Peter Schiff tells the story of a six guys stranded on a deserted island: five Asians and an American. They divide up the work as follows: one Asian hunts, one Asian fishes, one Asian gathers vegetables, one Asian cooks, and one Asian tends the fire. The American has the job of eating.
Peter says that an economist would look at the situation and explain that the American is the key to the whole enterprise. Without the American, the Asians would not have jobs.
The truth is that supply is its own demand. Whatever you produce that is surplus, you can trade for another's surplus. The problem in economics is not how to increase demand, but how to increase supply: how can people produce more useful things so that they can trade their surplus for the surplus of others.