Most of what people believed about the origins and makeup of Earth before about 1700 bore the imprint of mythology or merely bad science. Predominant among these theories were the Creation account from the biblical Book of Genesis and the notion of the four elements inherited from the Greeks. These four elements—earth, air, fire, and water—were said to form the basis for the entire universe, and thus every object was thought to be composed of one or more of these elements. Thanks in large part to Aristotle, this belief permeated (and stunted) the physical sciences.
To call the biblical Creation story mythology is not, in this context at least, a value judgment. The Genesis account is not scientific, however, in the sense that it was not written on the basis of observed data but rather from religious principles. The concept of the four elements at least relates somewhat to observation, but specifically to untested observation; for this reason, it is hardly more scientific than the Genesis Creation story. The four elements were not, strictly speaking, a product of mythology, but they were mythological in the pejorative sense—that is, they had no real basis in fact.
The biblical explanation of Earth's origins is but one of many creation myths, part of a larger oral and literary tradition that Dorothy B. Vitaliano, in her 1973 book Legends of the Earth, dubbed geomythology. Examples of geomythology are everywhere, and virtually every striking natural feature on Earth has its own geomythological backdrop. For instance, the rocky outcroppings that guard the western mouth of the Mediterranean, at Gibraltar in southern Spain and Ceuta in northern Morocco, are known collectively as the Pillars of Hercules because the legendary Greek hero is said to have built them.
Geomythological stories can be found in virtually all cultures. For instance, traditional Hawaiian culture explains the Halemaumau volcano, which erupted almost continuously from 1823 to 1924, as the result of anger on the part of the Tahitian goddess Pele. Native Americans in what is now Wyoming passed down legends concerning the grooves along the sides of Devils Tower, which they said had been made by bears trying to climb the sides to escape braves hunting them.
In Western culture, among the most familiar examples of geomythology, apart from those in the Bible, are the ones that originated in ancient Greece and Rome. The Pillars of Hercules represents but one example. In particular, the culture of the Greeks was infused with geomythological elements. They believed, for instance, that the gods lived on Mount Olympus and spoke through the Delphic Oracle, a priestess who maintained a trancelike state by inhaling intoxicating vapors that rose through a fault in the earth.
Much of Greek mythology is actually geomythology. Most of the principal Greek deities ruled over specific aspects of the natural world that are today the province of the sciences, and many of them controlled realms now studied by the earth sciences and related disciplines. Certain branches of geology today are concerned with Earth's interior, which the Greeks believed was controlled by Hades, or the Roman god Pluto. Volcanoes and thunderbolts were the work of the blacksmith god Hephaestus (the Roman deity Vulcan), while Poseidon (known to the Romans as Neptune) oversaw the area studied today by oceanographers.
Among the most persistent geomyths with roots in Greek civilization is the story of Atlantis, a continent that allegedly sank into the sea. Over the years, the myth grew to greater and greater dimensions, and in a blurring between the Atlantis myth and the biblical story of Eden, Atlantis came to be seen as a lost utopia. Even today, some people believe in Atlantis, and for scholarly endorsement they cite a passage in the writings of Plato (427?-347 B.C. ). The great Greek philosopher depicted Atlantis as somewhere beyond the Pillars of Hercules, and for this reason its putative location eventually shifted to the middle of the Atlantic—an ocean in fact named for the "lost continent."
Given the layers of mythology associated with Atlantis, it may come as a surprise that the story has a basis in fact and that accounts of it appear in the folklore of peoples from Egypt to Ireland. It is likely that the myth is based on a cataclysmic event, either a volcanic eruption or an earthquake, that took place on the island of Crete, as well as nearby Thíra, around 1500 B.C. This cataclysm, some eight centuries before the rise of classical Greek civilization, brought an end to the Minoan civilization centered around Knossos in Crete. Most likely it raised vast tidal waves, or tsunamis, that reached lands far away and may have caused other cities or settlements to disappear beneath the sea.
