The Rules of the Game: The Original Rulebook
We obviously have no certain knowledge of the picture of reality that prehistoric peoples had. We do not know, for example, whether early human types, such as Homo habilis, even had the mental capacity to form an overall picture of the world. Even if we assume that such a capacity did not exist prior to the evolution of Homo sapiens, it is likely that early sapiens’ conceptions of the world leaned heavily on magical and supernatural explanations, although we cannot know to what degree. With sapiens we do have cave art from a variety of locations, but it is difficult to infer specific meanings from much of it, and one cannot often glean from it the conceptual schemes of the world and the Universe held by prehistoric peoples. We can gain some insights into prehistoric conceptions through the study of mythology, especially as it has been handed to us in oral traditions, but we must assume that these stories have themselves gone through long processes of development, and only give us hints of the thinking of our earliest ancestors.
The ability to conceive of tools is evidence of a self-reinforcing intellectual capacity, and the technology of the earliest humans was one of their survival advantages. Indeed, the possession of technology is one of the criteria by which our genus is often defined. The technology that was devised by the earliest humans was starkly utilitarian and crude, and few tangible advancements were made in it for many centuries. But it sufficed for most purposes, and the skills prehistoric people possessed allowed them to exploit and survive in a wide variety of environments on the Earth’s outer crust. As their tool kits became more varied and sophisticated and their skills databases expanded over the millennia, so did their ability to increase their mastery of these environments. But however skilled they were, we must assume that our ancestors’ theoretical knowledge of the physical world was effectively nil. They knew how to make a living out of the world, but they didn’t know what the world was or how it worked.
The human attempt to understand the mechanics of the world began in earnest (as far as we know) when humans formed societies in which at least some people commanded the ability to use written symbols to convey meaning. As language (including mathematical language) became more sophisticated, so did the hypotheses offered to explain how the world worked. So what did our ancestors know of the physical reality in which they lived? How much insight did they really have?
A (Very) General Summary of Pre-Modern Knowledge of the Physical World
Mesopotamia and Egypt
The Egyptians developed a decimal-based number system as early as 3000 BCE, although its symbols lacked the utility of the Hindu-Arabic numerals in use today. The skill of the ancient Egyptians in using mathematics for engineering almost goes without saying. Most notably, the Egyptians developed a practical calendar of reasonable accuracy. But their knowledge of the principles of the physical sciences was non-existent. The Egyptian picture of the cosmos was at first severely limited in conception, essentially a box with Egypt at the center of the box’s bottom section, lit by fixed lights attached to the roof of the box. Later, there were attempts to explain the movements of the stars and the reasons the Sun rose recurringly in the east.1
In Mesopotamia, the Babylonians developed more advanced mathematics than the Egyptians, and it was used, among other purposes, in the service of astronomy. By 500 BCE Babylonian astronomers were skillful enough to make astronomical predictions with some accuracy, although this skill was often put to the service of astrological nonsense. But it cannot be said that any comprehensive theory of the world’s functioning emerged from Mesopotamia’s long history. There were, of course, religious cosmologies that were formed, but they were as parochial in nature as those of Egypt.2
In pre-modern China, the study of physics was not strong, and the Chinese never developed an atomic theory, tending to conceive of matter and energy purely in wave-like terms. There was a great deal of interest in magnetism, in the study of which Chinese scholars exceeded all others. This led to the development of useful compasses as early as the eighth century CE. There was also much study done in optics. Serious research on optics was well advanced by the fourth century BCE, particularly within a circle of philosophers known as the Mohists, who described many of the properties of mirrors and refraction. Chinese thinkers attempted to systematically define terms related to movement, mass, and measurement, and worked to standardize the system of weights and measures. Chinese researchers attempted to describe such phenomena as the center of gravity, buoyancy, and displacement of objects in water. Well before the Common Era some Chinese researchers postulated that sound was a sort of vibration, and much later, Chinese scholars studied the properties of music and made some genuine progress in acoustics.
