Tag: covid

Bayesianism vs scientism

There is an unfortunate divide in the rationalist tribe between Bayesians and believers in scientism. Bayesians are those who rationally incorporate all sources of information when choosing what credence to have in different propositions. You have prior credences that are set by common sense, theoretical arguments, empirical information and so on. You then update from those priors with new information, whether that is from personal observation, social science, theory or whatever. Believers in scientism in contrast form their beliefs by putting lots of weight on published scientific evidence over other types of evidence.

I think scientism is the wrong approach and can be costly. It is also among the leading reasons not to defer to the scientific establishment on some key questions; it is a case where the requirements of epistemic modesty are not as they might appear. A lot of experts with comprehensive knowledge of the scientific literature have the wrong epistemology and oftentimes, for that reason, we shouldn’t defer to them. I will illustrate this with examples.

Masks

The Bayesianism vs scientism cleavage has played out recently in the disagreement between experts about the efficacy of face masks. Some experts have come out strongly in favour of masks, whereas some have cast doubt on their efficacy. For example, in August, a Swedish epidemiologist said:

“Mr Ludvigsson noted that in a meta-analysis by the WHO of 29 studies that showed face masks were effective, only three concerned their use outside hospitals and of those that did not none involved Covid-19.”

This is a paradigmatic scientistic attitude. Mr Ludvigsson casts doubt on whether masks work outside hospitals and for covid because there haven’t been any studies testing them outside hospitals and for covid. The Bayesian approach, in contrast, would update on the information from all of the studies, even though the context is not exactly the same in the studies as what is being proposed now. 

They would also take into account the basic science of viral transmission, and use common sense. We know that covid spreads via droplets that are released from the mouth or nose when an infected person coughs, sneezes, or speaks. People can catch covid when those infectious droplets get into their mouth, nose or eyes. This is where common sense kicks in: if you put a mask in the way of the droplets from my mouth or nose, then that makes it less likely that the droplets will get from my mouth or nose into yours. We even have video footage of masks doing the blocking.

Even if masks have only been tested for influenza and not covid, we still understand the mechanism by which they work – droplet blocking. If they work for influenza, which spreads in the same way as covid, then they will very likely also work for covid. 

The scientistic view is that to know whether we should recommend that people wear masks in enclosed spaces like shops, buses and the tube, we would need to have a high-quality study (preferably an RCT) of that exact thing. However, that exact thing can never be done twice. Any intervention that we impose will be different in some way from the version of the intervention that has been tested. 

To illustrate, consider this dialogue:

Scientism: Ok, we have the evidence: masks work on buses. 

Bayesian: Great! One thing – all the masks you tested were blue. Do yellow masks work?

Scientism: Well, we didn’t study that, but of course yellow masks work.

Bayesian: How do you know if you didn’t study it?

Scientism: There is nothing about yellow masks that would make them not work if blue masks work – colour is irrelevant.

Bayesian: Do you have a scientific study showing that colour is irrelevant?

Colour is indeed irrelevant. The argument for this is that the colour of the masks is not going to have an effect on the mechanism by which the mask works, which is blocking droplets. Knowledge of the mechanism of transmission tells us the results will generalise to yellow masks. But this argument is not available to scientism. 

This is why the experts have disagreed about masks. World-leading experts have got this one wrong, and it is down to their mistaken scientistic epistemology. Unusually, someone who just relied on sturdy common sense would be more likely to be right than an expert who knew the whole scientific literature really well but assimilated it in a scientistic way. 

The minimum wage

I am going to preface this by saying that I am in favour of more redistribution – I am opposed to the minimum wage because it is bad for low-skilled people. Economics 101 states that if you introduce a minimum wage, employers will demand less labour – they will lay people off or demand fewer hours from them. If you think the demand curve for labour slopes downwards, then a minimum wage will cause firms to economise on labour.

