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After writing the previous post, I remembered something I saw more than a decade ago. During a partial solar eclipse, I saw the image of the crescent Sun projected onto the ground through tree leaves. The leaves act as pinhole cameras by blocking out all but a small portion of the light.
This doesn’t happen only during an eclipse, of course. Next time you walk under a tree on a bright summer day, look for small, roundish images on the ground below the tree. These are images of the Sun, created by the leaves over your head! Even without a lens, the tree has created a picture of the Sun. The world is an amazing place.
Listening to Science Friday yesterday, I was struck again by the difference between the world and the world we perceive. The guest was talking about a camera that doesn’t have a lens, so it doesn’t form images. And it hit me. Lenses are the unusual things. We think of the world as the world we see, but what we see is the image formed by lenses directing light to our eyes. Those images don’t exist as such until our eyes form them.
To a blade of grass, for instance, the Sun isn’t a ball in the sky. Rather, it is the spread-out light that changes in intensity as the day progresses from morning to afternoon to evening. In the same way, the light bouncing off our bodies and going off in all directions isn’t a picture of us. It’s just light – diffuse, unfocused light. Only when a lens – in someone’s eye, in a still camera, in one of those amazing hand-held video cameras – captures that light do we become images. To most of the universe, we’re just fuzzy obstacles that block the light.
What would the world be like with light but no lenses?
I’m listening to a book called “Your Inner Fish” by Neil Shubin. The beginning of the book struck me again with a hard truth about evolution, maybe one of the hard truths that makes evolution so hard for people to really, really accept.
And it is hard. It’s not just stupidity or ignorance or willful neglect of the facts. There’s something unsettling about the whole idea of evolution, and Shubin’s book reminded me of it again.
Shubin was interested in the origin of tetrapods. He went looking for a fossil that would show the transition from fish to amphibian, and he found it in a creature called Tiktaalik. Tiktaalik is very much midway between water-living fish and land-living tetrapods. While it has scales and fins, those fins contain finger and wrist bones, showing that Tiktaalik sometimes supported its own weight. More obvious upon first glance, though, is that Tiktaalik has a neck.
According to Shubin, this was a key development. Fish never have necks; their heads are attached directly to their shoulders. But Tiktaalik has evolved a neck.
And this is where, if you think enough about it, things get uncomfortable. What does it mean that Tiktaalik evolved a neck? It means that over a great many generations, a fish ancestor had enough variation in its offspring that a tendency toward “neckiness” was advantageous. But evolution can have no direction. There must have been lots of other variation, too, most of which led – nowhere.
But what does nowhere mean? It means death. Most creatures with variations from the norm die. Most creatures with variations never reproduce, and so their genes don’t contribute to the future. From this pruning – a pruning whose immediate cause is differential reproduction but whose ultimate cause, almost always, is death – comes the “direction” we sometimes see in a directionless process.
It’s maybe not so uncomfortable when we think about fish. But when it comes closer to home, this differential reproduction, caused most often by death, becomes a lot more personal. I like to think of my daughters as new voices added to the universal song, seeds of individualism, hope, and potential, another chance for the universe to know itself. I like to think of them, in other words, as anything other than what we know, via evolution, what they are. They are variations in the genome, dice rolled across the field of natural selection. Perhaps the dice have come up with positive variations, perhaps the dice this time came up negative. It’s not something I can control, and its not something I can stop.
The strategy becomes clear when you think about something like the HIV virus. HIV is dangerous, partly because it is rotten at reproducing itself. When HIV reproduces, it creates millions of approximate copies of itself, with lots of variation mixed in. Most varieties won’t be very good, but that’s no big deal to HIV, with its myriad offspring. The sacrifice of so many useless viruses is worth it for the chance to create a variety even better at what it does. And so HIV keeps avoiding our efforts to pin it down.
The basic idea works in the animal kingdom, too. Every “invention” of natural selection is produced on a pile of death, countless failed experiments that resulted in a life that was nasty, brutish, and short. Life is uncertain, reproduction is a risky proposition, and evolution is the direct result of that uncertain risk.
This, by the way, is a perfect example of the difference between what is and what ought. Evolution is a fact. It is the way the world works. However, that doesn’t make it a model for society. Evolution is brutish. It is without forethought. It made us quite by accident. But now we’re here. We can crash the party. We can hold evolution off, at least some of its more unpleasant aspects. We can care for individuals with variation, because we recognize that natural selection is not the measure of all things. We can choose to cherish a few offspring, instead of flooding the world with as many copies as we can, hoping a few will turn out. We can even plan ahead, to avoid genetic combinations that stack the dice against our children before they’re even conceived.
Probably that last bit makes some people cringe. Again, that’s this discomfort with the fact of evolution coming through. Reproduction is throwing dice. Which is more cruel, to allow deadly variation to happen, or to fix the game to avoid its consequences?
Remember the fish’s neck, and all the dead creatures on which that neck was built. Evolution is hard.
I don’t really want to grow up.
Problem is, I’m 41 years old with a mortgage, a family, an aging car, and a neurotic dog. The world wants me to grow up. It’s tiring to keep fighting.
So I try to find ways to fake it. For instance, when talking about educational philosophy with colleagues, I pretend to be fancy. I talk about cognitive dissonance and Piaget’s ideas of assimilation vs. accommodation. I talk about how discrepant events can create a sense of imbalance in my learners, an imbalance that they are motivated to equilibriate. It all sounds very impressive.
But it’s crap. Shhh, don’t tell!
