In view of the magnitude of an economic system, it would take only a very small percentage of improvement in economic stability or growth to make alm… - Kenneth Arrow

I was a very polite person, though. Paul Samuelson tells these stories how he used to correct his professors. I assume that’s true. But I wasn’t that type.

I disagree with the widely accepted proposition that econometric models should have expectations consistent with them. To the extent, it is argued, that the economic theory underlying the model involves anticipations, the anticipations that appear in the model as determining individual behavior should be equal to the forecasts made from the model. More generally, in fact, I would disagree with the weaker proposition that anticipations made by individuals should be necessarily dependent on broadly available general data about the economy and in particular about government actions.

The problem of measuring utility has frequently been compared with the problem of measuring temperature. This comparison is very apt. Operationally, the temperature of a body is the volume of a unit mass of a perfect gas placed in contact with it (provided the mass of the gas is small compared with the mass of the body). Why, it might be asked, was not the logarithm of the volume or perhaps the cube root of the volume of the gas used instead? The reason is simply that the general gas equation assumes a particularly simple form when temperature is defined in the way indicated. But there is no deeper significance.