Complete freedom is not definable once two wills exist in the same interdependent universe. We can sometimes find two situations in which Choice A is… - Paul Samuelson

The museums of science are replete with fossils of species that could not last the course. The leading-coinciding-lagging indicators might be buried forever in old footnotes. But occasionally Sleeping Beauty is brought back to life by the kiss of a new Prince Charming.

In the preface to the reissue of Risk, Uncertainty and Profit, Frank Knight makes the penetrating observation that under the conditions envisaged above the velocity of circulation would become infinite and so would the price level. This is perhaps an over-dramatic way of saying that nobody would hold money, and it would become a free good to go into the category of shell and other things which once served as money. We should expect too that it would not only pass out of circulation, but it would cease to be used as a conventional numeraire in terms of which prices are expressed. Interest bearing money would emerge. Of course, the above does not happen in real life, precisely because uncertainty, contingency needs, non-synchronization of revenues and outlay, transaction frictions, etc., etc., all are with us. But the abstract special case analyzed above should warn us against the facile assumption that the average levels of the structure of interest rates are determined solely or primarily by these differential factors. At times they are primary, and at other times, such as the twenties in this country, they may not be. As a generalization I should hazard the hypothesis that they are likely to be of great importance in an economy in which there is a “quasi-zero" rate of interest. I think by this hypothesis one can explain many of the anomalies of the United States money market in the thirties.

There is really nothing more pathetic than to have an economist or a retired engineer try to force analogies between the concepts of physics and the concepts of economics. How many dreary papers have I had to referee in which the author is looking for something that corresponds to entropy or to one or another form of energy. Nonsensical laws, such as the law of conservation of purchasing power, represent spurious social science imitations of the important physical law of the conservation of energy; and when an economist makes reference to a Heisenberg Principle of indeterminacy in the social world, at best this must be regarded as a figure of speech or a play on words, rather than a valid application of the relations of quantum mechanics.