In astronomy, the Chinese made an impressive number of observations, and the Chinese attributed great significance to astronomical phenomena, owing to the central role the heavens played in China’s cosmic-oriented religion. China’s astronomical records are often the only ones in the world that still exist for the period of the fifth century BCE to the 15th century CE. Chinese astronomers catalogued over 1,000 major stars, identified many constellations, noted recurring events such as the appearance of comets at fixed intervals, and recorded eclipses as early as 734 BCE. A Chinese observer noted what we now believe to have been a nova event as early as 1300 BCE, and Chinese astronomers were the only ones in the world to record a massive supernova event in 1054 CE, one of only three such events ever recorded in the pre-modern era. In short, for many centuries China led the world in this important natural science.
But Chinese discoveries, such as the existence of magnetism, were often put to such dubious uses as divination, and Chinese astronomy was always entangled with astrological pseudoscience. Moreover, religious mysticism permeated much of the investigation of nature in China, as it did in so many other places. Most critically, science in China was not honored in the same way that skill in philosophy or government was, and brilliant Chinese researchers often worked in isolation. The Chinese used their technical skills to create a great many practical inventions and processes, and their achievements in engineering were remarkable, yet those who made such achievements possible usually possessed second-rate status in educated Chinese society. We must conclude, therefore, that although the Chinese learned a great deal about the outward phenomena of nature, they did not possess a strong grasp of the principles underlying those phenomena.3
Early in the Common Era, astronomers in India knew that the Earth was a sphere, and in the 7th century CE the astronomer Brahmagupta made a fairly accurate estimate of the Earth’s circumference. But the fact of the Earth’s sphericity was opposed by India’s religious leaders, who insisted that we live in a flat world. In astronomy, Greek ideas filtered into India, were augmented by Indian discoveries in mathematics, and circulated back to Europe by way of the Arabs. Indian astronomers identified five planets outside the Earth, but generally adhered to the idea of a geocentric Universe. There was an Indian astronomer in the 5th century CE, Aryabhata, who postulated a heliocentric solar system, but his ideas never gained wide acceptance.
In physics, Indian scholars generally conceived of five elements (fire, air, earth, water, and ether). Indian scholars postulated an atomic theory, and thought the five elements to be atomic in nature. Indian atomism was not based on experimentation, of course, but rather on guesswork and the application of logic. Indian physicists never devised a comprehensive gravitational system, although some of them speculated about the existence and nature of gravity. By 700 CE some Indian researchers understood that sound was propagated by waves, and attempted to explain the various kinds of physical motions. But it cannot be said that physics in India was anything but rudimentary in nature, and in India, as elsewhere, applied science and technology far outstripped pure science.4
Sub-Saharan African societies made great strides in applied science, particularly agronomy, engineering, and metallurgy, but there is little evidence of extensive theoretical inquiry, a pattern typical of almost all human societies. There is evidence that mathematical consciousness, in the form of tally sticks, was emerging in southern Africa during the Paleolithic Era. A number of stone megaliths have been discovered in eastern and central Africa, but whether they were astronomical in nature is difficult to determine.5 Impressive stone buildings, begun in the 11th century CE, have been found in Zimbabwe, and the medieval empires of West Africa, specifically Ghana, Mali, and Songhai, incorporated a great deal of Arab scientific thought (along with Islam) into their own storehouses of knowledge. In northeastern Africa, Egyptian, Greek, and various Middle Eastern cultures cross-fertilized each other, sharing and disseminating knowledge in a complex manner. And, as in most cultures, African conceptions of the Universe were saturated with religious thinking.
The Islamic World
Islamic scholars generally embraced Ptolemy’s views on the nature of the Universe (see below). The great Arab mathematician al-Khwarizmi helped introduce Hindu-Arabic numbers to the West and made a major contribution to the development of algebra. The Arabs preserved much of the scholarship of classical Greece, most notably the work of Aristotle, and in physics Arab scholars studied optics, investigated specific gravity, and examined the physical properties of music. The Arabs made great strides in medicine, particularly ophthalmology, and throughout the Islamic world engineering and construction reached advanced levels. In late medieval Europe the greatest libraries on the continent were in Islamic Spain, and Christian scholars traveled there to partake of their holdings. A thriving Jewish intellectual community existed in Islamic Spain as well.
