Grappling with assumptions and knowledge bias

Say you are going to visit someone, but for thought-experiment reasons you know absolutely nothing about them, not even their name or gender or anything of the like. What can you confidently say about this person you don’t even know?

Well you can confidently say that they’re human, since I did specify that they were a “person,” and since there’s no evidence aliens exist on Earth. That means they eat food and breath air and all that other stuff. But besides the most vague generalities about human nature, you cannot confidently assert *anything* about them. If I forced you to guess about their qualities, you would only be able to guess the vaguest things that are almost universal among humans, like their physical traits (probably 2 arms and 2 legs) or human universalities (probably love their family, probably like food and traveling).

The only things you can confidently say about this person would be the *common and non-unique traits* that they probably share with all other humans. Because with so little to go on, it would be illogical to assume a set of very unique traits instead.

But then I tell you this person is an American. OK, you can now assume they almost certainly speak English (though it’s not totally certain, and they could always be a baby or a mute anyway). You can assume they know at least some of the cultural touchstones of Americanism (although again, they could be a baby), like they’ve heard the Star Spangled Banner, and they know what Star Wars and Marvel Movies are. They probably know that Hollywood is famous for movies, and that Texas is famous for oil.

But can you confidently say that they are a basketball player? Do you know if they enjoy Handel, Hershel, and Bach? Can you say anything about their politics wahtsoever?

If I then tell you they’re a climatologist, you get even more details. They’re likely on the left-side of the political spectrum. They’re almost certainly well-educated (a pre-requisite for climatology), and they’re far more likely to be an office worker than a manual laborer (although I guess *someone* has to install all those temperature stations).

Now let’s say that this person you’re going to meet is my friend Dave, who’s about 25 years old. Dave is a great basketball player, but he hates watching it because “the modern game is boring.” He likes jazz renditions of famous Baroque music. He plays Minecraft fanatically, although he’s never modded it. And he is a climatologist working at a local university, but he’s also deeply religious and prays before every meal.

The less you knew about Dave, the more generic he seemed. Just a person? There’s 8 billion of those. An American? They’re also common. Even a climatologist doesn’t seem unreasonably unique or special.

But when I gave you more details about his personality, he suddenly seemed fairly out of the ordinary: he’s both sporty and sciency, he’s young but also religious, he plays a popular game sure, but he also like an incredibly eclectic style of music.

But is Dave *actually* unique? Or does his appearance of uniqueness come from *our knowledge* of him? I’d hazard than many of you can think of people in your lives with an even more unique set of traits, compared to the very few things I’ve told you about Dave. And when I was slowly describing Dave, before you knew how unique he was, you had to fill in the blanks with guesses based on common traits. This is true of anyone we don’t know well. People seem more common as we know less about them, more unique as we know more.

For every person we’ve ever met, we have a very limited set of knowledge about them, and we fill in whatever blanks exist with the “most likely” choices. That’s why even your parents or loved ones can still surprise you, as you may not have known that they did drugs in college, or ran a local newspaper, and you had just filled in those blanks with something else before they told you.

But that means that by definition, we default to assuming everyone around us has “common” and “ordinary” sets of traits. I’d hazard a guess that every person in the world has some set of traits that makes them extremely unique or out of the ordinary, even if these are things that you’d only know if you were close friends with them.

The office worker who reads about 2 books a week: that’s very out of the ordinary. The financial analyst who’s written a dozen murder mysteries: that’s very uncommon. The American who speaks fluent Korean: this is less common in America than having written a book. But if all you knew was “office worker,” “financial analyst,” or “American,” you’d think these people were more normal and less unique than my friend Dave up there, even if they end up being as or more unique than him when you know all their traits.

Extraordinary-ness is realized as we get more and more data about a person, as we find more and more things that are clearly *outliers* to the common trends. Because until we know those things, we naturally fill in the gaps in our knowledge with the “ordinary” placeholders, the “expected” values.

And the reason I’m talking about all that is that I’m almost certain this though process underlies claims about the uniqueness of our own sun and planet.

The Fermi Paradox and the Rare Earth Hypothesis

To shift gears slightly: many people have pondered about why Earth hasn’t been visited by aliens yet. If there are billions of stars in the Universe, and the Universe has existed for billions of years, then there should have been plenty of time for alien species to evolve, become technologically advanced, and start joyriding around the galaxy. As Enrico Fermi said: “where is everyone?”

A potential answer people have caught on is that intelligent life is unbelievably uncommon, and that Earth just happened to have a very very specific set of Astronomical circumstances that made life, and intelligent life, possible. Under this “Rare Earth Hypothesis,” life may evolve around only one in a quadrillion stars, there may only be a *single* life-bearing world in our galaxy: Earth.

