I have often said that economics, to the extent it is a science, is like biology rather than physics. Let me try to make that clearer. By biology, I do not mean the study of the human cell, which we have made a great deal of progress understanding though there is more to learn. I am thinking of biology in the sense of an ecosystem where competition and emergent order create a complex interaction of organisms and their environment. That sounds a lot like economics and of course it is. But we would never ask of biologists what the public and media ask of economists. We do not expect a biologist to forecast how many squirrels will be alive in ten years if we increase the number of trees in the United States by 20%. A biologist would laugh at you. But that is what people ask of economists all the time. Economists should be honest and say that the tasks they are often asked to do are outside the scope of economics as we know it and perhaps outside the scope of economics as it will ever be known.

—Russ Roberts on whether economic methods are scientific.

At long last, I’ve finished reading the responses to the 2011 Edge question: “What scientific topic would improve everybody’s cognitive toolkit?” Here are my favorites, arranged (sort of) by concept. Toss a few in your toolbox.

UPDATE: Whoops—I thought these were posted at the end of the year! 190 new responses to the 2012 question were published today. Here is a Darth Vader “Nooo” button to press as necessary.

Causality, Emergence, Complex Systems

Cooperation and Cultural Evolution

Rationality and Cognitive Biases

Risk, Probability, Uncertainty

Methods

Sensory Perception

You are Not a Special Snowflake

Look Again

“One thing I have learned in a long life: that all our science, measured against reality, is primitive and childlike—and yet it is the most precious thing we have.”

—Albert Einstein, Letter to Hans Muehsam, 9 July 1951

In the light of this 1898 Moon model, Mills observed the way we humans nest knowledge, building little models of the world in our own minds. Go read his post.

It’s awe-inspiring that both minds and museums hold “models for countless phenomena you will never witness, never touch or feel, and yet whose shape and behavior you can predict with stunning accuracy.” It’s amazing that as the Moon reflects on us, our minds reflect a moon. But I’m more interested in the dark.

I can imagine myself as a child in this curiously empty exhibit. First, I’d stand at about the same distance as the photographer and try to take it all in. (How nice that there’s nobody to get in the way!) Next, I’d run up as close as the guard would allow, examining each crag and crater above me. And then I’d start to wonder: what’s hiding in that dark corner? Why can’t I see the other side?

The scene brings back memories of the hemisperic Moon model in front of my hometown planetarium. On school trips, my classmates and I were always scheming to climb on top or crawl under when our teacher was distracted. The moon in my brain wasn’t so complicated then, and I wondered what it was like on the inside and where I could find the other half. Sure, I knew the thing on the lawn was just a model. But the thing in my mind couldn’t yet account for not knowing, for the idea that maybe there was no other half.

This is the truly astonishing thing about the Moon: for thousands and thousands of years, we never saw the other half. At the time my Moon model was made—sometime, I think, in the 60s—we still hadn’t modeled the far side! This grainy composite from the Soviet Luna 3 probe was the very first glimpse, sent back in 1959:

Of course, the other half was there in the models (and thus, in the brains). No one was surprised to find that the far side of the Moon looked very much like the near one. Even the earliest astronomers assumed the Moon was some sort of sphere. But the magnitude of our not-knowing, the undiscovered geography on the other side of our models, has always been as staggering as their complexity. Consider the Moon map.

Below is the first Moon map, Knowth Orthostat 47, a Neolithic rock carving in Ireland around 5,000 years old. It’s a fascinating image—the first sign of a model, a piece of knowledge, that would continue to grow in complexity and explain ever more. It is our capacity to encode the model, to take it out of our mind and smudge it on a cave wall, that makes the growth of knowledge and the evolution of our models possible.

The map hadn’t changed much when Leonardo Da Vinci made this moon sketch around 1505:

But the model had. By the 5th century BC, astronomers grasped moon mechanics and lunar cycles, culminating in Ptolemy’s 2nd century theory of lunar motion. (The Umayyad astronomers would clean it up in the 14th century, followed by Copernicus, Kepler, Tycho, and Newton). By the end of the 5th century AD, our moon models had a theory of reflected light.

