Newton's Weird World

If you go to a bookstore and look through the popular science section, the books on physics will mostly be about the most mind-bending modern theories: quantum mechanics, relativity, big bang cosmology, black holes, and so on. You won't find many books about the basic classical physics you learn in school. Newton's laws of motion, prisms and rainbows, magnets and electric motors--these things don't seem to strike the popular imagination. I think that's because modern physics seems so exotic (and because reading about it makes you look smart). Space and time bend and meld, single particles go through two holes at the same time (unless you try to catch them at it), black holes slow time, capture light, and may even lead to other universes...that is freaky stuff.

Lately, though, I've been realizing how freaky and counter-intuitive the old-school physics of Newton and Galileo can be. People have an intuitive understanding of physics, and it's good enough to let us navigate the surface of this particular planet most of the time, but in the grand scheme of things, it's wrong. Sometimes dramatically wrong. Most of the people who ever lived went to their graves thinking the earth is flat. They were wrong about the shape of the surface they lived on every day of their life. I would too, if I hadn't been taught differently. It's a humbling thought. 

People also assumed for thousands of years that heavy rocks fall faster than light rocks. After all, doesn't a feather fall more slowly than a boulder? It's just common sense. But Galileo thought he would test the idea anyway, and it turned out common sense was wrong. Light things may fall more slowly on Earth because of air resistance, but the deeper law of nature is that in a vacuum, feathers fall just as fast as boulders. That's well known these days, of course, so we don't really feel how surprising it is. But for people living at the time, it was earth-shattering.

It's shocking to discover that natural law runs counter to our intuition, even for things we see every day. When you start thinking about all the ways that's true, dusty old textbook physics starts to gleam a little more. Here are some examples I like:*

When I go for one of my brief, agonizing runs, I always think about how strongly the earth is pulling down on me. But I never consider how I'm pulling up on it with the same amount of force. Every object with mass creates a gravitational field, and I assuredly have mass. And every force comes in pairs--nature is symmetrical that way. I tug on the Earth just as hard as it tugs on me. It's just that the earth is so much more massive that it accelerates me a lot more than I accelerate it.

I just said the earth is pulling "down" on me. That's because I go around thinking there's a real up and a real down. But of course there isn't. And north certainly isn't up, no matter how hard it is to think otherwise. "North is up" is just a convention, and early cartographers often drew maps "upside down" before that convention was established, as in this map of Europe and North Africa from 1459. I can look at that map and tell myself it's just as valid as "right side up" ones, but it's still looks wrong. It's not, though. I am.

The most basic rules of motion can be totally surprising. For example, if you hold a rifle five feet above the ground, and I hold a bullet in my hand at the same height, and I drop it at the same moment you shoot, the two bullets will hit the ground at the same time (disregarding air resistance, etc). The high-velocity bullet falls just as fast as the low-velocity bullet. You would think the lateral motion of the bullet from the gun would somehow interfere with its downward motion ("downward" I should say) but it doesn't. The two motions do combine to create a curved path, but their magnitudes are independent.

Speaking of falling objects, the moon is falling. It's dropping like the giant rock it is. It's just that its lateral motion is balanced with its "downward" motion in such a way that it falls around the earth instead of into it. It's been plummeting for billions of years, but it's never managed to land. We've been plummeting into the sun all that time, too. It makes me a little queasy thinking about it.

Another illusion I have is that when I throw a rock, I always feel like I'm giving it a certain amount of energy. I imagine this energy fades as the rock progresses, so it finally slows down and lands. But that's not what's happening at all. When the rock leaves my hand, it's going at a particular velocity, and it would keep going at the same velocity indefinitely in the absence of other forces. As Newton taught us, objects in motion tend to stay in motion. The rock slows and falls because air resistance exerts a force that decelerates it, while gravity works to return it toward the earth. Energy is always conserved, so the energy I give to the rock doesn't fade away. Some of it is transformed into heating the air that slows down the rock, but none of it disappears.

As for heat, it's funny, counterintuitive stuff, too. In fact, it's not even stuff. It's molecular motion, and it behaves in unexpected ways. When I step out of the shower and put one foot on the tile floor and the other on a bath mat, I could swear the bath mat is warmer than the floor. But it can't be--they're both at the same temperature as the rest of the room. It's just that the tile conducts heat better than the fibers in the mat, so it sucks heat away from that foot more efficiently. That's why it feels colder, even though it isn't.

Of course, I'm speaking metaphorically when I say the tile "sucks heat", even though I may not realize it. It's not really what happens. In fact, the idea of suction is an illusion. If I take a drink through a straw, I'm not exerting a "force of suction". I'm lowering the air pressure in the straw, and that allows the pressure of the atmosphere (a surprisingly high 14.7 pounds per square inch) to push the drink into the straw. It doesn't sound right, does it? It goes against common sense.

And that's the problem with common sense.

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* You probably know these things as well as I do. My point isn't to say "Did you know that....", but to say, "We both know this; let's stop and think about how amazing it really is." That's how most of my posts are intended, actually. 

The Light Fantastic

"My own suspicion is that the universe is not only queerer than we suppose, but queerer than we can suppose" - JBS Haldane

Have you ever gotten a new camera, and decided to finally learn something about how photography works? You know, f-stops, exposure, ISO, all that stuff? I have. Multiple times, actually, because I can't seem to remember it. I'm learning again now. I was trying to figure out how aperture--the size of the hole light passes through in the lens--affects focus. I learned (once again), that the smaller the hole is, the greater your depth of field will be. Not only will your subject be in focus, but the background will be too. Make the hole bigger, and the background will be all blurry. But then I started wondering why that actually happens. Why does light that goes through a little hole stay more focused than light that goes through a big hole? That ignited my curiosity about light and lenses, and before long I had gotten out an old physics book from college to try to wrap my head around all that stuff.

That got me thinking about an idea I've always found fascinating. When you really start looking at how light behaves, it almost starts to seem intelligent. I mean, it's not really, but it gives that impression. Consider this: lenses work because they refract light, which just means they bend light rays. The reason they do is that light travels more slowly in glass than air. If you shine a beam of light through a thick piece of glass (at an angle) and onto a wall, it will bend and slow down when it enters the glass, and then bend again when it leaves. And here's where it gets weird--if a beam of light goes from point A to point B, as shown below, somehow it's able to choose the one path, among the many possible, that takes the least amount of time. That path isn't necessarily a straight line, because if it moves more slowly in glass, then it should alter its course so the distance through the air is farther, and the distance through the glass shorter.

The classic analogy is a with a lifeguard rushing to save a drowning swimmer. Imagine you're that lifeguard, standing on the beach. You look out to your left and see the swimmer in trouble, as shown below. Should you make a beeline--running, and then swimming, straight at him? No...sometimes the fastest route between two points isn't a straight line. You can run faster than you can swim, so you should run a little farther down the beach, so you don't have to swim so far. There's an optimal route that's faster than any other. Most lifeguards won't hit on it exactly. But light is smarter than a lifeguard, at least in that sense. It finds the fastest route, and it does so at, well, the speed of light. It doesn't matter if it has to bend and straighten its way through several layers of air and glass--the path it chooses will be the one that takes the least time.

How does it do that? How does it "know" which path to take? Christian Huygens came up with a plausible answer back in 1678, by thinking of light as moving in a wave, and of a wave front as the combination of many smaller waves. He was able to model refraction that way, as in this image. As the wave fronts approach the glass at an angle, each one changes angles as it slows down and enters. The change in direction will be at an angle that minimizes the time it takes for light to get from one point to another. Huygens was also able to model reflection this way, and a guy named Fresnel applied the idea to other "wavy" phenomena, like diffraction and interference. Nature is full of things that move in waves, and thus behave in all these ways, including water waves, sound waves in the air, and even seismic waves through the earth. Applying the idea to light helped turn the tide of scientific opinion away from Newton's idea theory that light was made of particles, and got physicists thinking of light as ripples propagating through space.

The Huygens-Fresnel idea does seem to provide a mechanism for how light "chooses" the shortest path, and it accurately predicts what that path will be. The problem is, light doesn't really work that way. At least, it's a lot more complicated than Huygens realized. Since the early 20th century, physicists have known that light is as much particle as wave. A beam of light is composed of countless discrete particles called photons. Each one has a frequency, which is what determines the color of visible light. Physicists once thought that brightness (amplitude) was analogous to the height of water waves--brighter light was thought to have higher crests and lower troughs. But it turns out that all photons of a particular wavelength carry the same amount of energy. A bright light is just spewing out more photons per second than a dim light.

This gums up the works for Huygens' wave theory. Even if you send one photon at a time through a piece of glass, light will still pick the fastest path. That's pretty crazy when you thing about it. How can a single particle do that? The simplistic wave theory also falls apart when you look closely at reflection. If you shine a light on a pane of glass, most of it will go straight through. But up to 16% of the photons will bounce back, which is why you see a dim reflection even in transparent glass. Light reflects from both the front side and the back side of the glass, and how much it reflects depends on how thick it is. And that's where it gets crazy once again. If you put a light detector inside a very thick pane of glass and aim a stream of photons at it, you can measure how many photons are reflected by just one surface--the front--and you'll find it's about 4% in most kinds of glass. But if you send the light all the way through the glass, and measure how much is reflected, you find a strange trend. As you keep making the glass thicker, you find that the amount of light reflected will rise and fall regularly--rising gradually from zero up to 16 percent, falling back toward zero, and then rising again. Think about that zero percent. That means, even though four percent of photons bounce off the front surface of glass, if you add a back surface it can cut that percentage to zero. What?? How does the light "know" how far away the back of the glass is when it's just getting to the front? Somehow it does, even if the glass is several meters thick. It's like light isn't just smart...it's psychic.