But Islamic scholarship has always been harnessed to the service of the Islamic faith, and the Koranic view of reality has always been given priority. There was a decline in Arab science in particular beginning in the 14th century, as the rationalism that lies at the very foundation of scientific thought came under attack by religious authorities.6
Both Mayan and Aztec astronomers constructed viable calendars, deeply intertwined with religious observations. The Mayans and Aztecs in Mexico and the Incas in Peru were accomplished in the engineering and construction of major buildings and even whole cities. They also had great skill in agriculture and metallurgy. Native Americans north of Mexico often made observations of the stars, and an American anthropologist writing in the early 20th century argued that there were Pawnees who arranged villages to represent objects in the sky, chiefly as part of star worship.7 Native Americans north of Mexico mastered a huge range of practical skills and built considerable settlements and monuments in some regions. The cosmologies of the Native Americans both north and south of the Rio Grande were overwhelmingly religious in nature. There is little evidence of any organized scientific endeavors.
Pre-modern Europeans had a great many practical survival skills, and as the Paleolithic Era waned into the Mesolithic, beginning around 8000 BCE, we see evidence that their skill in making stone, wooden, and bone tools had grown to be very sophisticated. There is evidence of metallurgy in southeastern Europe as early as the seventh millennium BCE as well. Pre-modern Europeans established permanent settlements in some places, such as the lakeside settlements in Switzerland, and they constructed monoliths such as Stonehenge. Stonehenge, indeed, may—may—have been an astronomical calculator. There is evidence that other ancient European megaliths may also have had astronomical significance. But the star-observations of the ancient Europeans in all probability simply supported their religious cosmologies, and before the Greek philosophical experiment began in the sixth century BCE, there is little evidence of any attempt to explain the world in a dispassionate manner.
Some researchers have, in recent years, presented evidence that the aboriginal inhabitants of Australia, split into many different tribes, had a surprisingly advanced knowledge of the objects they saw in the night sky, distinguishing planets, constellations, and according to some sources, even the presence of galaxies outside of our own. Aboriginal observers noted both solar and lunar eclipses, and speculated about comets and asteroids. There was also calendar making based on the positions of stars at various times, with as many as six seasons noted. Naturally, Aboriginal peoples possessed an extensive tool-making tradition, which helped them survive in Australia’s beautiful but austere environment, as well.
But aboriginal Australian conceptions of the Universe were thoroughly intertwined with their mythology, as they were used to explain The Dreaming or Dreamtime, the creation of the world by the gods in the distant past. There was no separation between this mythology and the many observations of the night sky that were made.8
The Pacific Islands
The Polynesians who settled much of the Pacific before 1000 CE were superb boat builders, and it has been said with justice that their excursions into the uncharted Pacific in dugout canoes were the equivalent of heading into outer space without a map. The Pacific Islanders possessed a large array of tools, and developed a widespread system of aquaculture in the Hawaiian islands, a system that became a major food source. Perhaps their most spectacular achievement was the building of the stone figures on Easter Island, the construction of which showed great engineering prowess. But although there were phenomenal celestial navigators among the Pacific Islanders, there is no evidence of any organized scientific attempt by the Polynesians or the Tahitians to comprehend the physical Universe.
It is clear from this admittedly cursory examination, one that encompasses perhaps 20,000 years of human prehistory and history, that a pattern asserts itself in human societies again and again: know-how far outstrips theoretical knowledge. And even in that study of natural phenomena that did take place in many parts of the human world, observation greatly exceeded explanation. It is one thing (admittedly a necessary one) to catalogue large numbers of stars. It is quite another to understand how those stars work and the role stars have played in bringing humans into being. Scientists in the pre-modern era often glimpsed what was happening, but they had little conception of why it was happening, at least why it was happening on the deep physical level. Moreover, the knowledge accumulated by Mesopotamian, Egyptian, Chinese, Indian, African, Muslim, pre-Columbian American, ancient European, aboriginal Australian, and Pacific island scholars was not shared to anywhere remotely near the degree that knowledge is shared now, and the knowledge that was shared was often conveyed haphazardly over a very long period of time.
