Macroeconomics, even with all of our computers and with all of our information - is not an exact science and is incapable of being an exact science.
Paul SamuelsonThe failure of market catallactics in no way denies the following truth: given sufficient knowledge the optimal decisions can always be found by scanning over all the attainable states of the world and selecting the one which according to the postulated ethical welfare function is best. The solution 'exists'; the problem is how to 'find' it.
Paul Samuelson