Posts Tagged Milton Friedman
I have previously discussed Milton Friedman’s infamous 1953 essay, ‘The Methodology of Positive Economics.’ The basic argument of Friedman’s essay is the unrealism of a theory’s assumptions should not matter; what matters are the predictions made by the theory. A truly realistic economic theory would have to incorporate so many aspects of humanity that it would be impractical or computationally impossible to do so. Hence, we must make simplifications, and cross check the models against the evidence to see if we are close enough to the truth. The internal details of the models, as long as they are consistent, are of little importance.
The essay, or some variant of it, is a fallback for economists when questioned about the assumptions of their models. Even though most economists would not endorse a strong interpretation of Friedman’s essay, I often come across the defence ’it’s just an abstraction, all models are wrong’ if I question, say, perfect competition, utility, or equilibrium. I summarise the arguments against Friedman’s position below.
The first problem with Friedman’s stance is that it requires a rigorous, empirically driven methodology that is willing to abandon theories as soon as they are shown to be inaccurate enough. Is this really possible in economics? I recall that, during an engineering class, my lecturer introduced us to the ‘perfect gas.’ He said it was unrealistic but showed us that it gave results accurate to 3 or 4 decimal places. Is anyone aware of econometrics papers which offer this degree of certainty and accuracy? In my opinion, the fundamental lack of accuracy inherent in social science shows that economists should be more concerned about what is actually going on inside their theories, since they are less liable to spot mistakes through pure prediction. Even if we are willing to tolerate a higher margin of error in economics, results are always contested and you can find papers claiming each issue either way.
The second problem with a ‘pure prediction’ approach to modelling is that, at any time, different theories or systems might exhibit the same behaviour, despite different underlying mechanics. That is: two different models might make the same predictions, and Friedman’s methodology has no way of dealing with this.
There are two obvious examples of this in economics. The first is the DSGE models used by central banks and economists during the ‘Great Moderation,’ which predicted the stable behaviour exhibited by the economy. However, Steve Keen’s Minsky Model also exhibits relative stability for a period, before being followed by a crash. Before the crash took place, there would have been no way of knowing which model was correct, except by looking at internal mechanics.
Another example is the Efficient Market Hypothesis. This predicts that it is hard to ‘beat the market’ – a prediction that, due to its obvious truth, partially explains the theory’s staying power. However, other theories also predict that the market will be hard to beat, either for different reasons or a combination of reasons, including some similar to those in the EMH. Again, we must do something that is anathema to Friedman: look at what is going on under the bonnet to understand which theory is correct.
The third problem is the one I initially honed in on: the vagueness of Friedman’s definition of ‘assumptions,’ and how this compares to those used in science. This found its best elucidation with the philosopher Alan Musgrave. Musgrave argued that assumptions have clear-if unspoken-definitions within science. There are negligibility assumptions, which eliminate a known variable(s) (a closed economy is a good example, because it eliminates imports/exports and capital flows). There are domain assumptions, for which the theory is only true as long as the assumption holds (oligopoly theory is only true for oligopolies).
There are then heuristic assumptions, which can be something of a ‘fudge;’ a counterfactual model of the system (firms equating MC to MR is a good example of this). However, these are often used for pedagogical purposes and dropped before too long. Insofar as they remain, they require rigorous empirical testing, which I have not seen for the MC=MR explanation of firms. Furthermore, heuristic assumptions are only used if internal mechanics cannot be identified or modeled. In the case of firms, we do know how most firms price, and it is easy to model.
The fourth problem is related to above: Friedman is misunderstanding the purpose of science. The task of science is not merely to create a ‘black box’ that gives rise to a set of predictions, but to explain phenomena: how they arise; what role each component of a system fills; how these components interact with each other. The system is always under ongoing investigation, because we always want to know what is going on under the bonnet. Whatever the efficacy of their predictions, theories are only as good as their assumptions, and relaxing an assumption is always a positive step.
Consider the following theory’s superb record for prediction about when water will freeze or boil. The theory postulates that water behaves as if there were a water devil who gets angry at 32 degrees and 212 degrees Fahrenheit and alters the chemical state accordingly to ice or to steam. In a superficial sense, the water-devil theory is successful for the immediate problem at hand. But the molecular insight that water is comprised of two molecules of hydrogen and one molecule of oxygen not only led to predictive success, but also led to “better problems” (i.e., the growth of modern chemistry).
