Comparing Post-Keynesianism and Modern Monetary Theory: The Importance of Ontology and Sociology

Phil Armstrong and Neil Wilson

In this paper we utilise Marc Lavoie’s 2024 critique of Modern Monetary Theory (MMT) to contrast the ontological foundations, methodologies, and policy implications of MMT with those of Post-Keynesian (PK) economics. We argue that disagreements between these schools reflect fundamental ontological divergences rather than technical nuances.

Post-Keynesian economics models the economy as a private-sector-led system where the state intervenes reactively, while MMT positions the state as the constitutive architect of monetary systems, designing market operations through taxation, currency issuance, and fiscal policy. Key areas examined include treasury-central bank operations, external sector dynamics, unemployment, and interest rate policy. The paper also addresses MMT’s intellectual origins in financial practice rather than heterodox theory and analyses sociological factors shaping its contentious reception within economics.

We conclude that constructive MMT-PK dialogue requires acknowledging these ontological roots to reconcile divergent policy prescriptions.

References

Aboobaker, Adam, and Esra Nur Ugurlu. 2023. ‘Weaknesses of MMT as a Guide to Development Policy’. Cambridge Journal of Economics 47 (3): 555–74. https://doi.org/10.1093/cje/bead009.

Armstrong, Phil. 2018. ‘Modern Monetary Theory and a Heterodox Alternative Paradigm’. The Gower Initiative for Modern Money Studies, December 26. https://gimms.org.uk/wp-content/uploads/2018/12/Modern-Monetary-Theory-and-a-Heterodox-Alternative-Paradigm-Phil-Armstrong.pdf.

Armstrong, Phil. 2020a. Can Heterodox Economics Make a Difference?: Conversations With Key Thinkers. Edward Elgar Publishing. https://doi.org/10.4337/9781800370890.

Armstrong, Phil. 2020b. ‘Modern Monetary Theory and Its Relationship to Heterodox Economics’. Solent University. https://pure.solent.ac.uk/en/studentTheses/modern-monetary-theory-and-its-relationship-to-heterodox-economic.

Armstrong, Phil. 2023. ‘“Tombstone for a Tombstone”: Dealing with the “Bad Science” behind Mainstream Criticism of MMT’. The Gower Initiative for Modern Money Studies, January 28. https://gimms.org.uk/2023/01/28/tombstone-for-a-tombstone/.

Armstrong, Phil. 2024. ‘The Contribution of Modern Monetary Theory to Heterodox Economics’. Chap. 4 in Post Keynesian Economics, edited by Therese Jefferson and John E. King. Edward Elgar Publishing. https://doi.org/10.4337/9781803922232.00008.

Armstrong, Phil. Forthcoming. Warren Mosler: Under the Bonnet. Lola Books.

Bank of Canada. 2022. An Overview of Lynx, Canada’s High-Value Payment System. Bank of Canada. https://www.bankofcanada.ca/wp-content/uploads/2022/05/Overview-Lynx-Canadas-High-Value-Payment-System.pdf.

Bank of Canada. 2025. ‘The Bank of Canada’s Settlement Account Policies for Payments Canada Payment Systems’. https://www.bankofcanada.ca/core-functions/financial-system/bank-canadas-settlement-account-policies-for-payments-canada-payment-systems/.

Berkeley, Andrew, Josh Ryan-Collins, Richard Tye, Asker Voldsgaard, and Neil Wilson. 2025. ‘The Self-Financing State: An Institutional Analysis of Government Expenditure, Revenue Collection and Debt Issuance Operations in the United Kingdom’. Journal of Economic Issues (JEI) 59 (3). https://www.tandfonline.com/loi/mjei20.

Berkeley, Andrew, Richard Tye, and Neil Wilson. 2023. ‘How Does the Government Spend? A Functional Model of the UK Exchequer’. Chap. 1 in Modern Monetary Theory, edited by L. Wray, Phil Armstrong, Sara Holland, Claire Jackson-Prior, Prue Plumridge, and Neil Wilson. Edward Elgar Publishing. https://doi.org/10.4337/9781802208092.00009.

Bilgrami, Akeel. 2015. ‘Truth, Balance, and Freedom’. In Who’s Afraid of Academic Freedom?, edited by Akeel Bilgrami and Jonathan Cole. Columbia University Press. https://doi.org/10.7312/columbia/9780231168809.003.0002.

Buiter, Willem H. 2009. ‘The Unfortunate Uselessness of Most “State of the Art” Academic Monetary Economics’. SSRN Scholarly Paper No. 2492949. Social Science Research Network, March 6. https://papers.ssrn.com/abstract=2492949.

