"A couple of others, however, suggested that the juxtaposition of higher core inflation and somewhat lower unemployment could imply that the level of potential output was lower than had been thought."The economy grew 0.7% in the first six months of the year, and we are still below the previous peak, but we're close to potential output?! My guess is that "the couple of others" includes Plosser. In other words, this guy thinks that around 9 percent unemployment is close to the natural rate. Nothing like believing that anything is full employment to convince yourself that markets actually produce optimal outcomes.