If economists want to offer lucid explanations of the economy, they are heading down the wrong path (in fact this is something employers have complained about with economics graduates: lost in theory, little to no practical knowledge).
The fifth problem is one that is specific to social sciences, one that I touched on recently: different institutional contexts can mean economies behave differently. Without an understanding of this context, and whether it matches up with the mechanics of our models, we cannot know if the model applies or not. Just because a model has proven useful in one situation or location, it doesn’t guarantee that it will useful elsewhere, as institutional differences might render it obsolete.
The final problem, less general but important, is that certain assumptions can preclude the study of certain areas. If I suggested a model of planetary collision that had one planet, you would rightly reject the model outright. Similarly, in a world with perfect information, the function of many services that rely on knowledge-data entry, lawyers and financial advisors, for example-is nullified. There is actually good reason to believe a frictionless world such as the one at the core of neoclassicism leaves the role of many firms and entrepreneurs obsolete. Hence, we must be careful about the possibility of certain assumptions invalidating the area we are studying.
In my opinion, Friedman’s essay is incoherent even on its own terms. He does not define the word ‘assumption,’ and nor does he define the word ‘prediction.’ The incoherence of the essay can be seen in Friedman’s own examples of marginalist theories of the firm. Friedman uses his new found, supposedly evidence-driven methodology as grounds for rejecting early evidence against these theories. He is able to do this because he has not defined ‘prediction,’ and so can use it in whatever way suits his preordained conclusions. But Friedman does not even offer any testable predictions for marginalist theories of the firm. In fact, he doesn’t offer any testable predictions at all.
Friedman’s essay has economists occupying a strange methodological purgatory, where they seem unreceptive to both internal critiques of their theories, and their testable predictions. This follows directly from Friedman’s ambiguous position. My position, on the other hand, is that the use and abuse of assumptions is always something of a judgment call. Part of learning how to develop, inform and reject theories is having an eye for when your model, or another’s, has done the scientific equivalent of jumping the shark. Obviously, I believe this is the case with large areas of economics, but discussing that is beyond the scope of this post. Ultimately, economists have to change their stance on assumptions if heterodox schools have any chance of persuading them.
Milton Friedman is quite a revered figure – among economists, conservatives, libertarians and some leftists – partly, of course, because he was a prolific economist, but also in large part due to his debating skills. He is generally perceived as able to shut down arguments from the left with simple, easy to understand, often amusing one liners. However, I have always found him unconvincing, and here I hope to show why.
There will be, of course, numerous conceptual disagreements which I will try not to discuss in this post: the phony market-government dichotomy, where government is some exogenous entity; the general idea that self interest will lead to the best of all outcomes; the invocation of the mythical ‘free market.’ Nor is the purpose of this post to draw attention Friedman’s major intellectual arguments themselves – though I have already done that with his stance on assumptions, corporate social responsibility, and I suppose by proxy I have commented on his interpretation of the Great Depression.
Instead what I want to do here is show Friedman’s general debating techniques are highly questionable. Many of his arguments rest on an abuse of the reductio ad absurdum. Sometimes Friedman was either ignorant about the evidence or just plain dishonest. Many of the ‘facts’ he cites don’t stand up to even a brief fact check. Here are some examples:
Here, Friedman references the late 19th century land deals as ‘minor.’ One billion acres of land is not minor. Much of this land was taken from citizens directly in the interests of privately owned corporations, and/or involved widespread fraud and corruption. The sheer volume of land seized suggests the deals played a massive part in establishing the railway lines, along with many other industries across the U.S. Would these engines of growth have been built if not for the coercive grabbing of masses of land?
The fact is that even cursory glance at social mobility in the United States puts lie to Friedman’s claims about it being high. Similar results hold for most developed countries, generally only changing as they become more Social Democratic.
In general I’ve noticed Friedman makes repeated vague references to ‘all of history,’* for which he never provides specifics, and which are actually completely at odds with the evidence. I can only conclude that what he says is based not on history but on armchair analysis of what must have happened, based on his own logic. But there is strong reason to doubt this logic – as I have discussed in my previous posts A Brief Anti-Economist History and How Natural is Capitalism, Exactly?, Western Capitalism did not just spring out of nowhere due to the magic of the market.