Carnevali, Emilio, and Matteo Deleidi. 2023. ‘The Trade-off between Inflation and Unemployment in an “MMT World”: An Open-Economy Perspective’. European Journal of Economics and Economic Policies Intervention 20 (1): 90–124. https://doi.org/10.4337/ejeep.2022.0080.

Cîrstea, Andreea. 2014. ‘The Need for Public Sector Consolidated Financial Statements’. Procedia Economics and Finance 15: 1289–96. https://doi.org/10.1016/S2212-5671(14)00590-5.

Davidson, Paul. 1972. ‘Money and the Real World’. The Economic Journal 82 (325): 101. https://doi.org/10.2307/2230209.

Davidson, Paul. 2003. ‘Are Fixed Exchange Rates the Problem and Flexible Exchange Rates the Cure?’ Eastern Economic Journal 29 (February). https://www.jstor.org/stable/40325413

Dow, Shiela. 2018. ‘Pluralist Economics: Is It Scientific?’ Chap. 1 in Advancing Pluralism in Teaching Economics: International Perspectives on a Textbook Science, 1st ed., edited by Samuel Decker, Wolfram Elsner, and Svenja Flechtner. Routledge Advances in Heterodox Economics. Routledge.

Drumetz, Françoise, and Christian Pfister. 2021. ‘Modern Monetary Theory: A Wrong Compass for Decision-Making’. Intereconomics 56 (6): 355–61. https://doi.org/10.1007/s10272-021-1014-5.

Ehnts, Dirk. 2022. ‘Modern Monetary Theory: The Right Compass for Decision-Making’. Intereconomics 57 (2): 128–34. https://doi.org/10.1007/s10272-022-1041-x.

Ehnts, Dirk. 2024. ‘Fiscal Policy in the Eurozone’. Chap. 28 in The Elgar Companion to Modern Money Theory, edited by Yeva Nersisyan and L. R. Wray. Edward Elgar Publishing. https://doi.org/10.4337/9781788972246.00039.

Ehnts, Dirk, and L. Randall Wray. 2024. ‘Revisiting MMT, Sovereign Currencies and the Eurozone: A Reply to Marc Lavoie’. Review of Political Economy, February 9, 1–15. https://doi.org/10.1080/09538259.2023.2298448.

Forstater, Mathew, and Warren Mosler. 2005. ‘The Natural Rate of Interest Is Zero’. Journal of Economic Issues 39 (2): 535–42. https://doi.org/10.1080/00213624.2005.11506832.

Godley, Wynne, and Marc Lavoie. 2012. Monetary Economics: An Integrated Approach to Credit, Money, Income, Production and Wealth. 2nd ed. Palgrave Macmillan.

Harvey, John T. 2009. Currencies, Capital Flows and Crises: A Post Keynesian Analysis of Exchange Rate Determination. Routledge.

Harvey, John T. 2025. ‘Post Keynesian Theories of Exchange Rate Determination: A Critical Survey’. Journal of Post Keynesian Economics, May 13, 1–33. https://doi.org/10.1080/01603477.2025.2503153.

HM Treasury. 2018. ‘Financial Relationship between HM Treasury and the Bank of England: Memorandum of Understanding’. June. https://www.bankofengland.co.uk/-/media/boe/files/memoranda-of-understanding/financial-relationship-between-hmt-and-the-boe-memorandum-of-understanding.pdf.

Invernizzi, Ivan. 2021. ‘MMT – Theory of Exchange Rate’. MMT France, June 20. https://mmt-france.org/2021/06/20/mmt-theory-of-exchange-rate/.

Jefferson, Therese, and John E. King, eds. 2024. Post Keynesian Economics: Key Debates and Contending Perspectives. Edward Elgar Publishing. https://doi.org/10.4337/9781803922232.

Kaldor, Nicholas. 1970. ‘The New Monetarism’. Lloyds Bank Review, July, 1–18. https://www.scribd.com/document/516900044/Kaldor

Keen, Steve. 2018. ‘HHF0048 - Evidence on Household Finances: Income, Saving and Debt’. https://committees.parliament.uk/writtenevidence/88379/html/.

Keen, Steve. Forthcoming. ‘Money and Macroeconomics from First Principles, for Elon Musk and Other Engineers’. Preprint. https://profstevekeen.substack.com/api/v1/file/f9e5ed4a-3464-4ec9-a527-fc54102ef502.pdf.

King, John E. 2001. ‘Labor and Unemployment’. Chap. 7 in A New Guide to Post-Keynesian Economics, edited by Richard P. F. Holt and Steven Pressman. Routledge. https://doi.org/10.4324/9780203466681.

Lavoie, Marc. 2013. ‘The Monetary and Fiscal Nexus of Neo-Chartalism: A Friendly Critique’. Journal of Economic Issues 47 (1): 1–32. https://doi.org/10.2753/JEI0021-3624470101.

