Pointing in the opposite direction, here's a bit of cold water splashed on the value of our collectively rediscovered enthusiasm for economics - although it's easy to make broad points, it's difficult to really predict what outcome given policies will have. Here's a bit from a recent John Kay column .
Some economists... believe there is a deep underlying structure from which laws of economic behaviour that are universal in time and space can be deduced. I think that search is a wild goose chase and that the best we can do is to identify empirical regularities that apply to particular contexts. Whoever is right, it is evident more work needs to be done in understanding the relationships.
But the killer is that dynamic complexity interacts with non-linearity. If that statement sounds like an extract from a monologue by Gordon Brown, UK prime minister, recall the (false) story that your predecessor, Richard III, lost the crown at Bosworth Field for want of a nail in the shoe of his horse. The point is that small differences in initial conditions can have dramatic differences in ultimate outcomes. The problem is often expressed through the metaphor of the butterfly which, by flapping its wings on one side of the world, sets in train a chain of consequences that results in a tornado many thousands of miles away.
The nature of such complex, dynamic, non-linear systems is that we may be able to say a lot about their general properties, while being unable to make specific predictions. You will recognise this characteristic in the work of your Meteorological Office, which can tell you fairly reliably when spring will follow summer, or how much cooler or warmer it will be when you visit far-flung outposts, but which can never predict what the weather will be more than a few days ahead, or even with certainty what it will be like tomorrow.