Of course, it's not really, but the truth is just about that weird. All this stuff is explained by the theory of quantum electrodynamics, or QED. Let's go back to light taking the fastest path through a piece of glass. If I understand it correctly, QED says that each photon takes every path from one point to another--even long ones, where it goes way off to the side and then back again. It spreads out all over the place in a very un-particle-like way, but then arrives as a particle. Each of those paths has a certain "probability amplitude" (the quantum world is all about probabilities) and oddly enough, most of the paths are about equally probable. But the probabilities mostly cancel each other out, except for those very close to the one that takes the least time. So that's the direction the light goes. A similar interaction of probabilities determines how much light will reflect off glass of various thicknesses. That all sounds crazy, and I certainly don't understand it in any deep sense, but apparently the math works just fine. Even physicists who have mastered the equations can't really explain what's going on--they don't understand why those equations work.

But they do work, smashingly. QED describes the quantum basis for most of the physical processes we see all around us; how light moves, how electrons orbit nuclei, how atoms bond together to create different materials...basically everything except nuclear physics, gravity, and certain kinds of radioactivity. Not only that, it's one of the most accurate theories in science. One of the originators of the theory, Richard Feynman, compared its accuracy to measuring the distance across the United States with a margin of error smaller than the width of a human hair. But the theory is also completely mind-boggling. As Feynman also said, "The theory of quantum electrodynamics describes Nature as absurd from the point of view of common sense. And it agrees fully with experiment. So I hope you accept Nature as She is--absurd." Light, and everything else at the quantum level, is pretty freaky stuff. But Feynman had a deep reverence for nature, and I think his point was more about common sense than nature itself. Light is more fundamental and ubiquitous than we are--it's pervaded space and time since the universe began. Looking at nature at a wide angle, we're the anomaly, not light or any other quantum phenomenon. If we find that it's absurd from the point of view of common sense, then we've discovered yet another flaw in common sense. Who are we to say what's absurd?

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QED: The Strange Theory of Light and Matter / Richard Feynman

I never explained how depth of field works. Here's a video that does

Good video introduction to QED

An even more mind-blowing, but more widely known, phenomenon of quantum physics is demonstrated by the double slit experiment. Good video on it here.

We are Stardust. No...Seriously.

We are stardust                     
We are golden                       
    We are billion-year-old carbon
                         - Joni Mitchell

Crab Nebula: A Supernova Remnant

Sometimes my fellow skeptics get on my nerves. So many of them focus too much on negatives--on what's false, rather than what's true. They get so fixated on debunking falsehoods and quackery that they forget to talk about how amazing the real world is. Don't get me wrong...nonsense certainly needs to be exposed, and naked emperors should assuredly be mooned. But still, there's a balance to be struck. Why spend all your time talking about what you don't believe? Why define yourself negatively--in terms of what you reject?

Since I spent my last post talking about astrology and other things I reject, in this one I want to tip the scales in a more positive direction and talk something not only beautiful and wondrous, but scientifically sound to boot. I want to talk about the stars--the stars of the astronomers, not the astrologers. Astrologers have always been fascinated by stars, and rightly so, but I think they miss what's really amazing about them. It's not that the stars influence our personality or destiny in any direct way. They are, after all, giant balls of incandescent plasma, and even the closest are almost inconceivably far away. There's zero scientific reason to think they influence our daily lives--they don't care about some race of featherless bipeds on a faraway planet, and they couldn't do anything about it if they did. But that doesn't mean we have no connection to them. The stars aren't about us, however much we might want them to be, but we are about them. Joni Mitchell was basically right--we really are stardust.

To be more specific, most of the atoms in our bodies, and almost all the elements in the periodic table, were forged billions of years ago in the interiors of stars. Many of the heavier elements were created in stellar death throes, in the titanic explosions known as supernovae. All these processes of element creation are still going on today. The elements that weren't formed in stars (mainly hydrogen and helium) have an even more impressive provenance--they were formed in the Big Bang itself, 13.8 billion years ago.

When scientists are asked what is the most amazing scientific fact they know, many of them talk about how we are made of stardust (star-forged atoms, technically). I tend to agree with them. It's an idea as stunning as anything I've ever heard, and unlike astrological ideas, it's almost certainly true. Here's the basic story scientists have pieced together.

Less than a second after the universe began, protons, neutrons, electrons, and various other particles had formed. As the infant universe expanded and cooled, between the first 3 and 5 minutes, protons and neutrons clumped together to form what would become the nuclei of hydrogen (which has a single proton), and helium (which has two). Conditions were such that this created 6 helium nuclei for every 76 hydrogen nuclei. After about 380,000 years, the radiation that had been knocking electrons away from nuclei cooled enough to allow atoms to form. The hot, glowing universe went dark, but this radiation can still detected today in the form of weak microwaves that permeate space. Astronomers call it the Cosmic Background Radiation--the afterglow of the creation of the universe.

The early universe, then, was a homogenous sea of hydrogen and helium atoms (along with a little bit of lithium). If it had stayed that way, we wouldn't be here--two elements don't make a rich-enough atomic alphabet to create complex structures like, say, us. But as things kept expanding and cooling, the weakest force of nature--gravity--began to assert itself. Matter attracted matter, and great clouds of hydrogen/helium gas started to collapse into spheres. When the pressure got high enough at their core, hydrogen nuclei were squeezed together into helium nuclei. Nuclear fusion reactions had ignited, and the dark universe lit up once again, this time with the light of countless stars. (At larger scales, of course, stars and other matter had formed galaxies, which grew as "small" galaxies combined into larger ones.)

The Cat's Eye Nebula (A Planetary Nebula)

After these primordial stars had burned for a few million or billion years (depending on their mass), a core of helium formed at their center.* The more massive the star, the hotter it burned, and the faster the helium core formed. When it did, helium started to fuse into carbon, which would one day become the backbone element for life. But the carbon core couldn't support the weight of the star, so it started to contract, while the hydrogen and helium around it burned even hotter. This caused the star to puff out its outer layers, forming a huge, cool(er), red giant star. Eventually this behemoth would blow away its outer layers entirely, forming a luminous cloud called a planetary nebula. The core would remain as an intensely hot, small, dense star called a white dwarf, which might be smaller than the earth but more massive than the sun.

Things got a little more exciting in bigger stars, several times as massive as the sun. Here again, hydrogen burned to create a core of helium, which then burned to create a core of carbon. This time, though, temperatures got high enough (hundreds of millions of degrees) for carbon to start fusing into neon. And on it went--neon fused into oxygen, oxygen into silicon, and silicon into iron. Now there was an iron core surrounded by all these other elements, still burning furiously in concentric layers. Once the iron core formed...game over. As tough as iron might seem to us, it couldn't support the weight of all those layers. The iron nuclei were torn apart, and then the protons combined with electrons to form neutrons. The core of the star collapsed and then rebounded, sending a shock wave shrieking through the outer layers of the star--blasting them apart in a supernova. Supernova explosions can release more energy in a few months than our sun ever will in ten billion years; causing the dying star to glow as bright as a small galaxy. The explosion was energetic enough to create all the remaining elements of the periodic table, and then blast them into space. All that remained of the core was a neutron star--a ball of neutrons as dense as an atomic nucleus but as big as a city, spinning several times per second and spewing jets of radiation from each pole.

These dying stars enriched interstellar space with clouds of elements beyond hydrogen and helium, capable of combining into an enormous variety of molecules, which could in turn combine into all kinds of complex, intricate structures. The new interstellar clouds of heavy elements and molecules then began to collapse again, forming a new generation of stars like our sun, born with a full suite of heavy elements. Around many of these stars, little balls of metal, rock, gas, and ice formed. We call those planets. Many of them have a wide variety of elements--potential building blocks for complex structures. On at least one of these planets, that potential was realized in the form of carbon-based life, which formed shortly after the Earth cooled. It's been evolving and diversifying ever since, creating millions of unique life-forms, from slime molds to blue whales, from giant sequoias to seahorses. Lately, it even created a race of odd, upright, talkative apes; quarrelsome creatures, but clever, too--clever enough to discover that they're made from the dust of exploding stars.

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* Helium was actually first discovered on the sun, based on characteristic spectral lines in the light it emits. It wasn't discovered on earth until later. It's named for Helios, the Greek god of the sun.

Postscript: I've heard the Joni Mitchell's song Woodstock probably a thousand times in my life (mostly the Crosby, Stills, Nash and Young version), and I never noticed that line about "billion year old carbon" until I looked up the lyrics today. Nice work, Joni.

Spa Enlightenment: What's So Spiritual About "New Age", Anyway?

"The universe is cool enough without making up crap about it." - Phil Plait

One of the most interesting things about being a librarian is that it lets you see what other people are interested in. The books you keep reshelving are the ones that strike people's fancy. Some of the books that fly off the shelves the most, at least in my library, have Dewey Decimal numbers in the 130's: Parapsychology and Occultism. That's where you find the books on psychic phenomena, astrology, ghosts, occult practices, and ancient aliens who built the pyramids (or even the moon, according to one book). People eat that stuff up. Every month or so I reshelve a book called Fairies 101: An Introduction to Connecting, Working, and Healing with Fairies and other Elementals. And every month I think, "I can't believe I'm putting this in the non-fiction section."

A closely-related genre that I'm always reshelving is alternative medicine--herbalism, homeopathy, acupuncture, crystal healing, and so on. Those check out at least as often as the books on mainstream medicine. Not all alternative medicine is a kooky as the notion that fairies really cavort in our gardens, but some of those books are pretty out-there, and the people that read them also tend to be drawn to the parapsychology and occult section.

