Religion comes from the period of human prehistory where nobody—not even the mighty Democritus who concluded that all matter was made from atoms—had the smallest idea of what was going on. It comes from the bawling and fearful infancy of our species, and is a babyish attempt to meet our inescapable demand for knowledge. Today the least educated of my children knows much more about the natural order than any of the founders of religion.

—Christopher Hitchens1

THEY HAD IT (MOSTLY) RIGHT

The view of nature proposed over two thousand years ago by the Greek philosophers Leucippus, Democritus, and Epicurus, and preserved for posterity by the Roman poet Lucretius, has been validated by modern physics, cosmology, and, where applicable, by the rest of science. However, I need to continually emphasize that what we are talking about here, whether from antiquity or from the twenty-first century, is a just a model that describes what we observe with our senses and scientific instruments. We have no way of knowing what is the ultimate reality that lies behind that model.

The atomic model, in which the universe is composed of matter and nothing else, is adequate to explain everything we observe and experience as human beings. In this model, matter itself is composed of elementary particles that move around in an otherwise completely empty void. Until the twentieth century, the particulate nature of matter was not directly observable but by the twentieth century was well confirmed empirically.

After its rediscovery in the Renaissance, atomism became the foundational principle of the scientific revolution of the seventeenth century. It reached fruition with the discovery in the nineteenth century that the chemical elements are well described as particulate, and in the twentieth century with the discovery that those elements are in fact composed of even more elementary constituents: quarks and electrons. At this writing, the latest triumph of atomism is the apparent confirmation in 2012 of the existence of the Higgs boson, which had been predicted forty-eight years earlier, as the source of the masses of elementary particles.

Because of its implicit and sometimes explicit atheism, the particulate model of matter has had many opponents throughout history—from Aristotle to Christian theologians, to nineteenth-century chemists and philosophers. While theists today must accept the fact that the evidence for the atomic theory of matter is overwhelming (just as is the evidence for evolution), they reject the theological implications of that theory—namely, atheist materialism.

Included in the assumptions of ancient atomism now confirmed by science are indeterminism and the dominant role of chance in the universe. Furthermore, our universe is very possibly just one of many in a multiverse unlimited in space and eternal in time. Any gods that may exist play no role in nature, including human life. The atomists also envisaged the evolution of life and a kind of survival of the fittest.

In short, they pretty much had it right, at least in general terms. The job of science since has been to fill in the details.

MATTER

In today's science, we find no evidence for any ingredient in nature other than matter. If some other immaterial substance exists, such as what is usually referred to as spirit, it has no effect on our senses or instruments that we can verify scientifically. Nowhere can you point to an observation or measurement that requires us to introduce some immaterial substance into our models in order to explain the data. Where we have observations for which no full explanation exists, such as the nature of dark matter and dark energy, these phenomena still produce measurable effects that identify them as material. We have measured the mass/energy density of these components. We know they exist by their gravitational effects. Presumably, gravity doesn't act on spiritual stuff.

Matter is defined as a substance with inertia. When you kick a chunk of matter, it kicks back. A material body is characterized by three measurable properties: mass m, energy E, and momentum p. Momentum is a three-dimensional vector whose magnitude |p| we write as p and whose direction is the same as the velocity vector of the body. In units where the speed of light in a vacuum c = 1, m² = E² – p². While E and p depend on the reference frame in which their measurements are performed, m is invariant. It is the same in all reference frames.

Unfortunately, the term energy is much misused in common discourse and in mythology. An acupuncturist, trained in ancient Chinese medicine, claims to redirect the flow of “qi,” an imagined form of energy, through your system. A touch therapist, often trained in an accredited nursing college, claims to adjust your “bioenergetic field.” Today, the practice of complementary and alternative medicine is filled with unsupported claims of healing methods that use the term energy in one form or another, usually with the implication that it is associated with some spiritual force.2

However, as far as physics is concerned, it is incorrect to regard energy as something immaterial, something separate from mass. It is a property of matter just as is mass and momentum. In particular, light is fully material, composed (in our model) of particles called photons. Although a photon has zero mass, it has nonzero energy and momentum.

Our senses and instruments detect material objects and presumably are unable to sense spirit. However, this does not provide much credence to the hypothesis that immaterial objects might still exist. Of course, we can never fully rule out that they might show up someday. But in what sense can we say immaterial objects exist if they have no measurable effects on the material objects we do observe? And if they have no effect, who cares?