Our planet and solar system do seem very rare. In the search for exoplanets, we rarely find ones with lots of gas giants so *far* away from their star, most gas giants appear way closer than ours do. Our sun also isn’t a binary star (like most sun-like stars are), and it has fewer flares and superflares.

But I would contend that, like my friend Dave above, we only notice our solar system’s “uniqueness” because we know so MUCH about our Sun and so LITTLE about exoplanets and their stars. We are *assuming regularity on all the variables we don’t have data for.*

Like, let’s take one of those stars that has a Jupiter-like gas giant orbiting close to the star. Maybe some of those Jupiters have large, rocky moons with complete atmospheres, and maybe these moons can support liquid water, which could support life. That’s probably uncommon, but is it more or less uncommon than our own system having its gas giants so far away?

Our planet has a very large moon, but are there exoplanets with rarer configurations, like an Earth sized planet with 4 or more smaller moons? Or an Earth sized planet with Saturn-like rings?

And our sun has unusually few flares, but is there a planet out there with an unusually strong magnetic field and an unusually thick water atmosphere, one that can easily protect its life-bearing planet from life-killing solar flares?

For this last example, let’s imagine that life has indeed evolved on such a world, intelligent life. They, like us, might think they’re the only life in the universe. They, like us, might think that their planet is unbelievably unique, and that their specific uniquenesses are what allowed their solar system to have life.

Maybe their solar system has a large gas giant orbitting close to the star, and the gas giant’s magnetic field, combine with their own planet’s uniqueness, serves to limit the damage of stellar flars coming to their planet. The gas giant could act like a kind of “shield,” sitting between their own planet and their star, too small to dim the star’s light, but with an incredibly strong magnetic field that blocks the force of any Coronal Mass Ejections (the technical name of large stellar flares).

These people might say “well of course life only evolved on *our* planet, how common is it to have a rocky terrestrial planet outside the orbit of a gas giant? We’ve never seen that in exoplanets. And our gas giant plus or magnetic field are unusually good at protecting us from solar flares. And since essentially all stars have large solar flares, then all planets but our own get blasted to death by Coronal Mass Ejections before intelligent life can evolve.”

But they wouldn’t be right, because we on Earth would still exist. And they’d be assuming every other star out there was “normal,” that there wasn’t a rocky planet *closer to its star* than a gas giant, orbiting an unusually quiet star. And since it would be so hard to get data on *our* star, they’d see our star and assume it was just another “ordinary” lifeless system (we’d have trouble knowing our own star had planets if we didn’t orbit it, it’s difficult to see by the most common measurement techniques)

See, I think Earth only seems *rare* because of how much we know about it. Just like Dave only seems *unique* because of how much I told you about him. If I’d just given you his more common traits (he’s 25, American, plays sports), he wouldn’t seem that unique or special at all.

The jar of marbles thought experiment

Imagine for instance that there’s a jar with 100 marbles in it, each numbered 1 to 100. You pull out number 8 and, aha! This is an exceptionally unique marble! No other marble has this specific number on it, and this marble is 1 in 100, isn’t that unique?

But in this jar, ALL the marbles are unique, they’re ALL 1 in 100. They’re just unique in different ways by having different numbers on them.

Or if you prefer, let’s say the jar of marbles has 999,900 marbles that are unlabeled, and 100 marbles numbered 1 to 100. Again you pull out marble number 8 and, aha, this time it’s even MORE unique! This time it’s a 1 in a MILLION marble! No other marble has this number!

But again, the numbered marbles are ALL 1 in a million, they have different numbers on them, different “things that make them unique,” but they are all still unique.

This marble thought experiment is how I think of the rare Earth hypothesis. Yes our Earth is rare, it’s got a number on it (life), and we think most other stars in the galaxy don’t have life, we assume most of them are unnumbered. But just because we’re 1 of a kind, with our own special number ENTIRELY DIFFERENT FROM ANYONE ELSE’S, doesn’t mean that another marble with another number doesn’t exist somewhere in the Galaxy, even somewhere close by.

We assume that life can only evolve if the marble has the number 8 on it, ie if a planet and solar system have our very unique set of traits (gas giant arrangement, large moon, quiet star, etc). But we don’t have telescopes powerful enough to *see the numbers* on any other marbles out in the galaxy, so we don’t know for sure if they have life or not. We assume that they are normal, that they have all the “common” traits stars have and that they don’t have anything special on them that would make them unique or life-bearing. But we don’t know.

There could be a number 9 marble right next door to us, a planet orbiting a star with its own collection of unique traits completely different from ours, but thinking just as we do that they are the only life-bearing system in the entire galaxy, because our star doesn’t have their star’s unique traits.

And they’d be wrong. And we’d be wrong too. Just something to think about: we should be more humble when trying to argue from “uniqueness.”

Anyway I still want to post part 2 of my fusion power post, so stay tuned for that very soon.