Robert Solow (1985), "Economic History and Economics" http://www.jstor.org/stable/pdfplus/1805620.pdf:
  • Economics is a social science. It is subject to Damon Runyon's Law that nothing between human beings is more than three to one. To express the point more formally, much of what we observe cannot be treated as the realization of a stationary stochastic process without straining credulity. Moreover, all narrowly economic activity is embedded in a web of social institutions, customs, beliefs, and attitudes. Concrete outcomes are indubitably affected by these background factors, some of which change slowly and gradually, others erratically. As soon as time-series get long enough to offer hope of discriminating among complex hypotheses, the likelihood that they remain stationary dwindles away, and the noise level gets correspondingly high. Under these circumstances, a little cleverness and persistence can get you almost any result you want. I think that is why so few econometricians have ever been forced by the facts to abandon a firmly held belief. Indeed, some of Fortune's favorites have been known to write scores of empirical articles without once feeling obliged to report a result that contradicts their prior prejudices.

  • If I am anywhere near right about this, the interests of scientific economics would be better served by a more modest approach. There is enough for us to do without pretending to a degree of completeness and precision which we cannot deliver. To my way of thinking, the true functions of analytical economics are best described informally: to organize our necessarily incomplete perceptions about the economy, to see connections that the untutored eye would miss, to tell plausible-sometimes even convincing-causal stories with the help of a few central principles, and to make rough quantitative judgments about the consequences of economic policy and other exogenous events. In this scheme of things, the end product of economic analysis is likely to be a collection of models contingent on society's circumstances-on the historical context, you might say-and not a single monolithic model for all seasons....

  • The other direction of influence, what economic history offers to that kind of economic theory, is more interesting. If the proper choice of a model depends on the institutional context-and it should-then economic history performs the nice function of widening the range of observation available to the theorist. Economic theory can only gain from being taught something about the range of possibilities in human societies. Few things should be more interesting to a civilized economic theorist than the opportunity to observe the interplay between social institutions and economic behavior over time and place....

  • If the project of turning economics into a hard science could succeed, it would surely be worth doing. No doubt some of us should keep trying. If it did succeed, then there would be no difference between economics and economic history other than the source of data.... There are, however, some reasons for pessimism about the project. Hard sciences dealing with complex systems-but possibly less complex than the U.S. economy-like the hydrogen atom or the optic nerve seem to succeed because they can isolate, they can experiment, and they can make repeated observations under controlled conditions. Other sciences, like astronomy, succeed because they can make long series of observations under natural but essentially stationary conditions.... Neither of these roads to success is open to economists....

  • [T]here is a clear and productive division of labor between the economist and the economic historian. The economist is concerned with making and testing models of the economic world as it now is, or as we think it is. The economic historian can ask whether this or that story rings true when applied in earlier times or other places, and, if not, why not.... [E]conomic history can offer the economist a sense of the variety and flexibility of social arrangements and thus, in particular, a shot at understanding a little better the interaction of economic behavior and other social institutions...