“道德风险”是“套套逻辑”？-经管之家官网！

转自CENET</P>
张五常(lijunhui引用):
为什么“道德风险”是“套套逻辑”？仍以买了保险故意撞车为例。以我对张五常的解释的理解，应该是这样的。人们买了保险，的确是会放松警惕，车祸的比例会上升。但为什么会出现这种情况？你不能说是因为“道德风险”，因为“道德风险”的定义就是买了保险故意撞车，用定义去解释定义，不是同义反复是什么？
dzz：
道德风险研究的主要是如何避免道德风险和合约的设计，而不是解释买保险后车祸上升的现象。
lijunhui：
解释现象和解决问题的不同……解决问题只需要把握规律，不需要构建理论；而解释现象是要构建规律以外的抽象理论。所以，把解决问题当成解释现象是犯了“事实不能解释事实”的错误。
Ah sa：
Moral hazard models are not aimed to answer the question why people cheat ... Instead, they consider, given a moral hazard setting, how can we explain certain behaviour of agents or contractual arrangements.
DNKM:
套套逻辑并不可怕，关键你施加了什么现实约束；我暂且不提“道德风险”的定义是什么，就算是套套逻辑，那又怎么样？老伯在批驳"道德风险"的时候怎么丝毫不提约束？难道MV＝PT可以收窄，而“道德风险”就不能。
Ah sa:
transaction cost is a composite concept. Certain types of transaction cost is relevant to wage contract, but most are irrelevant. For example, we don't think increasing the cost of booking a tennis court will affect the wage contract!
So, how should we remedy？Probably we should divide transaction cost into transaction cost A and transaction cost B. Cost A is relevant and B is irrelevant. To identify the set A, we may choose"monitoring cost"is relevant,"information cost"is relevant, .... "talking cost"is irelevant,"kissing cost"is irrelevant ....
If this is the way to do, why do we bother to use the concept of"transaction cost"in this case, but not use the well defined concept of information strcture or monitoring structure？</P>