Economists have know for 500 years that a currency must have some inflation, otherwise people will hoard it and it will not be available for use as a currency.
During the past 500 years, there were long periods of effectively zero inflation where economies boomed. In the industrial revolution in Britain, for example.
Also, I don't think there was such a thing as an economist 500 years ago.
As much as I hate to agree with the professor... but Wikipedia (
) says that the history of economic sciences stretches back to 500 BC. So at least there were at least proto-economists as far back as before the time of Jebus.