Expanding The Arc
Have you ever watched one of those shows where a person wakes up from some traumatic experience and can remember nothing, not even who he is or where he is? He is frightened and feels alone, not recognizing anyone or anything. He looks at the room around him, but the furniture is not familiar. He goes out the door into a street, but, again, nothing is familiar; the buildings are strange, the people are not dressed as he is. He asks a passerby where he is, but the person doesn’t understand him, pulls away from him, and speaks in a language he has never heard. Eventually someone takes pity on him, takes him in, feeds him, and begins to teach him the local language. He is introduced to new places and people, but his amnesia is complete; he cannot remember anything about his past and does not know how he wound up where he is. The story then usually focuses on his attempt to regain his memories and find out who he really is and what happened to him.
This scenario happens to all of us when we are born. Can anyone remember where she was before she was born? This is a ridiculous question for most people. Our memories and self-concept begin as we learn our way going forward after we are born. If we are lucky, we start by learning about our mother and father, then perhaps our brothers and sisters and our extended family, then our house and neighborhood. At some point, we go to school and begin to learn about the wider world around us, about numbers and letters, art and history, math and science—the accumulated knowledge of our species. Most people are also told stories. They are taught specific belief systems, ways of thinking and relating to the world at large, some that go back hundreds, even thousands of years.
So, as we grow up we are influenced in what we think about ourselves, other people, and the world we inhabit by what our parents tell us, what other people who hold respected positions in our society tell us, such as teachers and preachers, by what our friends tell us, and, increasingly, by what various communication media tell us. And so we form a picture of our world, our place in it, and how we should act and think about it.
In a larger context, this metaphor of amnesia, birth, and learning our way can also be applied to our species Homo sapiens. We began as a small group, learned about our immediate environment, passed on what we had learned to our descendants, expanded, traveled around the world, began to farm and live in cities, built cultures, and fought among ourselves—most of the time expanding what we knew of the natural world around us. The societies we formed began to develop hierarchies, with leaders, big men, and eventually pharaohs and kings who were respected and looked up to. Life became easier, if more complex. But we also wanted to know how we fit in with all the other living things on earth, why people died, and what happened to us after death. We had a lot of questions. To answer these questions, we began telling each other stories about our origins, about the stars in the sky, about where people went when they died. These stories were added to, changed, and passed from one generation to another. They became the stories that defined a group, that gave the individuals in the group an identity and told them how they fit into the scheme of things around them. People were no longer alone in a strange world. They knew who they were; there amnesia was gone.
Today there are many voices, many people, who want to tell us who we are, how we got here, and where we are going (or should be going). Teachers, preachers, newspapers, magazines, and modern electronic media—radio, television, the internet, social media—all clamor for our attention and want to tell us “the truth” about the world and how we should think. Many times what we are told is contradictory. For example, most people are aware of the issue of climate change. Is it happening? Are the glaciers and ice caps melting? Are human activities causing climate change? A number of respected people say “yes,” the world’s climate is changing in ways that will drastically affect us humans—and humans, and the CO2 we are emitting—are the major cause of this change. They say that societies around the world must act to mitigate the changes already underway. Others, however, say climate change is a hoax. It is not happening. If it is, it is a natural cycle that we humans can do nothing about. Voices on both sides scream at us. What are we to believe? What should we think?
We could simply ignore this issue, and all the other issues that confront us at this time, and go about our lives. Maybe it is simpler not to think about things—to let someone else think for us and tell us what to believe. After all, thinking is hard. Yet most people want to know the truth; like the amnesiac, they want to know where they are and what happened to them before they woke up in that room.
It is hard to go forward when you don’t know where you have been. So let us look at what we know about where we are in space, and how we got to here in time. Most of the information that follows you should have heard before; it is not controversial. Details of what we know about space, time, and history—like all things—are subject to revision as we gain new knowledge, but the basic information has been repeatedly verified.