More important are the types of immaterial, supernatural entities that most people want to believe play a central role in nature and human life. In that case, they should produce observable effects on material objects. So far, after thousands of years of looking, we see no sign of such effects. This should rule them out beyond a reasonable doubt.3

The objects we call “atoms” today, the elements of the chemical periodic table, are now known to be composite and not truly elementary. Nevertheless, atomism achieved strong substantiation in the 1970s with the standard model of particles and forces that has agreed with all empirical data for four decades. In that model, familiar objects from cats to stars are composed of just three fundamental particles: u and d quarks that form the protons and neutrons in the nuclei of the chemical elements, and electrons that swarm in clouds around these nuclei. With the photon added to provide light and other electromagnetic radiation, we have everything that is involved in the life of almost every human on Earth (particle physicists and cosmologists excepted) reduced to the interaction of just four particles. If that isn't a triumph for atomism, I don't know what a triumph would entail.

In a high-energy collision, in cosmic rays or particle accelerators, many short-lived particles are produced as some of the energy of the collision is converted into mass. All these generated particles fit into a scheme that contains a total of six quarks and their partner antiquarks and six leptons along with their antileptons. Additionally, twelve gauge bosons, including the photon, are responsible for the forces by which particles interact with one another: the electromagnetic force, the weak nuclear force, and the strong nuclear force. In the standard model, the electromagnetic and weak forces are united as a single electroweak force. It is split into the two distinct forces at the low energies of common experience, and, until recently, all laboratory experiments as well.

Gravity is currently treated separately from the standard model; it has negligible effect on the subatomic scale but ultimately must be included in any fully unified theory. However, all observed gravitational phenomena remain consistent with Einstein's 1916 general theory of relativity. In short, for decades now physics has had fundamental theories that agree with all observations. They just have not yet been combined into a single theory.

All the quarks, leptons, and gauge bosons of the standard model have been verified experimentally. Until July 4, 2012, the one gap remaining in the standard model was the Higgs boson, which had been proposed in 1964 to provide the mechanism by which elementary particles get mass. With the observation in 2012 of what looks very much like the Higgs of the standard model, that picture seems to have emerged victorious.

Nevertheless, the standard model is unlikely to be the final story. It requires over twenty parameters such as particle masses and force strengths that must be determined experimentally, as well as leaving many questions unanswered. That doesn't mean they ever will be. Perhaps the standard model is all we have and the rest is accident. In any case, it is hard to imagine ever reaching the time when every question has been answered. I have little confidence that a so-called theory of everything will ever be achieved, at least in the foreseeable future. But I may be wrong, which would be unfortunate because it would mean the end of physics.

None of these uncertainties detract from the continual success of the atomic picture. Even when they did not know anything about the chemical atoms, physicists succeeded in explaining the behavior of gases in terms of particles. Even when they did not know anything about the structure of these atoms, chemists built an enormously useful science based on the periodic table. Even when they did not know that the nucleons inside the nuclei of chemical atoms were composed of quarks, physicists developed nuclear energy. Each of these was an achievement for atomism.

MATERIALISM DECONSTRUCTED?

Now, those who read the popular literature might have received the impression that, in fact, modern physics has not confirmed the picture of atoms and the void or perhaps even refuted it. For example, in The New Sciences of Religion: Exploring Spirituality from the Outside In and Bottom Up, Christian apologist William Grassie says, “The concept of materialism deconstructed itself with the advent of quantum mechanics and particle physics.”4 To be ecumenical, he quotes the Hindu physicist Varadaraja V. Raman: “Physics has penetrated into the substratum of perceived reality and discovered a whole new realm of entities there, beyond the imagination of the most creative minds of the past.”⁵

Now, maybe Democritus did not imagine quarks. But he imagined material particles, and quarks are material particles. The “new realm of entities” uncovered in modern physics is hardly beyond imagination. They are imagined in the quantum theory of fields, although just imagining something does not make it real—despite what some theologians claim and what some physicists seem to believe.

FIELD-PARTICLE UNITY

The claim that quantum mechanics has revealed a reality beyond matter is based on the mistaken notion that two separate realities exist: discrete, particulate matter and a plenum that is reminiscent of the long-discredited aether. However, the electromagnetic aether was at least material. The new aether is more abstract, more in tune with the duality of mind and body that is embedded in all religious thought. Unsurprisingly, theologians and spiritualists delight in this new dualism—handed to them on a platter by theoretical physicists.

