In Friedman’s original work, the natural unemployment rate was a purely theoretical conjecture, founded on an assumption described as “rational expectations,” even though it ran counter to any normal definition of rational behavior.
No trabalho original de Friedman, a taxa de desemprego natural era uma conjetura puramente teórica, fundada num pressuposto descrito como “expectativas racionais”, mesmo que contrariasse qualquer definição normal de comportamento racional.