Lavoie, Marc. 2024. ‘Modern Monetary Theory: The Good, the Bad and the Ugly’. Chap. 5 in Post Keynesian Economics, edited by Therese Jefferson and John E. King. Edward Elgar Publishing. https://doi.org/10.4337/9781803922232.00009.

Lawson, Tony. 2020. ‘Professor Tony Lawson’. Chap. 27 in Can Heterodox Economics Make a Difference?: Conversations With Key Thinkers, by Phil Armstrong. Edward Elgar Publishing. https://doi.org/10.4337/9781800370890.

Lee, Frederic. 2009. A History of Heterodox Economics: Challenging the Mainstream in the Twentieth Century. 1st ed. Routledge. https://doi.org/10.4324/9780203883051.

Lerner, Abba P. 1943. ‘Functional Finance and the Federal Debt’. Social Research 10 (1): 38–51. JSTOR. https://www.jstor.org/stable/40981939

Lerner, Abba P. 1944. The Economics of Control: Principles of Welfare Economics. Macmillian.

Mann, Catherine L. 2020. ‘Some Observations on MMT: What’s Right, Not Right, and What’s Too Simplistic’. Business Economics 55 (1): 21–22. https://doi.org/10.1057/s11369-019-00153-4.

Mazier, Jacques, and Sebastian Valdecantos. 2019. ‘From the European Monetary Union to a Euro–Bancor: A Stock–Flow Consistent Assessment’. European Journal of Economics and Economic Policies: Intervention 16 (1): 8–26. https://doi.org/10.4337/ejeep.2019.0043.

Mitchell, William F. 1998. ‘The Buffer Stock Employment Model and the NAIRU: The Path to Full Employment’. Journal of Economic Issues 32 (2): 547–55. https://doi.org/10.1080/00213624.1998.11506063.

Mitchell, William F., and Warren Mosler. 2002a. ‘Fiscal Policy and the Job Guarantee’. Australian Journal of Labour Economics (AJLE) 5 (2): 243–59. https://billmitchell.org/publications/journals/J40_2002.pdf

Mitchell, William F., and Warren Mosler. 2002b. ‘Public Debt Management and Australia’s Macroeconomic Priorities’. Preprint, November. https://www.fullemployment.net/publications/wp/2002/02-13.pdf.

Mitchell, William F., L. Randall Wray, and Martin Watts. 2019. Macroeconomics. Macmillan Education UK.

Moore, Basil J. 1979. ‘The Endogenous Money Stock’. Journal of Post Keynesian Economics 2 (1): 49–70. https://www.jstor.org/stable/4537511

Mosler, Warren. 2010. The 7 Deadly Innocent Frauds of Economic Policy. Vallance Co Inc.

Mosler, Warren. 2012. ‘Proposals for the Banking System, the FDIC, the Fed, and the Treasury’. Chap. 4 in Monetary Policy and Central Banking, edited by Louis-Philippe Rochon and Salewa ‘Yinka Olawoye. Edward Elgar Publishing. https://doi.org/10.4337/9781849807364.00012.

Mosler, Warren. 2013. Soft Currency Economics II. CreateSpace Independent Publishing Platform.

Mosler, Warren. 2021. MMT White Paper. https://moslereconomics.com/mmt-white-paper/.

Mosler, Warren. 2023. ‘A Framework for the Analysis of the Price Level and Inflation’. Chap. 4 in Modern Monetary Theory, edited by L. Wray, Phil Armstrong, Sara Holland, Claire Jackson-Prior, Prue Plumridge, and Neil Wilson. Edward Elgar Publishing. https://doi.org/10.4337/9781802208092.00012.

Mosler, Warren, and Mathew Forstater. 2018. A General Analytical Framework for the Analysis of Currencies and Other Commodities. March 27. https://moslereconomics.com/wp-content/uploads/2018/04/A-General-Analytical-Framework.pdf.

Palley, Thomas I. 2014. Modern Money Theory (MMT): The Emperor Still Has No Clothes. February. https://www.thomaspalley.com/docs/articles/macro_theory/mmt_response_to_wray.pdf.

Palley, Thomas I. 2015. ‘The Critics of Modern Money Theory (MMT) Are Right’. Review of Political Economy 27 (1): 45–61. https://doi.org/10.1080/09538259.2014.957473.

Palley, Thomas I. 2018. Job Guarantee Programs: Careful What You Wish For. September 14. https://thomaspalley.com/?p=1213.

Palley, Thomas I. 2020a. ‘Dr Thomas Palley’. Chap. 13 in Can Heterodox Economics Make a Difference?: Conversations With Key Thinkers, by Phil Armstrong. Edward Elgar Publishing. https://doi.org/10.4337/9781800370890.

