At virtual Jackson Hole this year FOMC Chair Jerome Powell redefined inflation for the third time in my lifetime. By removing the Phillips Curve from the landscape Powell will now guide monetary policy by the desire to create inflation expectations, a kind of first derivative of inflation under the mostly irrelevant Quantity Theory of Money (QTM).
I talked about Powell's dilemma and why he had to make this change in a post right after that speech. And I outlined what the Austrian criticism of the QTM was — a myopic focus on the supply of money rather than the interplay of it with the demand for money.
The better definition of inflation expectations is to think of it as the velocity of human action.