People do lots of things which annoy me, but there's one thing many of them do which annoys me a lot. Noah Smith talks about it in a roundabout way in What is "derp"? The answer is technical.
Bayesian probability basically says that "probability" is, to some degree, subjective. It's your best guess for how likely something is. But to be Bayesian, your "best guess" must take the observable evidence into account. Updating your beliefs by looking at the outside world is called "Bayesian inference". Your initial guess about the probability is called your "prior belief", or just your "prior" for short. Your final guess, after you look at the evidence, is called your "posterior." The observable evidence is what changes your prior into your posterior.
How much does the evidence change your belief? That depends on three things. It depends on A) how different the evidence is from your prior, B) how strong the evidence is, and C) how strong your prior is.
What does it mean for a prior to be "strong"? It means you really, really believe something to be true. If your start off with a very strong prior, even solid evidence to the contrary won't change your mind. In other words, your posterior will come directly from your prior.
(And where do priors come from? On this, Bayesian theory is silent. Let's assume they come directly from your...um...posterior.)
Yes, that's exactly where most strong human beliefs come from—people take them right out of their ass.
There are many people who have very strong priors about things.
Yes, there are.
For example, there are people who believe, very strongly, that solar power will never be cost-efficient. If you confront them with evidence of solar's rapid price declines, they will continue to insist that, despite this evidence, solar will simply never be cost-competitive with fossil fuels.
That they continue to insist this does not necessarily make them irrational in the Bayesian sense; they simply have very strong priors. Someday they may be convinced - for example, if and when unsubsidized solar power starts being adopted on a mass scale.
Take that with a big grain of salt. Noah Smith thinks humans are rational. He's an economist. Sigh.
It'll just take a LOT to convince them. (A more entertaining example can be seen in this classic comedy video.)
But here's the thing: When those people keep broadcasting their priors to the world again and again after every new piece of evidence comes out, it gets very annoying.
Yes, it does get very annoying.
After every article comes out about a new solar technology breakthrough, or a new cost drop, they'll just repeat "Solar will never be cost-competitive." That is unhelpful and uninformative, since they're just restating their priors over and over.
Thus, it is annoying. Guys, we know what you think already.
English has no word for "the constant, repetitive reiteration of strong priors". Yet it is a well-known phenomenon in the world of punditry, debate, and public affairs. On Twitter, we call it "derp".
So "derp" is a unique and useful English word. Let's keep using it.
Noah Smith does not think in psychological terms—most people do not. Thus he takes a rather superficial view of this mindless repetition of "strong priors."
Another word closely related to "derp" in this context is the psychological notion of an idée fixe, or simply put, an unhealthy preoccupation of the mind, or obsession. The point Smith struggles to make is that close-minded or obsessed people are not amenable to argument or evidence—they have a story and they're sticking to it. In Smith's terms, such people "keep broadcasting their priors to the world again and again" even after evidence contradicting those prior views surfaces again and again. When contradictory evidence is consistently ignored, obsession becomes delusion.
We could argue about when close-mindedness or the idée fixe morphs into faith-based belief (religion). Obviously if you've got faith, no amount of evidence is going to turn you around.
If you want an example, people obsessed with peak oil come to mind for me because I used to write so much about the subject. It's not so much that the world's oil supply won't peak and decline at some point in the 21st century—it will. (I won't play the dating game.) For the peak oil obsessed, this much dreaded event is always around the next corner, although evidence has been piling up for some years now that humans have found a few clever ways to stave off the inevitable for a while.
But evidence doesn't matter to these people. No amount of evidence will dissuade them from their fixed belief that industrial civilization is on the verge of collapse because of peak oil. And of course the obsession with peak oil often means that other subjects (e.g. the destruction of marine ecosystems, the related mass extinction) don't even exist, or, perhaps more commonly, do not matter. It's peak oil, or nothing (or bust?).
But that's just one example. Pick a subject—any subject. Like night follows day, you will find humans which have fixed ideas about that subject, and no argument or evidence will ever, ever change their minds about it, although in a few psychologically unhealthy people, their views will undergo a dramatic reversal from one extreme position to the diametrically opposed extreme position.
Regardless of the subject, such people are extremely annoying to me. They are essentially brain dead. As such, they are breathing air, drinking water, and eating food which could be consumed by other, more worthy creatures, human or not.
I just had to get that off my chest.
This site has discussed the very small number of realists in this world. To be a realist do you have to have no idee fixe..ever? Finding the completely open mind may take a long time, especially outside of this blog.
Posted by: Ken Barrows | 06/09/2013 at 12:16 PM