Galileo was one of the first to glimpse a sliver of the far side, but through a glass, darkly, during lunar librations, when a bit of the edge was briefly visible through his telescope. Here are his moon sketches from around 1610:

Dutch astronomer Michael van Langren made the first real selenographic map in 1645 (Compare with a famous, roughly contemporary map of the Earth):

The complexity of our Moon models—our knowledge—has accelerated ever since. The latest moon-modeler, NASA’s Lunar Reconnaissance Orbiter, sent back 192 terabytes of data, resulting in this beautiful map:

I gaze at this moon, and think of how lucky we are to smudge our models on a cave wall somewhere outside our minds. (The moon in my brain now has two sides covered in craters, might even account for some not-knowing, but it doesn’t come close to terabytes of detail!) The Moon is so, so close—merely a few hundred thousand miles from the mote of dust trying to make sense of it. The quasars Deutsch describes are billions of light years away. And yet for five thousand years, half of it was blank, unmodeled, out of reach of our minds.

We have cultivated so much knowledge with science, built complicated and elegant and awe-inspiring models, and yet knowledge is still so fragile and circumscribed, so primitive and childlike—and the most precious thing we have. The things we see in the light are clear and bright and wonderful. But what humbles and awes me, as always, is stopping for a moment and staring into the dark.

TL;DR: This is the best model of the Moon. You are an astronomer in a doofy hat.

(via mills)

Source: Flickr / field_museum_library

The Umwelt

In 1909, the biologist Jakob von Uexküll introduced the concept of the umwelt. He wanted a word to express a simple (but often overlooked) observation: different animals in the same ecosystem pick up on different environmental signals. In the blind and deaf world of the tick, the important signals are temperature and the odor of butyric acid. For the black ghost knifefish, it’s electrical fields. For the echolocating bat, it’s air-compression waves. The small subset of the world that an animal is able to detect is its umwelt. The bigger reality, whatever that might mean, is called the umgebung.

The interesting part is that each organism presumably assumes its umwelt to be the entire objective reality “out there.” Why would any of us stop to think that there is more beyond what we can sense? In the movie The Truman Show, the eponymous Truman lives in a world completely constructed around him by an intrepid television producer. At one point an interviewer asks the producer, “Why do you think Truman has never come close to discovering the true nature of his world?” The producer replies, “We accept the reality of the world with which we’re presented.” We accept our umwelt and stop there.

To appreciate the amount that goes undetected in our lives, imagine you’re a bloodhound dog. Your long nose houses two hundred million scent receptors. On the outside, your wet nostrils attract and trap scent molecules. The slits at the corners of each nostril flare out to allow more air flow as you sniff. Even your floppy ears drag along the ground and kick up scent molecules. Your world is all about olfaction. One afternoon, as you’re following your master, you stop in your tracks with a revelation. What is it like to have the pitiful, impoverished nose of a human being? What can humans possibly detect when they take in a feeble little noseful of air? Do they suffer a hole where smell is supposed to be?

Obviously, we suffer no absence of smell because we accept reality as it’s presented to us. Without the olfactory capabilities of a bloodhound, it rarely strikes us that things could be different. Similarly, until a child learns in school that honeybees enjoy ultraviolet signals and rattlesnakes employ infrared, it does not strike her that plenty of information is riding on channels to which we have no natural access. From my informal surveys, it is very uncommon knowledge that the part of the electromagnetic spectrum that is visible to us is less than a ten-trillionth of it.

Our unawareness of the limits of our umwelt can be seen with color blind people: until they learn that others can see hues they cannot, the thought of extra colors does not hit their radar screen. And the same goes for the congenitally blind: being sightless is not like experiencing “blackness” or “a dark hole” where vision should be. As a human is to a bloodhound dog, a blind person does not miss vision. They do not conceive of it. Electromagnetic radiation is simply not part of their umwelt.

The more science taps into these hidden channels, the more it becomes clear that our brains are tuned to detect a shockingly small fraction of the surrounding reality. Our sensorium is enough to get by in our ecosystem, but is does not approximate the larger picture.

I think it would be useful if the concept of the umwelt were embedded in the public lexicon. It neatly captures the idea of limited knowledge, of unobtainable information, and of unimagined possibilities. Consider the criticisms of policy, the assertions of dogma, the declarations of fact that you hear every day — and just imagine if all of these could be infused with the proper intellectual humility that comes from appreciating the amount unseen.

—David Eagleman, in response to the 2011 Edge question, “What scientific concept would improve everybody’s cognitive toolkit.”

You might have heard his stories on the radio. This is one of my favorites.

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