Why we are skeptical of economic forecasts

Economists have been known, on occasion, to joke about “physics envy”. The laws of physics are not up for debate, and most members of the public feel unqualified to offer opinions on whether, for example, string theory offers a promising route towards a Theory of Everything. The laws of economics, on the other hand, are treated as though they are based on no more than opinion or even ideology, and many people seem to feel qualified to offer opinions on whether, for example, carbon taxes will reduce emissions, all else equal.