The most common umbrella term for all these things, of course, is New Age. New Age is big business, and like most people in this country, I've met some very New Agey people. One thing that always fascinates me about them is that they seem to see New Age pursuits as a kind of enlightenment--as a means of spiritual growth; a pursuit of knowledge about the great cosmic mysteries. That always strikes me as odd, because it seems almost perfectly backward. In fact, you could make an argument that most New Age pursuits are the very opposite of enlightenment.

Let me explain. If you look at a shelf full of books on New Age ideas, or the kookier forms of alternative medicine, it's hard at first to see what they all have in common. What do ancient aliens have to do with psychic divination or telepathy? Why do the people who check out books on crystal healing also check out the ones on astrology? If you think about it, these are all very different ideas. All they have in common, I think, is an air of exotic mystery. They remain in the realm of the unproven, and outside the realm of mainstream science and medicine. They are, in other words, titillating. Not only that, but they can be personalized. A horoscope doesn't just  tell you about distant stars--it tells you what those stars mean for you. I'm convinced that more people are into astrology than astronomy because, as exotic and mind-expanding as astronomy is, it doesn't have that sexy air of magic and mystery, and it will never be about us.

That's why things like astrology seem like the very opposite of any kind of enlightenment to me. Surely a crucial aspect of enlightenment, whether it's spiritual or intellectual, is to see the wonder in the universe as it really is. It's about seeing the magic in the mundane, not ignoring the mundane because you're too preoccupied with exotica. Consider this: we have specialized organs in our heads that can detect a kind of mysterious energy. This energy pervades the universe and passes in waves through empty space. It can give us detailed information about the world, if we just open our eyes to it. No really. Those organs I'm talking about are our eyes, and that mysterious energy is called light. Light and sight are both entirely astonishing things, if you stop and think about them.

The problem is that we don't. Why are so many people more fascinated by unproven phenomena like auras and psychic divination than by the sense of sight? Because they experience sight every day, and because there are no great mysteries remaining about it. If they had been blind all their lives, and suddenly started seeing, then they would see just how astounding the sense of sight really is. On the flip side, if we were all psychic, and had grown up reading each others' minds, people would be bored with that, too. It's the mystery that grabs people. The problem is that it grabs them so much that they lose interest in the staggering wonders they've seen every day of their lives, and get stuck on exotic-sounding but fictional phenomena. That's not enlightmentment--that's distracted escapism. The real wonders are just that--real. It's just that people are bored with them.*

As I said, though, most of those real wonders aren't about us in any personal way, and that's another strike against them for many new agers. But that just shows another way that New Age thinking and real spiritual growth are opposed. Wouldn't real enlightenment involve some kind of transcendence of selfish concerns? New Age culture is far too self-focused to be considered enlightened. Once I was walking down the street in a city with a large New Age presence (I can't remember which one...maybe Boulder?) Anyway, I noticed a day spa offering various kinds of personal pampering, many involving manipulation of imagined "energies." The place was called Spa Enlightenment. I thought, "Yep, that pretty much sums up the whole mindset. Self-indulgence and fantasy as enlightenment."

Once again, I don't claim any particular enlightenment myself. But I can't help thinking truly enlightened people aren't to be found living in a pretty New Age paradise getting weekly chakra alignments. They'll be in some slum or developing country, trying to help someone besides themselves. And I don't think they'll talk much about horoscopes, crystals, or aliens. They won't be distracted by a set of ideas that have nothing in common except their air of mystery and titillation. They'll be too awestruck by the endless wonders they've been surrounded by all their lives.

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* I'm certainly not saying there's no place in the world for fantasy or fiction. It's just that we shouldn't mistake fantasies for reality, or too get wrapped up in them to notice amazing things that really do exist. Fairy tales are great, but that doesn't mean there are fairies under my bed. I'm also not saying no New Age or alternative medicine idea could ever turn out to be valid and proveable. But if it does go mainstream, I bet a lot of people will lose interest in it, because it won't seem mysterious anymore. Finally, I'm not saying all people with New Agey tendencies are selfish or kooky. Some I know are much more compassionate than I am, but it's not because they read their horoscopes.

Global Warming, Public Opinion, and Other Hazards

I spend a lot of time thinking about other people's opinions. I'm always reading polls and comment threads, trying to get a sense of how others see the world. It's not that I'm intrinsically interested in John Q. Public's worldview. In fact, sometimes I find it pretty disturbing. But I feel like I have to pay attention, because opinions matter--they determine, at least in part, how people will act. And how people act will determine our future. There are 7 billion of us on this planet now (up from 6 billion just over a decade ago). If too many people believe things that are at odds with reality, we're going to have a collision with reality, and reality doesn't budge.

One of the opinions that worries me most is the idea that environmental issues like global warming or deforestation are not real problems, so we don't need to worry about them. I've gotten more tuned into this the last couple of weeks, after reading the following: "A new paper in the journal Science finds that climate change is now set to occur at a pace "orders of magnitude more rapid" than at any other time in the last 65 million years." 65 million years. If that's true, then many plants and animals may not be able to adapt fast enough to changing climate, as they have in the past. That's a scary thought. And Science is not some radical environmentalist magazine. It's arguably the most influential and respected scientific journal in the world. So that article got my attention.

Many people don't realize that there's a clear consensus among climate scientists that global warming is real and caused by human activity. That's what at least 90% of them believe, and probably more. Yet nearly half of Americans don't believe in global warming, or don't think it's caused by humans; while 59% don't think there's a scientific consensus, and 37% actually think global warming is a giant hoax. So, whether global warming is real or not, there's a huge gap between what scientists believe and what the public believes.

One of the most commons reasons for denying global warming was stated unusually plainly the other day by Rush Limbaugh: "See, in my humble opinion, folks, if you believe in God, then intellectually you cannot believe in manmade global warming … You must be either agnostic or atheistic to believe that man controls something that he can’t create."

Obviously that isn't true; lots of people who believe in God can and do believe in global warming. And we clearly affect many things we didn't create. We didn't create the passenger pigeon or the dodo, but we sure did kill them off. So, Rush's statement is demonstrably wrong. But doesn't mean his views are uncommon. I suspect a lot of religious conservatives use a similar thought process: God is in charge, and He will determine the ultimate fate of the earth and humankind. Many literal-minded Christian conservatives believe the world will end as described in the book of Revelation, and perhaps soon, so worrying about other potential catastrophes is silly (many seem to look forward to it, which scares me more than anything in the whole world.) Others believe mere humans couldn't significantly alter what God created, so things like global warming can't possibly be real.

Others deny global warming for different reasons. One is just plain old wishful thinking--I don't want it to be true, therefore it isn't. Another common reason, I think, is that global warming conflicts with free market ideals. Those who believe that free markets can solve most of the worlds problems don't like to think a major global issue could arise despite free markets, or even because of them. The much-lauded Invisible Hand of the marketplace isn't supposed to turn around and slap us. I suspect that's what motivates most libertarians who deny global warming, since they don't tend to be especially religious, and they don't usually deny other well-established scientific theories. Conservatives may be motivated by both the religious and the free-market arguments. I think those are the main ideological reasons for denial in the United States, but in other places people surely deny it for other reasons. I imagine there are Marxists who deny it because it would conflict with the vision of the inevitable triumph of socialism.

In any case, the main point here is that these opinions are motivated by ideology. Why else would people oppose global warming more than other modern scientific theories, like plate tectonics or the expansion of the universe? Why single out global warming? Because it conflicts with a pre-existing ideology, that's why. Non-scientists who deny global warming rarely do so after unbiased, careful consideration of the evidence. Instead, they begin with a conclusion--global warming is not real--and then look for arguments to support that conclusion. And those arguments seem convincing, at least to people who want to believe them and don't want to look for contradictory evidence. It's confirmation bias in action--seek out arguments that support what you already believe, and disregard those that don't.

That's the opposite of how science works. Science, at least in theory, proceeds by observing the world, noticing certain patterns, and then formulating hypotheses to explain those patterns. Then the hypotheses are tested, and if they fail, they are (eventually) discarded. The ones the scientists can't knock down are the ones they keep. Of course, scientists are only human, so in the real world it's messier than that. But the process still works amazingly well--well enough to give us the know-how to land a robot car on Mars and eradicate smallpox, to give just two examples.

Science is an astoundingly powerful method for understanding the world, and the people who use it to study climate have concluded that global warming is real and caused by humans. And here's the thing: they don't believe that because of some ideology they already had. They believe it because they realized how much carbon we're pumping into the atmosphere, wondered if it might warm the planet, and then started trying to figure out if it really does. And the answer most of them have come to is, "Yes, almost certainly." A few have taken an honest look at the evidence, and remain undecided, or even skeptical. That's fine--science couldn't function without honest dissenters, because sometimes they turn out to be right. I don't have any beef with them unless they're skeptical because of some other ideology. Then they aren't really doing science.

As for myself, I also believe in global warming, but not for the same reasons most climate scientists do. I understand the theory fairly well, but I can't honestly say I've mastered it, looked at all the evidence, and drawn an honest, educated conclusion. I've done that with simpler theories, like the theory of evolution (whose fundamental ideas really are very simple). But climatology is an unbelievably complex field, with all kinds of variables interacting in complex, counter-intuitive ways. I would have to immerse myself in it for months to have a truly informed opinion. So I go with what the majority of scientists think. I have enough faith in the process of science, with its checks and balances, to think that's a good bet. And like most scientists, I don't have any ideological dog in the fight already. In fact, I would much rather believe global warming isn't happening. But I simply can't help thinking it is. What I wish were true has absolutely no bearing on what is true.