For example, was Friedman aware of hunting restrictions such as the Black Acts, which brutally enforced limits on peasant activity and so contributed to the initial rise in the industrial workforce? The rise in enclosure acts, which did something similar? Is he aware of the large amount of U.S. tariffs during the country’s rise to prominence, and similar trends in other Western countries, as well as more recently developed countries in Asia? Such historical debates are lost in a sea of sweeping assertions about the efficacy of the apparently omnipresent ‘free enterprise system,’ with narratives that would have Friedman fail a first year history essay.
To be sure, as with all historical analysis, there is always room for discussion, but Friedman’s arguments rest upon one interpretation of ‘facts’ that are usually incomplete or a blatant misrepresentation of what actually happened.
So it’s quite easy to find instances of Friedman presenting questionable evidence to support his arguments. But what about his famous purely logical put downs? Do they stand up to scrutiny? Here is quite a widely watched YouTube clip (always worth noting that the young man is not actually Michael Moore):
The issue raised is whether Ford acted immorally by failing to install some safeguarding blocks in their infamous Pinto cars, which resulted in a large amount of deaths. Friedman suggests the problem is amoral, and simply a matter of price: nobody can place an infinite value on a human life, so whether the car should have been released rests on a monetary trade off. Friedman suggests the young man who posed the question is not interested in principle, only price. In fact this is not true; Friedman simply asserts it and builds his argument from there.
A moment’s thought will suggest to any reasonable person that the important principle is not price, as Friedman suggested, but human life, as the young man seemed to think. Consider: if the automobile will kill 10,000 people a year unless the defect is fixed, does it really matter how much it will cost to fix the problem? Surely, if fixing the defect in the automobile is affordable, then the defect should be fixed. On the other hand, if fixing the defect in the automobile is not affordable, then defective car should not be released. A profit driven firm necessarily insists that the lower manufacturing cost that does not include fixing the defect in the automobile that makes it more dangerous to drive substantially outweighs saving a certain number of lives each year. Friedman abuses the reductio ad absurdum by taking the issue – where it was clear Ford simply should have installed the boxes – out of context, and focusing on price as the important variable.
Here is another example where Friedman abuses the reductio ad absurdum:
What the man posing the question to Friedman is actually alluding to – in a roundabout sort of way – is a simple concept called the ‘income effect:’ reducing somebody’s income via taxation may well increase the amount they work (and empirical studies suggest it does), hence increasing overall production. Of course, if you increase it to 98% you will impoverish people and destroy the economy, but nobody actually suggested that.
Perhaps some might interpret this as cherry picking. So, finally, here is a full interview with Milton Friedman. I will discuss Friedman’s remarks throughout the interview:
(1) At 2:06, the presenter asks if a place such as Central Park would exist in a ‘pure market’ situation. Friedman fails to answer the question directly, but during his response he blames Central Park’s problems during the 1980s on public management. But Central Park is in fact a public private partnership, where the private firm employs 4 out of 5 of people maintaining the park. Again, Friedman either has no idea what he is talking about or is lying.
(2) At 4:10, the presenter brings up Thalidomide. Friedman’s response contains two problems. First, when he says that the FDA stalls potentially beneficial drugs from being used, he fails to distinguish between a Type 1 error – falsely rejecting, say, a perfectly safe drug – and a Type 2 error – failing to reject an unsafe one. Type 1 is generally considered worse on the logic of ‘convicting an innocent person.’
Second, Friedman suggests that the company responsible for Thalidomide did not make a profit, therefore the market would ‘signal’ for it to go bankrupt. I am not sure whether they made a profit in that particular instance. What I am sure of, however, is that the company is still around today. Again, Friedman references facts that are questionable on even a cursory inspection.
Lastly, when Friedman suggests that the airlines will make sure all of its planes are safe, he neglects the ‘weighing up logic’ we saw in the Ford Pinto video. (I am playing Devil’s Advocate, as I don’t think any sane person would defend current U.S. airport security.)
(3) From the beginning the interviewer asks Friedman about the government setting information requirements on packaging. I don’t really understand how Friedman can make the ‘if it mattered a profit seeking firm would take advantage of it’ argument when the interviewer has explicitly stated that the government had to start to enforce information requirements because private firms were not doing it.
