I have a short story coming up soon. The spark that lit the story and this post was this tweet from Neil deGrasse Tyson:

Earth needs a virtual country: #Rationalia, with a one-line Constitution: All policy shall be based on the weight of evidence

— Neil deGrasse Tyson (@neiltyson) June 29, 2016

This tweet set off an intense internet debate on the merits of such a country. Many people — mostly of a Lefty persuasion — embraced the idea. Many people — mostly of a Righty persuasion — wrote a number of good and readable critiques of this idea, going over some ideas I’ll discuss later.

Tyson later expanded on this idea, basically arguing, even if Tyson doesn’t realize it, for a negative view of governing: that policy should be implemented only after the massive weight of evidence shows that it would advance the cause being supported. But even with this caveat, there are three principle problems with Rationalia.

History

What brought this back to the front burner were several signs at the March for Science yesterday that argued that fighting racism, sexism, homophobia, etc. are scientific issues. Surely, in Rationalia, there would obviously be no such things.

But this is not the case. Science, in the past, has often been used to justify prejudice. The 19th/early 20th century progressive movement claimed to be the embodiment of rational, scientific thought. The scientific methods that had figured out the steam engine and the light bulb were going to be used to shape human society. They were an early version of Rationalia.

And what did they do? The embraced eugenics, which supposedly was supported by the Theory of Evolution. They embraced prohibition on the idea that they could scientifically perfect human society. And these tendrils of supposedly scientific thought snaked throughout the 20th century, manifesting in everything from claims that women were intellectually inferior, that Jews were subhuman or that homosexuality was a mental illness. All of this was supposedly backed by science.

The Soviet Union and its satellite dictatorships around the globe considered Marxism as proven as the Law of Gravity. They considered it so proven, in fact, that disagreeing with it was regarded a sign of mental illness. Lysenkoism also flourished in the Soviet Union, supposedly as the rational scientific alternative to Western pseudo-science.

Now we recognize these ideas as nonsense. But what other nonsensical economic and social ideas are being bruted about today as “scientific” that will one day prove to the result of bias and prejudice? The long awful history of the 20th century warns us that when you marry politics and science, the result is not to “scientize” the politics but to politicize the science.

The reason liberals are more likely to embrace Rationalia is because of the Liberal Conceit: the notion that liberals are more reasonable and rational and fact-based than conservatives¹. And while that’s true on certain topics, that rationality evaporates the second the facts cross their pre-conceived notions. The Right, of course, is infamous for global warming denial, which they claim is based on scientific skepticism. But the Left will happily cite 40-year-old studies to claim that universal pre-K more than pays for itself while ignoring studies from Tennessee, Quebec and Head Start that show it doesn’t help. The Right will pretend that evolution is a myth, while the Left will cite garbage studies claiming gun control works. The Right will claim the Laffer Curve means tax cuts pay for themselves while the Left will claim that the Law of Supply and Demand is magically suspended for low-wage labor. Conservatives claim absurdly that regulations cut the size of our economy by 83%. And liberals claim, equally absurdly, that free IUDs cut teen pregnancy 40%. And in all cases, they regard their case as proven by the overwhelming weight of evidence.

Nowhere has junk science been more prevalent than the issue of sex trafficking. My friend Maggie McNeill has an entire page devoted to the giant pile of junk studies and fake numbers that are used to justify crackdowns on consensual sex work. And both parties happily embrace these myths.

No matter what policies were proposed in Tyson’s Rationalia, supporters would undoubtably find some supposedly overwhelming body of evidence to support them.

Science is a Moving Target

“But Mike,” you say, “in Rationalia we will remove these biases and assumptions. We will have some gang of worthies who will weigh all the evidence.” OK, then. Let’s pretend that we can take the politics out of science and make decisions based entirely on the weight of the evidence. Well … what happens when the evidence isn’t clear? What happens you have studies that are executed perfectly but, by random chance, produce bad results? Do we outlaw guns one day and legalize them the next?