Our space, the universe, is immensely large. It is composed of stars, planets, galaxies, gas, comets, and many other objects. Space itself is not empty, and what we can see and detect is only a part of what we know is out there. As Timothy Ferris points out in “First Glimpse,” a 2015 article in National Geographic, cosmologists, people who study the universe, say that “all the stars and galaxies they see in the sky make up only 5 percent of the observable universe. The invisible majority consists of 27 percent dark matter and 68 percent dark energy. Both of them are mysteries” (112). Cosmologists use the word “dark” because we cannot detect this matter or energy with any of our instruments. “How do they know it is there if they cannot detect it?” you should be asking. Because the universe is expanding at a faster rate that it should, given the force of gravity and the amount of matter in it. Want to know more? Consult your favorite source, the internet.
Stars, the bright sparklers of the night sky, clump up into galaxies and groups of galaxies. Our neighborhood, the Milky Way Galaxy, is about 100,000 light years across. A light year is the distance light travels in a year, at about 186,000 miles an hour. That translates into 588 quadrillion, 141 trillion, 200 billion miles across. It is hard to understand large distances and large numbers like this. To put them in perspective, Neil deGrasse Tyson, an astrophysicist and narrator of the recent remake of the Cosmos series, tells us in “Fear of Numbers”: “If you start counting by reciting one number per second, you will need 12 days to count to a million and 32 years to count to a billion. Counting to a trillion will take you 32,000 years, which is as much time as has elapsed since people first drew on cave walls.” So we have a pretty large neighborhood. Near the edge of one of the spiral arms of this galaxy, the Sagittarius arm, is our street, the solar system, composed of our star, the sun, eight planets and their moons, planetesimals, asteroids, comets, dust, and debris. While we have observed the stars for thousands of years, we have only recently begun to explore our street in some detail. The first moon landing occurred in 1969. We have also sent probes to the other planets (and beyond—Nasa’s New Horizons probe recently sent back the first clear pictures of Pluto), and we currently have several rovers on Mars.
We have spent thousands of years, on the other hand, exploring our own house, planet earth. It too, from an individual point of view, is quite large, about 8,000 miles in diameter and almost 25,000 miles in circumference. We have spread out to inhabit most of the land areas (the rooms) of this house with the exception of Antarctica—but we do maintain bases there.
Like the man who wakes up in a strange house and rushes into the street to look for other people, we also want to know if there are other houses and other people. Is earth the only planet with people on it? We have known about some of the other planets for a long time, and we have been looking at them in detail at least since Galileo’s time in the early seventeenth century. As far as we know, in early 2017, there is no life on any of the other planets in our neighborhood. Some astronomers think that there was, at one time, life on Mars, and the recent Mars’ rovers are looking for it. There may also be life on Enceladus, a moon of Saturn, and Europa, a moon of Jupiter, as both have water, the basis of life as we know it. As for life beyond our solar system, we can only guess. Beginning in 1995, however, with new techniques and improved instruments we have discovered that planets seem to be quite common in our neighborhood. By January of 2015, astronomers had discovered 1,800 exoplanets. But most of these are too large (gas giants), too close, or too far from their parent stars to contain life as we know it—life based on liquid water. NASA launched the Kepler observatory in 2009 specifically to look for earth-size planets in the habitable zone (also known as the Goldilocks zone). One, Kepler 452b, “is the closest thing that we have to another place that somebody else might call home,” according to Ames Research Center’s Jon Jenkins. Again, check out the NASA Kepler website for more details.
So we know a lot about where we are, but there are still many things we do not know about our space, our neighborhood, our street, and even our house. But we are curious creatures, and what we have learned so for is amazing. If we are to survive as a species, and we know that many species have gone and are going extinct—think of the dinosaurs—we must continue to explore and learn about where we are.
In addition to knowing where we are, it is also important to know where we came from. We have all heard stories of adopted children who spend large amounts of time and money tracking down their birth parents. They think it extremely important to know where they came from. In the same way, we humans have always wondered where we came from and have told ourselves many stories about our origins and the origins of life.