As important as such Greek stories are, no geomythological account has had anything like the impact on Western civilization exerted by the first nine chapters of the Bible. These chapters contain much more than geomythology, of course; in fact, they introduce the central themes of the Bible itself: righteousness, sin, redemption, and God's covenant with humankind. In these nine chapters (or, more properly, eight and a half chapters), which cover the period from Earth's creation until the Great Flood, events are depicted as an illustration of this covenant. Thus, in 9 Genesis, when God introduces the rainbow after the Flood, he does so with the statement that it is a sign of his promise never again to attempt to destroy humanity.
As with Atlantis, the story of the Great Flood appears in other sources as well. Its antecedents include the Sumerian Gilgamesh epic, which originated in about 2000 B.C. , a millennium before the writing of the biblical account. Also as in the case of Atlantis, the biblical flood seems to have a basis in fact. Some modern scientists theorize that the Black Sea was once a freshwater lake, until floods covered the land barriers that separated it from saltwater.
The Flood occupies chapters 6 through 9 of Genesis, while chapters 3 through 5 are concerned primarily with human rather than geologic events. The story of Adam, Eve, the serpent, and the fruit of the Tree of Knowledge is a beautiful, complex, and richly symbolic explanation of how humans, born innocent, are prone to sin. It is the first conflict between God and human, just as Cain's murder of Abel is the first conflict between people. Both stories serve to illustrate the themes mentioned earlier: in both cases, God punishes the sins of the humans but also provides them with protection as a sign of his continued faithfulness.
In fact, the entire Creation story, source of centuries' worth of controversy, occupies only two chapters, and this illustrates just how little attention the writers of the Bible actually devoted to "scientific" subjects. Certainly, many passages in the Bible describe phenomena that conflict with accepted scientific knowledge, but most of these fall under the classification of miracles—or, if one does not believe them, alleged miracles. Was Jesus born of a virgin? Did he raise the dead? People's answers to those questions usually have much more to do with their religious beliefs than with their scientific knowledge.
Most of the biblical events related to the earth sciences appear early in the Old Testament, and most likewise fall under the heading of "miracles." Certain events, such as the parting of the Red Sea by Moses, even have possible scientific explanations: some historians believe that there was actually an area of dry land in the Red Sea region and that Moses led the children of Israel across it. The account of Joshua causing the Sun to stand still while his men marched around the city of Jericho is a bit more difficult to square with science, but a believer might say that the Sun (or rather, Earth) seemed to stand still.
In any case, the Bible does not present itself as a book of science, and certainly the Israelites of ancient times had little concept of science as we know it today. Some of the biblical passages mentioned here have elicited controversy, but few have inspired a great deal of discussion, precisely because they are generally regarded as accounts of miracles. The same is not true, however, of the first two chapters of Genesis, which even today remain a subject of dispute in some quarters.
Actually, 2 Genesis concerns Adam's life before the Fall as well as the creation of Eve from his rib, so the Creation story proper is confined to the first chapter. One of the most famous passages in Western literature, 1 Genesis describes God's creation of the universe in all its particulars, each of which he spoke into being, first by saying, "Let there be light." After six days of activity that culminated with the creation of the human being, he rested, thus setting an example for the idea of a Sabbath rest day.
As prose poetry, the biblical Creation story is among the great writings of all time. It is also a beautiful metaphoric description of creation by a loving deity; but it is not a guide to scientific study. Yet for many centuries, Western adherence to the Genesis account (combined with a number of other factors, including the general stagnation of European intellectual life throughout much of the medieval period) forced a virtual standstill of geologic study. The idea that Earth was created in 144 hours reached its extreme with the Irish bishop James Ussher (1581-1656), who, using the biblical genealogies from Adam to Christ, calculated that God finished making Earth at 9:00 A.M. on Sunday, October 23, 4004 B.C.
