张五常作品

There is no logical flaw at all to say in a one-man world Giffen good exists, in the sense that an inferior good may exist to the point where the indifference curves of an individual bear the characteristics of a Giffen good.  There is no market price in a one-man world, but relative opportunity costs or constraint changes may in logic lead to a Giffen good result.  The same may be said of an individual in society who chooses not to participate in the market.

However, for a good that is actually transacted in the market, a Giffen good cannot logically exist because someone will bid the price so high that the good will not be traded in the market.

（按：下期“五常考室”的题目改在星期天发布。）