Monday 23 May 2016

On Burdens of Proof

This post, like several other recent posts was inspired by Scott Alexander’s Slate Star Codex blog and some of the discussion in the comments there.

In one particular exchange there, I attempted (albeit poorly) to advocate the position that there is nothing special about the presence of an international border which changes the fundamental nature of trade.


I.
Here’s a hypothetical example:

Alice and Bill both live in Wonderland.  Alice produces apples.  Bill makes burgers.  Neither Alice nor Bill wish to live on apples or burgers alone.  So, they decide to trade with one another.  Let’s say they agree to an exchange rate of 5 apples per burger.  Each week they meet up and Alice gives Bill 35 apples; Bill, in turn, gives Alice 7 burgers.  Both are extremely satisfied with this arrangement.

Now, let’s change the example slightly:

Alice lives in Wonderland.  Humpty Dumpty lives in Mirrorland.  Alice produces apples.  Humpty makes burgers.  Neither Alice nor Humpty wish to live on apples or burgers alone.  So, they decide to trade with one another.  Let’s say they agree to an exchange rate of 4 apples per burger.  Each week they meet up and Alice gives Humpty 28 apples; Humpty Dumpty, in turn, gives Alice 7 burgers.  Both are extremely satisfied with this arrangement.

The question that must be answered by advocates of protectionism, in it’s various forms, is:

What about the fact that Humpty Dumpty resides in Mirrorland, rather than in Wonderland, changes the fundamental nature of the above trade?

Or, asked another way:

What is it about the fact that Humpty Dumpty resides in Mirrorland that makes the trade between Alice and Humpty different from the trade between Alice and Bill in a way that justifies placing certain restrictions on the former, but not placing the same restrictions on the latter?

These questions are not rhetorical.  And despite the lighthearted appearance of my examples, they are serious questions that require serious answers by advocates of protectionism.

In numerous discussions of these issues with advocates of protectionism, I have not yet received satisfactory answers to such questions.  I find this somewhat baffling.


II.
In one such exchange, I asserted that, as the ones proposing that the government actively intervenes by imposing trade restrictions – thereby restricting the freedom of individuals and businesses to conduct peaceful, mutually beneficial exchange – the burden of proof falls on advocates of protectionism to back-up their calls for such trade restrictions with evidence that they are either necessary or desirable.

One response I got to this was that my appeals to ‘burden of proof’ were a red herring.

In one sense, this is quite correct.

The protectionist claims: ‘There is a substantive difference between intranational and international trade that justifies the imposition of certain restrictions on the latter that do not apply to the former.’

The free-marketeer claims: ‘There is no substantive difference between intranational and international trade that justifies the imposition of certain restrictions on the latter that do not apply to the former.’

This is analogous to Matt Dillahunty’s jar of gumballs example.

The protectionist is claiming the number of gumballs is even.
The free-marketeer is claiming the number of gumballs is odd.

In both cases, we have two equal and opposite – and mutually exclusive – claims being made.

As explained on Wikipedia [emphasis added]:
“Either claim could be explored separately; however, both claims represent the same proposition and do in fact ask the same question.  Odd in this case means ‘not even’ and could be described as a negative claim. 

Before we have any information about the number of gumballs, we have no means of checking either of the two claims.  When we have no evidence to resolve the proposition, we may suspend judgment.  From a cognitive sense, when no personal preference toward opposing claims exists, one may be either skeptical of both claims or ambivalent of both claims. 

If there is a claim proposed and that claim is disputed, the burden of proof falls onto the proponent of the claim.”

So, the sense in which ‘burden of proof’ being a red herring is correct is:

If a protectionist wants to claim there is a substantive difference between intranational and international trade that justifies the imposition of certain restrictions on the latter that do not apply to the former, they ought to be able to back-up such a claim with some kind of evidence.

Of course, this is symetrical.  If a free-marketeer wants to claim there is not a substantive difference between intranational and international trade that would justify the imposition of certain restrictions on the latter, but not on the former, they also ought to be able to back-up such a claim with some kind of evidence.

In short, advocates of either position ought to be able to back up their position with evidence and reasoning.  Appeals to ‘burden of proof’ (i.e. pointing to the lack of evidence for the opposing position) are not sufficient and are kind of a cop-out.  Just because the evidence for the opposing position is weak or nonexistent doesn’t mean the evidence for your position is any better.


