�Let us now praise famous men, ��

(Ecclesiasticus, 44:1)

Milton Friedman, who died in the early morning of November 16, 2006, was a world-famous economist, and an ardent and effective advocate of the free market economy. Much of his celebrity derived from his role as public intellectual, an aspect of his work that was reflected largely in popular books, such as Capitalism and Freedom (1962) and the hugely successful Free to Choose (1980)�both co-authored with his wife, Rose (and the latter based on the television documentary of the same title)�and in the Newsweek opinion columns he wrote for many years.

Though he was already well-known by the time he received the Nobel Prize in Economics, in 1976, both his stature as public figure and his effectiveness as policy advocate were greatly enhanced by that award, and this is what has been mostly stressed in the vast outpouring of obituaries and public testimonials prompted by his recent passing.

It is important to recall, however, that there was another aspect of his career, one which most professional economists (and probably Friedman himself) would regard as far more important than his incursions in the policy arena. Indeed, even if �Friedman the public intellectual� had never existed, �Friedman the economic scientist� would still be renowned and respected (though perhaps not as a bona fide world-class celebrity), and his memory will live long in the lore of economics.

It is primarily this other aspect of his life and work that I wish to focus on in this essay.

1. Education and Professional Background

Milton Friedman was born in Brooklyn, New York, on July 31, 1912, the youngest child in a family of poor Jewish immigrants from Carpatho-Ruthenia (then in the Hungarian part of Austria-Hungary, nowadays a part of independent Ukraine).

His early schooling was in the public school system of Rahway, New Jersey, were he grew up, and in 1928 he obtained a state scholarship to attend Rutgers University, which he entered with the intention of majoring in mathematics (his original career plan was to eventually become an actuary). In college, however, chance intervened, as he puts it, in the form of �two extraordinary teachers [of economics] who had a major impact on my life�: Homer Jones and Arthur F. Burns (Friedman, 2004, p. 68). Under their influence, he switched majors from mathematics to economics.

Upon graduation from Rutgers in 1932, in the middle of the Great Depression, Friedman received two scholarship offers for graduate study, one to study economics at the University of Chicago, the other to study applied mathematics at Brown University. Both, it seems, were equally attractive: �It was close to a toss of a coin that determined which offer I accepted� (Friedman, 2004, p. 69). In the event, he opted for Chicago, and became an economist.

At Chicago, where he earned his master�s degree in 1933, his teachers included Frank Knight, Lloyd Mints, Henry Simons, Henry Schultz, and Jacob Viner. There, he also met two fellow graduate students, W. Allen Wallis and George J. Stigler, who would become life-long friends and colleagues. His friendship with Stigler was especially significant, as the Stigler-Friedman team, more than any other pairing of individuals, would eventually define and personify what came to be known as the �Chicago School� of economics.

The following year he went to Columbia University, where he studied mathematical statistics under Harold Hotelling, and economics with Wesley C. Mitchell and John M. Clark. In 1935, Friedman returned to Chicago as research assistant to Henry Schultz, who was then working on his massive study of empirical demand curves. From 1937 to 1940 he worked on analysis of income-expenditure surveys at the National Bureau of Economic Research (NBER).

At this point it is perhaps useful to pause and reflect on this remarkable educational experience. Though it resulted from a seemingly fortuitous combination of circumstances, it would have been very hard to deliberately plan a program better suited to his future professional development. At the theoretical level, the Chicago influence was of course decisive, though one of the most important aspects of Friedman�s approach to economic research�his careful and detailed analysis of empirical evidence�did not come from Chicago, but from his contact with Wesley Mitchell and the NBER. In fact, though empirical research is now regarded as a hallmark of �Chicago� economics, this is at least partly due to the later influence of Friedman himself. In the 1930�s, and with the somewhat marginal exceptions of Henry Schultz and Paul Douglas, at Chicago the emphasis was more on theory than on empirical analysis (Reder, 1982).

