Theories for Everything highlights the rich, compelling stories behind science’s greatest discoveries and the minds and methods that made them possible. Authoritative, entertaining, and easy to follow, it provides indispensable information on our current theories about the natural and physical world as well as a concise overview of how those ideas evolved.
Each discovery is presented as a detective story: the narrative focuses on how inquisitive investigators posit, revise, and improve upon their descriptions of nature. And like any first-rate mystery, it entices its readers, inviting them to match wits with the scientific sleuths whose theories for everything have unraveled nature’s riddles and reshaped how we see our world.
Introduction from Theories for Everything
By Bruce Stutz
When we turn on the radio or television, when we receive a vaccination to prevent disease, when we recognize that although the sun seems to rise and set that it’s actually the Earth, and not the sun, that is moving—we are reaping the benefits of thousands of years of human determination to comprehend Earth’s physical and biological phenomena. And while much mystery remains, we have come to know a great deal about the nature of the planet on which we live, as well as the natures of the planets, stars, and universe beyond. The pursuit of such knowledge we call science, a word whose Greek root means not only “to know,” but “to discern,” “to separate one thing from another.” The object of science is not to simply discover facts, but to construct from facts general truths and fundamental laws. Scientist call such constructions “theories.”
In science, “theory,” does not mean “speculation” or “idea,” as it does in everyday conversation. A scientific theory is a presentation of fact. It has been arrived at by what is known as the “scientific method” by which scientists test an hypothesis with careful observation, experiment, and measurement. An hypothesis, or set of hypotheses, that has withstood every attempt to prove it false may be called a theory. The theories of gravity or evolution are not conjectures. They describe fundamental facts about life on Earth just as do Newton’s “laws” of motion, Boyle’s law of gases, Mendel’s laws of heredity, and the law of conservation of energy.
Can a theory be proven false? If science finds contradictory evidence and that evidence, once tested, proves sound, then a theory will either be changed, if it can be, to accommodate the new evidence, or discarded. A theory must be potentially falsifiable—that is, made up of assertions that in principle can be proved wrong by evidence—since, as opposed to ideas or conjectures, a theory’s truth must be able to be tested so that it can be proved or disproved.
Although “science,” as we know it—a distinct discipline ruled by formal methods of investigation—has only existed for a few hundred years, our present knowledge has ancient antecedents. We might not even recognize some of them as science, for science itself has changed the way we look at the world. As a survey of the histories of scientific theories, then, this book may also be seen as a history of the way in which humans came to see and understand the world.
This kind of knowledge rarely arrives in dramatic “Eureka!” moments of unanticipated discovery. Just as rare is the unerring path from hypothesis to breakthrough. Science may appear to be a continuous process in which each generation improves upon the previous generation’s insights—an unbroken sequence of revelations that lead to greater enlightenment—but it’s more messy than that. The journey to most insights often includes countless blind alleys, wrong or only partially right ideas that may be vigorously defended and in their apparent correctness sometimes obscure the truth.
The sudden emergence of a single set of concepts or one uncommonly brilliant thinker does not typify normal scientific progress. Great minds more often than not synthesize the work of many minds. Isaac Newton, a great mind with a capacious ego, wrote that “if I have seen farther, it is by standing on the shoulders of giants.” If the names of these other “giants” do not appear very often beside the more familiar names of Newton, Faraday, and Einstein, they nonetheless helped make their scientific journeys possible.
Science has no doubt altered the course of history, but the reverse is also true. Commerce, cultural exchange, voyages of discovery, war, religion, and art, have all had their effects on the development of science.
So has technological innovation. This book does not purport to be a history of technology, but throughout are examples of tools, techniques, and instruments that helped to propel the scientific process. The telescope and microscope gave scientists glimpses into worlds as yet unseen. Electrical generators, x-ray machines, and computers facilitated discoveries that without them would have been impossible. Some innovations caught science unawares. Both gunpowder and the steam engine altered the course of history before the science of either one was fully understood. On the other hand, the invention of the radio and electric generator came out of advances in scientific understanding.
