It is during this time that, as scientists, when we try to make sense out of how things occur in economics, that we continually realize that it doesn't make sense, and that many of the things that occur often do not have clear rules and patterns. So I guess an article like this one, arguing why economics will NEVER be like physics no matter how hard it tries, really is a no-brainer.
My bet is that economics will always remain as squishy as anthropology, political science, history and other social sciences. The physical sciences address phenomena-ranging from electrons, elements and the nuclear forces up to stars, galaxies and gravity-that are relatively stable and well-defined. In contrast, economies vary wildly across space and time. The U.S. economy today is radically different than it was a decade or even a month ago. Economists are chasing a rapidly moving and mutating target.
It gets worse: Protons, plasmas, planets and other strictly physical systems don't care what scientists think about them. Social systems, on the other hand, consist of objects that read newspapers, journals, books and blogs and change their behavior as a result. Newton's model of planetary motion did not affect Jupiter's course, but an initially persuasive model of dollar-yen exchange rates may affect those rates in a way that soon renders the model totally obsolete.
In other words, the effort to understand economies or indeed almost any human social system changes the system! I'm not talking about some subtle quantum-observer effect but something much more dramatic. Marx creates Marxists, Keynes Keynesians, Hayek Hayekians, leading to wars and depressions, bubbles and recessions.
It is because of this that it irritates me whenever politicians (and even economists) can talk about many policies with such utter certainty. You see politicians arguing about this policy versus that policy which can (or cannot) create jobs, or doing such-and-such will cause taxes to fall, or people to lose jobs, etc, etc. And of course, the public will buy it, details unseen as always. It certainly is ironic that fields in "hard" sciences are more concerned about uncertainty and "error bars" in our work and experimental data, while "soft" science such as politics, economics, and social sciences that deal with less-verified principles are presented with such definite certainty.