In spite of this, as this IGM poll shows, there is active disagreement among leading economists about whether minimum wages will make it harder for the lower paid to find work:

Some of the experts’ answers are influenced by how interpret the term ‘noticeably’, but others justify their arguments with scientistic claims, such as 

  • “I’m not aware of any strong evidence demonstrating this result.” (David Autor)
  • “The empirical evidence now pretty decisively shows no employment effect, even a few years later. See Dube, Lester and Reich in the REStat” (Michael Greenstone)
  • “Yes, I know the Econ 101 answer but the evidence suggests the effect on employment is between small and 0.” (Richard Thaler)

These statements suggest that one’s view of the minimum wage should be determined by what the median study finds about the effects of the minimum wage. But really when we are assessing this claim we need to consider economic theory, common sense and all the other evidence that demand curves for labour slope downward. Here is Bryan Caplan on the strength of the case from economic theory and common sense:

“In the absence of any specific empirical evidence, I am 99%+ sure that a randomly selected demand curve will have a negative slope. I hew to this prior even in cases – like demand for illegal drugs or illegal immigration – where a downward-sloping demand curve is ideologically inconvenient for me. What makes me so sure? Every purchase I’ve ever made or considered – and every conversation I’ve had with other people about every purchase they’ve ever made or considered.”

He goes on to argue that empirical evidence from other parts of economics should also update us towards minimum wages having a disincentive effect. This includes

  • The literature on the effect of low-skilled immigration on native wages. The strong consensus is that high levels of low skill immigration have little effect on native wages. This implies a near horizontal demand curve for low-skilled labour. 
  • The literature on the effect of European labor market regulation, which shows that regulations that increase the cost of hiring people causes high unemployment in Europe. 
  • The literature on Keynesian macroeconomics. Keynesian macroeconomics suggests that nominal wage rigidity causes short-term unemployment. This makes it highly likely that government-imposed wage rigidity causes unemployment. 
  • The literature on the effects of price controls, on rent, energy and agriculture, which bolster the textbook story of price floors. 

On this last point, Caplan makes a version of the point I made above about masks:

“If you object, “Evidence on rent control is only relevant for housing markets, not labor markets,” I’ll retort, “In that case, evidence on the minimum wage in New Jersey and Pennsylvania in the 1990s is only relevant for those two states during that decade.” My point: If you can’t generalize empirical results from one market to another, you can’t generalize empirical results from one state to another, or one era to another. And if that’s what you think, empirical work is a waste of time.”

The empirical work on the employment effects of the minimum wage is mixed. The majority of studies find a negative effect on employment, but some prominent studies do not. But this is pretty much what we would expect to find if the minimum wage did indeed have a negative effect on employment. Empirical social science research is not very good. Most published research is false. John Ioannidis has found that nearly 80% of the reported effects in the empirical economics literature he studied are exaggerated, typically by a factor of two, and with one third inflated by a factor of four or more. 

Minimum wage studies are especially likely to find false negatives. Studies of the minimum wage usually test the effects of minimum wage levels that are low ($4 – $11) and so they are antecedently likely to find effects that are dotted either side of zero. Moreover, when assessing the effect of the minimum wage, you are comparing a counterfactual to the real world that is affected by innumerable other forces, including every other labour market policy, the plans of literally every business in the area, all other economic forces that could affect a region, etc. Then there is the problem of actually measuring changes in demand for labour properly. So, we have very noisy data measuring a small treatment effect – of course we will find some surprising results, which are very likely false negatives. The rational thing to do is not to update very much.

In advance of examining any evidence about the employment effects of the minimum wage, your prior that it reduces employment should be something like >99%. Upon observing any study showing that the minimum wage does not have an effect on employment, you shouldn’t update much because empirical research is not very good. Caplan establishes this formally here.

Libertarian pandemic policy

Libertarians are, sociologically, much more likely to be sceptical of COVID lockdowns than most people. Often their arguments appeal to government curtailment of freedom and the economic and social costs of lockdowns. But libertarianism is really about rights, not weighing up costs and benefits: it says that people may do what they want, provided they don’t violate the rights of others, such as rights to life, liberty and property. The government may step in and coercively and forcibly prevent people from violating the rights of others. For instance, the police may stop me from going on a murderous rampage by locking me up.

The concern that governments have not done a proper cost-benefit analysis on lockdown policies is an interesting one, but cost-benefit analysis is in large part irrelevant to libertarianism. What then, does libertarianism imply about lockdowns?

