An Interview with Roger Farmer by Phil Armstrong: Part 2 of 4: On Conventional Theories of Money

An excerpt from Chapter 5 of  Can Heterodox Economics Make a Difference, published by Edward Elgar in 2020. Here is a link to the Table Of Contents, and a link to the biographies of all those interviewed for the project.  


[Then] there is the question of whether central banks should intervene by controlling the yield curve. … [My] answer is yes and, I would go further. Central banks should control the price of a basket of risky assets. Policies of this kind are not currently in the remit of the Bank of England or the Fed. But they should be. I remain optimistic that my work is leading them in that direction.
— Roger E. A. Farmer

PA: Are you familiar with the credit and state theories of money?

RF: Peripherally. I’ve been following a debate going on right now on Twitter. Some non-mainstream economists, Jo Michell at Bristol is an example, have been critical of textbook theories of money.

You gave us a set of questions we would discuss in this interview. I laughed when I saw question 7 which reads, “Do you consider the quantity of money to be determined exogenously or endogenously?”, to which my answer is “Yes.” Here’s what I mean by that.

I’m a general equilibrium theorist, in the sense that I want to conceive of the things I observe in the macroeconomy – this comes back to methodological individualism – as choices made by individuals in markets. To answer the question of exogeneity, you have to ask, first of all, what money is. That’s a hard question and there are many different ways of thinking about it. If you go back to worlds where there were commodity monies – gold and silver – it’s quite clear that the quantity of money was exogenously determined. At a point in time, the quantity of precious metals is fixed. There have always been trading mechanisms, trade credit for example, whereby other objects would serve as a medium of exchange. In today’s world where gold and silver have been replaced by fiat money provided by national governments, the distinction between exogenous and endogenous money depends very much on the policies that central banks follow. 

I’ve never understood the criticism of traditional monetarist thought by advocates of modern monetary theory. Orthodox monetary theorists, and here I would include most of the New Keynesians, would agree with the statement that money is endogenous in modern fiat money systems when the central bank pegs the interest rate on short-term debt. But there is a sense in which asking if money is endogenous is the wrong question. The right question is: what determines the absolute price level? Here there is an active debate centred around the question of uniqueness, or non-uniqueness, of equilibrium in macroeconomic models. In all models where the central bank sets the interest rate, as opposed to the quantity of bank reserves, the quantity of money is endogenous. 

Let me return to the question; what is money? A bank is an institution that allows many more objects to be used in exchange than in economies that don’t have banks. In that sense, private banks create money.

If you hold shares in Apple and you go into a  car show room and you try to buy a new Honda by offering them shares in Apple, you’re not going to be very successful because the value of the shares in Apple fluctuates on an hourly basis and nobody really knows quite what they’re worth. Now, imagine an institution –  a bank – that lends to firms and households. The bank holds liens on machines and factories to back its loans to firms and it holds liens on houses to back its loans to households. The banks acts as a guarantor of the value of these assets. 

Take the example of a mortgage.   You go to the bank and you borrow money for a mortgage on your house. The bank manager (at least in the past) knew who you were and had a relationship with you and realised that you were capable of repaying the mortgage. The bank manager’s guarantee turns your house into a negotiable asset that appears on the liabilities side of the bank’s balance sheet and the account that is created by lending you money can then be used in exchange. In that sense, banks create money.  

Bank lending is profitable because the interest rate earned on long-term loans is higher than the rate that banks must pay on their short-term liabilities. The quantity of money that banks create is limited by the need to hold cash and other liquid assets to meet the needs of their customers. The amount of available liquid assets is limited by central bank actions that control the price of credit by buying and selling assets in the markets for short-term funds. Before the 2008 financial crisis, cash and bank reserves did not pay interest, but short-term government bonds did. In that period, there was a positive opportunity cost of holding money. 

Since the financial crisis of 2008, the interest rate on short-term liabilities has been very low and, in some cases zero. And central banks began to pay interest on reserves.  In that environment reserves, which are part of the monetary base, become perfect substitutes for short-term government debt and theories of endogenous money come into their own.  When the opportunity cost of holding money falls to zero, monetary general equilibrium models have even less to say about the determination of the price level than they do when money is scarce. 