Innovation and invention have always moved and been moved by science. Two million years ago, Homo habilis, a distant ancestor of Homo sapiens, developed wood and stone tools. The regularity of these artifacts is evidence that Stone Age humans realized that similar techniques eventually produced consistently similar results. The use and mastery of fire that began around a million years ago was another key ancient technology.
Until relatively recently, human beings were hunter-gatherers. Around 8000 b.c., as the menacing glaciers of the last ice age receded, humans began to develop a talent for planting and raising crops, and corralling wild animals. Gradually, humans domesticated both plants and animals and, through much trial and error, and across several parts of the world in succeeding centuries, developed new hybrids and breeds. By 6000 b.c., inhabitants of the Fertile Crescent in the Middle East had succeeded in breeding more productive kinds of wild barley and wheat. People in what is now Mexico were in the process of domesticating teosinte, the wild ancestor of modern maize. Cultures arising in present-day Peru, central Africa, and eastern China, were raising animals.
The success of this agricultural revolution as it spread across the Earth altered the future of all human cultures. People began to give up their nomadic existences and live in permanent habitations. These grew into cities. As stable population centers arose, it became more efficient to share resources. Sharing resources also meant sharing and comparing knowledge. In these ancient settings, in such places as Babylon and Mesopotamia, the first rudimentary sciences flourished.
The need to account for stores of grain or head of cattle, to measure and record the weight of a bushel or jugful, the size of a plot of land let to numbering systems. These numbering systems—at first no more than symbols cut into clay—eventually grew into written language. By about 2400 b.c., Sumerians in Mesopotamia had developed a numbering system based on the position of these symbols. That method, called positional notation, made counting and mathematics considerably easier and, in turn, allowed mathematical thinking to become more complex.
The Mesopotamian numbering system, and later versions that developed from it and spread through the region, used a base of 60. Although our numbering system is a base-10, or decimal, system, the vestiges of the ancient base-60 system are still everywhere in our daily lives. We have 60 minutes to the hour, 60 seconds to the minute, and 360 degrees to the circle thanks to this 4,000-year-old Middle Eastern practice. (What none of the great Mesopotamian cultures—the Sumerians, Babylonians, and Chaldeans—were able to develop, however, was the concept of zero or a cipher to represent it.)
As early as 1800 b.c.—more than a thousand years before the first Greek philosophers—Mesopotamian thinkers had developed a sophisticated geometry and could solve the equivalent of equations with powers of two. Moreover, they compiled tables of what are now termed Pythagorean triples, numbers that could represent the length of the sides of a right triangle. A general theorem stating the relationship of those lengths—known as the Pythagorean theorem after the sage Pythagoras—would not arrive until the time of the Greeks.
Numerical patterns, of course, were largely a creation of the human mind. But there was another, far more fundamental source of regularity in life: the daily course of the sun and nightly rotation of the moon and stars. Because the position of the sun and the orderly progression of the seasons affect human life directly, they were the subject of early and careful record-keeping. For this reason, astronomy was the first highly organized science.
By 3000 b.c., if not earlier, the Egyptians had developed a 365-day calendar. Their year began with the annual flooding of the Nile, an event of paramount importance for agriculture. The zodiac—the observed positions and movements of stars—was formulated and systematically described around 1600 b.c. by the Chaldeans. By 750 b.c., the Babylonians were recording solar and lunar eclipses. During the same period, the Chinese were already keeping detailed and sophisticated astronomical records that, in the 19th and 20th centuries, would prove useful in confirming the cycles of comets.
Astronomy not only occupied a great deal of intellectual effort but also frequently called for a stupendous amount of physical labor in erecting what some experts believe were the first observatories. For example, around 2500 b.c., the inhabitants of what is now the Stonehenge, England, somehow transported 14-foot long, 30-ton blocks of stone from a 20-mile radius in order to build a circle of stone columns on the nearby Salisbury Plain. Whether Stonehenge served an astronomical purpose in the modern sense or not is still uncertain. (Our present distinction between the exact science of astronomy and the pseudoscience called astrology did not then exist, and would not for thousands of years.) But dutiful celestial observation were made, even if with the intent of finding, in the heavens, some presumed portent of good or ill.