Our brief examination of the scientific progress, especially in physics and astronomy, of various cultures of the pre-modern era reveals that their knowledge of the physical world was sketchy at best, uneven, and riddled with religious conceptions that obscured rather than clarified the workings of nature. Knowledge of how the world worked was crude—there is no way of denying it. In every instance, supernatural and mythological thinking pervaded the knowledge that was gathered. Before the emergence of the modern scientific era, there was little attempt made to distinguish between discovery and belief, and indeed, discovery was almost always put in the service of belief.
Even the much-vaunted Greek exploration of the world was filled with error and misconceptions. But it captured the imagination of educated people in many parts of the world, influencing thinking in south Asia, the Middle East, and most significantly, the Roman world. It was the breadth of the Greek inquiry that aroused interest in so many others, and the earnest way in which the best Greek scholars pursued knowledge evoked widespread admiration.
The Greek Quest and Its Inheritors
In the sixth century BCE, the philosophers who lived on the eastern shore of the Aegean Sea began their project to figure out the shape and composition of the Earth, the Earth’s position in space, and the motions of the various bodies, both terrestrial and cosmic, that humans observed. The inquiry they started differed from all the others to which I have just referred in one crucial sense: these thinkers were going to make an attempt to understand the world without recourse to supernatural explanations.
The earliest of the Greek philosophers who speculated about these matters was Thales (c. 620-c. 546 BCE), from the town of Miletus. Thales speculated that water was the most significant element, and that the Earth was a flat disc that floated in water. Thales is also reputed to have predicted a solar eclipse in 585 BCE, but modern researchers tend to discount this. Anaximander (c. 610-546 BCE) believed that the Earth was a cylinder that floated unsupported in space, and that the surface we live on is the flat top of the cylinder. Anaximenes (d. 528 BCE) believed that air was the source of all things and that the Earth was a flat disc. We smile at what we suppose to be the naïveté of such notions, but these philosophers did the best they could with the extremely limited knowledge they had, and they did not try to invoke mystical explanations when they were baffled.9
But not all pre-Socratic thinkers separated the mystical from the physical. Pythagoras (circa 570-500 BCE) is still a major figure in intellectual history, but nothing he wrote has survived. He is known only through his acolytes. Pythagoras looked to mathematics as the foundation of reality, seeking in it the nature of the Universe. The Pythagoreans established certain key principles, such as the qualities of geometric figures (most notably triangles), advanced the notions of mathematical proof, and also discovered the link between numbers and the sounds we perceive as music. But the Pythagoreans’ discoveries were thoroughly imbued with mysticism, and they ascribed magical qualities to numbers, using what can only be described as numerological pseudo-science. The followers of Pythagoras believed all manner of nonsense about the Universe (such as the weird notion of the “music of the heavenly spheres”). Pythagoras’s name will always be attached both to the concepts of mathematical logic and the sheer irrationalism of his followers.10
Plato (427-347 BCE) conceived of a reality that was knowable only through philosophical reflection, which he believed to be superior to sensory experience. In The Republic, he asserts that humans see only the shadows of reality. In Plato’s view, humans must tear themselves away from the shadow-play that they have been taught is real and go out into the blinding sunlight of true reality. (See Inside the Cave, Inside the Theater, in a later volume, for more on this.) Elsewhere, Plato asserted that planetary motion is perfectly circular in nature. It was Plato’s bizarre (to my mind) insistence that it must be so because the realm of the stars and planets cannot be anything except perfect and the circle was a “perfect” form. Plato was, in effect, imposing his preferred notion of symmetry on the Universe, one grounded in aesthetic rather than scientific principles.
Aristotle (384-322 BCE) must be seen as the founder of Western physics, if only because of the extent of his influence. He attempted to establish principles by which physics could proceed, but unfortunately did not underpin his system with rigorous mathematical reasoning, preferring to use philosophical ideas of his own devising. Aristotle was also seemingly averse to experimentation. He believed, based on logic, that if an object is twice as heavy as another object, it must fall twice as rapidly. It never occurred to him, evidently, to conduct even the simplest test of this utterly false hypothesis.