When the interest rate is zero, money and bonds become perfect substitutes and there is a continuum of price levels and a continuum of associated values for the stock of money, all of which are equilibrium values in a monetary general equilibrium model.  In those environments, the supply of money is determined by the public’s perceptions of future prices. Beliefs become fundamental in the way I described in my books, The Macroeconomics of Self-Fulfilling Prophecies (Farmer, 1993), Expectations Employment and Prices (Farmer, 2010) and Prosperity for All (Farmer, 2016).[1] The same phenomenon occurs when the central bank pays interest on reserves. Although cash is still costly to hold, cash is a shrinking component of the monetary base.  When the interest rate on reserves is roughly equal to the interest rate on Treasury bills, the economy is in a liquidity trap similar to the one that characterized much of the period in the 1930s in the United States.  The payment of interest on reserves puts us in a whole new world. 

PA: I think your interpretation [of monetary theory] is thought-provoking…. I might go slightly away from the original script to a question that’s very interesting from my perspective: when you talk about equilibrium, do you see it as an ‘ultimate end’ of a tendency, like a point that a force that will take you towards but may not actually reach? Or is it a set point that things adjust to and what would be the adjustment speed of the pathway?

RF: To answer that question, let me use the concept of temporary equilibrium theory. 

PA: …I think it’s called a ‘traverse’, the idea of how quickly you get there, what happens on the way.

RF: Indeed. In the temporary equilibrium story, we all meet in a market every Saturday. When we meet, there must be a mechanism to determine what gets traded. That could be Walrasian market clearing, it could be sticky price equilibrium, or it could be some version of search theory, for example,  ‘Keynesian Search Theory’, a term I coined in my book Prosperity for All. On Saturday we observe the trades that take place, we observe the prices that take place, and we record those trades as a list of numbers on an Excel spreadsheet. Now, if nothing in the world ever changed, our models predict that the list of numbers we record will converge to a constant list. I would call that a steady-state equilibrium. A physicist would simply call it an equilibrium. 

The reason that these uses differ is that the word ‘equilibrium’ in economics is used to mean a Nash equilibrium, which is a set of plans and prices that are consistent with each other in a sense that was made precise for temporary equilibrium models by Roy Radner (Radner, 1972). In a Nash equilibrium, the values of the list of numbers in the Excel spreadsheet may be changing from one period to the next. What qualifies them as ‘equilibrium numbers’ is that at each point in time the numbers record prices at which the quantity of each good demanded is equal to the quantity of each good supplied.  

PA: You’ve really answered the question about banks, so how would you consider interest rates to be determined in theory and practise? Do you think there’s a disconnect between theory and practise?

RF: Well, there’s at least one interest rate that’s set by central banks, which is the overnight rate. Then there’s a whole spectrum of interest rates that are determined in markets. Traditional monetary theory argued that central banks could control only one interest rate but, in the 2008 financial crisis, central banks appeared to exert influence over a whole range of rates. So, in that sense yes, there was a disconnect between traditional monetary theory and practice. 

PA: Would you consider that the central bank could control the spectrum of rates? I’m not saying it should, but if it wanted to, would you think it a feasible thing?

RF: OK, those are two separate questions. I have never subscribed to traditional monetary theories that are set in the context of a single representative agent and in all of my work, central banks can control a whole spectrum of interest rates at different points in the yield curve. 

Second; there is the question of whether central banks should intervene by controlling the yield curve. Again, my answer is yes and, I would go further.  Central banks should control the price of a basket of risky assets. Policies of this kind are not currently in the remit of the Bank of England or the Fed.  But they should be. I remain optimistic that my work is leading them in that direction.


[1] See my entry in the Oxford Research Encyclopedia of Economics and Finance on ‘The Indeterminacy School in Macroeconomics (Farmer, 2020). The Indeterminacy School is an approach to macroeconomics that was initiated at the University of Pennsylvania and at CEPREMAP in Paris in the 1980s. It has continued to evolve over the last forty years. The identifying feature of the Indeterminacy School is the willingness to embrace models with multiple equilibria to explain real world phenomena.

