It is my opinion that major areas of neoclassical economics rest on misinterpretations of original texts. Though new ideas are regularly recognised as important and incorporated into the mainstream framework, this framework is fairly rigid: models must be micro founded, agents must be optimising, and – particularly in the case of undergraduate economics – the model can be represented as two intersecting curves. The result is that the concepts that certain thinkers were trying to elucidate get taken out of context, contorted, and misunderstood. There are many instances of this, but I will illustrate the problem with three major examples: John Maynard Keynes, John Von Neumann and William Phillips.
Keynes, in two lines
It is common trope to suggest that John Hicks‘ IS/LM interpretation of Keynes’ General Theory was wrong. It is also true, and this was acknowledged by Hicks himself over 40 years after his original article.
IS/LM, or something like it, was being developed apart from Keynes by Dennis Robertson, Hicks and others during the 1920s/30s, who sought to understand interest rates and investment in terms of neoclassical equilibrium. Hence, Hicks tried to annex Keynes into this framework (they both, confusingly, called neoclassicals ‘classicals’). Keynes’ theory was reduced to two intersecting lines that looked a lot like demand-supply. The two schedules were derived from the equilibrium points of the demand and supply for money (LM), and the equilibrium points of the demand and supply for goods and services (IS). In order to reach ‘full employment’ equilibrium, the central bank could increase the money supply, or the government could expand fiscal policy. Unfortunately, such a glib interpretation of Keynes is flawed for a number of reasons:
First, Keynes did not believe that the central bank had control over the money supply:
…an investment decision (Prof. Ohlin’s investment ex-ante) may sometimes involve a temporary demand for money before it is carried out, quite distinct from the demand for active balances which will arise as a result of the investment activity whilst it is going on. This demand may arise in the following way.
Planned investment—i.e. investment ex-ante—may have to secure its ” financial provision ” before the investment takes place…There has, therefore, to be a technique to bridge this gap between the time when the decision to invest is taken and the time when the correlative investment and saving actually occur. This service may be provided either by the new issue market or by the banks;—which it is, makes no difference.
Since Hick’s model relies on a ‘loanable funds’ theory of money, where the interest rate equates savings with investment and the central bank controls the money supply, it clearly doesn’t apply in Keynes’ world. An attempt to apply endogenous money top IS/LM will result in absurdities: an increase in loan-financed investment, part of the IS curve, will create expansion in M, part of the LM curve. Likewise, M will adjust downwards as economic activity winds down. So the two curves cannot move independently, which violates a key assumption of this type of analysis.
Second, Keynes did not believe the interest rate had simple, linear effects on investment:
I see no reason to be in the slightest degree doubtful about the initiating causes of the slump….The leading characteristic was an extraordinary willingness to borrow money for the purposes of new real investment at very high rates of interest.
But over and above this it is an essential characteristic of the boom that investments which will in fact yield, say, 2 per cent. in conditions of full employment are made in the expectation of a yield of, say, 6 per cent., and are valued accordingly. When the disillusion comes, this expectation is replaced by a contrary “error of pessimism”, with the result that the investments, which would in fact yield 2 per cent. in conditions of full employment, are expected to yield less than nothing…
…A boom is a situation in which over-optimism triumphs over a rate of interest which, in a cooler light, would be seen to be excessive.
So, again, the simple, mechanistic adjustments in IS/LM are inaccurate. The magnitude of the interest rate will not change just the level, but also the type of investment taking place. Higher rates increases speculation and destabilise the economy, whereas low rates encourage real capital formation. This key link between bubbles, the financial sector and the real economy was lost in IS/LM, and also in neoclassical economics as a whole.
Third – and this is something I have spoken about before - Hicks glossed over Keynes’ use of the concept of irreducible uncertainty, which was key to his theory. The result was a contradiction, something Hicks noted in the aforementioned ‘explanation’ for IS/LM. The demand for money was, for Keynes, a direct result of uncertainty, and in a time period sufficient to produce uncertainty (such as Keynes’ suggested 1 year), expectations would be constantly shifting. Since both the demand for money, savings and investment depended on expectations, the curves would be moving interdependently, undermining the analysis. On the other hand, in a time period short enough to hold expectations ‘constant’ and hence avoid this (Hicks suggested a week), there would be no uncertainty, no liquidity preference and therefore no LM curve.
Hicks’ attempt to shoehorn Keynes’ book into his pre-constructed framework led to oversimplifications and a contradiction, and obscured one of Keynes’ key insights: that permanently low long term interest rates are required to achieve full employment. The result is that Keynes has been reduced to ‘stimulus,’ whether fiscal or monetary, in downturns, and the reasons for the success of his policies post-WW2 are forgotten.
Phillips and his curve
Another key aspect-along with IS/LM-of the post-WW2 ‘Keynesian’ synthesis was the ‘Phillips Curve,’ an inverse relationship between inflation and unemployment observed by Phillips in 1958. Neoclassical economists reduced this to the suggestion that there was a simple trade-off between inflation and unemployment, and policymakers could choose where to select on the Phillips Curve, depending on circumstances.
