I am old-fashioned enough to retain David Hume’s view that one can never derive “ought” propositions from “is” propositions. The two issues, method a… - Kenneth Arrow

What can be concluded? We cannot be sure that the principles of democracy and socialism are compatible until we can observe a viable society following both principles. But there is no convincing evidence or reasoning which would argue that a democratic-socialist movement is inherently self-contradictory. Nor need we fear that gradual moves in the direction of increasing government intervention will lead to an irreversible move to “serfdom.”

Ever since I encountered Hicks’s Value and Capital while I was still a graduate student, I had the aim of completing and extending his vision of the economic system in its purest form. This was not because I believed that the economic world was perfectly competitive or that it was clearly self-equilibrating; after all, Chamberlin, Robinson, and Keynes were dominant intellectual influences, and I had the even more powerful influence of the facts of massive unemployment and large corporations. But the idea that the economic world was a general system, with all parts interdependent, seemed (and seems) to me to be an essential of good analysis. I regret what appears to be a revival of single-market thinking both among monetarists and among some of the younger empirical analysts. Then as now, the only game in town that offered a general system of economic interdependence was general competitive equilibrium, an idea to which the name of Leon Walras is imperishably linked. At least, such a system would provide a starting point for analysis of the market’s imperfections.

There is little warrant for the belief that we know the laws of history well enough to make projections of any great reliability. Most of the turning points of history, great and small, were surprises to both their participants and the analysts of the day, whatever their doctrine.