In the early stages of his career, however, the most important influence was that of Hotelling. Indeed, at first Friedman showed more signs of becoming an eminent statistician than a great economist. One of his first professional publications developed a non-parametric technique for the analysis of variance under certain conditions (Friedman, 1937). As in the case of most of his analytic contributions, the motivation for the �Friedman test� was to facilitate the solution of practical problems posed by data analysis (in this case, income and expenditure data).

During World War II, and after a brief stint at the Treasury Department, Friedman was a member of the �Statistical Research Group� at Columbia, working on combat problems and quality inspection for war materials. This group comprised a truly dazzling collection of brilliant statistical minds, and their joint efforts would result, inter alia, in the development of �sequential analysis,� a very important advance in statistical theory. Essentially, Friedman, together with Allen Wallis and a Navy captain (Garret Schuyler), noticed that the conventional method of taking samples of a predetermined size was inefficient, since it did not take into account information generated by the sample process itself. The idea was later rigorously developed by Abraham Wald, who proved the basic theorem underlying sequential testing, which was quickly adopted and adapted as the standard method for inspection sampling.

After the war, Friedman served briefly on the faculty of the University of Minnesota, and in 1946 he returned to the University of Chicago as professor in the Department of Economics, where he stayed until his retirement in 1977. The return to Chicago coincided with a major change in the focus of his research activity, which shifted away from pure statistics, and eventually centered almost entirely on economics.

He was back home.

2. The Methodology of Positive Economics.

Friedman had a profound impact on economic research during his lifetime, and his influence reached far beyond the particular fields he chose for his own research. Much of this influence was due to his opinions on methodological issues, which were clarified at an early stage of his career. A famous 1953 essay on �The Methodology of Positive Economics� is arguably his most well-known work among professional economists, as well as one of the most controversial.

Friedman began his essay by distinguishing between positive economics, a �body of systematized knowledge concerning what is,� and normative economics, �a body of systematized knowledge discussing criteria of what ought to be� (Friedman, 1953, p. 3; unless otherwise stated, all page references in parentheses in this section are to this work). Both disciplines are related, though the conclusions of positive economics are independent of ethical positions or normative judgments. The purpose of positive economics is to �provide a system of generalizations that can be used to make correct predictions about the consequences of any change in circumstances� (p. 4). Economic theories should be evaluated according to strictly empirical criteria: �Viewed as a body of substantive hypotheses, theory is to be judged by its predictive power for the class of phenomena which it is intended to �explain.� Only factual evidence can show whether it is �right� or �wrong� or, better, tentatively �accepted� as valid or �rejected�� (p. 8). This is stressed repeatedly throughout the essay:

� the only relevant test of the validity of a hypothesis is comparison of its predictions with experience. The hypothesis is rejected if its predictions are contradicted (�frequently� or more often than predictions from an alternative hypothesis); it is accepted if its predictions are not contradicted; great confidence is attached to it if it has survived many opportunities for contradiction (pp. 8-9, italics in the original).

Using language that is nowadays associated with Karl Popper�s philosophy of science (Popper, 1959 [1934]), Friedman added that �factual evidence can never �prove� a hypothesis; it can only fail to disprove it, which is what we generally mean when we say, somewhat inexactly, that the hypothesis has been �confirmed� by experience� (p. 9).

To be sure, the nature of economic phenomena presents special difficulties, since it is usually impossible to perform controlled experiments, explicitly designed to eliminate complicating factors. Therefore, �we must rely on evidence cast up by the �experiments� that happen to occur� (p. 10). Friedman held, however, that �the inability to conduct so-called �controlled experiments� does not, � , reflect a basic difference between the social and physical sciences both because it is not peculiar to the social sciences�witness astronomy�and because the distinction between a controlled experiment and uncontrolled experience is at best one of degree. No experiment can be completely controlled, and every experience is partly controlled in the sense that some disturbing influences are relatively constant in the course of it� (p. 10).