Again, let’s start with the big picture, the universe. Did it begin at some moment in time? Or has it always existed, forever? As Timothy Ferris tells us in the above mentioned article in National Geographic: “After decades of research involving new and better telescopes, light detectors, and computers, cosmologists can now state with some assurance that the universe was born 13 billion, 820 million years ago, most likely as a bubble of space smaller than an atom” (112). Our universe exploded into existence in what has come to be known as “the Big Bang” (Not the nerdy TV comedy). How can we calculate when the universe began? Sort of in the same way we know how old we are. Just as you can count the years backward to when you were born, or ask your parents, astronomers use various techniques such as measuring the microwave background radiation left over from the big bang, and by measuring the expansion rate of the universe. Again, check out the exact methods astronomers use on the internet.
Our own house, the earth, is about 4.5 billion years old, formed from debris circling our newly born star, the sun. As science writer Carl Zimmer says in “How Old Is . . .”: “How can we possibly know this? Nature doesn’t print birth certificates or hammer a year on its creations as if they were coins. Scientists have learned to tell the age of bones, rocks, planets, and stars by using clocks that tick away in the very atoms that form them” (84). In that huge length of time (from our perspective), the earth has undergone vast changes. The way the earth looks to us today is nothing at all like it looked in the beginning, or even several million years ago. For example, only in the twentieth century did scientists come to understand the concept of tectonic plates, that the earth is made of large slabs that shift over time. We now know today’s continents were once joined in a super continent called Pangea that lasted from about 300 to 100 million years ago. It is the grinding of these plates against each other, by the way, that creates major earthquakes. Our house continues to change, both above and below us.
(University of California Museum of Paleontology—online)
Hadeon (4,6-4 billion years ago),
Archean (4-2,5 billion years ago),
Proterozoic (2,5 billion-542 million years ago),
Phanerozoic (542 mya to present)
Eras and Periods of the Phanerozoic
I. Paleozoic Era (542-251 mya)
A. Cambrian Period
B. Ordovician Period
C. Silurian Period
D. Devonian Period
G. Permian Period
II. Mesozoic Era (251-65 mya)
A. Triassic Period (251-299.6 mya)
B. Jurassic Period (199.6-145.5 mya)
C. Cretaceous Period (145.5-65.5 mya0
III. Cenozoic Era—the Age of Mammals (65.5 mya to present)
A. Paleogene Period (65.5-23.03 mya)
1. Paleocene Epoch
2. Eocene Epochs
3. Oligocene Epochs
B. Neogene Period (23.03-2.6 mya)
1. Miocene Epoch
2. Pliocene Epoch
C. Quaternary Period (2.6 mya-present)
1. Pleistocene Epoch (2.6-11.7 mya)
2. Holocene Epoch (11.7 mya-present).
And life? How long has there been life on earth? The oldest fossils we have found (in Australia) are those of cyanobacteria, about 3.5 billion years old. So life on earth has an old, albeit somewhat humble (again from our perspective) beginning. From that humble beginning life has flourished on earth, changing over billions of years. That life changes over time is not so hard to understand: Just think of the many changes you have undergone in your life—and, as difficult as it may seem to you, your parents once looked quite different than they do today. Yet life itself is precarious on our planet. We know that dinosaurs once ruled the earth, and that megafauna such as Woolly Mammoths and Mastodons once roamed North America. In fact, biologists tell us that all life itself almost went extinct at least 5 times during our history. Elizabeth Kolbert, in her recent book The Sixth Extinction, says: “Very, very occasionally in the distant past, the planet has undergone change so wrenching that the diversity of life has plummeted. Five of these ancient events were catastrophic enough that they’re put in their own category: the so called Big Five” (3). Her book catalogs the evidence that many life forms are currently going extinct. This time, however, it is us, Humans, who are causing the extinctions.