Let’s first think about what risk individuals impose on others through going to the shops or going to work. If I have covid and pass it on to someone else, I impose around a 1 in 200 chance of death on them, higher if they are over 50 or already ill. Let’s say that given prevalence in my area, there is a 1 in 500 chance that I have covid, and a 50% chance that I spread it to someone else on the tube. The chance I kill someone on a given day is therefore 1 in 200,000 if I get the tube to and from work. If I get the tube every work day in a year, the chance that I kill someone over the course of the year is around 1 in 400. 

What would a libertarian say about this? Two things to resolve first are: (1) what level of risk is unacceptable (2) whether others on the tube have implicitly accepted the risk by getting the tube.

What’s the risk threshold?

(1) is, I think, impossible to answer in a principled way because it requires us to put some kind of value or weight on a right. This would be very like saying how good the right is, but nonconsequentialism steadfastly avoids answering that kind of question. The justification for rights in nonconsequentialist philosophy looks like this:

? ⇒ right to bodily security 

On consequentialism, the justification looks like this:

Social welfare ⇒ right to bodily security 

Utilitarianism can fairly straightforwardly deal with cases of risk by quantifying the badness of an outcome and weighting according to the probability that we realise it. On rights-based theories it is quite unclear what justifies people’s rights and it is therefore very difficult to say about how important a given right is. As a result, we cannot get a clear answer by weighting outcomes according to their probability, so we cannot get a clear answer about what level of risk is unacceptable. This is a very big flaw of nonconsequentialist theories, like libertarianism.  

Anyway, imposing a 1 in 400 chance of dying on someone else looks far too high. Imposing a 1 in 200,000 risk of death on someone roughly quintuples their daily risk of dying. Is this an unacceptable level of risk? It is hard to say. I’m not sure what the risk of killing someone via drink driving is, but it is plausibly in the 1 in 20,000 to 1 in 200,000 ballpark, and libertarians think it is ok to ban drink driving. Michael Huemer, a great libertarian philosopher, argues that playing Russian Roulette with unwilling victims counts as aggression, and calls for a coercive response. That’s true even if you imagine a gun with a million chambers, so that the probability of shooting someone is only 1/1,000,000.

Acceptance of risk

Now, what about the point that others have implicitly accepted the risk by getting on the tube, and so have forfeited their right to life if they die. One counter-argument is that drivers know that they accept some risk of being killed by dangerous driving, but we should still prevent dangerous driving. Anyone who goes out on the street knows there is a risk of being mugged, but we should still prevent muggings. 

A difference here might be that everyone on the tube is in the same position with respect to the risk they impose on others, so this is a bit like everyone agreeing to get involved in a destruction derby, which does not call for state interference, according to libertarianism.

There are two problems with this as an argument against lockdowns. Firstly, there are externalities from widespread community transmission of covid. If lots of people get the tube, this increases community transmission of covid, which makes it more likely that people who are trying to avoid the risk will die. For instance, it increases the risk that old people will get it on the way to the shops or that the virus will get into care homes, or that people visiting their parents will inadvertently kill them. Thus, symmetry between individuals is not present here. This is more like a case in which everyone agrees to engage in a destruction derby, but the cars sometimes career off the track and kill unsuspecting pedestrians.

This point speaks in favour of lockdowns, from a libertarian point of view, just as it speaks in favour of the regulation of the destruction derby. To reiterate, the point that the benefits of the regulation might not be worth the costs is to a large extent beside the point – what matters is the evident risk that people’s basic rights will be violated.

Secondly, covid seems more like the drunk driver case than the destruction derby case. In the drunk driver case, no-one argues that we should not prohibit drunk driving merely because other drivers use the roads knowing that there is some chance of there being drunk drivers. In the destruction derby case, people choose to accept the risk and they have ample opportunities not to participate. With covid, there are some people who use the tube to go to work and are otherwise cautious and there are some people who use the tube to go to the pub and so expose the more cautious people to much greater risk than they would prefer.

Libertarianism therefore seems to imply that it would be ok to close pubs, restaurants and clubs in order to protect the people who have ventured out but are taking lower risks. In the same way, we should prevent drink driving to protect the rights of ordinary motorists. Again, from a libertarian point of view, the issue is not whether the economic or mental health costs are worth it, it is whether people’s right not to be aggressed against have been violated.

Conclusion 

The true implications of libertarianism for pandemic policy seem likely very different to how they have been interpreted by real world libertarians.