Furthermore, �evidence cast up by experience is abundant and frequently as conclusive as that from contrived experiments; thus the inability to conduct experiments is not a fundamental obstacle to testing hypotheses by the success of their predictions� (p. 10). On the other hand, such evidence is admittedly �far more difficult to interpret. It is frequently complex and always indirect and incomplete. Its collection is often arduous, and its interpretation requires subtle analysis and involved chains of reasoning, which seldom carry real conviction� (pp. 10-11). In short, the �crucial� experiment is seldom possible in economics, which hinders adequate hypothesis testing, though �this is much less significant than the difficulty it places in the way of achieving a reasonably prompt and wide consensus on the conclusions justified by the available evidence� (p. 11). The process of weeding-out failed hypotheses is slower than in other sciences. On occasions, however, casual experience provides evidence that is just as dramatic as any controlled experiment (the empirical correlation between monetary growth and price inflation is a good example).

In Friedman�s approach the criteria for acceptance or rejection of hypotheses are thus strictly empirical. Unlike his teacher Wesley Mitchell, however, Friedman was by no means opposed to abstract theory per se. In fact, one of his objectives in this essay was precisely to defend the abstract nature of neo-classical economic theory, which was often criticized due to its lack of realistic assumptions. Friedman thought these critiques were misplaced, and that scientific hypotheses should not be judged by the realism of their assumptions, since these can never be �realistic� in a descriptive sense. In fact,

� the relation between the significance of a theory and the �realism� of its �assumptions� is almost the opposite of that suggested by the view under criticism. Truly important and significant hypotheses will be found to have �assumptions� that are wildly inaccurate descriptive representations of reality, and, in general, the more significant the theory, the more unrealistic the assumptions (in this sense). The reason is simple. A hypothesis is important if it �explains� much by little, that is, if it abstracts the common and crucial elements from the mass of complex and detailed circumstances surrounding the phenomena to be explained and permits valid predictions on the basis of them alone (p. 14).

Theoretical assumptions are simplifications of reality, and in this sense they must be descriptively false (i.e., they take into account only the features regarded as important, since the success of the hypothesis shows that all other circumstances are irrelevant to the explanation of the phenomenon). To Friedman, the realism of the assumptions was unimportant, and �the relevant question to ask about the �assumptions� of a theory is not whether they are descriptively �realistic,� for they never are, but whether they are sufficiently good approximations for the purpose in hand,� which can be determined only by �seeing whether the theory works, which means whether it yields sufficiently accurate predictions� (p. 15).

The �Methodology� essay was (and still remains) quite controversial, and it generated a large secondary literature. Friedman, however, having stated his case, preferred to let others argue about it, and never responded to any of his critics. Instead, he decided to move on, and was more concerned with applying his principles in practice.

3. Monetary Studies.

Since about 1950 his interests began to center on monetary economics, and in this field he achieved his greatest prominence. A notable collection of empirical studies edited by Friedman (Studies in the Quantity Theory of Money, 1956) was based on doctoral dissertations supervised in his famous Money and Banking Workshop at Chicago. A longer run project resulted from his association with the NBER, where he took charge of the monetary aspects of a much larger-scale project on business cycles. The detailed investigations related to this project resulted in three volumes co-authored with Anna J. Schwartz: A Monetary History of the United States (1963), Monetary Statistics of the United States (1970), and Monetary Trends in the United States and the United Kingdom (1982).

The theoretical framework underlying this empirical research, and the link to previous monetary traditions at Chicago, was Friedman�s introduction to the Studies volume: �The Quantity Theory of Money�A Restatement� (Friedman, 1956). Friedman interpreted the Quantity Theory as, essentially, a theory of the demand for money. Though the monetary authorities might control the nominal money supply, what really matters for the public is the real money supply (the money supply expressed in terms of its purchasing power). The scientific problem consists in determining the variables affecting the demand for money, i.e., the amount of real monetary balances held by the public. According to Friedman, the demand for money is a stable function of real income and the opportunity cost of holding money. This idea and its implications were later explored empirically in Friedman (1959) and Friedman and Schwartz (1963a).

