Neil deGrasse Tyson tweeted to his 5.43 million followers on June 29: “Earth needs a virtual country: #Rationalia, with a one-line Constitution: All policy shall be based on the weight of evidence.” I’m a big fan of Tyson’s, but I think that tweet is a good illustration of why we can’t solve all of our problems just by handing over government to The Scientists.
- “Rationalia” isn’t. Humans are not so constituted as to be able to function in a world of pure rationality.
- A one-line constitution is not desirable.
- If you’re going to boil a nation’s goals down to one line, that’s the wrong line.
Perhaps what Tyson meant to say was that governments should not make policy that flies in the face of evidence. That, of course, I agree with, second, and decorate with gold stars. Governments absolutely should seek the best evidence and shape legislation accordingly. It’s just that that’s not all governments should do—it’s not the only criterion legislators should use. It’s necessary but not sufficient.
Policy doesn’t just flow from the weight of the evidence without human intervention, like a mountain stream flowing downhill. There are additional steps. Evidence can’t by itself tell us what we should be doing, because that word should depends on what we want—our goals and values. For instance, you can present evidence that wealth inequality has been widening in the United States for decades, or that wealth inequality is worse in the United States than in other developed countries, or that there is a massive wealth gap between blacks and whites in the United States—but doing so won’t by itself change the minds of people who think wealth inequality is a good thing because it rewards hard work and enterprise. Differing opinions on political and ethical issues are based on different intuitions about what is good, and what we mean by good, and what it is right to call good, and those intuitions are not easily shifted by data.
This applies to pretty much any policy issue you can think of. Even the ones that seem purely technical and empirical involve goals; if they didn’t, they wouldn’t be policy. Global warming is massively technical and evidence-based, but what (if anything) we decide to do about it does indeed depend on what we human beings want. If you look at climate change as purely a factual matter, then it’s just an interesting process that we’re seeing unfold. Watching glaciers calve is quite a dramatic spectacle, as are floods, hurricanes, typhoons, mudslides, avalanches, forest fires—nature’s own horror movies. Those of us who think it’s not good enough to view it as a spectacle are relying on evidence-based predictions but also on our thoughts and feelings about those predictions. Rising sea-levels will swallow coastal cities and displace millions of people, and that’s a bad thing. Rivers fed by Himalayan glaciers will dry up and there will be massive famines in southern Asia, and that’s a bad thing. Desertification will spread and crops will fail, and that’s a bad thing. There are facts, and there are our feelings about the facts, and policy-making depends on both.
Policy is the implementation of what we want as a society, and what we want is a matter of likes and dislikes—of what Hume called “the passions.” We can rationally want different things, and evidence doesn’t necessarily resolve disagreements on the subject. Some of us want more equality; others want more meritocracy. Some want freedom from religion; others want religion to permeate every aspect of life. Whatever the issue is, it has to matter to us. We don’t make policy about things that don’t matter to us.
And even when we do all agree that a particular issue matters, we don’t all agree on what to do about it. We have conflicting ideas and principles, such that pointing to evidence doesn’t always trigger a unanimous policy response. Statistics on crime prompt some legislators to suggest more prisons and harsher sentencing and others to suggest improvements to schools and housing. Further statistics can be presented to support each side’s proposals, but foundational ideas and principles don’t always give way to statistics.
Think for instance of the most familiar sentence in all of American government, the first sentence of the second paragraph of the Declaration of Independence: “We hold these truths to be self-evident, that all men are created equal, that they are endowed by their Creator with certain unalienable Rights, that among these are Life, Liberty and the pursuit of Happiness.” First of all, what jumps off the page is the staggering dishonesty, or hypocrisy, or at least lack of self-awareness—they held these truths to be self-evident, and yet many of them owned slaves. Yo, guys—if you really did hold those truths to be self-evident, what’s with the slave-owning? You didn’t seem to think your slaves had an unalienable right to liberty. And then there’s the restriction of these rights to only the male half of humanity.
But less visible than that, to us more than two centuries later, is that in the wider world hardly anyone did hold those truths to be self-evident. Even with all the hypocrisy and blindness, the claim was outrageously radical at the time. The bit about “self-evident” is amusingly brazen in a world of kings and peasants.
That’s the issue in a nutshell: different people hold different “truths” to be self-evident. The brother of Qandeel Baloch, for example, considers it self-evident that his sister deserved to be murdered for posting twerk-selfies on social media. Other people consider it self-evident that she deserved to go on being alive. What evidence could we offer Waseem Ahmed Azeem to convince him that he did a terrible thing in killing his sister?
Evidence alone is not enough. Compassion, generosity, solidarity, and other social emotions are also necessary for any country human beings can thrive in.