Economics vs. ‘Need’

One of the most common arguments for allowing more immigration is that there is a “need” for foreign workers to do “jobs that Americans won’t do,” especially in agriculture.
One of my most vivid memories of the late Armen Alchian, an internationally renowned economist at UCLA, involved a lunch at which one of the younger members of the economics department got up to go get some more coffee. Being a considerate sort, the young man asked, “Does anyone else need more coffee?”
“Need?” Alchian said loudly, in a cutting tone that clearly conveyed his dismay and disgust at hearing an economist using such a word.

http://spectator.org/archives/2013/06/11/economics-vs-need