And while we quite properly honor Aristotle for the range and depth of his thought, (and such contributions as his work in zoology) we must always bear this fact in mind: modern physical science only advanced when Aristotle’s ideas were overthrown. Virtually every one of Aristotle’s views on the natural world turned out to be mistaken, especially his Earth-centered cosmology. His syllogistically-based reasoning turned out to be deeply flawed as well. Of course, Aristotle cannot be blamed for the dogmatic way in which his ideas were embraced and defended by others, but it must be said nonetheless that his influence on science was, in certain respects, not a benign one.
In the Hellenistic Era, some remarkable breakthroughs were made. Aristarchus of Samos, as noted earlier, was the only major Greek thinker to postulate a Sun-centered Universe. Eratosthenes, using only geometry and simple arithmetic, was able to estimate the circumference of the Earth with surprising accuracy. [By the way, educated people have, for many centuries, understood that the Earth was a sphere. It is a myth that belief in a flat world was universal in the pre-modern era. It was the dimensions of the sphere that were in question, not the fact of the Earth’s sphericity itself.] Archimedes of Syracuse, whose life spanned most of the third century BCE, can reasonably be said to be the founder of mechanics and perhaps the greatest mathematician in the Greco-Roman world. Archimedes did major work in hydrostatics, the contribution for which he is best known. He also mathematically elucidated the principle of leverage, and was able to apply what he had learned in the construction of several innovative devices. Further, his mathematical discoveries proved to be catalysts for the thinking of mathematicians in proceeding centuries.11
In the fifth and fourth centuries BCE Leucippus and his much better known disciple, Democritus (from Abdera), promulgated the first true atomic hypothesis in the Western world. In their conception, atoms were the smallest and most fundamental of all things, indestructible and indivisible. They were too small to be seen, eternal, constantly in motion, and of different shapes. It was the atoms coming together to form objects or breaking apart to destroy objects and then recombining to make new ones that accounted for the ever-changing physical processes around us. The thinking of the atomists was later championed by the Roman poet Lucretius (c. 100-c. 55 BCE). Lucretius, living in a tumultuous period of Roman history, fixed his attention on what he considered timeless physical principles. His hypotheses about atoms (not scientifically-based) included the statement that sentient beings are composed of insentient atoms, that atoms are colorless in themselves, and that no visible object is composed of a single kind of atom. These are, of course, mere suppositions on his part, but he did strike a surprisingly modern-sounding materialistic note in one particular passage:
If anyone elects to call the sea Neptune and the crops Ceres and would rather take Bacchus’ name in vain than denote grape juice by its proper title, we may allow him to refer to the earth as the Mother of the Gods, provided that he genuinely refrains from polluting his mind with the foul taint of superstition. In fact, the earth is and always has been an insentient being. The reason why it sends up countless products in countless ways into the sunlight is simply that it contains atoms of countless substances.12
Early in the Common Era, the work of Claudius Ptolemy of Alexandria (~87-150 CE) became the accepted standard of astronomical thought. In his works, Mathematical Syntaxis and The Planetary Hypotheses, he presented a thorough and seemingly consistent picture of celestial mechanics, one that was successful in predicting the position of planets. It was based on a system of elaborate epicycles (the purported movement of planets in circles around an axis while they were also in orbit around the Earth) and a world system in which the Earth was motionless, occupying a fixed position in space. Ptolemy’s skill in mathematics and the success of his model in preserving the Universe as it appears to be won him tremendous acclaim. His Mathematical Syntaxis came to be known, ultimately, as The Almagest, and it was considered, particularly by Arab scholars, to be the definitive picture of physical reality.13
The European Middle Ages, contrary to the opinion of certain observers from the 18th century onward, were not an intellectual wasteland. As we will note elsewhere, Medieval civilization produced and disseminated a surprising range of technological innovations. And it is worth remembering that thinkers and researchers throughout the long European medieval era investigated many areas of the natural world, accumulating an impressive body of data and observations. Medieval scholars delved into the physical sciences in a number of ways, looking at such topics as force, inertia, and mass, and Roger Bacon speculated about the nature of light. Yet, after all is said and done, it must be said that the greatest minds of the Middle Ages were concerned above all with two main issues. The first was the nature of Christian doctrine and its relationship with the real world, such as Peter Abelard’s attempt to describe the limits of human reason in defining the Trinity,14 or Thomas Aquinas’s attempt to prove that Christianity was compatible with, and demonstrated by, reason. The second, which was thoroughly intertwined with the first, was the attempt to preserve what were seen as the timeless and true ideas of Greco-Roman civilization, such as Aristotle’s cosmology, and to reconcile the ideas of the Greek philosophers with Christian theology. So while it can be said that the Middle Ages were not bereft of scholarship, it must be said that the scholarship of the era was used chiefly to buttress the accepted worldview of the religious authorities of Europe, not to seek out new views about the ultimate nature of the physical world.