An Interview with Roger Farmer by Phil Armstrong: Part 1 of 4: On Economic Methodology

I claimed to be a methodological individualist –  and I think that’s a useful way of thinking about the world on Saturdays –  but on Wednesdays something changes. Let me explain that idea. [Roger E. A. Farmer]

In 2017 I gave a talk at the University of Greenwich where I met Phil Armstrong. Phil was finishing up a PhD in economics at the University of Southampton Solent and he asked me if I would agree to be interviewed for his dissertation on heterodox economists and to recruit some other mainstream economists to be interviewed for the book. Having recently written a piece that aimed to reunite Post-Keynesians with New-Keynesians, Phil figured that that I would be a good person for that role.  

Phil and I met up again at a pub in York in 2018 where I was giving a talk at the York Festival of Ideas. We had a very pleasant and substantive interview that Phil’s daughter transcribed and that appeared in Phil’s book Can Heterodox Economics Make a Difference, published by Edward Elgar in 2020. I encourage everyone to read the book. If you have access to a university library with a subscription to Elgar Online, the complete book is available to read electronically. Even if you do not, the chapter featuring myself, and the chapter featuring Tim Congden,  are open access and are free for anyone to download.  Here is a link to the Table Of Contents, and a link to the biographies of all the economists  interviewed for the project.  

The interview is quite long but I have broken it down into four manageable parts for readers of my blog. I have made a few edits to each of the posts to make them more concise but the original interview in its entirety is available here. I plan to put out a different part each week.  Here is the first part.

Part 1: On Economic Methodology

PA: Thank you for doing the interview. Which field of economics do you consider to be your specialism?

RF: Macroeconomics

PA: And within that specialism, what would you consider to be the main issues relating to your field?

RF: Oh, there are many. Much of my career has been spent on introducing beliefs as an independent driver of business cycles. I’m particularly interested in business cycles, business fluctuations, inflation, interest rates and unemployment –  how those things are all related to each other – and how the fact that beliefs matter should shape our approach to economic policy.  

PA: Quite a wide range there! How would you describe the underlying axioms or principles of your view?

RF: How long do you have?

PA: As long as it takes, within reason…

RF: Oh, goodness. I think that, to a large extent, I’d say methodological individualism, with lots of caveats. So, let me tell you how I think about that, and this is going to be a discursive discussion. If you go back to ‘what is methodological individualism?’ I take it to be the notion that a human being pops into the world at the age of eighteen with a preference ordering that makes him or her capable of making choices over every conceivable option that they might ever face in their life. That view of a human being  arrived into economics sometime in the 19th century when Walras started to formulate the notion that markets work well. 

There were other schools in England – but the Lausanne School in Switzerland –  specifically Walras, developed general equilibrium theory, followed by Pareto who introduced the notion of what it means for an outcome to be good in some sense. What Walras and Pareto were doing at that time was formalising Adam Smith’s notion of the invisible hand. In order to do that, they needed a concept of choice – if markets work well – what does that mean? What it means to Pareto is the very narrow sense that market economies are not wasting things. Now in order to develop that idea, you have to have –  first of all – a concept of what people want. That’s where the notion of a human being as a preference ordering enters economics. 

There’s another notion of a human being that predates Walras and can be found in the work of Adam Smith. Smith wrote ‘The Wealth of Nations’, but he also wrote ‘The Theory of Moral Sentiments’, which contains a view of human nature that is the furthest thing from the notion of a selfish human being that you can get. The selfish human being is very useful for thinking about economic liberty, and in particular, the efficiency of markets. However, it’s not at all useful for thinking about another component of the role of individuals in society, and that’s political liberty.  The development of general equilibrium theory by the Lausanne School is the point where economics breaks off from the other social sciences. 

I have a view, now somewhat unfashionable, that John Stuart Mill’s essay ‘on liberty’ should be on the reading list of every high school and university. In Mill’s essay, it’s impossible to think of a human being in the same way that a person is pictured in Walras and Pareto because Mill’s conception of liberty is that you and I can change our minds. When we have a conversation –  and we’re having one now – and you tell me, “Roger, I’m a modern monetary theorist for these reasons”, and I say to you, “Philip, that’s nonsense, because…”, and I give you an argument ... and perhaps the argument changes your mind; or maybe not.  Maybe you respond with an opinion that causes me to change my mind and, as a consequence of that conversation, I go out into the world and do something differently. I make a choice that was not the same one I would have made before we had the conversation. 