One final point to maintain our perspective about life. On the scale of our neighborhood, the Milky Way, life itself does not seem to be very important. As Alan Lightman, a physicist at MIT, says in his 2012 article “Our Place in the Universe: Face to Face with the Infinite”:
The totality of living matter on earth—humans and animals, plants, bacteria, and pond scum—makes up 0.00000001 percent of the mass of the planet. Combining this figure with the results of the Kepler mission, and assuming that all of potentially life-sustaining planets do indeed have life, we can estimate that the fraction of stuff in the visible universe that exists in living form is something like 0.000000000000001 percent, or one millionth of one billionth of 1 percent. (38)
That’s a sobering thought! But what about us? Humans? Where did we come from? How long have we been on earth? Who were our ancestors? These questions for many people, for most of human history, were answered by origin stories, called creation myths, told in different cultural traditions. The oldest go back to Sumeria and Babylon and start with an undefined chaos out of which the gods are born The gods then set about establishing order, separating the land from the waters, for example. They eventually create humans to serve them. Many of these early stories also feature a flood that destroys most humans. In Greek myth, for example, after a flood destroys most of mankind, Deucalion and Pyrra are lonely, so Zeus takes pity on them and tells them to throw stones over their shoulders. The stones become people, and thus the earth is replenished. Similar stories are told in other traditions around the world. In the Christian tradition, for example, a god creates the universe and everything in it, including the first man and woman, Adam and Eve.
But beginning in the nineteenth century people began discovering bones of long dead human-like creatures. The earliest and most famous was the discovery of what we call Neanderthal Man, so named from the first fossil uncovered in the Neander valley in Germany in 1856. Since then, we have uncovered fossil bones of many species of early humans, called hominins, and have begun to fill in our family tree. We now know that a common ancestor of the line that leads to chimpanzees, bonobos, and us “lived between about eight million and five million years ago,” according to Bernard Wood, a Professor of Human Origins at the Center for the Advanced Study of Human Paleobiology. Ian Tattersall, an anthropologist at the American Museum of Natural History, says that “the fossil record clearly shows that not much more than seven million years ago, our ancient precursor was an ape-like, basically tree-dwelling creature that carried its weight on four limbs and had a large projecting face and powerful jaws hafted in front of a very modest-sized braincase” (56). Our specific species, Homo sapiens, dates back about 200,000 years.
We have further been able to trace our connections to our nearest relations since decoding the human genome, the first draft of which was published in 2001. You are probably quite familiar with “DNA fingerprinting” from all the crime-drama shows on television. Since 2001, scientists have also decoded the genomes of other species and have compared them to ours, so that we are able to determine how close we are, and how we differ from, other species. For example, we are closely related, first to Neanderthals, and next to Chimpanzees. After emigrating out of Africa around 70,000 years ago, we moved into Europe and confronted Neanderthals, who had lived there for some 100,000 years. We shared Europe with them for thousands of years before they died out some 39,000 years ago. Obviously, we also interbred with them. Kate Wong points out in a September 2014 Scientific American article, “The Human Saga,” that up to 3 percent of non-African modern human DNA comes from Neanderthals, and that at least 20 percent of the Neanderthal genome persists in the gene pool of people today.” We are not sure why Neanderthals died out; some think we killed them off, just as we may have killed off the megafauna that inhabited North America when we arrived here. Others say we simply outcompeted them. As for our living close relations, chimpanzees, depending on the method of analysis and comparison, there is only a 1.2 to 5 percent difference according to the Smithsonian Institution web site.