Here’s the thing. When I was little, my Dad was good at everything – well, everything that mattered, anyway. He still is, and is one of the greatest people I know. He’s my hero and my model of how to live a good life. But he’s so good at stuff, I knew I could never be as good as him.
Stuff like fixing cars. Or furnaces. Or plumbing. You name it, if it broke he could fix it. My dad always had a corner on practical knowledge. Still does.
So I had to find another way. I had to find something my dad didn’t specialize in. I found science, particularly the esoteric, totally impractical, seemingly useless parts of science – stuff like cosmology, nuclear physics, quantum mechanics, evolution. Anything weird, bookish, and impractical, I was attracted to it. It gave me something that was mine.
It seemed that the coolest parts of these subjects were their utter unreality. Every common sense notion seemed to be turned on its head. The stars may seem like dots in the sky, but they’re actually suns, very far away. Time may seem constant, but it actually changes, depending on how you’re moving. Things may seem to be like particles, either here or there, but actually they sometimes behave like waves, a little here, a little there, a little somewhere else. These anti-commonsense ideas led me eventually to the idea of what they call in hoity toity circles “discrepant events.”
I love discrepant events. Most of my favorite science demonstrations hinge on some unexpected effect. In that way, I think they’re a little like magic tricks. They’re a chance for some showmanship, for playing up that moment when I know something the learners don’t. It’s a rush!
But as Jean-Luc Picard said in one of my favorite STTNG episodes, “I’m going to show them how the magic works.” That is of course the key to a discrepant event as a science demonstration. It’s where the whole cognitive dissonance thing comes in. Through surprising effects, it is our hoity toity hope as educators to cause our learners to not assimilate the discrepant event into their current worldview, but instead to accommodate their world views to take into account this discrepant event. Very impressive sounding. Also not the real reason I do it.
The real reason is I love the “wow” moment, the wide-eyed wonder of it all, the realization by the learner that the world is a more amazing and wondrous place than she ever thought. That’s what I’m after. Whether she gets the concept or not, I don’t really care. What I want is for her to think about the world in a different way.
And from this comes my fatal flaw, my utter contempt for the practical. It’s a horrible affliction, and keeps me from growing up. If you can take a wonderful, exciting discrepant event – electricity making a magnet, for instance – and turn it into something practical, then for me (I have to admit it, it’s what I feel), you’ve robbed it of its magic. Practical application depends on regularity, predictability, everything occurring as it should. Discrepant events are just the opposite. Hence my downfall.
What I really want my learners to “get” from my demonstration is not, “Wow, I could use this effect to create a practical bit of technology!” No, what I really want is my learner to say is, “Wow, the Universe is an amazing place. Maybe I can learn more about it!”
And then they’ll let me keep doing what I love.
I know. Hopeless.
I’ve been listening to The Pluto Files by Neil DeGrasse Tyson, director of the Hayden Planetarium in New York City. In 2001 the Hayden Planetarium took a big hit for leaving Pluto out of some depictions of the Solar System in their new Rose Center for Earth and Space Science. Later, when the astronomical community at large revoked Pluto’s planethood, it seemed that maybe the Rose Center got it right in the first place.
Tyson shares his own views on why their treatment of Pluto was educationally sound, and I think he’s exactly right. Tyson makes the point that counting planets is a pointless exercise. Much more useful, sensible, and educational is to group bodies together to compare and contrast properties. The terrestrial planets form a group, the asteroids form a second, the gas giants a third, and the Kuiper belt objects, of which Pluto is one of the largest we know, form a fourth. It makes eminent sense, which is of course why it fell on completely deaf ears.
The letters that Tyson shares in the book are both hilarious and depressing. The passion that people express for keeping Pluto a planet reveal so much about how we think. Children can be excused, I suppose, for wanting to “stand up for the little guy.” But adults, one would think, should know better.
There’s a compelling argument to be made that at least the whole controversy got people thinking about the universe. But when I look at the conversation as it came out, I see a missed opportunity.
Instead of tossing out Pluto, which isn’t really what happened but is what came out, the thing to toss out was the word “planet.” It’s just as well to say “body” or “world”, and that can include just about everything, including the seven moons bigger than Pluto, including the asteroids smaller than Pluto. In fact, the idea of “planet” was always a shaky one.
Consider Jupiter as compared with Earth, for instance. The two have virtually nothing in common. Jupiter is 318 times as massive as Earth. (Earth, in case you’re wondering, is 455 times as massive as Pluto.) Yet Jupiter is less than one-quarter as dense as Earth. Jupiter whirls around its huge, spread-out mass in less than 10 hours. It is covered in hundreds of miles of hydrogen-rich clouds, over a liquid hydrogen layer that stretches for perhaps 12,000 miles. Consider that the deepest ocean spot on Earth is at best a few miles deep. Below the liquid hydrogen is a layer of metallic hydrogen, and finally at its core is the rock and iron that mark the only real similarity between the two worlds. Yet this core of metal and rock would hardly be recognizable, 14 or more times the size of Earth and under tremendous pressure. While the Earth has a single natural satellite, Jupiter at last count is up to 62 worlds in its complex system, not including its rings.
My point is, if we’d somehow evolved on a gas giant, we probably wouldn’t consider puny bits of rock like Earth as anything like real “planets.” The concept of planet itself is the problem, not the way we decide to count them.
So instead of throwing Pluto out, let’s throw them all out! I suggest entirely new names for these bodies – Jovians, Terrans, and debris. Our solar system contains, then, four Terrans, four Jovians, and lots and lots of debris.
Sorry, Pluto, but you’re debris. No offense.