經濟學:稀少性的矛盾問題(免費物品定義)

係 Micro Economics, Free good同時有幾個定義,

1, There is no opportunity cost when using it, although there may be alternative use.
2, More of it is not preferred, but some is preferred to none.
3,When price = 0, Quantity demanded < Quantity supplied.

空氣係very abundant in supply, 並完全符合 free good既定義.
其實係最後一項定義最重要，當空氣唔使錢，都仍然有surplus，
就係free good，當然不存在scarcity，比對返定義，
Scarcity is that limited resource is insufficient to satisfy unlimited human want.
因為空氣已能夠satisfy human wants.


當然，你一定知道係缺氧、高山時空氣變成scarce good啦，我唔解喇~