The Modern Perspective Begins to Emerge
It was the seeming assault on the religious worldview that accounted, in large part, for the hostility that greeted the ideas of the Polish mathematician and astronomer Nikolai Koppernigk, better known as Nicolaus Copernicus (1473-1543). It was Copernicus, seeking to restore the simplicity and uniformity of circular planetary motion to astronomy, who posited a Sun-centered Universe in his 1543 work De Revolutionibus Orbium Caelestium. Copernicus (who wisely waited until he was on his death bed before authorizing the book’s publication) set off a firestorm of controversy which was to have far-reaching consequences. And in demonstrating that a Sun-centered system simply made more mathematical sense than an Earth-centered one, he (unwittingly) began the process of pushing humanity out of the central position it had occupied in human thinking since time immemorial. (For more see the chapter Science in a subsequent volume.)
But the first truly immense modern contributions to the Western understanding of the Universe, our Solar System, and physical motion itself came not from Copernicus but from two astronomers, one German, the other Italian, who set the stage for the true revolution that was to come. The German was Johannes Kepler (1571-1630), who rejected the teachings of his mentor Tycho Brahe, and destroyed geocentrism once and for all. Kepler also elucidated the laws of planetary motion. He proved that the orbits of the planets are elliptical rather than circular and effectively eliminated Plato’s notion of the “perfection” of heavenly motions. The other astronomer, the Italian, was Galileo Galilei (1564-1642). It was Galileo’s genius that truly ignited what has somewhat misleadingly been called the Scientific Revolution.
Galileo was an extraordinary observer of the cosmos. Using a telescope based on a Dutch model but much improved by Galileo’s own modifications, he observed the irregularities of the Moon’s surface, recorded the activity of sunspots, and was the first human to see the moons of Jupiter. Galileo was also a passionate and eloquent defender of the Copernican System, and in his seminal work, Dialogue Concerning the Two Chief World Systems, published in 1632, he so completely and thoroughly demonstrated the truth of the heliocentric view of reality that he stirred the ire of those authorities who still clung to the Ptolemaic System. Called before the Roman Inquisition in 1633, Galileo recanted his findings under threat. But the system of the world he proposed was gradually accepted by all but a stubborn few.
Galileo also worked on the basic laws of motion, developing the law of inertia (which describes the resistance of objects to changes in their velocities), the law of uniform acceleration (in a vacuum objects will fall at the same rate regardless of mass), and the effect of gravity in causing this acceleration. For his work in astronomy and the physical sciences, therefore, Galileo is justly considered one of the greatest of all scientists.
So, much of the groundwork had been laid by the early 17th century. But it would take an intellect of extraordinary dimensions and capacity for innovation to bring all of the various discoveries about the physical world together and illuminate them with his own blindingly brilliant insights and conceptions. That intellect, of course, belonged to Isaac Newton (1642-1727).