Note also that he doesn’t actually engage with the civil rights act question explicitly.
(4) During the final video the interviewer takes Friedman through every government program and Friedman advocates abolishing the majority of them. What confuses me about this part is that Friedman advocated some of these programs elsewhere – for example in his books. In Capitalism and Freedom, he advocated building infrastructure, a negative income tax, school vouchers, praised antitrust laws and more. This highlights Friedman’s dual roles as a propagandist and serious thinker, as a man who was willing to make sensationalist claims and advocate radical policies just to get attention, even if he didn’t truly believe in them. (Some may suggest Friedman was older and had matured here, but there are examples of him criticising these things he advocated elsewhere when he was younger, too. I also see no justification anywhere, ever, for his surreal last minute ‘abolish the federal reserve‘ position).
I don’t mean to suggest what I have to say is the final word; I merely hope to point out that Friedman was somewhat disingenuous and often used logical sleights of hand to get his point across. His interviewers and opponents rarely seemed to press him on it, and to be honest I never saw him go up against anyone particularly formidable. Furthermore, Friedman’s case highlights how little weight should be placed on verbal debates: one liners that seem persuasive at first can evaporate under close scrutiny; facts can be presented with few checks and balances; questions can be dodged and twisted. Friedman was prepared to argue the more ‘free market’ position merely for the sake of it, and was undoubtedly skilled at this role. But once you unpick some of the arguments and cross-check the evidence, his world view leaves a lot to be desired.
Economics has come under a lot of criticism recently, and proponents sometimes try to defend themselves by pointing to Milton Friedman’s methodology of positive economics. In this essay, Friedman
loses his mind argues that the assumptions of a theory do not matter as long as its predictions are correct. Of course, even if you accept this there are still plenty of criticisms of neoclassical economics – the theories internally contradict themselves, and it is also incredibly hard to verify empirical predictions in social science, making Friedman’s litmus test somewhat of a damp squib. However, let’s put these objections to one side.
In the essay, Friedman takes us on a typical Friedman logic train to his preordained conclusion and leaves you to puzzle over how you got there. He argues that to be completely realistic a theory would have include everyone on earth’s eye colour, qualifications, etc. But how do you test whether or not to include these things? You see whether evidence corroborates the theory without them! Fantastic – assumptions don’t matter.
In this case, Friedman’s sleight of hand lies in not properly defining the word ‘assumption’. This is, in fact, so significant that it means his paper is effectively advocating any methodology whatsoever (if I assume throwing darts at this board will give me the GDP figures for next year…). The crucial characteristic of assumptions in engineering or science is that they eliminate specific variables. A perfect gas is one where many of the smaller forces between molecules are ignored. Assuming a vacuum eliminates air resistance. This gives us an appropriate method, as ‘relaxing’ an assumption means adding in more variables, and this process can continue for as long as it is practically feasible.
However, many economic assumptions could not be argued to be eliminating a certain variable - assuming that people are rational self maximisers, or that firms calculate expenditure based on marginal costs and revenue, are actually hypotheses, not ‘assumptions’ in the scientific sense of the word. As such, the ‘assumptions’ themselves are empirically falsifiable and cannot be swept under the rug.
Furthermore, in science theories are only deemed as valid as their assumptions are realistic. A theory can always be improved by making the assumptions resemble reality more accurately. So even if we were to accept Friedman’s premise, we could still improve theories by abandoning rationality based on behavioural evidence, or abandoning marginal cost based on surveys*. Unsurprisingly, in the case of widely used economic models such as Arrow-Debreu, it is incredibly difficult to relax assumptions before the theory collapses – if this were true in physics, the model would be abandoned.
To be honest, it is a sad indictment of economics that an essay which contains the passage:
The articles on both sides of the controversy [regarding marginalist analysis]…concentrate on the largely irrelevant question of whether businessmen do or do not in fact reach their decisions by consulting schedules, or curves, or multivariable functions showing marginal cost and marginal revenue.
has to be critiqued formally. A theory’s assumptions are always relevant to its conclusions, and improving them will always yield more accurate results. That much is obvious to the man on the street, but clearly not to economists.
*Friedman argues surveys are as useless as asking octogenarians how they account for their long life. I can only interpret this as him saying businesses have no idea what they are doing, which sort of undercuts him intellectually elsewhere.