The stability of the demand for money had certain implications concerning effects of variations in the money supply that were inconsistent with the Keynesian analysis that prevailed at the time. The frontal assault on Keynesian theory appeared in an extensive empirical study (Friedman and Meiselman, 1963) which compared two basic theories: (1) a Keynesian multiplier model, relating national income to �autonomous� expenditures (investment, government spending, and net exports), and (2) a �monetarist� model (the term had not yet been invented), relating income to the money supply via the velocity of money. The results showed that in practice the money supply had far greater explanatory power than autonomous expenditures. The Friedman-Meiselman study set off the �Keynesian-Monetarist� debate that came to dominate discussions of macroeconomic policy for many years.

The main conclusions from this and later �monetarist� studies were that: (1) though increased public spending has an impact-effect on nominal income, it soon �fizzles out,� whereas an increase in the money supply has a permanent effect; (2) the adjustment of nominal income to an increased rate of monetary growth involves �long and variable lags�; (3) in the long run an increase in the rate of monetary growth affects only the inflation rate, and has no effect on real output; (4) in the short run, however, variations in the rate of monetary growth can have devastating effects, both on prices and on real output (the most notorious example being the �Great Contraction� of 1931-33, as explained in Chapter 7 of the Monetary History volume).

4. The Economist as Public Intellectual.

Shortly after receiving his Nobel Prize, Friedman retired from the University of Chicago, and the Friedmans moved to San Francisco, where he became associated for the rest of his life with the Hoover Institution, at Stanford University. Though he remained active in economic research for some years after retirement, most of his original scientific work had been done, and his interests shifted increasingly towards popular writing and involvement in public policy issues.

He was already well-known among the broader public as a staunch critic of government intrusions in the economy, and an exponent of the virtues of an unhampered free market, views which he had expressed in Capitalism and Freedom (1962), and in the tri-weekly Newsweek columns he wrote from 1966 to 1984. His leap to celebrity, however, came with the filming of the TV documentary series �Free to Choose,� and the publication of a book with the same title (Friedman and Friedman, 1980) which eventually became a world-wide bestseller.

There is no point in elaborating here on his general ideas regarding capitalism and the market economy, since these are well known. Rather, I will attempt to briefly explore some of the reasons for his remarkable success in spreading his ideas to the broader public.

Part of his success as a communicator was probably due to the fact that his rhetorical style was much less ideologically-driven than that of other free-market advocates. Though he himself had a strong ideological commitment to values such as personal liberty and individual responsibility, his arguments on specific policy issues tended to stress practical matters, such as economic efficiency and how government interventions often led to consequences that were worse than the evils they sought to avoid. This approach allowed many people to agree with him on specific issues, even though they might not coincide with his entire social philosophy. Related to this is what we might call his �incremental� approach to the ideal of a free-market economy. Many policy issues are not a matter of �all or nothing� but of �more or less,� and Friedman was often quite willing to settle for a compromise solution if it offered a clear possibility of moving closer to the free market ideal.

A good example is his active role in the movement which eventually ended the military draft in the United States. This was not an abstract question of �capitalism, take it or leave it,� but a very specific policy issue with enormous implications for the personal liberty of millions of flesh and blood individuals. It was also an issue that, at the time and in the midst of an unpopular war, could enlist the support of many people across the whole political spectrum. ]

Another example is his school-voucher proposal, elaborated in Chapter 6 of Capitalism and Freedom, and based on an earlier paper (Friedman, 1955). Under this system the government would, ideally, no longer be involved in the actual administration of educational institutions, though it would still be involved in the financing of education, so it is not a purely free-market solution. On the other hand, it was clearly a �step in the right direction,� from Friedman�s point of view. By separating government financing of education from government operation of schools, he argued, parents at all income levels would have greater freedom in choosing the schools their children attend. Moreover, one does not have to accept Friedman�s ultimate vision of a purely private market in education in order to appreciate the efficiency and welfare-enhancing features of the �intermediate� voucher solution: more choice would involve greater competition, and hence greater efficiency in school provision.