III.
In another sense, however, I don’t think the ‘burden of proof’ is entirely a red herring.  Maybe it’s only an orange herring?  That is to say, I think it may at least hint at something important.

In order to convince someone who doesn’t agree with me, I have to show her such-and-such evidence according to her standards.  If she wants to convince me, she has to show me such-and-such evidence according to my standards.  This is the philosophic burden of proof that we’ve been discussing thus far.

But what if we're discussing the passing of legislation?

Consider the example of drunk driving.  Driving whilst intoxicated is a crime in the vast majority of countries around the World.  Why?  What’s the moral justification for outlawing drunk driving?  I think it has something to do with there being a general consensus that the benefits that society gets from not having lots of drunk people driving around, causing chaos on the roads, getting into car accidents and killing lots of people, outweighs the costs to potential drunk drivers of not being able to drive home from the pub, having to catch a lift or have a designated driver with them, take a taxi or public transport home, or not have that second pint with dinner.

That is, laws that prohibit drunk driving pass some sort of cost-benefit test.

Sure, we can quibble about the finer details of some of the exact costs and benefits.  Maybe you could argue that the optimal level to set the drink-drive limit at should be 0.06% BAC (Blood Alcohol Content) instead of 0.05% or 0.08% BAC.  I don’t know precisely what the optimal limit is, viewed in terms of its total costs vs. its total benefits to society.

Some countries take a zero tolerance approach* – any amount of alcohol detected in your breath/blood/urine will be met with sanctions of some sort – this is probably too strict.  On the other hand, there are a handful of countries** that don’t appear to have any limit on how much alcohol you can drink before getting behind the wheel and this is almost certainly too permissive.

What I don’t think is in much doubt, is that it makes sense to have some sort of limit.

Asking what the appropriate limit is, is partly an empirical question and partly a values question.  There is no objectively ‘right’ answer, there is only a range of broadly socially tolerable answers.

This is similar to the example used by Steven Landsburg in one of his books*** when he asks what the optimal level of pollution is?  The answer depends on your values and on how you define ‘optimal’, but is almost certainly not zero.


IV.
In English common law – which forms the underlying basis for much of the English speaking world's legal codes – there is a presumption in favour of individual freedom.  That is, anything not expressly prohibited by law is permitted.

So, for example, driving drunk wasn’t illegal in the UK until 1967 when the Road Safety Act was passed, prohibiting it.

It may be a red herring to talk about burden of proof in a philosophical sense, but in order to enact legislation that restricts individual freedom it should be incumbent on advocates of that legislation to prove – to themselves at least as much as anyone else – that that legislation is worthwhile having.

If someone advocates a certain policy, call it ‘X’, that person should be able to provide some sort of justification for their belief that policy ‘X’ is either necessary or desirable.

It seems crazy to me that anyone would advocate for any particular policy without also holding the belief that said policy is necessary or desirable.  And presumably they have reasons for holding those particular beliefs.  And if I ask them ‘what are your reasons for holding those particular beliefs?’ and they can’t articulate an answer to me.  And they instead respond with ‘well, what are your reasons for NOT holding these particular beliefs?’ that’s not very helpful, nor is it conducive to productive discourse.

Part of my reasons for not holding those particular beliefs may be because no-one has ever been able to present to me any strong evidence or articulate any good reasons for doing so.



* These are mostly majority Muslim countries where there are strong social norms against alcohol consumption and alcohol is typically more strictly controlled.  e.g. Afghanistan, Azerbaijan, Comoros, Indonesia, Iran, Libya, Turkmenistan, and the UAE.  Although the Czech Republic, Hungary, Nepal, Paraguay, Romania, and Slovakia all also take a zero tolerance approach.
The list gets even longer when one takes into account countries that take a zero tolerance approach for certain types of drivers (but not all drivers), such as learners or newly qualified drivers, commercial and professional drivers.  This includes Australia, Germany, Macedonia, New Zealand, Palau, Serbia, Slovenia, Tanzania, and Thailand.
This list is by no means complete or definitive.

** I’m looking at you Guatemala, Kenya, Niger, Togo, and The Gambia.

*** It was either ‘The Armchair Economist’, ‘More Sex is Safer Sex’ or ‘The Big Questions’, I can’t remember which, but read them all, they’re all excellent.

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