Palley, Thomas I. 2020b. ‘What’s Wrong with Modern Money Theory: Macro and Political Economic Restraints on Deficit-Financed Fiscal Policy’. Review of Keynesian Economics 8 (October): 472–93. https://doi.org/10.4337/roke.2020.04.02.

Palley, Thomas I. 2022. ‘The Macroeconomics of Government Spending: Distinguishing Between Government Purchases, Government Production, and Job Guarantee Programs’. Review of Political Economy 34 (4): 692–708. https://doi.org/10.1080/09538259.2022.2040907.

Portes, Jonathan. 2019. ‘Nonsense Economics: The Rise of Modern Monetary Theory’. Prospect Magazine, January 30. https://www.prospectmagazine.co.uk/ideas/economics/42224/nonsense-economics-the-rise-of-modern-monetary-theory.

Potts, Nick. 2020. ‘Associate Professor Nick Potts’. Chap. 30 in Can Heterodox Economics Make a Difference?: Conversations With Key Thinkers, by Phil Armstrong. Edward Elgar Publishing. https://doi.org/10.4337/9781800370890.

Prates, Daniela. 2020. ‘Beyond Modern Money Theory: A Post-Keynesian Approach to the Currency Hierarchy, Monetary Sovereignty, and Policy Space’. Review of Keynesian Economics 8 (4): 494–511. https://doi.org/10.4337/roke.2020.04.03.

Sawyer, Malcolm. 2003. ‘Employer of Last Resort: Could It Deliver Full Employment and Price Stability?’ Journal of Economic Issues 37 (4): 881–907. https://doi.org/10.1080/00213624.2003.11506635.

Sawyer, Malcolm. 2005. ‘Employer of Last Resort: A Response to My Critics’. Journal of Economic Issues 39 (1): 256–64. https://doi.org/10.1080/00213624.2005.11506790.

Stigler, George J. 1958. ‘Ricardo and the 93% Labor Theory of Value’. The American Economic Review 48 (3): 357–67. https://www.jstor.org/stable/1809772

Stockhammer, Engelbert. 2011. ‘Wage Norms, Capital Accumulation, and Unemployment: A Post-Keynesian View’. Oxford Review of Economic Policy 27 (2): 295–311. https://doi.org/10.1093/oxrep/grr013.

Stockhammer, Engelbert. 2020. ‘Professor Englebert Stockhammer’. Chap. 18 in Can Heterodox Economics Make a Difference?: Conversations With Key Thinkers, by Phil Armstrong. Edward Elgar Publishing. https://doi.org/10.4337/9781800370890.

Tcherneva, Pavlina R. 2018. ‘The Job Guarantee: Design, Jobs, and Implementation’. SSRN Electronic Journal, ahead of print. https://doi.org/10.2139/ssrn.3155289.

Tcherneva, Pavlina R. 2020. The Case for a Job Guarantee. The Case for Series. Polity Press.

Tye, Richard. 2023. ‘Credit and the Exchequer since the Restoration’. Chap. 2 in Modern Monetary Theory, edited by L. Wray, Phil Armstrong, Sara Holland, Claire Jackson-Prior, Prue Plumridge, and Neil Wilson. Edward Elgar Publishing. https://doi.org/10.4337/9781802208092.00010.

Vergnhanini, Rodrigo, and Bruno De Conti. 2018. ‘Modern Monetary Theory: A Criticism from the Periphery’. Brazilian Keynesian Review 3 (2): 16. https://doi.org/10.33834/bkr.v3i2.115.

Watts, Martin, and Phil Armstrong. Forthcoming. ‘A Macroeconomic Policy Framework for Developing Countries: An MMT Perspective’. Preprint.

Wilson, Neil. 2023. ‘Tax as a Hygiene Factor: Setting UK Taxation Policy Using Modern Monetary Theory’. Chap. 9 in Modern Monetary Theory, edited by L. Wray, Phil Armstrong, Sara Holland, Claire Jackson-Prior, Prue Plumridge, and Neil Wilson. Edward Elgar Publishing. https://doi.org/10.4337/9781802208092.00017.

Wray, L. Randall. 1998. Understanding Modern Money: The Key to Full Employment and Price Stability. Edward Elgar Publishing.

Wray, L. Randall. 2007. ‘Minsky’s Approach to Employment Policy and Poverty: Employer of Last Resort and the War on Poverty’. SSRN Scholarly Paper No. 1014163. Social Science Research Network, September 12. https://doi.org/10.2139/ssrn.1014163.

Wray, L. Randall. 2015. Modern Money Theory: A Primer on Macroeconomics for Sovereign Monetary Systems. 2nd ed. Palgrave Macmillan.

Wray, L. Randall. 2025. Understanding Modern Money Theory: Money and Credit in Capitalist Economies. Edward Elgar Publishing. https://doi.org/10.4337/9781800375154.

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