Homo sapiens’ ancestors (Indiana University)
So we did not arrive ex nihilo, out of nothing. Just as each of us individually has parents, grandparents, and ancestors, so too does our species H. sapiens. We arose in Africa, but our exact origin on the continent is still in dispute, with fossils from west, east, and south Africa claiming attention. Also in dispute is when we dispersed out of Africa—probably between 40 and 100 thousand years ago. Early humans, however, left traces of themselves, just as you may have pictures of your great-grandmother. They left intricate paintings on the walls of caves in Altimira, in Spain, and Lascaux and Chauvet in France. Some claim that the earliest symbolic human artifact is a 100,000 year-old inscribed stone found in a cave at the tip of southern Africa. Again, the internet can tell you a lot more about these sites, and about our early ancestors in general.
Next, when did humans first get to America? According to Glen Hodges in an article called “First Americans,” by 32,000 years ago humans occupied an area called Beringia—which includes the Kamchatka peninsula, Northern Alaska, and the Aleutians. He says that “A population with two-thirds East Asian and one third Eurasian DNA” became isolated in Beringia. Genetic mutations then resulted in “new, unique DNA markers that are found in modern Native Americans but not Asians.” After that, some 15,000 to 14,000 years ago, about 5,000 individuals headed south along the Pacific coast. Some 2,000 years later, when a land bridge opened between the ice sheets in western north America, humans began dispersing south to people the rest of North and South America. During our trek out of Africa, our human ancestors experienced a number of ice ages, the last ending about 11,000 years ago. These dramatic climate changes are associated with changes in Earth’s orbit, but are not completely understood.
After the last ice age, there is little evidence of contact between humans living in Eurasia and those living in the Americas. We know that civilizations advanced in both places, with great cultures arising not only in Europe and Asia, but also in America. We know that the first Europeans to travel to America after thousands of years were Norse sailors under Leif Erikson in 1001. In 1963, a settlement was discovered at L’anse-aux-meadows at the tip of Newfoundland. It was similar to eleventh-century European Viking long houses. And finally, of course, we all know that Columbus, ignorant of the existence of the Americas, sailed west in 1492, hoping to find a shorter route to India. Many of us are descendants of the Europeans who followed him.
So we now have a pretty good idea of where we humans are, and how we got here. Our house is large, our neighborhood vast, and our ancestors stretch back a million years. But we have only come to know all this, really, in the past 500 years. Our progress in understanding who we are and how we got here has advanced and ebbed over the last 10,000 years, over what we call the historic period, the outline of which is quite familiar today. Here is a very brief sketch to complete our context.
As an old book title put it, History Begins in Sumer. What we call “civilization” began when our hunter-gatherer ancestors domesticated wheat and began farming in settled communities. That led to social organization and hierarchies—and to the invention of writing to keep track of everything. The earliest known writing dates back to Sumeria, the area between the Tigris and Euphrates rivers in modern Iraq. It began as a series of symbols, pictographs, for objects, and later developed into syllabic writing. It is known as cuneiform and was inscribed with a pointed stylus into wet clay tablets which were then dried in the sun. The earliest stories we have also date from this period. You may have read a translation of Gilgamesh, our first epic story, or some of the Babylonian creation stories such as the one about a great flood. There are a number of other civilizations that arose around the same time, such as the Egyptian along the Nile, the Harappan along the Indus, and the Xia along the Yellow river.
Humans in all these civilizations, and later in the Chinese and Greco-Roman worlds, were curious about the very questions we started with at the beginning of this exploration. They wanted to know where they were and where they came from. They also had practical concerns, such as when to plant crops and how to defend themselves against marauding bands of other humans. So they began gathering information about the world around them and writing it down for their descendants. For example, the earliest astronomers began studying the stars in ancient Babylon, and some of the earliest advances in math and geography occurred in ancient Greece. With the Greco-Roman civilization, Europe reached a peak not seen again until the beginnings of the Renaissance between the twelfth and fifteenth centuries. For example, the Greek Eratosthenes, living in the late third and early second centuries BCE (Before the Common Era), came up with a method to calculate the circumference of the earth. It was close to what we know it to be today. Further, philosophers such as Thales, Pythagoras, and Euclid developed mathematics and geometry. The foundations of many modern sciences, as well as philosophy, art, literature, and politics were also set during the Greco-Roman period.