Over the last few years, we have found that many many studies — studies that policy has been based on — could not be reproduced. Science — particularly social science — is suffering from a massive replication crisis in which up to 90% of published studies can not be reproduced. A study that claimed conservatives were more psychotic turned out to have its data swapped; another that claimed countries start failing when debt exceeds 90% of GDP turned out to have a bad spreadsheet. Decades of science claiming salt was lethal were wrong. The food pyramid was wrong. The idea that fat kills us was wrong. Studies on second hand smoke were wrong. Studies highlighting the dangers of GMOs were wrong. A test that supposedly measured racism was wrong. And all of these were used as the basis of policy.

One of the things I’ve often said about science is that it is only mediocre at identifying theories that are right. What it’s really awesome at is identifying theories that are wrong. Science isn’t a series of received truths but a way of testing and discarding bad ideas. It’s slow, tedious and prone to error. But it is better than any other approach we’ve taken to figuring out the world.

But while the corrective mechanism in science is good, it’s not perfect. Scientists can turn down blind alleys for decades before finally realizing their error. And the more subtle the effect you’re trying to measure, the more prone it is to bias and error. Basing policy purely on science is basing policy on a moving target.

Values:

All of this merely scratches the surface of the problem with Rationalia. The biggest problem is that politics is not defined by some sort of evidentiary calculus. Politics is decided ultimately by values.

Let’s do a thought experiment. Let’s suppose that the objective evidence indicated that doing away with trial by jury would make our society much safer. Crime would be reduced, murders would plunge, rapes would disappear. I don’t believe that, but we’re already playing with spherical cows here. So … would Rationalia abolish the Sixth Amendment?

Returning again to gun control: let’s pretend that the weight of evidence did support removing guns from law-abiding citizens. Many people would still oppose it because they value their freedom.

Or take abortion. How do we do the calculus on that? It depends on whether you think the fetus has rights or not. If you do, then abortion must be outlawed as it destroys a life. If you don’t, then it should be legal. This is not an issue that lends itself to the weight of evidence because people disagree on what that evidence means. Where do you draw the line on outlawing abortion: Birth? Viability? Fetal pain? Brain development? When the chance of spontaneous abortion (miscarriage) reduces to a certain threshold? Each of those points has a “rational” argument behind it. But which argument you accept depends on your values and how you value the rights of the unborn versus the rights of women.²

Slave societies do poorer economically than free ones. But the argument for abolishing slavery is based on the dignity of the individual human being, not the economics of servitude. Racism, sexism, religious discrimination .. these are wrong. But not because they are scientifically wrong; it’s because they are morally wrong. If one group of people were scientifically proven to be intellectually superior to others, would that justify elevating their status as human beings and denigrating others as inferior? Of course not. “All men are created equal” is a philosophical argument, not a scientific one.

It would be nice if issues could be settled by the careful weight of evidence but they’re not. What we value, how much we value it, what rights we believe our fellow humans possess, how those rights interact with each other in a free society — this is how we debate and decide issues. These are not subject to rationality tests. They are moral tests. And science, by definition, is amoral.

Science does have a role to play in our politics in that it provides crucial facts with which we can debate issues. We should pay attention to science when it sounds alarm bells about things like global warming. Science can provide the critical data needed to decide policy on crime, poverty and public health. But it is only part of the political equation. It is not a magic wand.

^{1. The Conservative Conceit is that they are more moral than liberals. I see little evidence that either conceit is true.↩}

^{2. In fact, a “rational” argument could be made that abortion should be outlawed altogether. The utility of eliminating abortion could be “proven” from the Repugnant Conclusion or the need for a populace to sustain the welfare state. And the most effective way to reduce abortion rates is to outlaw it. I’m pro-choice, so I wouldn’t sign on for that even if the rational case for abortion were ironclad. But that’s because I value freedom, not because I’m more rational or fact-based.↩}