Religion alone is far from the only force that has slowed the progress of science over the years. Sometimes the ideas of scientists or philosophers themselves, when formed on the basis of something other than scientific investigation, can prove at least as detrimental to learning. Such is the case when thinkers become more dedicated to the theory than to the pursuit of facts, as many did in their adherence to the erroneous concept of the four elements.
Today scientists understand an element as a substance made up of only one type of atom, meaning that unlike a compound, it cannot be
During the twentieth century, with the discovery of the atomic nucleus and the protons within it, scientists further refined their definition of an element. Today elements are distinguished by atomic number, or the number of protons in the atomic nucleus. Carbon, for instance, has an atomic number 6, meaning that there are six protons in the carbon nucleus; therefore, any element with six protons in its atomic nucleus must be carbon.
Atomic, or corpuscular, theory had been on the rise for some 150 years before Dalton, who built on ideas of predecessors that included Galileo Galilei (1564-1642) and Sir Isaac Newton (1642-1727). In any case, the first thinker to conceive of atoms lived more than 2,000 years earlier. He was Democritus ( ca. 460- ca. 370 B.C. ), a Greek philosopher who described the world as being composed of indivisible particles— atomos in Greek. Democritus's idea was far from modern scientific atomic theory, but it came much closer than any other theory before the Scientific Revolution ( ca. 1550-1700).
Why, then, did it take so long for Western science to come around to the atomic idea? The answer is that Aristotle, who exerted an almost incalculable impact on Muslim and Western thought during the Middle Ages, rejected Democritus' atomic theory in favor of the four elements theory. The latter had its roots in the very beginnings of Greek ideas concerning matter, but it was the philosopher Empedocles ( ca. 490-430 B.C. ) who brought the notion to some kind of maturity.
According to the four elements theory, every object could be identified as a combination of elements: bone, for instance, was supposedly two parts earth, two parts water, and two parts fire. Of course, this is nonsense, and, in fact, none of the four elements are even really elements. Water comes the closest, being a compound of the elements hydrogen and oxygen. Earth and air are mixtures, while fire is the result of combustion, a form of oxidation-reduction chemical reaction.
Nonetheless, the theory had at least some basis in observation, since much of the physical world seems to include liquids, things that grow from the ground, and so on. Such observations alone, of course, are not enough to construct a theory, as would have become apparent if the Greeks had attempted to test their ideas. The ancients, however, tended to hold scientific experimentation in low esteem, and they were more interested in applying their intellects to the development of ideas than they were in getting their hands dirty by putting their concepts to the test.
Aristotle explained the four elements as combinations of four qualities, or two pairs of opposites: hot/cold and wet/dry. Thus, fire was hot and dry, air was dry and cold, water was cold and wet, and earth was wet and hot. It is perhaps not accidental that there were four elements, four qualities, or even perhaps four Aristotelian causes.
Much earlier, the philosopher and mathematician Pythagoras ( ca. 580- ca. 500 B.C. ), who held that all of nature could be understood from the perspective of numbers, first suggested the idea of four basic elements because, he maintained, the number four represents perfection. This concept influenced Greek thinkers, including Empedocles and even Aristotle, and is also probably the reason for the expression four corners of the world.
That expression, which conveys a belief in a flat Earth, raises an important point that must be made in passing. Despite his many erroneous ideas, Aristotle was the first to prove that Earth is a sphere, which he showed by observing the circular shadow on the Moon during a lunar eclipse. This points up the fact that ancient thinkers may have been misguided in many regards, yet they still managed to make contributions of enormous value. In the same vein, Pythagoras, for all his strange and mystical ideas, greatly advanced scientific knowledge by introducing the concept that numbers can be applied to the study of nature.