I'm not saying people should or shouldn't believe in global warming. I'm just saying they should try to step back from whatever ideology they have and take the time to actually understand the theory--and the level of support it has among scientists--before rejecting it. Is that so crazy? A whole lot of people who reject it do so without coming close to understanding it. I know that because when the subject of global warming comes up, I've seen lots of people deny it...and then start talking about holes in the ozone layer. That's a completely different issue. Anyone who confuses global warming with ozone depletion hasn't understood either issue, and has no business making pronouncements about them. Most global warming skeptics I've talked to either reject it out of hand, without doing any research, or Google it and find a few reasons to deny it, without ever really understanding what the theory says.

That's a huge problem, because there's a whole lot riding on the theory. It has enormous bearing on the future of the whole planet. It's too important for knee-jerk reactions based on wishes or ideology. And it's not the only issue like that. There are all kinds of ways we could wreck the planet, and therefore wreck human civilization. It's not just global warming. In the last 60 years or so, humans have become fully capable of devastating, and possibly even ending, life on Earth. We could do it with nuclear weapons, or uncontrolled population growth, or runaway global warming, or any number of other screw-ups we only dream about now. This isn't hyperbole. This is realism. We're numerous enough and we're powerful enough to do it. As a species, we're like a child who's just found a stick of dynamite and a box of matches. We've suddenly gained a whole lot of power, but not the wisdom to control it.

We really are living in a uniquely dangerous period in human history; one in which our potential global impact has suddenly become explosive. If you don't believe that, I invite you to take a look at the graph below, which plots the human population over the last 12,000 years. Population isn't the only thing that has suddenly gone exponential. The growth in computing speed, scientific knowledge, and potential human impacts on nature are following similar curves. We're living in an age of explosions, and if we don't learn to control them, we will blow ourselves to bits.

My main point in this post, then, is not about global warming. It's about the idea that catastrophic human impacts are impossible. That's probably the most dangerous notion I've ever heard of. It leads to apathy, overconfidence, and outright hubris in the face of very real problems. This idea--that God or the marketplace won't let us wreck the world--could wreck the world. It really could. Global catastrophes have happened before in Earth's history (just look up "mass extinctions"), and there's no reason to think they couldn't happen again. It's just that now we've become the most likely cause of the next catastrophe. As Pogo famously said, "We have met the enemy, and he is us." We no longer have the luxury of wishful thinking and comforting ideologies. We've got to learn to pay attention to what's really true, not what we think should be true, so our opinions don't put us on a collision course with reality.

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The Climate Is Set to Change 'Orders of Magnitude' Faster Than at Any Other Time in the Past 65 Million Years - The Atlantic Monthy

Climate change: A guide for the perplexed - New Scientist (has a great list of common objections to global warming, and their rebuttals)

http://climate.nasa.gov/scientific-consensus

http://en.wikipedia.org/wiki/Public_opinion_on_climate_change

http://en.wikipedia.org/wiki/Scientific_consensus

Myths, Morals, and Facts

Once when I was having dinner at a friend's house, he showed me an antique steamer trunk he had just bought. "You know," he said, "The word 'posh' originated as a label on trunks like this. It was an acronym for 'Port Out, Starboard Home'. Wealthy people had P.O.S.H. printed on their trunks to tell the luggage carriers where to put them on the ship, so it turned into a word about wealth and luxury."

I thought that was a great bit of trivia, and I told people about it every time I heard the word "posh." Not long ago, I heard someone talking about a "posh" home. Hearing my cue, I started telling my story about the word's origin. "Wait a minute." he interrupted, "Are you going to tell me about labels on trunks? You know that's just a myth, right?" Sure enough, I consulted a dictionary and it said "Posh" originated as a slang term for a dandy or fastidious dresser, and that the story about steamer trunks is not true. It is indeed a myth, and I had been passing it along.

That kind of myth is all too common in the modern world. A lot of historical "facts" are really just stories or images that get passed on because they're interesting, even though they aren't true. Marie Antoinette, for instance, never said "Let them eat cake." Her opponents made up the story to stir opposition against her. Vikings never wore horned helmets--some artist drew a picture of burly guy with a horned helmet, and the image stuck. Educated people in Columbus' time didn't think the world was flat. Humphry Bogart never said "Play it again, Sam". And of course, we've all heard the urban myths about dogs choking on severed fingers or people getting cooked in tanning beds. What these images and stories have in common is that they strike chords in our imaginations. We find them fascinating for some reason, whether it's shear morbidness in the case of urban myths, or vividness, like the image of blond warriors with horned helmets. Their appeal outweighs the fact that they aren't actually true, so they get passed on.

Looking up the history of the word "posh", with its real and its mythical origin, I started thinking about the word "myth" itself. People often refer to common misconceptions, like the ones above, as myths. This sense of the word--an appealing and common, but false, story or idea--is different than the other sense of the word; of myth as in mythology. Mythology is myth in the sense of powerful stories of heroes, deities, and the creation and destruction of worlds. There are similarities between the two kinds of myth. Both are perpetuated because of their human appeal, and neither are literally true, at least not entirely. But when we talk about myths in the sense of "mythology", we're not focusing on their falsehood.

We don't study mythology to make fun of the misguided notions of ancient or pre-scientific peoples. We study it because of the power of the myths, and the insights they give us into the common themes of the human imagination; themes of heroes, quests, gods and goddesses, monsters, doomed lovers, and natural disasters, all of which show up around the world. Myths reflect the deepest fascinations and concerns of a culture. They aren't often thought about this way, but I think they evolved, in a way that's analogous, though not identical, to biological evolution. Like species, myths evolved through a process of variation and selective retention. Variation occurred when storytellers would forget parts of a story, or add new twists. Selection was based on how well these variations resonated with the people that heard them. If they were found meaningful and appealing they stuck; they were passed on. This is surely one reason mythology can be so powerful. Myths have evolved to reflect people's deepest curiosities, fascinations, and fears.

Mythology is a fascinating part of the history of human ideas, because it represents the most ancient way cultures interpret the world. Originally, people didn't distinguish literal, emotional, ethical, and aesthetic truth. Pre-scientific mythology was an all-purpose worldview. Myths combined explanations of natural phenomena with religious or ethical lessons, in the form of vivid, memorable stories. In the absence of modern scientific instruments, literal truth was often unattainable anyway. So, the more meaningful or vivid the story, the better. For example, theres an ancient Hindu myth about the primal divinity Purusha. Purusha is the first being, and has no gender at the time. Feeling all alone in the universe, Purusha swells up and splits in two, becoming a man and a woman. They desire each other because they had originally been two halves of one being, but the woman fears it would be incestuous for them to mate (incest is a common mythological theme, since mythic first people are usually related). She tries to hide from him by turning herself into a series of animals, but he follows her. When she turns into a cow, he becomes a bull, and they mate and have offspring. He continues to pursue her, and they reproduce as every animal in turn, thus creating all of the animals on earth.

This story clearly serves many purposes. First, it's beautiful and memorable. It also offers explanations for facts about the world, including the existence of men and women, their mutual attraction, and the origin of the animals. It has an ethical component--the taboo against incest. Myths, then, formed the ideological, explanatory, and poetic background by which primal cultures defined themselves. This kind of worldview had its advantages. Because myths combined artistic, explanatory, and ethical ideas, there was little fragmentation of belief. The entire culture shared the same myths, which gave everyone a common understanding of where they came from, who their gods or spirits were, and how they should act. The only problem was that most myths were not literally true.

In the modern world, we find ourselves in the opposite situation. We have access to all kinds of factual truth (if we can track it down amidst all the nonsense). We now know the sun is a giant nuclear fusion reaction, not Apollo racing his chariot across the sky. Today we have theories about the natural world that are demonstrably more coherent and accurate than the old mythological explanations, so myth has come to be equated with falsehood. The problem is that people no longer share a coherent, poetic view of the world. Our beliefs have become fragmented into compartmentalized disciplines and rival camps. We've attained a great deal of literal truth, but we've lost a worldview.

That's a problem, but I think it's is a necessary step toward a better situation. We can no longer, in good conscience, believe things simply because they're poetic or traditional. We know too much. to the extent that ethical, artistic, and scientific ideas don't overlap in the real world, we need to disentangle them. Mythology is good literature, but it isn't good science. Science is good for describing nature, but it leaves many ethical questions unanswered. We need to differentiate these realms of human inquiry because they have different aims and serve different purposes.

But we can't simply pull them apart and leave it at that. These distinct realms of meaning aren't completely separate. Sometimes they do overlap. For example, our idea of factual truth has ethical implications, because believing something that isn't true can cause ethical mistakes. In many myths, including the one about Adam and Eve in the Bible, there's a theme where men were created first, and women were later, almost as an afterthought. Science offers no evidence for this. If we make the factual mistake that men are primary, we're more likely to make the ethical mistake of treating women as secondary. So, we have to perform a balancing act. We have to differentiate the areas of knowledge--mythology should not be mistaken for science--but then we need to integrate them, to see where they do connect, and how they fit together. Ethics, for example, can be informed by science (and vice versa). To move beyond fragmentation, we have to fit the various realms together, without letting them collapse back upon each other.

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I wrote the first version of this about ten years ago. Here's that version in its original context. http://www.knowledgetreeproject.org/treeknowledgechaptview.htm

The Purusha story in the Upanishads

Touring Orion: Astronomy and the Depth of Wonder

When I heard the learn’d astronomer,

When the proofs, the figures, were ranged in columns before me,

When I was shown the charts and diagrams, to add, divide, and measure them,

When I sitting heard the astronomer where he lectured with much applause in the lecture-room,

How soon unaccountable I became tired and sick,

Till rising and gliding out I wander’d off by myself,

In the mystical moist night-air, and from time to time,

Look’d up in perfect silence at the stars.

