What I am going to talk about with you today is The Enlightenment. This was an intellectual and philosophical movement that began around three centuries ago, also called The Great Awakening. It concerns the most important questions we humans face: how we understand life and the world; how we see ourselves in that world, how we live. The ideas of the Enlightenment are central in my own life. And in advanced societies today, in a lot of ways, Enlightenment thinking is the dominant way of thinking. Though not as dominant as I might like.

I was very lucky to have been born in America, in a pretty typical American family, where it was taken for granted that I would get a good education and have a good professional career. That culture really made it easy for me. So I went to law school and became a lawyer. But then I actually had trouble finding a job, because I was immature and had lousy people skills. But it worked out, because the job I finally did get was really very rewarding.

Another thing I had trouble finding was a wife. In America, your family is not part of finding a wife, you're on your own. Which is good, really. But my poor social skills made it hard for me. Not till I was 40 did I find Therese, who is absolutely the most wonderful woman in the world, who's been my wife for 31 years, and we have a wonderful life together. And a wonderful daughter.

And coming here today, to this school, being able to meet you and talk to you, is really a highlight of my life. Everybody wants to find meaning in their lives; to feel they exist for a reason, and are part of something bigger than themselves. This project of creating schools in Somaliland, to help build this country, does that for me; it is something I feel I was very fortunate to learn about, and to be part of.

So I have been very lucky.

Luck is actually a philosophical issue. It relates to the problem of justice. Does justice mean people getting what they deserve — either punishments or rewards? Did I deserve my good fortune? Well, you might say it was because of some character qualities: intelligent, responsible, hard working, and so forth. But — wasn't my having those character traits in the first place simply a matter of luck? Did I somehow deserve to have them? Compared to someone not lucky enough to have them? So do I really deserve to have a better life than him? It's a tough question, with no simple answer.

But let's talk about humanity as a whole. We've existed for many thousands of years, and for most of that time, lived in pretty miserable conditions. The famous line from the philosopher Thomas Hobbes is that life was "nasty, brutish, and short." Because we did not know anything. Did not know how to make better lives. We did manage to make a little progress, but for a long time, it was very very slow.

Here's where the Enlightenment comes in, about three centuries ago. Now some people started to say: the Universe is not unknowable. It is not an impenetrable mystery. It works by orderly natural laws. And we can figure out those laws. It's very hard, but we can use our reason to do it. Our logical,

thinking minds, that understand that two plus two equals four. And when we use our rational thinking minds to get that knowledge about the laws of nature, then we can use it to make better lives.

This is science. What, actually, does that word "science" mean? It is how we know things — based on putting together facts in ways that make logical sense and can be verified. The latter is very important. The philosopher Karl Popper called it falsification — meaning something is capable of being proven false if it is false. If there's no possible way to prove whether some proposition is wrong, then it's not science. (PIC 4) Here's an example. Are all swans white? A thousand white swans doesn't actually prove it. But if you find one black swan, that would prove it's not true all swans are white.

Proving things wrong is how we advance our knowledge.

Now in the rest of this talk, I will be discussing things science says. I believe what I'll be telling you stands on very strong ground. But what you believe is, of course, up to you. You must make up your own minds. In fact, this too is a key principle of the Enlightenment: people should make up their own minds, about what they think is true, rather than just believing something because someone tells them that's what they should believe. Even if that someone is me. If you do believe what I say, it should be because you apply your own thinking brain to it.

So let's get into it. Here's a question about how nature works. If I drop something, it falls down to the ground. Why? Who knows the answer? Gravity! OK, so how does gravity work? Can anybody answer that? Well, that's actually a very difficult question.

People used to think that if you drop something, the heavier it is, the faster it will fall. It seems logical. But in the 1600s a scientist named Galileo proved it isn't true. By going to the top of the highest tower and dropping two balls of different weights, and they hit the ground at the same time. But another thing is that when anything falls, it falls faster and faster the farther it falls. This actually follows a mathematical formula, which another scientist named Isaac Newton, later in the 1600s, figured out.

The fall accelerates at the rate of 32 feet per second per second. That means, in the first second, it will fall 32 feet; in the next second, it falls 64 feet; in the third second, 96 feet. So if you fall out of an airplane, that will take a lot of seconds, and you will hit the ground at a very high rate of speed. That's why we invented parachutes.

And another thing: it may seem obvious that the gravity between the Earth, say, and some other object, gets less strong the farther apart they are. But it's actually not proportional to the distance; it varies with the SQUARE of the distance. That's not obvious at all. But Isaac Newton figured that out too. Really an amazing human achievement.

But we still didn't actually know how gravity does what it does. How can one object move another without touching it?

Einstein gave us the answer. Imagine a big rubber sheet. Then plop a heavy ball in the center. It bends the surface of the rubber. Any nearby object will roll down into the bend. Gravity works the same way; an object warps the space around it. Now, that rubber sheet is in two dimensions, and actual space is in three dimensions, so it's hard to visualize, but the concept is the same. Gravity is objects warping the space around them.

