In the first place, economic theory provides a comparatively detailed specification of the demand relationships for individual consumers' goods, but … - Richard Stone

From 1931 to 1935, I was an undergraduate at Cambridge in my father's old college, Gonville and Caius, which was particularly strong in medicine and the law. However, after two years of law I switched to economics, much to my father's disappointment. At that time the world was in the depth of the great depression and my motive for wanting to change subject was the belief, bred of youthful ignorance and optimism, that if only economics were better understood, the world would be a better place.

The usefulness of observation and measurement in testing economic theories arises because the theorems of economics are supposed to relate to the actual world... Any economic theorem rigorously deduced from given postulates may be regarded as a hypothesis about the actual world which xperience may show to be false.

A choice may have to be made between a biased estimator which is believed to be relatively accurate and an unbiased estimator which is demonstrably highly inefficient, and it is by no means obvious that the latter is always to be preferred.