It was Newton, beginning in the 1660s, who brought all the strands together, building on the work of others (such as the great 17th century mathematician Pierre de Fermat), conceiving of new experiments, developing a new mathematical tool (the calculus) to assist him, and establishing no less than an over-arching conception of the Universe itself, one that persisted for almost 250 years before it was modified. Newton’s most famous work was Philosophiae Naturalis Principia Mathematica, published in 1687, a forbiddingly difficult work that summarized Newton’s mathematical descriptions of motion and his ideas on universal gravitation. Newton formulated the inverse square rule of gravitational attraction, and described a Universe which essentially ran as a mechanism.
The most famous of Newton’s ideas about the mechanics of the Universe were summarized as…
The Laws of Motion
In Newton’s own words, these laws are as follows (from Principia, 1729 edition, published two years after Newton’s death):
Every body continues in its state of rest, or of uniform motion in a right line, unless it is compelled to change that state by forces impressed upon it.
The change of motion is proportional to the motive force impressed; and is made in the direction of the right line in which that force is impressed.
To every action there is always opposed an equal reaction: or, the mutual actions of two bodies upon each other are always equal, and directed to contrary parts.15
The wording of Newton’s laws has been refined over the years. These laws are now typically expressed in this manner:
Law of inertia: Every object persists in its state of rest or uniform motion in a straight line unless it is compelled to change that state by forces impressed upon it.
Law of acceleration: Force is equal to the change in momentum (mV) per change in time. For a constant mass, force equals mass times acceleration, F = ma.
Law of action and reaction: For every action, there is an equal and opposite reaction.
Law of action and reaction: For every action, there is an equal and opposite reaction.
It was these physical laws, along with Newton’s concept of gravitation, that educated humans saw as the basis of physical reality itself—a reality that was knowable and comprehensible. The precise, interconnecting, clockwork Universe postulated by Newton was so orderly, so open to rational inquiry, so overwhelmingly Euclidean in its straight lines, and so seemingly comprehensive a description of reality that it engendered an excitement among the West’s intellectuals. This excitement led to the conviction that if the laws of nature itself were discernible and understandable, how much more so must be the laws that govern human society and human history. Newton’s thought therefore had a huge influence on the rise of the Enlightenment (Voltaire was particularly taken by him), and it was Newton’s view of the Universe that shaped the view of the Universe held by virtually all educated Westerners.
The Other Major Physical Laws
Over the course of the decades following Newton’s life, the physical and chemical sciences expanded their inquiry into the nature of the world. Perhaps no work was more important than the discovery of the laws that govern the transference of heat from one body to another, and the conversion of energy and heat into work. Beginning in the 1820s with Sadi Carnot, this research was later carried forward by such figures as James Joule (who did significant work in ascertaining the properties of energy), Rudolf Clausius and William Thomson (aka Lord Kelvin). By the 1860s, the basic thermodynamic rules had been worked out, and with them, a major set of principles which govern our reality.
The Laws of Thermodynamics
First Law of Thermodynamics
The First Law states that energy is conserved, or more formally, the change in internal energy of a system is equal to the heat added to the system minus the work done by the system. In other words, energy can be neither created nor destroyed. It can only be converted from one form to another. (But see the discussion of Zero Point Energy in the chapter Beginning.)
Second Law of Thermodynamics
The Second Law of Thermodynamics is one of the most significant discoveries in the history of the physical sciences. It is also one that is commonly misinterpreted. Stated succinctly, it states that in a closed system, energy-matter will invariably arrive at complete entropy, a state of total non-action and permanent stasis. The implications of this are very significant. It means that it is impossible for heat to move in any way except from a hot object to a cooler one. It means that all energy will eventually be dissipated. It means that order inevitably devolves into chaos. It means that all of physical reality is, overall, in complete thermal equilibrium. And it means that the entire Universe is headed, ultimately, to a state of complete entropy.
