲生命的方式来捍卫公平，在这种情况下，可能会引发个体暴力事件。对社会而言，若当社会不公平导致社会大部分人的总效用为负值时，可能会引发社会骚乱甚至导致社会革命。另外，从最后通牒整个群体博弈过程看，分配方案越公平，会有越多人接受分配方案，最终越有利于实现整个群体物质收益和精神收益总和的最大化。所以，从社会角度看，我们也可以这样认为，对每个个体的初始权利界定越公平，最终自愿交易导致社会资源配置的整体效率会越高。

至于对于科斯定理的第二种情况，权利的初始界定，更应考虑公平问题。因为若交易成本不为零，在以后的市场运行过程中，不公平的初始权利界定，最终会导致社会运行陷入更大范围的不均衡。 由此，本人认为，不管是第一种情况，还是第二种情况，科斯定理正确的表述应是：从社会整体角度看，只有公平或满足一定程度公平的初始资源或产权配置，人们的自愿交易才有可能实现社会整体的资源最优配置（注意：这里是指有可能实现最优配置，并非必然是最优配置，因为社会整体的资源配置，还受其它许多因素制约，比如社会大众的理性水平、道德水平、信息不对称等情况，都是重要的制约因素）；从个人局部决策角度看，人们是按照物质成本加精神成本的总和最小化或物质收益加精神收益的总和最大化来考虑资源配置最优的，并不仅仅是只考虑物质成本最小化或物质收益最大化。

总之，一般而言，对社会发展而言，公平问题要比产权明晰问题更为重要。公平正义是社会的首要价值。

作者：甘肃省委党校教授

Song Guiwu Coase Theorem needs to be corrected and improved

Professor Song Guiwu of the Party School of Gansu Provincial Committee believes that Coase Theorem needs to be corrected and improved.There are many disputes about Coase Theorem.One is whether there is a Coase Theorem or whether the Coase Theorem is a theorem. In addition, if there is a Coase Theorem, there are also different arguments about what the true meaning of the Coase Theorem is.At present, the mainstream view is that the Coase Theorem should exist, and some scholars mainly attribute the Coase Theorem to two situations: first, in the case of zero transaction costs, no matter how the rights are initially allocated, the final voluntary transaction will lead to the minimization of resource allocation costs or the maximization of benefits; second, in the case of non-zero transaction costs, different definitions of right allocation will bring different effects of resource allocation, so the setting of property rights system is the basis for optimizing resource allocation. For the first situation, Coase believed that if the transaction cost is zero, no matter how the rights are initially defined, the parties can achieve the optimal allocation of resources through transaction. There is an ultimatum game case in economics, which can be regarded as a resource allocation with zero transaction costs, but the result of its voluntary transaction does not conform to the first situation of the Coase Theorem. Because the actual situation is that when the other party's share is less than 30%, people tend to refuse, which is contradictory to the first case of Coase Theorem.How to solve this contradiction? The author thinks that the concept of cost and income in Coase Theorem should be expanded here.The cost and income in Coase Theorem mainly considers material cost or material income, but does not consider spiritual cost and spiritual income.But in the ultimatum game, the parties (whether they decide to allocate or accept the allocation) actually consider the sum of material cost, material income and spiritual cost and spiritual income, and decide the resource allocation strategy according to the minimization of the sum of material cost and spiritual cost and the maximization of the sum of material income and spiritual income.At the same time, in the ultimatum game, we also see that from the perspective of groups, in the case of zero transaction cost, the resource allocation result is closely related to the initial definition of rights (distribution ratio), but not without relationship, in which the initial definition of rights must consider fairness.If it is not fair, it will cause different degrees of social confrontation. For a person, if the negative utility caused by unfairness is greater than the positive utility of a person's life, the person may even sacrifice his life to defend justice. In this case, individual violence may be triggered.For society, if social inequality leads to a negative total utility for most people in society, it may lead to social riots or even social revolution.In addition, from the perspective of the whole group game process of ultimatum, the more fair the distribution scheme is, the more people will accept the distribution scheme, and the more conducive it is to maximizing the sum of material and spiritual benefits of the whole group.Therefore, from the perspective of society, we can also think that the more fair the initial definition of each individual's right is, the higher the overall efficiency of social resource allocation will be caused by voluntary transactions. As for the second case of Coase Theorem, the initial definition of rights should be more fair.Because if the transaction cost is not zero, in the later market operation process, the unfair initial definition of rights will eventually lead to a wider range of imbalance in social operation. Therefore, I think, no matter the first case, or the second case, the correct statement of Coase Theorem should be: from the perspective of the whole society, only fair or meet a certain degree of fair initial resource or property rights allocation, people's voluntary transaction is possible to achieve the optimal allocation of resources as a whole society (note: here it means that it is possible to achieve the optimal allocation, but not necessarily the optimal allocation, because the allocation of resources as a whole society is also restricted by many other factors, such as the rational level of the public, the moral level, the information asymmetry and so on, which are all important restrictive factors); from the perspective of individual local decision-making, people consider the optimal allocation of resources according to the minimization of the sum of material cost and spiritual cost or the maximization of the sum of material income and spiritual income, not only the minimization of material cost or the maximization of material income. In short, in general, for social development, the issue of fairness is more important than the issue of clear property rights.Equity and justice are the primary value of society.