Much of current academic teaching and research has been criticized for its lack of relevance, that is, of immediate practical impact... The trouble is caused, however, not by an inadequate selection of targets, but rather by our inability to hit squarely any one of them... The weak and all too slowly growing empirical foundations clearly cannot support the proliferating superstructure of pure, or should I say, speculative economic theory.

p. 1. - "Theoretical assumptions and nonobserved facts," 1971