So are we making a mistake putting our faith in economics? Are economists themselves just charlatans, to be scorned as medieval cranks? Or for all their flaws, are they really the best experts we have? I don't have a definitive answer, just like there is no good answer to the problem of the Royal Physician. But having gone through an economics PhD, I do know a few things that I think the public should realize about the field.
To start, we need to talk briefly about what it is economic theorists do. Essentially, they make models, which are mathematical tools that are supposed to describe how the economy functions. The problem is that economists haven't really built a model of the whole economy that works. A lot of smart people have spent a lot of time creating tools with names like "dynamic stochastic general equilibrium." But as of this moment, those models can't really forecast the economy like our meteorologists can forecast the weather. Furthermore, they contain a lot of obviously wrong assumptions. To give just one example, many of the models stipulate that companies are only allowed to change their prices at random times! Crazy, right? Economists include things like that to make the models easier to use, and they hope that those zany assumptions are actually decent approximations to the way the world really works. But even with these kludges in place, none of the existing models can do much to predict the economy.