Both freshwater and saltwater (for reference, these refer to geographical locations in the US: Chicago and Minnesota near lakes, and MIT, Harvard, Yale, Stanford, etc. near the coasts) claim that you can&#x27;t run out of demand, in the long run.<p>These schools differ in their analysis of the business cycle, that is the fluctuations around equilibrium output that are called booms and recessions&#x2F;depressions.  Saltwater economists believe that you can have too little&#x2F;too much demand during booms&#x2F;recessions.  These are generally called &quot;out of equilibrium&quot; conditions.  Neither group claim that in equilibrium, you can run out of demand.<p>Source: I have a PhD in economics.<p>EDIT: also see vezzy-fnord&#x27;s answer, most &quot;Freshwater&quot; economists are and were some kind of Keynesian.