Predictably, this is not really what Phillips had in mind. What he observed was not ‘inflation and unemployment,’ but inflation and money wages. Furthermore, it was not a static trade off, but a dynamic process that occurred over the course of the business cycle. During the slump, society would observe high unemployment and low inflation; in the boom, low unemployment would accompany high inflation. This is why, if you look at the diagrams in his original paper, Phillips has numbered his points and joined them all together – he is interested in the time path of the economy, not just a simple mechanistic relationship. The basic correlation between wages and unemployment was just a starting point.
Contrary to what those who misinterpreted him believed, Phillips was not unaware of the influence of expectations and the trajectory of the economy on the variables he was discussing; in fact, it was an important pillar of his analysis:
There is also a clear tendency for the rate of change of money wage rates at any given level of unemployment to be above the average for that level of unemployment when unemployment is decreasing during the upswing of a trade cycle and to be below the average for that level of unemployment when unemployment is increasing during the downswing of a trade cycle…
…the rate of change of money wage rates can be explained by the level of unemployment and the rate of change of unemployment.
Finally, whatever Phillips’ theoretical conclusions, it is clear he did not intend even a correctly interpreted version of his work to be the foundation of macroeconomics:
These conclusions are of course tentative. There is need for much more detailed research into the relations between unemployment, wage rates, prices and productivity.
Had neoclassical economists interpreted Phillips correctly, they would have seen that he thought dynamics and expectations were important (he was, after all, an engineer), and we wouldn’t have been driven back to the stone age with the supposed ‘revolution‘ of the 1970s.
An irrational approach to Von Neumann
In microeconomics, the approach to ‘uncertainty’ (a misnomer) emphasise the trade-off between potential risks and their respective payoffs. Typically, you will see a graph that looks something like the following (if you aren’t a mathematician, don’t be put off – it’s just arithmetic):
The question is whether a company will invest at home or abroad. There is an election coming up, and one candidate (B) is an evil socialist who will raise taxes, while the other one (A) is a capitalist hero who will lower them. Hence, the payoffs for the investment will differ drastically based on which candidate wins. Abroad, however, there is no election, and the payoff is certain in either case; the outcome of the domestic election is irrelevant.
The neoclassical ‘expected utility’ approach is to multiply the relative payoffs by the respective probability of them happening, to get the ‘expected’ or ‘average’ payoff of each action. So you get:
For investing abroad: £200k, regardless
For investing at home: (0.6 x £300k) + (0.4 x £100k) = £220k
Note: I am assuming the utility is simply equal to the payoff for simplicity. Changing the function can change the decision rule but the same problem – that what is rational for repeated decisions can seem irrational for one – will still apply.
So investing at home is preferred. Supposedly, this is the ‘rational’ way of calculating such payoffs. But a quick glance will reveal this approach to be questionable at best. Would a company make a one off investment with such uncertain returns? How would they secure funding? Surely they’d put off the investment until the election, or go with the abroad option, which is far more reliable?
So what caused neoclassical economists to rely on this incorrect definition of ‘rationality’? A misinterpretation, of course! One need look no further than Von Neumann’s original writings to see that he only thought his analysis would apply to repeated experiments:
Probability has often been visualized as a subjective concept more or less in the nature of estimation. Since we propose to use it in constructing an individual, numerical estimation of utility, the above view of probability would not serve our purpose. The simplest procedure is, therefore, to insist upon the alternative, perfectly well founded interpretation of probability as frequency in long runs.
Such an approach makes sense – if the payoffs have time to average out, then an agent will choose one which is, on average, the best. But in the short term it is not a rational strategy: agents will look for certainty; minimise losses; discount probabilities that are too low, no matter how high the potential payoff. This is indeed the behaviour people demonstrate in experiments, the results of which neoclassical economists regard as ‘paradoxes.’ A correct understanding of probability reveals that they are anything but.
Getting it right
There are surely many more examples of misinterpretations leading to problems: Paul Krugman’s hatchet job on Hyman Minsky, which completely missed out endogenous money and hence the point, was a great example. The development economist Evsey Domar reportedly regretted creating his model, which was not supposed to be an explanation for long run growth but was used for it nonetheless. Similarly, Arthur Lewis lamented the misguided criticisms thrown at his model based on misreadings of misreadings, and naive attempts to emphasise the neoclassical section of his paper, which he deemed unimportant.
This is not to say we should blindly follow whatever a particularly great thinker had to say. However, indifference toward the ‘true message’ of someone’s work is bound to cause problems. By plucking various thinker’s concepts out of the air and fitting them together inside your own framework, you are bound to miss the point, or worse, contradict yourself. Often a particular thinker’s framework must be seen as a whole if one is truly to understand their perspective and its implications. Perhaps, had neoclassical economists been more careful about this, they wouldn’t have dropped key insights from the past.