- Walt Whitman, When I Heard the Learn'd Astronomer

People look at you funny when you talk about outer space. The artists and poets think you're too cold and analytical, and others think you're a nerdy space cadet who should come down to earth. People think pondering the depths of space just isn't cool. But, then, people can be pretty silly. And as much as I love Walt Whitman, he was being a little silly, too. His mistake in the poem above was thinking we have to choose between science and the experience of gazing in awe at the night sky. It's a false dichotomy. You can have both at the same time, if you just decide your mind is big enough to hold them both. Besides, science can make the experience of looking up at a night sky all the more awe-inspiring, by telling you just how ancient and far away those stars really are.

So, if you're one of those people who think space is either too square or too dorky, I'd like to try to convince you otherwise.

First, let's just walk out and take a look at the night sky, like Mr. Whitman did. Imagine that we're walking out in the early spring, to see something like the image below. There's the Milky Way arched across the sky, and Orion the hunter with his bow outstretched. The little cluster of stars on the right is the Pleiades, and the bright star on the left is Sirius, the Dog Star.  Between Orion and the Pleiades is Jupiter, which is not a star at all, but the biggest planet in the solar system. If you had a pair of binoculars, you could look up and see four of it's moons. It's the first warm night of the year, and the frogs are singing off in the distance. Altogether, it's a glorious, overwhelming experience.

But what if we could look deeper? What if we could take a closer look at those distant worlds, and see them as more than just points of light? Well, we can, at least in our imaginations. And the reason we can is all those learn'd astronomers with their charts and figures, which helped them figure out so much about what's really going on out there.

So let's take an imaginary trip, straight into Orion and beyond, to see how much deeper the sky is than we can see with our naked eyes. First, let's consult a map to see where we're going. Here's our itinerary:

The trip seems to jump around so much because we're starting with the closest objects, and making our way toward the most distant ones. We're going to start with Jupiter, and then go deeper and deeper into space, in the general direction of Orion. I'm not going to dwell on the planets much, because most people learned those in school pretty well. What most people don't know is how things are arranged out beyond the solar system. That's where we're headed, but we'll stop at Jupiter, since it's on the way.

Jupiter is the first and largest of the gas giant planets out beyond Mars and the asteroid belt. It's not a solid object, except at its rocky core. Its famous bands are formed by rising and falling clouds of ammonia ice and ammonium hydrosulfide. Jupiter is the big boy of the solar system--over 1400 Earths would fit inside it, and it's twice as massive as all the other planets combined.

But Jupiter is a pipsqueak compared to the sun, which is over 1000 times as massive. Really, the planets are just bits of detritus around the sun, and even the sun isn't that impressive by astronomical standards. This becomes obvious if we look backward and remove the constellation lines, to see the inner solar system as it would really look from Jupiter. The sun just looks like an unusually bright yellow star from here, and we wouldn't even recognize the inner planets--including our own--if they weren't labeled. But then, we've come a long way, by our normal standards. To put the distance to Jupiter in perspective, if you could point your car there and start driving at a steady 75 miles per hour, it would take several hundred years to get there. You would need to bring a lot of music.

But we've barely gotten started. Our next stop is Sirius, which is 8.6 light years away--a whole different level of far away. A beam of light, which can goes fast enough to circle the world over 7 times a second, would take 8.6 years to get to Sirius. And Sirius is one of the closest stars to Earth. If the Voyager 1 spacecraft, which has just reached the edge our solar system after 35 years, were heading for Sirius, it would take about 180,000 years to arrive. Travel to the stars is still pure science fiction.

Luckily, we're taking an imaginary trip, so we can get to Sirius in no time at all. As we approach, we see the single point of blue-white light resolve into two stars. It turns out Sirius is a binary star system, with two stars orbiting a common center of mass. The bigger one, Sirius A, is about twice as massive as our sun, but it's much hotter, and thus 25 times as bright. Sirius B is an entirely different story. It's a white dwarf star, slightly smaller than the earth, but more massive than the sun. In other words, it's astoundingly dense--a piece of it the size of a sugar cube would weigh about a ton. Try dropping that in your coffee.

White dwarfs like Sirius B are the shrunken cores of larger, deceased stars. Around 120 million years ago, Sirius B resembled Sirius A, but it became unstable as it used up all its fuel. This caused it to swell up into a huge red giant star, and eventually puff its outer layers of gas into space, creating a luminous nebula which has long since dispersed. All that remained was the hot, tiny core, which will burn with stored heat for billions of years to come, until it finally cools down into cold, dark object called a black dwarf.

The next leg of the trip is a big one. We're going to the Pleiades, or Seven Sisters, a group of stars at least 390 light years from Earth. That means the light we now see on earth when we look at them has been traveling through space since around the time the Mayflower landed. Unlike most constellations, the Pleiades are an actual group of stars, called an open cluster. But I like to think of them as a litter, because they are siblings--born together in a giant cloud of collapsing gas. The bright blue stars we see are blue giants, which are bigger, hotter, and far brighter than most of the other 1000 or so stars in the cluster. Blue giants are like rock stars, living hard and dying young, burning through their fuel at a furious pace. Some of the ones in the Pleiades are already showing their age, and they're a mere 100 million years old. The smaller yellow and red stars take the slow and steady approach. They will live on for billions of years, some of them for many times the current age of the universe.

Rogelio Bernal Andreo (Creative Commons Att. Share Alike)

Now it's time to head for Orion itself. First, let's take another, closer look at Orion as it appears from earth.  The amazing photo to the right is a long-exposure mosaic showing the clouds of gas and dust that fill the constellation. The red clouds, called emission nebula, glow because they're heated up by the stars forming in and around them. If you look closely, you can see darker clouds too, which show themselves by blocking the stars behind them. The Orion region is one of the most active regions of star formation known. In fact, some of the stars visible around Orion's belt and sword were born together out of those clouds. It's unusual for the stars in a constellation to be related, but many of the stars in Orion are, possibly including the next two we're going to meet.

Our next stop is Betelgeuse, the enormous red supergiant that defines Orion's left shoulder. When I say Betelgeuse is enormous, I mean it's really just stupendously huge. If the center of Betelgeuse were where our sun is, it would swallow all the planets up through Mars, and come nearly to the orbit of Jupiter. But Betelgeuse is nearing the end of its life, and it's really starting to fall apart. It roils and pulsates, belching plumes of gas as large as our solar system. In about a million years, it will collapse and then explode as a supernova. Anyone still around on earth will see it shine as bright as the moon for a few weeks, even though it's 640 light years away.

The brilliant blue star that forms Orion's right foot is called Rigel. It's a young blue supergiant star, around 8 million years old. It's no small fry itself. If the sun were the size of a BB, Rigel would be about the width of a beach ball. It's not nearly as big as Betelgeuse, but it's big. It's also tremendously bright--at least 117,000 times as bright as the sun. Its brilliance caused partly by its size, but mostly by its intense heat (with stars, size is not nearly as important as heat). Rigel's brilliance is the reason we see it so clearly, even though it's about 860 light years away, and the light we see left it around the time Genghis Khan was born.

If you walk out on a clear night and look up at Orion, the middle of his sword is actually not a star at all, but a glowing red cloud called the Orion Nebula. It's one of the most spectacular star formation sites known, so let's go take a closer look. As we approach the nebula, about 1,344 light years from earth, we see that it's really a bright cavity in a more extensive cloud. It's like an amphitheater full of thousands of stars. The brightest, as usual, are blue giants and supergiants, but there are stars of all other sizes and temperatures being born too. Some are still wrapped in discs of dusty debris which will one day aggregate into planets. Others are in the so-called bipolar outflow stage, with great jets of gas shooting out from each pole. Astronomers have even seen brown dwarfs, balls of gas too small for fusion reactions to ignite, so they never quite turn into stars. If we could look into the cloud with infrared vision (and astronomers can do just that) we would see even younger stars forming from the dense gas. After they form, stellar winds of radiation will push back and illuminate the gas, deepening the cavity of the Orion Nebula. This, in turn, will cause gas further back in the cloud to collapse toward stardom. Starbirth propagates itself like spreading wildfire, so that as we move deeper and deeper into Orion, we find younger stars. Looking back toward Earth, stars like Rigel and Betelgeuse may be older progeny of the same great cloud across Orion, born in clusters like the stars of the Orion Nebula, but drifting away from their siblings over millions of years.

We've gone straight through the heart of Orion, and now we're on the other side. Let's keep going, to see what we can see. Our next stop, the Crab Nebula, is many times farther away than anything we've seen so far--6,500 light years. That means we see it as it was about a thousand years before the Sumerians built the world's first cities. The Crab Nebula is a completely different animal than the Orion Nebula. It's what's left over from a supernova explosions in 1054 AD. Chinese astronomers at the time recorded a "guest star", which appeared all the sudden, bright enough to be seen in the daytime. What we see today is a cloud of glowing gas 11 light years across, and still expanding at about 1,500 kilometers per second. Yes, per second. At the center of the cloud is the leftover core of the old star. When the core collapsed and then rebounded, the pressure was so great that it collapsed protons and electrons into neutrons, forming a ball of neutrons as dense as an atomic nucleus, but as large as a city. It's still spinning about 30 times a second, pouring radiation out from each magnetic pole. We see this radiation as rapid-fire pulses, so this kind of neutron star is also known as a pulsar. It's hard to believe anything this extreme really exist out there, but nature is full of surprises.