Finally, another likely factor that explains his greater success in spreading his ideas, especially among professional economists, is that Friedman (and Chicago economists in general) used essentially the same language as most mainstream economists. Indeed, as Israel Kirzner noted many years ago:

The price theory that underlies the contribution of the �Chicago� writers is not fundamentally different from that accepted by American economists generally, including those holding the efficiency and justice of the market system in deep mistrust. It is merely that the �Chicago� economists apply their price theory more consistently and more resolutely, assigning to it a scope of relevance far wider than that granted by others �. �Chicago� price theory, like that taught in most United States economics departments, is solidly in the Anglo-American neoclassical tradition associated most importantly with Alfred Marshall (Kirzner, 1967, p. 102).

In this sense, to use a bit of economic jargon, one might say that Friedman had a �comparative advantage� in communicating with mainstream economists, as compared to other leading classical liberal economists such as Ludwig von Mises and F. A. Hayek, whose �Austrian School� background was much more alien to other members of the profession.

Of course, these are my personal impressions and conjectures, and I may be quite wrong in my interpretation of the reasons for Friedman�s phenomenal success as social critic and policy advocate. Whatever the reasons for his success, however, the fact itself is indisputable.

V. A Personal Reminiscence.

A couple of years ago Alan Greenspan prepared a foreword to a collection of essays honoring Milton and Rose Friedman, and in that foreword he wrote the following:

My first contact with Milton was in 1959, when I mailed him a copy of an article on the impact of the ratio of stock prices to replacement cost on capital investment. I am sure he had never heard of me, yet he took the time to reply with several very thoughtful suggestions. I have never forgotten that (Greenspan, 2004, p. xii).

This was not the first time I had heard or read about similar experiences, and I do not think they are isolated cases. In fact, Greenspan�s experience reflects an important aspect of Friedman�s personality. He was very generous with his time, even to complete strangers, and I can attest to this personally.

I too once maintained a correspondence with Milton Friedman. The first time I wrote him was to comment on one of his Newsweek articles. At that time I lived in Bolivia, and was working at a sugar mill. Of course, I did not expect him to reply. Why would he? To a perfect stranger? Imagine then my surprise when I got in the mail a very polite and detailed letter in response.

I answered him, and he answered back! And that was the beginning of a correspondence that lasted several years. I even got the chance to meet him in person, soon after I began my career as a university professor. At the time I was translating some of his monetary studies. He was interested in the project, and encouraged me, and it was all by letters�no e-mail then�and since I was constantly consulting him about many minor details, at one point he suggested that maybe I should visit him, so we might sit down for a whole day with the materials and resolve all my queries. Well, I did just that. We agreed on a date, and I traveled to San Francisco and we met in his office at Stanford University.

It was a very productive meeting, although I soon realized that, though the purpose of the meeting was ostensibly to discuss his papers, he wasn�t really much interested in talking about his work. Rather, he seemed much more interested in my own projects and concerns. What courses was I teaching? Had I published any papers? What other things was I working on? It so happens that I was then working on a book of my own, my first book, on Latin American inflation, and as I recall, we actually spent more time that day talking about my book than about his own writings.

At midday he invited me to lunch at the Faculty Club (we were joined by George Stigler), and in the afternoon we talked some more, and kept on talking until it was time for me to catch my return flight. I will always remember his gracious generosity, his encouragement, and his willingness to devote part of his valuable time to a young, budding academic. It meant the world to me.

Milton Friedman was a great economist and a fine man. He had a long and productive life. May he rest in peace.

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