In any case, the emphasis on fours trickled down through classical thought. Thus, the great doctors Hippocrates ( ca. 460- ca. 377 B.C. ) and Galen (129- ca. 199) maintained that the human body contains four "humors" (blood, black bile, green bile, and phlegm), which, when imbalanced, caused diseases. Humoral theory would exert an incalculable toll on human life throughout the Middle Ages, resulting in such barbaric medical practices as the use of leeches to remove "excess" blood from a patient's body. The idea of the four elements had a less clearly pernicious effect on human well-being, yet it held back progress in the sciences and greatly impeded thinkers' understanding of astronomy, physics, chemistry, and geology.
Aristotle's teacher Plato had accepted the idea of the four elements, but proposed that space is made up of a fifth, unknown element. This meant that Earth and the rest of the universe are fundamentally different, a misconception that prevailed for two millennia. Aristotle adopted that idea, as well as Plato's concept of a Demiurge, or Prime Mover, as Aristotle called it. Centuries later Aquinas equated Aristotle's Prime Mover with the Christian God.
Building on these and other ideas, Aristotle proceeded to develop a model of the cosmos in which there were two principal regions: a celestial, or heavenly, realm above the orbit of the Moon and a terrestrial, or earthly, one in what was known as the sublunary (below the Moon) region. Virtually everything about these two realms differed. The celestial region never changed, whereas change was possible on Earth. Earth itself consisted of the four elements, whereas the heavens were made up of a fifth substance, which he called ether.
If left undisturbed, Aristotle theorized, the four elements would completely segregate into four concentric layers, with earth at the center, surrounded by water, then air, and then fire, bounded at the outer perimeter by the ether. The motion of bodies above the Moon's sphere caused the elements to behave unnaturally, however, and thus they remained mixed and in a constant state of agitation.
The distinction between so-called natural and unnatural (or violent) motion became one of the central ideas in Aristotle's physics, a scientific discipline whose name he coined in a work by the same title. According to Aristotle, all elements seek their natural position. Thus, the element earth tends to fall toward the center of the universe, which was identical with the center of Earth itself.
On these and other ideas, Aristotle built a complex, systematic, and almost entirely incorrect set of principles that dominated astronomy and physics as well as what later became the earth sciences and chemistry. The influence of Aristotelian ideas on astronomy, particularly through the work of the Alexandrian astronomer Ptolemy ( ca. 100-170), was especially pronounced.
It was through astronomy, the oldest of the physical sciences, that the Aristotelian and Ptolemaic model of the physical world ultimately was overthrown. This revolution began with the proof, put forward by Nicolaus Copernicus (1473-1543), that Earth is not the center of the universe. The Catholic Church, which had controlled much of public life in Europe for the past thousand years, had long since accepted Ptolemy's geocentric model on the reasoning that if the human being is created in God's image, Earth must be at the center of the universe. Copernicus' heliocentric (Sun-centered) cosmology therefore constituted a challenge to religious authority—a very serious matter at a time when the Church held the power of life and death.
Copernicus died before he suffered the consequences of his ideas, but Galileo, who lived much later, found himself in the middle of a debate between the Church and science. This conflict usually is portrayed in simplistic terms, with Galileo as the noble scientific genius defending reason against the powers of reaction, but the facts are much more complex. For centuries, the Church had preserved and encouraged learning, and the reactionary response to Copernican ideas must be understood in light of the challenges to Catholic authority posed by the Protestant Reformation. Furthermore, Galileo was far from diplomatic in his dealings, for instance, deliberately provoking Pope Urban VIII (1568-1644), who had long been a friend and supporter.
In any case, Galileo made a number of discoveries that corroborated Copernicus' findings while pointing up flaws in the ideas of Aristotle and Ptolemy. He also conducted studies on falling objects that, along with the laws of planetary motion formulated by Johannes Kepler (1571-1630), provided the basis for Newton's epochal work in gravitation and the laws of motion. Perhaps most of all, however, Galileo introduced the use of the scientific method.
The scientific method is a set of principles and procedures for systematic study using evidence that can be clearly observed and tested. It consists of several steps, beginning with observation. This creates results that lead to the formation of a hypothesis, an unproven statement about the way things are. Up to this point, we have gone no further than ancient science: Aristotle, after all, was making a hypothesis when he said, for instance, that heavy objects fall faster than light ones, as indeed they seem to do.