In the long history of the Milky Way galaxy, there have been countless supernova explosions like the one that created the Crab Nebula. In fact, we owe our existence to them. When the universe was born in the Big Bang, the only elements that existed were hydrogen, helium, and traces of lithium. Then, when the first stars lit up, they burned by fusing hydrogen and helium into heavier elements, creating the rest of the periodic table--the atomic alphabet that makes life possible. All stars create a few heavier elements, but some of the most crucial elements for life, including sulfur, sodium, and potassium, are created in supernova explosions. We are, quite literally, made of stardust--stardust blasted into space in some of the most violent explosions in the universe. It's a pretty amazing heritage, and we share it with everything in the solar system.

Maybe we've come far enough for now. We're over 6,500 light years from home, farther than light could have traveled in all of written history. But just how far is that, in the grand scheme of things? Not very. In the picture below, the yellow line shows roughly where we have been so far. Except for the Crab Nebula, which is in the Perseus Arm of the Milky Way, everything we saw on our tour was in the little sub-arm of the galaxy known as the Orion Spur.

The galaxy as a whole is over 100 thousand light years across, and it contains at least 200 billion stars--more than you could count in several lifetimes. We've only seen a tiny section of it, and then only in our imaginations. A real trip like this is still completely beyond our grasp, and will be for the foreseeable future. And the Milky Way is just one galaxy; part of a small group of galaxies on the edge of a giant cluster that contains thousands of others, in a universe that contains untold numbers of such clusters. We could keep on traveling outward, to see where our galaxy fits in with others, but we've surely gone far enough for now. 

Now, here's the question. If you walk out one night and look up at Orion, does the tour we just took make  looking up at a night sky somehow less amazing? I don't see how it could. For me, it just makes a great thing that much greater, showing us wonders we never could have imagined if learn'd astronomers hadn't made all those charts and figures.

More Things in Heaven and Earth: Thoughts on Openmindedness and Skepticism

Like most people, I like a good quotation, and I have several favorites. A good, pithy observation can stick in my head for years. Some stick because they make me say, "Yes! Exactly! That's just how I would have said it if I were clever enough." Others stick because they bother me.  That happens when I can't quite decide what I think about them, but I'm pretty sure the answer is important.

One of these bothersome quotations is from Hamlet:

There are more things in heaven and earth, Horatio, than are dreamt of in your philosophy.

The context here is that Hamlet has been having a chat with his father's ghost. The ghost vanishes, and Hamlet's friends Horatio and Marcellus walk up. Hamlet makes them swear not to reveal his plans to avenge his father's murder. From beneath the grave, the ghost backs him up, saying, "Swear". Horatio, understandably taken aback, says, "O day and night, but this is wondrous strange!" Hamlet replies, "And as a stranger therefore give it welcome. There are more things in heaven and earth, Horatio, than are dreamt of in your philosophy".

I've loved that quote ever since I first heard it. It's a great reminder to be openminded. We live in a great big weird universe, and our little minds have just begun to understand it. There are plenty of things out there that we have no idea about, so we shouldn't get too smug about our theories. Taken that way, Hamlet's statement is similar to Newton's reflections about his discoveries: 

I was like a boy playing on the sea-shore, and diverting myself now and then finding a smoother pebble or a prettier shell than ordinary, whilst the great ocean of truth lay all undiscovered before me.

But the Hamlet quotation is commonly used in a different way. It comes up in discussions of astrology, miracles, and yes, ghosts, whenever someone says they are skeptical of those things. Then, the quote is used to tell those people, "Stop being so skeptical! You don't know everything, so how do you know it's not true?" 

I don't know Shakespeare's feelings on such things, but I don't care for that use of his quotation. Yes, we should be intellectually humble and open to the possibility that the universe is full of surprises, but that doesn't mean any particular claim about ghosts, miracles, etc. is true. Maybe there are such things as ghosts and maybe not. I doubt it, but if I ever saw enough evidence that they existed--evidence that couldn't be debunked as a hoax by skeptics--then I would have to conclude that they exist. The point is that to say "the world is full of unexpected things, therefore this particular unexpected thing is real" is fallacious reasoning. 

Open-mindedness is a virtue, but only to a degree. Which brings me to another saying that comes up often in these discussions, but not often enough: 

I believe in an open mind, but not so open that your brains fall out. 

I say it's a saying, and not a quotation, because no particular person seems to have said this exact thing. It's often attributed to Arthur Hays Sulzberger, longtime publisher of the New York Times, but it may predate him. Like many common "quotations", it's probably evolved into a more streamlined and memorable phrase over time (the Newton quote above often takes a shorter form, for example). 

Wherever it came from, it's a good thing to remember. We live in a big, complex, hard-to-understand world, and there are plenty of hucksters and charlatans in it, trying to get us to do what they want and buy what they are selling. It doesn't do to be open-minded to the point of gullibility. Truth doesn't come easy, and there are a lot more false claims than true ones. As P.T. Barnum, one of the great hucksters in history, said:

There's a sucker born every minute.

I don't know about you, but I don't want to be a sucker. What's needed, I think, is a balance between openmindedess and skepticism. As I've said elsewhere in this blog, those things can be seen as two sides of the same coin: an attitude of not clinging too tightly to any idea, whether you currently believe it or not. If you're willing to consider--or abandon--any idea according to its merits, then you are both openminded and skeptical. They aren't mutually exclusive. At their best, they are mutually necessary.

I've been saying this for years, but I've recently remembered where I got the idea: from a book by Carl Sagan called The Demon Haunted World: Science as a Candle in the Dark. Here's an extended quote, where he explains the essential balance we need to strike:

what is called for is an exquisite balance between two conflicting needs: the most skeptical scrutiny of all hypotheses that are served up to us and at the same time a great openness to new ideas. Obviously those two modes of thought are in some tension. But if you are able to exercise only one of these modes, whichever one it is, you’re in deep trouble. If you are only skeptical, then no new ideas make it through to you. You never learn anything new. You become a crotchety old person convinced that nonsense is ruling the world. (There is, of course, much data to support you.) But every now and then, maybe once in a hundred cases, a new idea turns out to be on the mark, valid and wonderful. If you are too much in the habit of being skeptical about everything, you are going to miss or resent it, and either way you will be standing in the way of understanding and progress. On the other hand, if you are open to the point of gullibility and have not an ounce of skeptical sense in you, then you cannot distinguish the useful as from the worthless ones. If all ideas have equal validity then you are lost, because then, it seems to me, no ideas have any validity at all. Some ideas are better than others. The machinery for distinguishing them is an essential tool in dealing with the world and especially in dealing with the future. And it is precisely the mix of these two modes of thought that is central to the success of science.

This balance is certainly central to science, but I think (and I think Sagan would have agreed) that it has an even wider reach than that. It also works when trying to think about any idea, to try to determine whether it's true or at least useful. 

There's another balance that has to be struck, though, when it comes to skepticism--the balance between skepticism and cynicism. Contrary to popular belief, the two aren't the same. Skepticism is a probing, realistic view of the world, whereas cynicism is an overly-negative view. A cynic thinks the world is nastier than it really is. Still, it's easy to slip from skepticism into cynicism if you're not careful. Realism, for one thing, can be depressing. There's no guarantee that skepticism will make you feel better about the world. It's easy to come up with all kinds of false, but comforting, ideas about how the things are. In fact, comfort seems to be a more popular criteria for judging ideas than evidence or truth. Studies have shown that depressed people are more realistic about some things (how well other people like them, for example) than happy people. That's a depressing fact in itself, huh? If you stay skeptical all the time, a lot of the things people do can start to seem a little nonsensical--arbitrary at best and farcical at worst. That happens to me sometimes, and it is a little depressing.

The trick, I think, is to remember two things (though I don't always remember them). First, focusing on negativity doesn't do anybody any good (unless you're trying to change something negative, and then it's still more effective to stay as upbeat as possible). Winston Churchill has a good quote here, as he so often does: 

I am an optimist. It does not seem to be much use being anything else.

Optimism here doesn't mean self-delusion, or turning a blind eye to injustice. It just means remembering the good and the hopeful, while staying mindful of the bad. That's the second thing to remember: to pay attention to the good things. Sure, this world is full of nasty stuff, from dishonest politicians, to wars, to brain-eating amoebas. But it's full of a lot of love and goodness and beauty, too, and remembering that is the way to keep from slipping into cynicism. It's possible to be skeptical while still maintaining a sense of awe and humility, and a respect for beauty and goodness. If that hackneyed word "spirituality" means anything to a skeptic, it means that kind of attitude. Unlike some smaller-minded skeptics, Carl Sagan respected spirituality in that sense. The older I get, the more I'm amazed by Sagan's intellect and elequence, so I think I'll end with another quotation from him. Once again, he's talking about science in particular here, but there's no reason it shouldn't apply to the search for truth in general.

Science is not only compatible with spirituality; it is a profound source of spirituality. When we recognize our place in an immensity of light‐years and in the passage of ages, when we grasp the intricacy, beauty, and subtlety of life, then that soaring feeling, that sense of elation and humility combined, is surely spiritual. So are our emotions in the presence of great art or music or literature, or acts of exemplary selfless courage such as those of Mohandas Gandhi or Martin Luther King, Jr. The notion that science and spirituality are somehow mutually exclusive does a disservice to both.