Now, people always looked up at the sky and tried to understand what they were seeing. They had a sense it was not just like wallpaper, but had important meaning. As you may know, they started out thinking the Earth was flat, and was stationary, in the center of everything; and the Sun and everything else revolved around the Earth. That was actually the way it seemed, it was actually reasonable, based on what they could see. All the stars did seem to just move all together like they were all attached to some gigantic sphere. Well -- all the stars except a few. And that was a huge puzzle. Those few they called "planets," which means "wanderers" because they seemed to move around in a different way that was hard to make sense of.

So two thousand years ago there was an astronomer named Ptolemy who tried to solve the puzzle.

He postulated all the stars circling around the Earth attached to great rings. The planets did too — but they were attached to special rings of their own, and those rings were attached to bigger rings. Rings upon rings. He called them "cyles" and "epicycles." It was a very complicated system, but it actually did work, to explain the motions of the planets. It was wrong, but it was brilliant.

So eventually there came along a thinker in Poland, Copernicus, who believed Ptolemy's system of rings upon rings had to be wrong. There had to be a simpler explanation. What if it's not actually the Earth at the center, but the Sun? And the planets revolve around the Sun, not the Earth? So he did the calculations. And guess what? Voila! It worked beautifully. So Copernicus wrote a book explaining this. The first copy off the press was handed to him on his deathbed.

You might think everybody would learn of Copernicus's work and say, "Oh! Of course! That's the answer!" Of course that didn't happen. People didn't like the idea that the Earth was not at the center. They continued to insist everything had to revolve around us. Then finally, the telescope was invented. At first it was like a toy, and useful in some ways.

But here comes Galileo again. Same guy who dropped the balls from the tower. He had the bright idea to lift a telescope to look at the sky. And found some very interesting things. Like Jupiter having moons that were clearly revolving around it. Which proved that not everything in the Heavens revolves around the Earth. Galileo published his findings in a book titled, in Latin, Sidereus Nuncius -- The Starry Messenger. Or, what the stars tell us. And now people finally began to get the message.

Meantime, there was another problem — how actually do planets move?

There was another scientist named Johannes Kepler; a German; and this was the problem he worked on. Realize he came a little before Isaac Newton with his theory of gravity, so Kepler didn't have that knowledge to help his work. But he did have access to a huge database of very accurate astronomical observations that had been compiled by the famous Danish astronomer Tyche Brahe. Who had lost his nose in a duel and wore a fake nose made of brass. Now, Kepler had a firm conviction that cosmic perfection meant the planets must move in perfect circles. He was determined to prove it. But hard as he worked, the facts would not cooperate. The answer he got was not the answer he wanted.

But he accepted the true answer, that planets move not in circles, but ellipses. That's how science works — again, by falsification — proving that something is not true. Kepler proved his own cherished belief was not true. It's facts and evidence that guide beliefs, not the other way around. For me, Kepler stands as the epitome of the Enlightenment — using our human reason to discover what is true.

By the way, this is a principle I try to apply myself. Basing my beliefs on what I see as facts; rather than letting my beliefs determine what I see as facts. (Not everybody does this!)

Now let's jump forward to 1929. Until then, we thought the only stars were in our own galaxy. There were some tiny smudges of light we assumed were just gas or dust. But an astronomer named Edwin Hubble discovered these were actually separate galaxies, very far away. The Universe was full of them.

Suddenly it was humongously bigger than we'd realized. But there was more. Those other galaxies are moving away from us — the more distant they are, the faster. This meant the whole Universe was expanding. And if you run that movie backwards, you end up with everything squashed together. Which scientists believe was, indeed, the beginning of our Universe. The Big Bang -- estimated to have been 13.7 billion years ago.

Now here's another, very different scientific problem. The question of why the world is full of millions of different life forms — including us. How they came to be. This is the question at the very heart of the science of biology. And here again, for ages, we didn't have a clue. Biology wasn't even really a science. We could catalogue all the different varieties of plants and animals, but could make no sense of the whole picture. One problem was the idea that it was all unchanging, that all those species just are, and always were. But then we started to discover fossils — which are the remains of past creatures, many of which no longer exist. Some were dramatically different from anything we knew — like dinosaurs. This was extremely puzzling. Why all that change?

Charles Darwin was an Englishman, born in 1809, who went on a long sea voyage on which he studied all the animals he encountered. And then he spent twenty years thinking over everything he'd learned. And he figured it out, and wrote a book called On The Origin of Species. The answer is what he called natural selection. Here's how it works. No two animals, even of the same species, even children of the same parents, are ever exactly identical. There are always differences. Which means some will be more successful than others at surviving to adulthood, attracting mates, and reproducing. So their more successful characteristics get passed on to the next generation more often than do less successful characteristics. The difference between one generation and the next may be very small. But Repeat this a million times, and what you get at the end can be very different from what you started with.

But it can be faster. Here's an example that actually happened.