If you come from the view of homoeconomicus developed by Walras and Pareto, the only way that you can conceive of what just passed in our conversation is that one of us acquired information that was not previously in our information set; information that helped us to make the choices that we would otherwise not have made. Now that, I think, is not a very useful way of thinking about conversations. Conversations, that is, human interactions, change our preference orderings. 

I claimed to be a methodological individualist –  and I think that’s a useful way of thinking about the world on Saturdays –  but on Wednesdays something changes. Let me explain that idea. 

The framework I use to think about macroeconomics goes back to John Hicks. Hicks wrote ‘Value and Capital’ where he develops a concept that today we call temporary equilibrium theory.[1] People meet on Saturdays. They bring some goods to market. They make choices, they have beliefs about what they think is going to unfold in the future and there’s some mechanism by which they trade. In temporary equilibrium theory that mechanism is the Walrasian concept of market clearing. People go away and they come back next Saturday, and they trade again.

Almost all macroeconomics can be thought of in that framework, whether you’re a heterodox economist, a classical economist, or any other flavour of economist. Different schools of macroeconomic thought have their own views about  how people trade on Saturdays. If you’re an economist, all you need to develop a theory of the macroeconomy is a conception of time and a model of how economic transactions occur. Other social scientists don’t see the world in the same way.

A sociologist or a political scientist is not going to be comfortable with Hick’s notion of temporary equilibrium theory as a complete description of economic interaction in markets because they have a different view of the nature of human beings. The economist’s view of human beings and the sociologist’s view are perfectly consistent with each other. They describe different aspects of human interaction in social structures.

The way to integrate the economist’s and the sociologist’s concepts of human beings is to think about sequences of interlaced interactions. On Saturday we all go to market and trade with each other; given a fixed set of preferences. Then, on Wednesdays, we read a newspaper, or we read a book, or we have conversations. You open your iPad and you go on the internet –  the social interaction that ensues changes the preference ordering that you take to the market on the following Saturday. Now, economists have been very opposed to thinking about changing preferences, simply because once you take on that point of view you lose the ability to make value-free judgements about market allocations. The preferences you have might be changing. Economists want to believe that preferences are fixed because they want to make value-free statements about what is – and what is not – a good social outcome. 

PA: Well, some answers will be longer than others, that’s absolutely fine. In your work, to what extent would you say that history has a role to play? 

RF: History is important – but so is the history of thought, so is mathematics and so is statistics.  I’ve been asked many times if economics is a science, and my answer to that question is that it’s definitely a science, but it’s not an experimental science. Macroeconomics, in particular, is a little bit like sitting in the late nineteenth century, assembling a group of chemists, giving them an unknown substance and saying, ‘What is that? Find out what it is. But you can only conduct three experiments a century, and you can’t read the research notes of your predecessors.’ The history of thought is analogous to the research notes of our predecessors. The three experiments I refer to are big natural events like the Great Depression or the stagflation of the 1970s, and I would count the Great Recession we’ve just been through as the third big experiment in the last century.[2] These big natural experiments shake up the way we think. 

History is important because it represents our data. It is to a macroeconomist what a record of the heavens is to an astronomer. Neither astronomers nor macroeconomists can conduct controlled experiments. Nature conducts those experiments for us.

Mathematics is also an important skill because it ensures that our thinking is logically consistent. I think it was Marshall who wrote a letter to Bowley, he of the Edgeworth-Bowley Box; do you know that letter? 

PA: I don’t know the letter – I know about the Edgeworth Bowley Box, but not the letter.

RF: Marshall’s letter is a statement to the young Bowley about the uses of mathematics, and roughly speaking, he says, “Figure out a good problem, a good idea, and formalise it with mathematics.” And then –  I may be  getting the order wrong here – “…  translate it back into English and throw away the mathematics. Next look for some examples, and if you can’t find any good examples, throw away the English.” 

As a profession we’re not very good at following Marshall’s advice. I use a lot of mathematics in my own work.  As far as possible I try to bury it in the appendix, but there are just some parts where you can’t do without mathematics. There’s good economic writing that uses mathematics, and there’s bad economic writing that uses mathematics. An example of good economic writing is anything Ken Arrow ever wrote; the mathematics is there, but it’s explained in words, it’s not superfluous, and it’s key to everything he writes. For bad uses of mathematics in economic writing, read 90% of any modern economics journal.