What Is and What Ought to Be: Speaking Freely About the Big Questions

Sometimes I think all serious questions in life are just variations of two basic Big Questions. Big Question One is "What is true?" and Big Question Two is, "What is good or right?" Put another way, the Big Questions are: 1. What is? 2. What ought to be? For years, I was more interested in Big Question One. I wanted to figure out the basic facts about what reality was like, so I read all about science, history, and other fact-oriented fields. I even tried to write a humongous book attempting to tie the most important facts together in a coherent narrative. Nobody wanted to read it, of course, but I put it online just in case.

After all that time pondering Big Question One, it ocurred to me that I had mostly forgotten to consider a whole other dimension of life; Big Question Two. So, in the last couple of years I've gotten fascinated by the second Big Question, and thought a lot about the foundations of morality and ethics. I want to know what determines what's good and bad, and what's right or wrong. On what basis can we decide how to behave, and how to treat others? This blog has mostly turned into an exploration of those questions.

With both Big Questions, however, if you want to think and write about them, and discuss them with other people (and that is essential) then before long you'll run smack into religion, and then things get touchy. In this country, a majority of people try to answer one or both questions by turning to their Christian faith. Of course, Christianity is diverse, and the Bible is big, complex, and subject to a wide range of interpretations, so different Christians answer those questions in a different ways. Some think we were literally created in God's image sometime in the last few thousand years, while others think scientists are basically right about evolution and the age of the universe, but still think God's ultimately in charge. Some Christians think homosexuality--to take a currently contentious example--is wrong because of things the Bible says, while others think the negative passages about homosexuality should be dismissed as belonging to an ancient, pre-scientific, and rather cruel culture.

Since I live in a country with a large Christian majority, if I want to write openly and honestly about the Big Questions that interest me, I can't avoid discussing the traditional Christian answers to those questions. That's why I end up talking about religion a lot in this blog. I'm interested in morality, which is bound up with religion in most people's minds, and in science, which is often at odds with religion, at least when it comes to more literalist branches of Christianity. In both cases, I usually disagree with the conservative Christian interpretations of these things, and sometimes even the liberal Christian interpretations.

And these aren't trivial disagreements, like disagreeing about whether licorice tastes good or not (it doesn't--it's gross). These are disagreements about things that matter. It matters that people think gay people shouldn't be able to marry, or that global warming can't happen, because of their interpretation of the Bible. Those beliefs determine their actions, and their actions affect others. So I find myself at odds with conservative Christianity a lot of the time, even though I respect some conservative Christians a great deal (I'm planning to blog about the respect issue soon). 

Another reason I talk about religion a lot is that I think it's important for people in a country with freedom of speech to actually speak freely, so I've been much more open lately about being non-religious. These are Big Questions, after all. The answers are important; important enough that if I think some of the dominant religious answers are wrong, and even harmful, then I can't just keep my mouth shut about it for fear of offending the religious. To do so, I think, would be immoral. Which brings me to my next post.

The Two Creations: Why Genesis Can't be Taken Literally

In the last few months I've found myself doing something I swore off years ago: arguing with creationists. I had stopped because I realized you can't convince most of them that evolution is true, no matter how good you think your arguments are, or how much evidence you offer them. The problem is that creationism and science proceed in entirely different directions. Creationism takes it on faith that Genesis is literally true, and then (sometimes) seeks to find arguments that support that claim. Science (ideally) looks at nature, and then proposes theories that seem to explain it. If the theory seems to match the evidence, it's retained. If it doesn't, it's discarded.

So, with creationism, belief comes before evidence, while in science, evidence comes before belief. Darwin didn't start with a belief in evolution, and then set out to prove it. He observed the natural world, and then proposed a theory that seemed to explain it. Creationism values faith above all, while science values empirical evidence above all. That's why debating a creationist is like playing basketball with someone who refuses to count your baskets, and insists they've already won no matter how well you play. They've made up their minds that Genesis is literally true, so they aren't particularly interested in hearing reasons it might not be. I'm no Galileo, but it always makes me think about how he must have felt when people refused to even look through his telescope.

In other words, it's absolutely maddening, so I had given up the creation/evolution debate. For years, the topic rarely came up, because I wasn't around many people who liked to discuss it, and the ones who did took creationism no more seriously than Norse mythology. Honestly, I had forgotten how many Americans are biblical literalists who believe Genesis is fact, not parable or myth. Then came Facebook, which put me back in touch with old friends and family members, and gave me a window into their thoughts. They are good, funny, smart people, most of them—and an astounding number of them believe the Earth is just a few thousand years old. I was shocked by that, and they were shocked by me. Creationism and biblical literalism are certainly not uncommon. Gallup polls show that nearly 50% of people in the US think "God created humans in their present form at one time within the last 10,000 years."  Around 30% of people in the US agree with the statement  that "the Bible is the actual word of God, and is to be taken literally, word for word."

The difference between mainstream scientific views and young earth creationism is a huge one. If the earth is really 4.56 billion years old, and creationists think it's 6 to 10 thousand years old, that's equivalent to saying Texas is ten feet across. If mainstream science is right, then creationists aren't just a little bit wrong. They're outrageously, spectacularly wrong. From my perspective, hearing someone say the earth is a few thousand years old is just about as bewildering, and admittedly frustrating, as hearing someone insist that Texas is the width of a mobile home.

Anyway, I found myself in the creation/evolution debate again, but I soon remembered why I had stopped. There's no point in trying to convince creationists using scientific evidence. They're playing a different game; a game based on faith. So I decided to try to understand where they're coming from, and take another look at the creation story in Genesis.

And a fascinating story it is. One surprising thing is how short it is. In my New Oxford Annotated Bible, it's only a little over 5 pages from “In the beginning” to the expulsion of Adam and Eve from the Garden of Eden—and half of those pages are footnotes. Another surprising thing is that there isn't just one creation story. There are two, and they are very different. I had always heard this, but it's amazing to read them and see just how different they are.

The first (Genesis 1:1 through 2:3) is the one that describes the creation of the world in six days, and God resting on the seventh. In this version, the original Hebrew text calls God “Elohim”; which is basically a generic name for “god” or “deity”. The second narrative (Genesis 2:4 through 25) refers to God as Yahweh in the original Hebrew. If I understand it correctly, Yahweh is the personal name of this particular god (apparently, the early Hebrews believed in many gods, but came to worship the one named Yahweh exclusively. Only later did they come to believe there were no other gods). The name Yahweh is rendered in many Bibles as “the LORD”.

Before I get into what the two narratives say, a little background on Genesis as a whole might be useful. Genesis, of course, is the first book in the Old Testament. It describes the creation of the world, the fall of Adam and Eve, the Flood, the Tower of Babel, and the lives of Abraham, Isaac, Jacob, and Joseph—the lineage thought to give rise to the Jews. Genesis is the first of the five books traditionally thought to have been dictated by God to Moses: Genesis, Exodus, Leviticus, Numbers, and Deuteronomy. Jews call these five books the Torah, and Christians call them the Pentateuch. In the late Renaissance, when the risk of being killed or imprisoned for heresy began to decline, people started pointing out that the Torah/Pentateuch, like the rest of the Bible, gives the distinct impression of having been written by more than one person, in more than one style. In the 1800's, the German scholar Julius Wellhausen proposed that the first five books of the Bible were composed by four different people (or groups of people) who he called J (for Jahweh, German for Yahweh, because this is what J calls God), E (because this source calls God “Elohim”), P (for Priestly), and D (for Deuteronomist, because this source wrote much of Deuteronomy as well as some later books in the Old Testament). This line of thinking is known as the Documentary Hypothesis. The idea has been hugely influential, though it's become more controversial since the 1970's. Still, the basic idea that the Pentateuch was written by different people at different times is still accepted by all but the most conservative biblical scholars, and clear to anyone who takes a close look at both stories in Genesis.

The First Creation Story

The first creation narrative in the bible is thought to be written by P, the Priestly author (or group of authors). This source depicts God as a distant, all-powerful deity who creates an orderly cosmos from a primeval, watery darkness. He does this with the power of words, beginning with, “Let there be light”. In this narrative, God (Elohim) separates light from darkness on the first day, and names them Day and Night. On the second day, he divides the primordial waters by raising the dome of the sky, which separates the waters below from the waters above the dome. When this text was written, Hebrews thought of the Earth as a flat place surrounded by water. The sky was thought to be an actual, solid dome, and the sun, moon, and stars were lights embedded in the dome. In this narrative, there is water beyond the dome (a disconcerting thought, really). Later, Hebrews adopted the Greek idea that the world is a sphere, surrounded by a series of concentric domes. At the time this narrative was written, the world was not only thought to be the center of the universe, but a flat piece of ground in a dome-shaped bubble between primordial waters. Not even young-earth creationists these days are willing to take Genesis that literally.

On the third day, God creates land and commands it to bring forth plants. On the fourth, he says “Let there be lights in the dome of the sky to separate the day from the night; and let them be for signs and for seasons and for days and years”. Signs were important to the ancient Hebrews, who, like most other ancient people, took it for granted that you could see portents in the motion of the stars. God also creates the sun and moon, “the greater light to rule the day and the lesser light to rule the night”. On the fifth day God creates sea creatures (including “great sea monsters”) and birds. On the sixth day he creates land animals, and then says “Let us make humankind in our image”. This “us” is a puzzler, and it may indicate an ancient belief that God was the head of a heavenly court or counsel. The other members may have also been considered gods early on, but as monotheism evolved they were demoted to angels, cherubim, and such. In this narrative, unlike the next, God seems to create male and female simultaneously. Then he tells them to “Be fruitful and multiply, and fill the earth and subdue it; and have dominion over the fish of the sea and over the birds of the air and over every living thing that moves upon the earth”. He also says he has “given every green plant for food,” implying that all living things were vegetarians at the time. On the seventh day of course, God rested, and “blessed the seventh day and hallowed it.”