Some opponents of evolution (or at least of any evolutionary system that is not divinely guided) have seized on these facts to maintain that the order and complexity we see around us could not have arisen naturally. But a crucial fact must be understood: The Earth is not a closed system, and living things are not closed systems. The Earth and its complexity will someday be swallowed up in the death of the Sun, and the Milky Way Galaxy and all other galaxies and all other physical entities will eventually dissipate and the energy-matter of which they are composed will attain entropy. But the Earth exists in a locally-open system. Indeed, the Earth in space sits in the midst of a huge, ceaseless flood of energy. P. W. Atkins has put it this way, in discussing the ability of life to arise naturally:
When we come across a rabbit, there is no need to regard it as designed. Rabbits have emerged as a pathway by which the Universe degenerates and the quality of energy degrades. Rabbits, like primroses, pigs, and people, are part of the great network, the cosmic interconnection that allows temporary structures to emerge as degeneration ineluctably lowers the Universe toward its final equilibrium.16
The key phrase here is “temporary structures”. If we pour a cup of ink into a five gallon bucket of water, the ink will not disperse immediately. It will form swirl like patterns and some of it, affected by Brownian motion, will temporarily move upward after an initial descent. It will, in short, produce temporary structures, but ultimately all such structures will dissipate. All of the organization we see is, in effect, a way that the Universe is expending its energy. Such expenditure can produce elaborate results. And although that energy can construct organized objects along the way, the ultimate outcome is still ordained: complete entropy.
Third Law of Thermodynamics
The Third Law deals with the nature of matter at very low temperatures, and states simply that it is not possible to bring matter to a temperature of absolute zero, which is 0 degrees Kelvin, -273.15 degrees Celsius, and -459.67 degrees Fahrenheit. (The temperature of outer space, by the way, is 2.7 degrees Kelvin.)17
In our consideration of how the original rulebook was composed, we must also note the work of the chemists who finally banished the archaic four elements of the Greco-Roman world and laid the foundation for modern chemistry by discovering…
The Fundamental Chemical Laws
- Law of Mass Conservation: During a chemical reaction, the total mass of substances involved in the reaction does not change. This was first ascertained by Antoine Lavoisier in the late 18th century.
- Law of Definite (or Constant) Composition: The proportion of elements in a chemical compound remains fixed. First published by Joseph-Louis Proust in 1794.
- The Law of Multiple Proportions: If two elements can form more than one compound, the ratios of the elements that comprise the different compounds (such as the difference between CO and CO2 ) are expressed in whole numbers. This was first stated by John Dalton in the early 19th century, and buttressed his belief in the reality of atoms.18
And finally, the basic rulebook was seemingly complete with…
The Laws That Govern Electricity
The discovery of these laws was, more than anyone else’s, the work of Michael Faraday and James Clerk Maxwell. Many other researchers, of course, had studied electricity, and had identified key aspects of it, but these two scientists achieved the greatest 19th century breakthroughs in the field. The most important discoveries were:
· The Law of Induction. Discovered by Faraday in 1831. He proved that an electric field could be generated by a magnetic field, and that a magnetic field could be generated by an electric one. The name of this phenomenon is electromagnetic induction.19
- The First Law of Electrolysis (1832): In Faraday’s words, "the chemical action of a current of electricity is in direct proportion to the absolute quantity of electricity which passes."
- The Second Law of Electrolysis (1833): the weights of the ions deposited by the passage of the same quantity of electricity are in the proportion of their chemical equivalents. 20
- Maxwell’s Equations. In 1861, in a work entitled On Physical Lines of Force, Maxwell demonstrated that forces were actual entities, using the functioning of a magnetic field as his example. He also identified light as an electromagnetic phenomenon. His key equations were published in 1873 in A Treatise on Electricity and Magnetism. In them he proved that electromagnetic waves travel at light speed. His equations also put the laws discovered by Faraday, Karl Friedrich Gauss, and André Marie Ampère into concise, mathematically rigorous forms. Maxwell’s work was of immense importance. His discoveries influenced Albert Einstein’s thought (see the next chapter) and helped lay the basis for the entire modern world of electronics.21
From the laws of motion, the study of optics, the calculus, the laws of thermodynamics, the fundamental chemical laws, and the study of electricity sprang a host of other laws derived from them, less comprehensive in nature but still tremendously effective at describing the physical reality that humans dealt with on a daily basis. It seemed by the mid-19th century that the Rulebook was (almost) complete. But a revolution in our understanding of the world was in the offing, one which would write an entirely new Rulebook to go along with—and at times, supersede—the original one.