Not true. Too cynical. That the economy is amenable to quantification is unquestionably true. That it has so far completely resisted our advances is false.
Edit: Having said that I see where you're coming from.
Edit: Having said that I see where you're coming from.
I think the closest we can get is to compare the predictions from their theories to reality X years later. It anyone has done that, I'd be very curious to see it.
Economics is the study of a particular value system within society, that value system being the monetary/capital one. Human psychology comes into play (both at the individual and group level) because human evaluation and action is involved.