The Second Creation Story

The second narrative is very different from the first, and is identified with J in the documentary hypothesis. It's most likely the older of the two stories. J is so-called because the writer refers to God as “Yahweh” ("Jahweh" in German), or “Yahweh Elohim”. Sure enough, Genesis 2.4 begins by saying, “In the day the LORD God [Yahweh Elohim] made the earth and the heavens...”. In this narrative, the earth begins as a place with no rain or vegetation, watered by a stream. Here, God creates humans before he creates plants and animals. Instead of creating him with a word, he takes a more intimate approach: “the LORD God formed man from the dust of the ground, and breathed into his nostrils the breathe of life; and the man became a living being.” This first man is called Adam; a Hebrew word for “humankind”, which is also a play on the word “adamah” or “soil”.

After Adam is created, God plants the Garden of Eden, a beautiful place whose trees include the Tree of Life and the Tree of Knowledge of Good and Evil. God tells Adam he may eat fruit from every tree except the tree of knowledge of good and evil, “for in the day that you eat of it you shall die”. Only then, in this narrative, does God create the animals, letting Adam name each one. None of these are a fit “helper” or “partner” for Adam, though, so God makes Adam go to sleep, removes one of his ribs, and creates the first woman from it (some people to this day believe that men have one less rib than women).

The next part of the story is well known. The first couple is naked and unashamed at first, because they don't know the difference between good and evil. But a serpent (who really is just a serpent, and wasn't identified with the devil until later Christian thought) convinces the woman (she still doesn't have a name) that she won't really die if she eats from the tree of knowledge of good and evil. He's right—she eats it, and gives some to Adam. They don't die, but they do realize they are naked, and scramble for the nearest fig leaves. Then they hear God walking through the garden “at the time of the evening breeze” (the author of this creation narrative saw God in much more earthly terms than the other author). The people hide from God, because they are naked. God says “Who told you that you were naked? Have you eaten from the tree of which I commanded you not to eat?” Adam fesses up, and God curses him, his wife, and the serpent. He tells the woman he will “greatly increase your pangs in childbearing”, and that her husband will rule over her (Adam soon names her Eve). He tells Adam: “Cursed is the ground because of you; in toil you shall eat of it all the days of your life; thorns and thistles it shall bring forth for you; and you shall eat the plants of the field. By the sweat of your face you shall eat bread until you return to the ground, for out of it you were taken; you are dust, and to dust you shall return.”

Then God says,“See, the man has become like one of us [there's that “us” again], knowing good and evil; and now, he might reach out his hand and take also from the tree of life, and eat, and live forever.” Rather than risk Adam and Eve gaining immortality, he casts them out of the garden, and leaves cherubim with flaming swords to guard the tree of life. Before long, Eve gives birth to Cain (a farmer) and Abel (a herder). God likes Abel's offerings of sheep, but not Cain's offerings of grain, so Cain slays Abel in a fit of jealousy. It's the first of many, many murders in the Bible. Genesis continues with the story of the flood, which is strikingly similar to older Sumerian flood myths, down to the boat, and the bird sent out to look for land.

Biblical scholars call the section of Genesis from the creation to the flood the “primeval history”, because it's a highly mythic story in which serpents talk and people live for hundreds of years. It's not just about the ancestors of the Jews, but of all people. After the flood, people all speak one language, and start cooperating to build the great tower of Babel. God decides once again that people are getting too big for their britches, and “confuses their tongues” and scatters them. The next major character is Abram, who comes from “Ur of the Chaldeans” (a historical city in Mesopotamia). He will soon be renamed Abraham, and will become the ancestor of the Jews.

Should We Take The Creation Stories as the Literal Truth?

I could get into when these two narratives were written, and what the political currents of the time might have been, or whether the Priestly narrative was based in part on the Babylonian story of the great god Marduk creating the universe from the slain corpse of Tiamat, but this post is getting long, and those topics are controversial among scholars. So I'll get back to the reason I'm writing about this. First, I want to understand where my biblical literalist/creationist friends are coming from. Second, I want to investigate the idea that the creation stories in Genesis could be the the infallible word of God, and therefore the absolute, literal truth. I'm not going to discuss the scientific consensus on human origins. I've accepted that creationists aren't impressed by scientific evidence. Rather, I'd like to meet the creationists on their own turf, and take a critical look at Genesis itself. Does it make sense to think of the two creation stories in Genesis as the literal truth?

In a word, no. The two stories were obviously written by different people, and they are completely divergent; even contradictory. The first says plants and animals were created before people. The second says people were created before plants and animals. Which is it? You can believe one is literally true, or that the other is literally true, but you can't logically believe both any more than you can believe a square circle is possible. They can't both be true at once. There are other difficulties, too. It's obvious that the writer of the first narrative thought of the world as flat, and at the center of the universe, and thought that the sky as an actual, solid dome. I don't mean to belittle that author. The earth looks like it's flat, and if you watch the stars turn, it really does look like they're embedded in fixed places in a great cosmic dome that arches over the earth, spinning around the axis of the North Star. The sun and moon really do seem to orbit the earth. So, it's understandable that the author was mistaken, but he was mistaken nonetheless. If you are truly going to take the Genesis creation story literally, then you would have to reject Copernicus as well as Darwin. You would even have to reject Ptolemy, and declare that the world is flat. Hardly anyone believes that these days, of course, and that's a good thing.

Even the most ardent fundamentalist doesn't take the Bible absolutely literally, though he might claim to. You can't take every word of the Bible literally, because it contradicts itself, and some of it, like the idea of the solid dome of the sky, has turned out to be undeniably false. Everybody who follows the Bible has to pick and choose which verses to follow, and which to ignore, otherwise every Christian, Jew, and Muslim today would follow every rule in Leviticus. I've never met anyone who doesn't interpret at least some part of the Bible metaphorically. Once I went camping with an ardent young-earth creationist. We were talking about religion, and I brought up the story in Matthew 19 where a rich young man tells Jesus he has followed the law, and wonders what else he should do to be assured of eternal life. Jesus tells him to sell his possessions and give the money to the poor. The man goes away, dismayed. Jesus then tells his disciples—twice--how hard it is for a rich man to get into heaven: 

“Truly I tell you, it will be hard for a rich person to enter the kingdom of heaven. Again I tell you, it is easier for a camel to go through the eye of a needle then for someone who is rich to enter the kingdom of God.” 

When I asked my creationist acquaintance about this, he started telling me how the “eye of the needle” was really a narrow gate into Jerusalem. Here was a guy who was a literalist when it came to Genesis, but was only too happy to give an uncomfortable saying--from the mouth of Jesus himself--a metaphorical spin. It's true that Jesus did like parables, but there's no evidence for a gate called the "eye of the needle" in Jerusalem, and good reasons to think that this time, Jesus meant exactly what he said. But some people don't want to believe that, any more than they want to believe we came from monkeys.

My point is that nobody is a true biblical literalist, and it's a good thing, because if they were, we would still be acting like an ancient, violent, Iron Age tribe—stoning people to death for things like homosexuality and suspected witchcraft, owning slaves, wiping out rival peoples (like Joshua did at Jericho), and sequestering women in their “unclean” time of the month. Humankind has gotten, well, kinder since then, and less superstitious. At most, stories like the ones in Genesis should be taken as allegories, not seen as literally true. It's not clear that the even the original authors thought they should be taken literally, or they would have tried harder to iron out the inconsistencies. People like Karen Armstrong claim that people then were more comfortable thinking in mythic or allegorical terms than they are now. I don't know, but it's true that early Christian figures like St. Augustine and Origen thought Genesis should be seen as allegory. Consider the words of Augustine:

“It not infrequently happens that something about the earth, about the sky, about other elements of this world, about the motion and rotation or even the magnitude and distances of the stars, about definite eclipses of the sun and moon, about the passage of years and seasons, about the nature of animals, of fruits, of stones, and of other such things, may be known with the greatest certainty by reasoning or by experience, even by one who is not a Christian. It is too disgraceful and ruinous, though, and greatly to be avoided, that he [the non-Christian] should hear a Christian speaking so idiotically on these matters, and as if in accord with Christian writings, that he might say that he could scarcely keep from laughing when he saw how totally in error they are.”

This sounds a lot like the lament of many progressive Christians today, who are embarrassed by the literal-mindedness of their brethren. But we need to be careful even with allegory. St. Augustine, for example, based the idea of original sin on the fall of Adam and Eve. For hundreds of years, people pointed to Genesis as evidence that, not only are people basically bad, but it was women who got us into this sinful predicament in the first place. No wonder so many people have used the Bible to justify the subjugation of women. Even today, there are weddings where women are told to obey their husbands. Women still can't be priests in many denominations. Why? Partly because of the stories in Genesis.

We should know better these days. We've made a bit of progress in the 2,500-3,000 years since Genesis was written. Science has shown that men didn't come before women, and there is no reason to think there ever was a tree of knowledge of good and evil, much less a talking serpent. These stories read like mythology because they ARE mythology. That doesn't mean they are useless. They are actually rather beautiful in places, and they give us vital insights into how our ancient forebears thought; and where we came from culturally--just not biologically or cosmologically. The creation stories are valuable, but they should be taken with many, many grains of salt if we want to relate them to modern life. The Bible was written by many people, over many hundreds of years, in a violent and superstitious time. There's a great deal of wisdom in the Bible, but there are also innumerable horrors and hurtful superstitions. The Old Testament remains the most violent book I have ever read. Nobody takes it absolutely literally these days, even if they claim to. And that's a very good thing.