But, as every school girl learns, Rome fell, and Europe descended into a period of chaos it was not to emerge from for almost a thousand years. As Charles Freeman says in his book The Closing of the Western Mind: “In the fourth and fifth centuries A.D. . . . The principles of empirical observation or logic were overruled in the conviction that all knowledge comes from God and even, in the writings of Augustine, that the human mind, burdened with Adam’s original sin, is diminished in its ability to think for itself” (5). The earlier part of this period is known as the dark ages. Roman civilization was overrun by various Germanic tribes, cities were looted and destroyed, population declined, literacy disappeared. The city of Rome itself shrank from over a million people at its height to just 30 to 60 thousand. So, just as species go extinct, civilizations do as well. Even though Greco-Roman civilization continued in Byzantium (modern day Istanbul) and in various Islamic capitals for another thousand years, advances in our human understanding of where we are and how we got here virtually stalled.
But not completely. After the early period of decline and chaos in the West, after the raids of the Vikings in the eighth and ninth centuries, cities began to grow again, population increased, and the first universities—centers of learning where students gathered and hired teachers to instruct them—opened. These gradually expanded, as did trade with the civilizations of the East in Constantinople (aka Byzantium, modern-day Istanbul), Muslim centers of learning in Spain and the Middle East, and the Khan’s empire in China. But the picture of man’s place in the universe, who he was and where he came from, had hardened into dogma in Europe. It was thought, and the Catholic church taught, that God had created heaven and earth. That the earth set in the center of the universe. That the sun, the moon, and the known planets circled around the earth. That the stars were set in a crystalline sphere that also circled the earth, and that God himself surrounded the whole. Everything, including man and all other life forms, had been created separately by God in a period of six days. To disagree with any of this was to be a heretic, and, depending on where you lived, you could be excommunicated, punished, and even burned at the stake.
So when a Polish astronomer, Nicolas Copernicus, published a book (in Latin) in 1543 not long before his death, called On the Revolutions of the Heavenly Sphere, which put the sun at the center of the universe, he created a huge controversy. After his death his book was condemned as heretical by the church. It remained on the church’s list of forbidden books for over three hundred years. Copernicus’ heliocentric theory was based on his own research and observation, and because of the invention of the printing press it spread widely in spite of the church’s condemnation and that of Martin Luther (The Protestant Reformation had begun by this time.)
Copernicus’ idea gained credibility and was refined by Johannes Kepler, a German mathematician and astronomer (for whom the Kepler observatory is named). Soon after, Galileo, began using a new invention, the telescope, to observe the moon and the planets. He found that they were not perfect, as Aristotle and the church taught. He began teaching his students at Padua the new, heliocentric view of the universe. What happened to him is always presented as a cautionary tale—of a lone speaker of truth to power. Galileo was summoned to Rome in 1632 and found guilty of heresy by the Inquisition (the church tribunal for the discovery and punishment of heresy). He was placed under what we would call house arrest and forbidden to teach the Copernican theory any longer. He died in 1642, but his observations, and Copernicus’ theory, were soon vindicated.
Copernicus, Galileo, and the others who followed them shattered the cozy universe man thought he inhabited. They did it through adopting what today we call the scientific method. They used observation, logic, and math to test theories about the world. The old, earth-centered theory of the earth did not hold up to scrutiny; the Copernican theory did. What they had done was to show that we should not simply believe things about our world simply because someone in authority, or an ancient writer like Aristotle, tells us they are true. We can all think, and we should use reason and observation to test claims about the world, no matter who makes them.
Humans have continued to build on what these great thinkers of the Renaissance discovered. In 1687 Isaac Newton published the Mathematical Principles of Natural Philosophy (also in Latin and referred to as the Principia), stating his famous laws of motion, the foundation of what is called classical physics and the basis of the industrial age that followed several centuries later. Newton was revered throughout his life. When he died, the English poet Alexander Pope wrote a rhymed couplet as an epitaph in his honor. He wrote: “Nature and Nature’s laws lay hid in night. / God said, let Newton be, and all was Light.”