Galileo, however, went beyond the obvious, conducting experiments that paved the way for modern understanding of the acceleration due to gravity. As it turns out, heavy objects fall faster than light ones only in the presence of resistance from air or another medium, but in a vacuum a stone and a feather would fall at the same rate. How Galileo arrived at this idea is not important here; rather, his application of the scientific method, which requires testing of hypotheses, is the key point.
If a hypothesis passes enough tests, it becomes a theory, or a general statement. An example of a theory is uniformitarianism, an early scientific explanation of Earth's origins discussed elsewhere, in the context of historical geology. Many scientific ideas remain theories and are quite workable as such: in fact, much of modern physics is based on the quantum model of subatomic behavior, which remains a theory. But if something always has been observed to be the case and if, based on what scientists know, no exceptions appear possible, it becomes a law. An example is Newton's third law of motion: no one has ever observed or created a situation in which a physical action does not yield an equal and opposite reaction.
Even laws can be overturned, however, and every scientific principle therefore is subjected to continual testing and reexamination, making the application of the scientific method a cyclical process. Thus, to be scientific, a principle must be capable of being tested. It should also be said that one of the hallmarks of a truly scientific theory is the attitude of its adherents. True scientists are always attempting to disprove their own ideas by subjecting them to rigorous tests; the more such tests a theory survives, the stronger it becomes.
During the twentieth century, a movement called creationism emerged at the fringes of science. Primarily American in origin, creationism is a fundamentalist Christian doctrine, meaning that it is rooted in a strict literal interpretation of the Genesis account of Creation. (For this reason, creationism has little influence among Christians and Christian denominations not prone to literalism.) From the 1960s onward, it has been called creation science, but even though creationism sometimes makes use of scientific facts, it is profoundly unscientific.
Again, the reference to creationism as unscientific does not necessarily carry a pejorative connotation. Many valuable things are unscientific; however, to call creationism unscientific is pejorative in the sense that its adherents claim that it is scientific. The key difference lies in the attitude of creationists toward their theory that God created the Earth if not in six literal days, then at least in a very short time.
If this were a genuine scientific theory, its adherents would be testing it constantly against evidence, and if the evidence contradicted the theory, they would reject the theory, not the evidence. Science begins with facts that lead to the development of theories, but the facts always remain paramount. The opposite is true of creationism and other nonscientific beliefs whose proponents simply look for facts to confirm what they have decided is truth. Conflicting evidence simply is dismissed or incorporated into the theory; thus, for instance, fossils are said to be the remains of animals who did not make it onto Noah's ark.
Creationism (for which The Oxford Companion to the Earth provides a cogent and balanced explanation) is far from the only unscientific theory that has pervaded the hard sciences, the social sciences, or society in general. Others, aside from the four elements, have included spontaneous generation and the phlogiston theory of fire as well as various bizarre modern notions, such as flat-Earth theory, Holocaust or Moon-landing denial, and Afrocentric views of civilization as a vast racial conspiracy. Compared with Holocaust denial, for instance, creationism is benign in the sense that its proponents seem to act in good faith, believing that any challenge to biblical literalism is a challenge to Christianity itself.
Still, there is no justification for the belief that Earth is very young; quite literally, mountains of evidence contradict this claim. Nor is the idea of an old Earth a recent development; rather, it has circulated for several hundred years—certainly long before Darwin's theory of evolution, the scientific idea with which creationists take the most exception. For more about early scientific ideas concerning Earth's age, see Historical Geology and essays on related subjects, including Paleontology and Geologic Time. These essays, of course, are concerned primarily with modern theories regarding Earth's history, as well as the observations and techniques that have formed the basis for such theories. They also examine pivotal early ideas, such as the Scottish geologist James Hutton's (1726-1797) principle of uniformitarianism.
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