## Steve Keen, Noah Smith and heterodox ‘anti-math’ economics

21 August, 2016 at 15:56 | Posted in Economics | 5 CommentsResponding to the critique of his Bloomberg View post on heterodox economics and its alleged anti-math position, Noah Smith approvingly cites Steve Keen telling us there is

a wing of heterodox economics that is anti-mathematical. Known as “Critical Realism” and centred on the work of Tony Lawson at Cambridge UK, it attributes the failings of economics to the use of mathematics itself…

Although yours truly appreciate much of Steve Keen’s debunking of mainstream economics, on *this* issue he is, however, just plain wrong! For a more truthful characterization of Tony Lawson’s position, here’s what Axel Leijonhufvud has to say:

For a good many years, Tony Lawson has been urging economists to pay attention to their ontological presuppositions. Economists have not paid much attention, perhaps because few of us know what “ontology” means. This branch of philosophy stresses the need to “grasp the nature of the reality” that is the object of study – and to adapt one’s methods of inquiry to it.

Economics, it might be argued, has gotten this backwards. We have imposed our pre-conceived methods on economic reality in such manner as to distort our understanding of it. We start from optimal choice and fashion an image of reality to fit it. We transmit this distorted picture of what the world is like to our students by insisting that they learn to perceive the subject matter trough the lenses of our method.The central message of Lawson’s critique of modern economics is that an economy is an “open system” but economists insist on dealing with it as if it were “closed.”

Controlledexperiments in the natural sciences create closure and in so doing make possible the unambiguous association of “cause” and “effects”. Macroeconomists, in particular, never have the privilege of dealing with systems that are closed in this controlled experiment sense.Our mathematical representations of both individual and system behaviour require the assumption of closure for the models to have determinate solutions. Lawson, consequently, is critical of mathematical economics and, more generally, of the role of

deductivismin our field. Even those of us untutored in ontology may reflect that it is not necessarily a reasonable ambition to try to deduce the properties of very large complex systems from a small set of axioms. Our axioms are, after all, a good deal shakier than Euclid’s.The impetus to “closure” in modern macroeconomics stems from the commitment to optimising behaviour as the “microfoundations” of the enterprise. Models of “optimal choice” render agents as automatons lacking “free will” and thus deprived of choice in any genuine sense. Macrosystems composed of such automatons exclude the possibility of solutions that could be “disequilibria” in any meaningful sense. Whatever happens, they are always in equilibrium.

Modern economics has become increasingly irrelevant to the understanding of the real world. In his seminal book *Economics and Reality* (1997) Tony Lawson traced this irrelevance to the failure of economists to match their deductive-axiomatic methods with their subject.

It is — sad to say — as relevant today as it was seventeen years ago.

It is still a fact that within mainstream economics internal validity is everything and external validity nothing. Why anyone should be interested in that kind of theories and models is beyond my imagination. As long as mainstream economists do not come up with any export-licenses for their theories and models to the real world in which we live, they really should not be surprised if people say that this is not science, but autism!

Studying mathematics and logics is interesting and fun. It sharpens the mind. In pure mathematics and logics we do not have to worry about external validity. But economics is not pure mathematics or logics. It’s about society. The real world. Forgetting that, economics is really in dire straits.

To many mainstream economists, Tony Lawson is synonymous with anti-mathematics. But I think reading what Tony Lawson or yours truly have written on the subject, shows how unfounded and ridiculous is the idea that many mainstream economists have that because heterodox people often criticize the *application* of mathematics in mainstream economics, we are critical of math *per se*.

Indeed.

No, there is nothing wrong with mathematics *per se*.

No, there is nothing wrong with applying mathematics to economics.

Mathematics is one valuable tool among other valuable tools for understanding and explaining things in economics.

What is, however, totally wrong, are the utterly simplistic beliefs that

• “math is the *only* valid tool”

• “math is *always and everywhere* self-evidently applicable”

• “math is all that really counts”

• “if it’s not in math, it’s not really economics”

*• *“almost *everything* can be adequately understood and analyzed with math”

What is wrong with these beliefs is that they do not — as forcefully argued by Tony Lawson — reflect an ontological reflection on what can be rightfully expected from using mathematical methods in different context. Or as Knut Wicksell put it already a century ago:

One must, of course, beware of expecting from this method more than it can give. Out of the crucible of calculation comes not an atom more truth than was put in. The assumptions being hypothetical, the results obviously cannot claim more than a vey limited validity. The mathematical expression ought to facilitate the argument, clarify the results, and so guard against possible faults of reasoning — that is all.

It is, by the way, evident that the

economicaspects must be the determining ones everywhere: economic truth must never be sacrificed to the desire for mathematical elegance.

## 5 Comments

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Hello Lars,

Congratularions for your blog. Interesting and useful at the same time. I would like to know the source of the (always thougthfull) Axel Leijonhufvud citation.

Thank you very much!

Pablo, from Argentina

Comment by Pablo Mira— 21 August, 2016 #

Click on his blued name 🙂

Comment by Lars Syll— 21 August, 2016 #

oops. I see. Thank you very much!

Comment by Pablo Mira— 23 August, 2016 #

As a mathematician, your bullet points would be more obviously dangerous if you replaced ‘math’ by ‘the kind of math that mainstream economists cite’. My own view is that it would be worthwhile attempting to develop alternatives, perhaps like Keynes’.

Comment by Dave Marsay— 21 August, 2016 #

Very good piece!

You have previously featured Steve Keen favourably on austerity, I just wondered if you agree with his arguments on Brexit: https://www.youtube.com/watch?v=IcNBW9609HM

Comment by Peter Baker— 25 August, 2016 #