In the century after Newton’s death, natural philosophy (as science was then called) continued to advance our knowledge of the world. But many people, including many natural philosophers, continued to believe that the earth, and indeed the universe, had been created by God and was not very old. For example, early in the seventeenth century James Ussher, an Irish Archbishop, based on his study of chronology in the Bible, confidently claimed that the earth had been created around 2:00 p.m. on October 23, 4004 B.C. Many people continued to believe in what was called the “young earth” theory well into the nineteenth century. In fact, some people still cling to that belief even today. Again, look up “young earth creationism” on the web.
But the nineteenth century saw the development of Geology, the study of the earth, and soon people began to realize that many of the rocks found in layers around the world were very, very, old. For example, Charles Lyell published his three-volume Principles of Geology between 1830 and 1833. He disputed the idea that the earth was only about 6,000years old, and said that the key to the past was to study the geologic processes at work in the present. His work had an enormous influence on Charles Darwin, who began his famous five-year voyage around the world on board the Beagle in 1831. It was Darwin’s book, On the Origin of Species, published in 1859, that created shock waves that are still being felt today. Through meticulous observation and patient study over the years between 1831 and 1859, Darwin had become convinced that species were not immutable. He based his theory of evolution, in part, on the fact that humans have been altering species for a long time. We cross-breed animals, for example dogs and pigeons, to achieve certain desired characteristics—that is artificial selection. Likewise, he reasoned, conditions in nature are such that at specific times certain traits of individuals make them more adaptable to their environment, and thus more likely to pass on their traits to later generations—a process he called natural selection.
When the Origin was published, it sold out its first printing in a few days, making Darwin a reluctant celebrity. What he had written clashed with the accepted view of man’s place in the universe held by the Anglican church (the church of England), the catholic church, and other protestant denominations. This view held that each species, including man, was created by god in its present form and had not changed over time. Darwin’s carefully documented theory contradicted this view. On June 30, 1860, a debate on Darwin’s new theory was held at Oxford University. A number of prominent natural philosophers (scientists) and religious leaders took part, including Thomas Henry Huxley and William Wilberforce, Bishop of Oxford. Darwin himself was not there. He was not well and hated controversy, so he stayed at his home, Down House. The high point of the debate—though exactly how it fell out is in dispute—occurred when Wilberforce asked Huxley if he claimed descent from a monkey on his grandfather’s side, or on his grandmother’s side. Huxley’s famous reply was that he would not be ashamed to have a monkey for an ancestor, but he would be ashamed to be related to a man who used his great gifts of oratory to obscure the truth. If you want to see a staged video of this debate, included in the series The Voyage of Charles Darwin in 1978, look it up on YouTube.
Since Darwin’s time, the view that all life has evolved, changed, over time has been confirmed by numerous studies around the world. It is one of the most successful scientific ideas. And, of course, we have accumulated a lot more evidence since Darwin’s time. The discovery of numerous fossils of early hominins and the decoding of the human and other genomes, for instance, show that we, ourselves, evolved from earlier forms. Modern biology and the other life sciences would be impossible to understand without the idea of evolution. Yet many people have a hard time accepting this view. Evolution deniers, particularly in the United States, have tried again and again to stop the teaching of evolution in our schools. From the famous Scopes trial in Tennessee in 1925 (again see YouTube) to repeated attempts by members of the Textbook Selection Committee of Texas, groups have fought to restrict the teaching of one of the most-documented theories of modern science. Why? The answer to that question leads to another question: Why do we believe what we believe? Or, to put it another way, how do people acquire their beliefs? To explore some answers to these questions, read “Chapter 1: Belief and Reason,” in your textbook, Expanding the Arc.