They claim that a scientific discipline is to be judged primarily on its predictions, and on that basis, they suggest, economics doesn’t qualify as a science.
Prediction is certainly a valuable goal in science, but not the only one. Explanation is also important, and there are plenty of sciences that do a lot of explaining and not much predicting. Seismology, for example, has taught us why earthquakes occur, but doesn’t tell Californians when they’ll be hit by “the big one.”
And through meteorology we know essentially how hurricanes form, even though we can’t say where the next storm will arise.
In the same way, economic theory provides a good understanding of how financial derivatives are priced….But that doesn’t mean that we know whether the derivatives market will crash this year.
Perhaps one day earthquakes, hurricanes and financial crashes will all be predictable. But we don’t have to wait until then for seismology, meteorology and economics to become sciences; they already are.
Maskin’s examples should really indicate that seismology and meteorology do make predictions; they just happen to be probabilistic ones like ‘there will almost certainly be an earthquake measuring 7 on the Richter scale in California in the next hundred years’ or ‘this summer’s Atlantic hurricane season will most likely see more hurricanes in the Caribbean than last year’; it is on the basis of these rough and ready predictions and the historical record (and, of course, the extra-scientific assumption that the laws of physics will endure) that building codes in the relevant regions have changed in response.
Still, Maskin is on to something: most careless characterizations of science attribute far too many essential features to science.
Consider for instance, a definition of science that says a scientific discipline necessarily relies on experimentation and produces law-like statements about nature. The former would exclude cosmology, the latter biology. (Rosenberg and Curtain have been careful enough to not talk about laws or experimentation in their description of the ‘essential’ features of science.)
The model of science that Rosenberg and Curtain work with is, unsurprisingly enough, based on physics. Furthermore, the examples they use–predicting the orbit of a satellite around Mars, the explanation of chemical reactions in terms of underlying atomic structure, predictions of eclipses and tides, the prevention of bridge collapses and power failures–are derived from the same terrain. In general, there seems to be much consensus that a putative candidate for scientific status succeeds the more closely a description of it matches that of paradigmatic theoretical and experimental physics. As this similarity fades, more work has to be done to include that discipline in the scientific cluster.
It is still not clear to me that economics is a science. But that is not because it fails to meet some ‘essential feature’ of science; rather, it is because we still lack a complete understanding of what makes a discipline a science. There is a persistent difficulty of the characterization problem in the philosophy of science: most definitions of science–as any undergraduate in a philosophy of science class quickly comes to realize–fail to do justice to scientific practice through history and to the actual content of scientific knowledge.
The debate about whether economics is a science is most interesting because it shows the prestige associated with scientific knowledge; a successful classification as a science entails greater acceptance and entrenchment of its claims, and concomitantly, greater support–possibly financial–for its continued practice.
In the marketplace of competing knowledge claims, this is the truly important issue at hand.