PA: Didn’t Marshall put most of his maths in the footnotes?

RF: Yes, I think that’s right.

Stay tuned for Part 2 on Monetary Theory

[1] (Hicks, 1939).

[2] I am editing this transcript in March of 2020 and I would add a fourth natural experiment; coronavirus. The effects of that event are playing out as I write, and it is certain to be transformative for macroeconomics in ways that will help us sort between alternative theories.

Rebuilding Macroeconomic Theory

Image is from Chapter 22 of Dynamic Macroeconomics by George Alogoskoufis.

Image is from Chapter 22 of Dynamic Macroeconomics by George Alogoskoufis.

Martin Sandbu has written a nice piece in the FT about the latest issue of the Oxford Review of Economic Policy, which is dedicated to an idea I have been promoting for more than three decades. Multiple Equilibria matter. For David Vines and Samuel Wills, editors of the volume, this is a new revelation. For some of us labouring on the coal front, it has been obvious for a long long time. And Martin is correct to point out that the ship of research is finally beginning to change course, albeit thirty years after the initial ideas were first floated. Recent books that feature the Indeterminacy School are Dynamic Macroeconomics from George Alogoskoufis and A History of Macroeconomics by Michel De Vroey. Beatrice Cherrier and Aurélian Saïdi wrote a very nice survey piece linked here) and I recently published an encyclopaedia article on the history of The Indeterminacy School in Macroeconomics.

For a glimpse at the truly revolutionary implications of adopting the multiple equilibria approach see my piece “The Importance of Beliefs in Shaping Macroeconomic Outcomes” in the Vines-Wills volume (ungated preprint here). The Indeterminacy School in Macroeconomics is indeed revolutionary. And while I welcome David and Sam to the party, we don't, IMHO, need to rename the revolution after David’s mentor, James Meade.

The Indeterminacy School, as I have argued for sometime, has the potential to do for Keynesian economics what the RBC school did for classical economics. And don’t be fooled by the claim of ‘New’ Keynesian economists that economics has already ‘been there’ and ‘done that’. NK economics is neither new, nor Keynesian. It is a beautiful recreation of the verbal theory of business cycles that Pigou wrote about in 1923.

What’s missing in almost all NK economics, with some rare exceptions, is the possibility of being permanently stuck in a high unemployment equilibrium. Why has the mainstream ignored the existence of multiple equilibria for more than three decades? The answer, is that it was deeply subversive to the rational expectations agenda. When I published this piece in 1991 , Bob Lucas sent me a personal letter (quoted below in Aurelian and Cherrier’s) survey pushing back against the indeterminacy agenda.

“I don't see any reason to imagine that the fact that equilibrium is indeterminate on a 'big' set of parameters values in a certain class of theoretical models suggests that equilibrium is likely to be indeterminate in a 'lot' of real-world markets. Do you think that God is drawing pieces of reality at random from some probability space on a Kehoe-Levine parameter space?” 

There are great possibilities for pushing these ideas in new directions and for uniting them with Post Keynesian economics. If you are a grad student interested in pursuing a thesis that explores multiple equilibria, you can get some ideas from my second year lectures in the University of Warwick MRes programme linked here.

Self-Fulfilling Prophecies, Quasi-Non-Ergodicity and Wealth Inequality

inequality.jpg

Why is Jeff Bezos worth $200,000,000,000 while the median American has net assets of just $121,000? In a new working paper, co-authored with Jean-Philippe Bouchaud of the Collège de France, we argue that the vast inequalities we see in the world distribution of wealth are deeply connected to a somewhat esoteric concept from the theory of stochastic processes. The world is quasi-non-ergodic. Our paper is published as CEPR Discussion Paper 15573. It is also available on my website linked [here].

Our paper has two intertwined themes. The first is that it is impossible to accurately predict the future by averaging over what has occurred in the past.  The second is that the inability to learn from experience implies that reasonable people will continue to disagree forever. Together, these two observations explain why, in the real world, wealth is so much more unequally distributed than income.

Our taking off point is the Pólya urn model reviewed in Pemantle (2007). In this model, an urn contains M red balls and (N−M) black balls. A ball is chosen at random.  If it is red (respectively black) then 2 red balls (respectively black balls) are re-introduced in the urn, which now contains N+1 balls.  The probability of drawing a ball with a specific colour therefore increases with the number of times this colour was selected in the past.

