西方微观经济学什么是公共物品为什么有政府提供举例

Question

如题所述

Answer 1

In economics, a public good is a good that is both non-excludable and non-rivalrous in that individuals cannot be effectively excluded from use and where use by one individual does not reduce availability to others.
用中文来说，也就是一种物品是非竞争也非排他的，比如空气，国防设施等等。

指得注意的是，由于good这个词是一个双关词，有“物品”以及“好的”两个 意思，所以我们所说的公共品往往都是对个人有益的东西，而那些有害的则不属于public good，例如工厂废气（废气也满足非竞争和非排他特性）。
如果是原版英文教材，有一个与之对应的词叫public bad:
A public bad, in economics, is the symmetry of a public good. Air pollution is the most obvious example since it is non-excludable and non-rival, and negatively affects welfare.
许多书上给他取一个新名字叫： externality

Answer 2

政府提供免费服务的公共场地和设施，都是公共物品。比如（坐椅，公园，草坪，饮水机）等。