难道真的是太简单了？大家都不屑于回答？

你都说边际产值等于工资了，所以为什么不是n+1呢~

如果再增加一个劳动力的话，边际效益等于工资，也就是说雇不雇他都一样了，但是对于全社会来说，也是对于供需曲线来说，还是要雇的，因为毕竟少雇一个人产量就减少了么，而且还会增加失业率，你觉得呢？

真的是太简单了？

曼昆告诉我们: Rational people think at margin. 理性人考虑边际量
One point that is immediately obvious to the the most casual observer with the meanest intelligence is that most people do not think at the margin.For example, most people who buy orabges at the grocery  store think like this:"HMMM,oranges are $.25 each. I think I'll buy half a dozen." They do not think like this :"Hmmm, oranges are $.25 each. I am going to buy one, because my marginal value exceeds the markets price..."We konw most people don't think like this because most people don't fill their shopping baskets one orange at a times!
But we are now led inexorably toward a most unhappy conclusion.If as Mankiw says rational people think at the margin, and if as we all know most people do not think at the margin, then most people are not rational. Most people, in other wordsm are stupid.Hence my translation of the third principle of economics: people are stupid.
Before sinking into a despair for the fate of the human race, however, the reader would be wise to consider Mankiw's.