The long-term fate of the Pólya urn is surprising. As the number of draws tends to infinity, the probability to draw a red ball converges to a limiting value; but the value of this asymptotic probability is itself random.  Starting from the same urn with N red balls and N black balls, two different runs of the dynamics will lead to two limiting probabilities.   To  completely  characterize  the  behaviour  of  this  process one must introduce probabilities over probabilities. The dynamics of the Pólya urn are non-ergodic.

In my paper with JP, we build a model in which beliefs are described by a process, similar to the Pólya urn, but where there is no convergence to a number; instead, the probability of a given outcome is a random variable that converges to a limiting distribution. Stochastic processes of this form, where probabilities are themselves random variables, are referred to in physics as quasi-non-ergodic. In these models the averages of very long time series have the same mean as the mean of the invariant probability measure, but the length of time for that result to hold is astronomically long.

In our model, people trade assets contingent on an observable signal that reflects public opinion. The agents in our model are replaced occasionally and each person updates beliefs in response to observed outcomes. Interestingly, people continue to disagree forever, even though they are able to trade with each other in a complete set of financial markets. Trade continues because everyone believes that they know more than the market. 

Our model generates large  wealth inequalities that  arise from the multiplicative nature of wealth dynamics which  makes successful bold bets highly profitable. The flip side of this statement is that unsuccessful bold bets are ruinous and lead the person who makes such bets into poverty. People who agree with market prices have a low expected subjective gain from trading.  People who disagree may either become spectacularly rich, or spectacularly poor.

Lorenz Curve.png

In the paper, we simulate 300 years of weekly data for an economy with a million people and we show that equity prices in the model mimic equity prices in the real world. The outcome of this process is the wealth distribution in Figure 1. The Gini coefficient, a measure of inequality, is 0.7 in these simulated data, close to the wealth Gini’s we see in Western economics.

Why do people continue to bet with each other when these bets are highly risky?  The answer we propose is that everyone in our economy thinks that the market is wrong and that by betting, they will be able to make money on average.  They do not use the implied probability revealed by the markets to improve their estimates of true probabilities since this trading strategy is, in their opinion, sub-optimal.  

I started this post with a question: Why is Jeff Bezos rich? One answer is that Jeff Bezos created a company that has enormous social value and, as a consequence, his income is much greater than that of the average person. But although income is unequally distributed in the real world, income dispersion is not great enough to explain wealth inequality. In our model, everyone has the same income: But wealth is still highly concentrated because some people are luckier than others. 

Why are there no Warren Buffets who invest for the long run?  Our answer is that for any reasonable time period, the future is better approximated by averaging the frequency of recent observations than by assuming that the next draw of the stock market price is drawn from its unconditional long-run distribution. In the long run the market is correct.  But, as Keynes famously quipped: “In the long run we are all dead”.  

A Journey Through the Evolution of My Ideas

Last week, I finished a ten lecture series in macroeconomics for graduate students at the University of Warwick. You can access these lectures by registering here.

The first nine lectures are quite technical, but the last one is accessible to a general audience and I have posted it in two parts on YouTube. Here is how I described the lecture in the YouTube header.

Join Professor Roger Farmer in this first part of a two part lecture in which he takes you on a journey through the evolution of his ideas. In Part 1 Professor Farmer explains what's wrong with New Keynesian economics and why it cannot explain the facts. In Part 2, he provides an alternative paradigm -- Keynesian Search Theory -- that can explain these facts and that offers a rich research agenda for graduate students to build upon. This second part of the lecture is also available on YouTube.

These two parts represent the concluding lecture in a ten part series delivered to advanced graduate students at the University of Warwick in the Autumn of 2020. The other lectures are available on Professor Farmer's website at rogerfarmer.com. You can follow him on twitter @farmerf

Roger E. A. Farmer is a Professor of Economics at the University of Warwick and a Distinguished Emeritus Professor at the University of California Los Angeles. Part 1 is linked here and part 2 is here.

I’m excited to share these lectures with economists, non-economists and graduate students from around the world. If you are a graduate student, there is a rich source of possible thesis topics here. If you are a practicing economist in academia, the private sector or in government, there is something here to make you think. If you learn something, please cite my work.