There was a moth in England that birds liked to eat. But the birds usually couldn't find them, because the moths were mostly white, and they'd sit on trees with white bark. But then came factories putting out a lot of soot and the trees turned black. So now the white moths were easy for the birds to pick off — and the rare black ones had an advantage. Pretty soon, the whole species became black. That's natural selection. That's how species change, over time, and change into new and different species. For Darwin to figure it out was a tremendous insight.

It's even more remarkable that he didn't have the benefit of our modern knowledge of genetics. Inside all the cells in our bodies are microscopic strings of a molecule called DNA.

But every molecule of DNA is not identical; it's actually structured to contain a code, like a string of letters, and that code tells each cell what to do in constructing the animal. When parents have a child, the DNA from each parent splits and copies itself, and the child gets half from each. And in the copying, there can be occasional little mistakes. This is why members of the same species do have differences that are the basis for natural selection.

Recall again what I said about science progressing by proving ideas wrong. So might genetics and natural selection one day be proven wrong? Well, these concepts provide such a powerful, compelling explanation for literally everything in biology that disproving them just isn't going to happen.

Now, it happens that all the scientists I've mentioned were European (except for Ptolemy, who was Egyptian). I'd like to mention that the Muslim world did have its own intellectual flowering, and there were a lot of Muslim thinkers, scientists, mathematicians, and writers, who made important contributions. In fact, that was largely before the Enlightenment in Europe. As one example, the system of numbers we use in the West is based on Arabic numerals; that's what we still call them, Arabic numerals.

So anyway, all those scientists have figured out an awful lot of how life and the Universe work. Much more besides what I've talked about. And we have used all that knowledge, to create everything in modern life. We have made airplanes that fly. And a device in your pocket enabling you to access practically all the information in the world. Think about how fantastic this is. And all our medical advances, all the diseases we can now cure.

Here's a graph of average world life expectancy, it goes from the first century to now, it starts at about 25 -- yes, it was only 25 — and pretty much stays there until the last century, then look how fast it went up. Average lifespan is now over 70 worldwide, and around 80 in developed countries.

The knowledge we've gotten has also made people less poor and more wealthy, able to afford better lives. Most of us today really have no conception of just how poor people were in the past. Describing that past, one writer said people were considered well off if they could get food to survive another day. And he wasn't talking about Africa, but Europe.

Now, some people think as though there's only a certain amount of wealth in the world, most of which rich people somehow grab, making everyone else poor. But the Enlightenment tells us wealth is created — created when people combine knowledge with effort, to create things people need or want. And while world population has increased tremendously since pre-industrial times, wealth has increased tremendously more. How much more? For every dollar of wealth in the world before the Enlightenment, today there's $200. Enabling billions of people to have more and live better.

Here's a graph showing the rise of world GDP.

Like the last chart, for centuries it was practically flat. And then, once the Industrial Revolution kicks in, it goes through the roof.

Part of this is what's called the "green revolution." There was a thinker named Malthus, who wrote in 1798 that population must grow faster than food production, so people would always be starving. But the green revolution applied science to how we grow food, vastly increasing what we get from every acre. And Malthus was proven wrong. A German scientist, Fritz Haber, discovered a way to produce cheap artificial chemical fertilizer, making soil more productive. An American, Norman Borlaug, used the principles of genetics and natural selection, that I've talked about, to painstakingly breed high-yield and disease-resistant wheat plants.

Borlaug's work is reckoned to have saved a billion lives. The green revolution is estimated to have increased food production by 250% over 35 years. And today we can make similar advancements much more efficiently through what's called Genetic Modification.

All this is progress. The idea of progress itself was a new idea of the Enlightenment: the idea that progress is possible, and that we can make it happen by our efforts.

Now I want to talk about yet another very important thing that came out of the Enlightenment. Do you know about the American Declaration of Independence? That was in 1776.

And in 1991, your country, Somaliland, declared your independence too. It meant that now it's your own country. America's Declaration of Independence was the first one. It was a letter to the world explaining why we were declaring independence. It said that all people are created equal. (Actually, it said all men, but it really meant all men and women. Believe me, it meant that.) And it said all people have rights, that cannot be taken away. That we have a right to life, liberty, and the pursuit of happiness. And it also said that the job of government is to protect these rights; that's why we have government. And it said government is not the boss of the people -- the people are the boss of the government. That is what democracy means.

Aall this too is part of what The Enlightenment is about. It is about love for humanity. Thus a philosophy that puts individual human beings at the center, and making for us a better life here on Earth. A better life, in Somaliland too.

So will Somaliland become what's called a "developed nation" tomorrow? No. Next year? No. But in your lifetimes? Maybe yes. It can be achieved. It will take a tremendous amount of effort and work and courage, using your brains and your reason, and you will have to fight a lot of people who don't believe it and don't even want it, who will actually hate it. But it can be achieved. I believe it will be. That's really why I got involved in all this, and why I'm here today. I believe it will be done. And that you -- you students -- will do it.

There is an old sailor's prayer. It goes "O God, the sea is so big, and my boat is so small."

Well, the sea is very big, and our boats are very small. But with our brains, with our courage, our hopes and dreams, with our eyes to the far horizon and our faces to the wind, we human beings set out upon our journey.