The only rational defense of what may be termed a liberal position, or perhaps more precisely a principle of limited social preference, is that it is… - Kenneth Arrow

According to this point of view, knowledge is, so to speak, a by-product of production or of investment. In research, on the contrary, it can be said that knowledge is the primary product. The distinction between products and by-products is not important for ordinary goods, because in a competitive regime the marginal costs of the two must be equal. But since knowledge does not have the normal properties of an economic good, it is necessary to study each mode of its production.

I then follow up with four major aspects of economic research in the last 60 years, the period of my scholarly activity. One, econometric methodology and practice, is of such fundamental importance that it cannotgo unnoticed, although I played no role in it. With the other three, general equilibrium, dynamic processes, and uncertainty and information, I was more intimately involved.

I expect that ethical codes and informal nonprice organizations will continue to evolve where needed, for example in the control of product quality, to permit transactions which would be impossible because of differential information in markets where all individuals behaved in a purely selfish manner. The evolution of ethical codes is facilitated by the fact that productive units are organizations, not individuals, and individuals are mobile among these organizations.