Around the sixth century b.c., however, a new kind of thinking, one that would fundamentally alter the course of human development, arose in the burgeoning city-states of Greece. A bit of knowledge we take for granted will illustrate this new thinking:
Stretch a string between two points and pluck it. It creates a sound. Half the length of the string and pluck once again. Now the note sounds the same but its pitch is different—higher. Half the string again and once again the note sounds the same but once again it’s higher still. Sometime in the 6th or 7th century BC it was discovered that by halving the length of a string the pitch when it’s plucked is exactly an octave higher. (We know now that the string is vibrating at twice the frequency.) The same ratio worked with the length of pipe in a flute. The Greeks realized they could further subdivide the octave: At 2/3 its length the tone is a fifth higher and at 3/4 its length the tone is a fourth higher.
Although they developed a different musical scale, the Chinese came to the same realization at about the same time. They also found a practical use for their new knowledge. They replaced measurements based on parts of the human body for those based on the lengths of pitch pipes. The volumes of a bowls used for measuring grains were based on the pitch of the empty bowls when struck. In old Chinese the word for “grain measure” also means “wine bowl” and “bell.”
The Pythagoreans were not quite so practical, but the idea that sound could be described mathematically was one of a number of discoveries that led toward a realization that natural phenomena could be subjects not only to speculation and observation, but of quantitative analysis.
The era of classical Greek science was about to begin. Arising in the Ionian City of Miletos in the early 6th century b.c. where “natural philosophy” was born, broadening its influence along with its interests this great creative period lasted until early in the first century a.d. The names associated with this period—Thales, Anaximander, Heraclitos, Pythagoras, Parmenides, Socrates, Hippocrates, Plato, Eudoxos, Aristotle, Euclid, Archimedes, and Ptolemy—are those of men whose original thinking, formed the basis of sciences as diverse as astronomy, geology, geography, biology, medicine, geometry, and physics.
Much of their work would be preserved, revised, and advanced by scholars, scientists and mathematicians of the Islamic world with its capitals in Baghdad and Cairo. The sciences of Renaissance would build upon the discoveries made before them and with the introduction of the printing press give their age its own spirit of adventurous experiment and speculation. Voyages of discovery would widen the worlds of science just as would the telescope and microscope. All these discoveries would require new methods of investigation. Science, as we now know it, with its distinct fields of study, began to develop. By the 19th century, however, it began to become apparent that the distinctions between sciences might be less than thought. The forces of heat, light, electricity, and magnetism were found to be nearly identical. The forces they described acted on molecules and atoms very similarly as they did among planets and stars. With the discovery of DNA molecules in the 20th century, it was clear that living things, too, were subject to some of the same laws that ruled the microcosmos. Was there a theory that unified it all? That question remained in the 21st century, as did the new mysteries of viruses, prions, and ancient cells that lived deep in the oceans.
The history of science is not a single narrative. Advances in astronomy moved at a different pace than those psychology. Until the discovery of cells in living tissue, the science of biology progressed slowly and awkwardly, just as until the discovery of gases the science of chemistry and physics seemed stuck in the alchemist’s den. Each science has its own compellling story of discovery. And that is why this book is divided into six narrative histories: The Heavens, The Human Body, Matter and Energy, Life Itself, Earth and Moon, Mind and Behavior.
Since these often share their Greek and Islamic origins, the reader will soon become familiar with the scientists whose names appear and reappear: Plato and Aristotle, for instance, contributed insights that shaped scientific thought in many fields, just as did Galilleo, Newton, Bacon, Descartes, Lavoisier, Lyell, and Faraday. Essays in each chapter will focus on key milestones in understanding and theory. Fact boxes and diagrams will illustrate concepts that are often easier to visualize than to describe. Finally, links will indicate the points where one story and another converge which is, finally, what scientists themselves are always seeking.