Who were Francois Quesnay and the Physiocratic School of Economics?

Question

What was the essence of the Physicocratic School? In the Circular Flow Diagram are Income, Output and Expenditures equal – why?

Answer 1

Wow... Typing "Quesnay" or "Physiocrats" into a search engine would yield an answer in seconds... Oh well, here's some info to get you started:

http://en.wikipedia.org/wiki/Quesnay
http://en.wikipedia.org/wiki/Physiocrats

As to output and expenditures being equal, this is simply another way of saying that production of something only counts if someone consumes that something (and pays for it before consuming).