You will often see it written that abstract, holistic quantum fields are the deeper reality while particles are simply the excitations of the fields. For example, in The Atom in the History of Human Thought, which I have referred to often, historian Bernard Pullman writes,

To the extent that a Democritean influence has shaped our conception of the world, there has been a tendency to stress the corpuscular aspect of the standard model and to introduce a certain formal distinction between particles of matter and intermediary particles associated with force fields. As a result, we may have given the impression that this corpuscular aspect provides the most exact description of physical reality. Such a view would be unfortunate, as it might obscure what is considered today as the most plausible picture of reality, which not only unifies the concepts of particles and fields, but even considers fields preeminent over particles…. The fundamental and underlying reality of the world is embodied in the existence of a slew of fields and in their interactions.”6

Unfortunately, many theoretical physicists have contributed to the impression that quantum mechanics has done away with the concept of matter. For example, in an article in Scientific American, physicist David Tong says:

Physicists routinely teach that the building blocks of nature are discrete particles such as the electron or quark. That is a lie. The building blocks of our theories are not particles but fields: continuous, fluid-like objects spread throughout space.7

Pullman and Tong are expressing the Platonic view of reality, commonly held by many theoretical physicists and mathematicians. In order to test their models, physicists assume that the elements of these models correspond in some way to reality. But they are compared against the data that flow from our so-called particle detectors on the floor of an accelerator lab. It is the data that form the concrete foundation of our knowledge. What is fundamental in our model is not necessarily fundamental to our knowledge. Models are squiggles on the whiteboards in the theory section of the physics building. Those squiggles are easily erased; the data can't be.

Indeed, unpublished results are beginning to trickle in that the whiteboard squiggles of a generation of theorists describing their speculations on a theory called supersymmetry may soon be erased by data from the LHC. Although we need to wait and see, such a result would provide a dose of humility to those who think they can infer reality by their thoughts alone, as well as an impetus to explore more unorthodox approaches.

The application of Platonic reality to physics is fraught with problems. First, theories are notoriously temporary. We can never know if quantum field theory will someday be replaced with another more powerful theory that makes no mention of fields (or particles, for that matter). Second, as with all physical theories, quantum field theory is a model—a human invention. We test our models to find out if they work; but we can never be sure they correspond to “reality.” That's metaphysics. If there were an empirical way to determine ultimate reality, it would be physics, not metaphysics. Third, quantum fields all have quanta that we associate with the so-called elementary particles.

In relativistic quantum field theory, which is the fundamental mathematical theory of particle physics and the basis of the standard model, each quantum field has an associated particle called the quantum of the field. These are the elementary particles of the standard model. The photon is the quantum of the electromagnetic field. The Higgs boson is the quantum of the Higgs field. The electron is the quantum of the Dirac field. I know of no proven example where a quantum field exists without its quantum. Particles are just as much building blocks of our theories as fields. In fact, they are the same building blocks. There are no exceptions. For every field, we have a particle; for every particle, we have a field. So it is incorrect to think that field and particle exist as separate realities. We do not have a field-particle duality. We have, as Pullman says, a field-particle unity.

Please note that the elementary particles of the standard model are not to be thought of as classical objects like billiard balls; they obey all the rules of quantum mechanics. For example, as Feynman showed back in 1948, electrons can zigzag back and forth in space-time and thereby appear many places at the same time. This is usually called nonlocality, but a better term is multilocality. In this picture, the electron never moves faster than the speed of light.

WAVE-PARTICLE DUALITY

How does this relate to the so-called wave-particle duality that you read about in books on quantum mechanics? The authors often write, “An object is either a particle or a wave, depending on what you decide to measure.” This is very misleading and has led to the widespread belief that quantum mechanics shows that human consciousness has the ability to control reality, namely, to decide whether an object is a particle or a wave. I have confronted these claims in two previous books and shown them to be specious.8

For those who have not moved beyond nonrelativistic Schrödinger wave mechanics, the wave picture provides a perfectly good model to compute quantum effects without having to think about what is doing the waving. To nuclear and particle physicists who must deal with higher-energy phenomena, relativistic quantum mechanics and quantum field theory provide the tools for their calculations without having to think about which is more real—fields or particles. Both are fully materialistic and constitute triumphs for atomism.

In short, quantum physics has not done away with matter. When you kick a rock, it still kicks back. And when you kick an electron, it kicks back.

REDUCTION AND EMERGENCE

Far from demonstrating the existence of a holistic universe in which everything is intimately connected to everything else, relativity and quantum mechanics (and the standard model that was built upon their foundation) confirmed that the universe is reducible to discrete, separated parts. No continuous aether exists throughout the universe. Light is not some vibrating wave in a cosmic medium but is best modeled as a beam of photons streaming through the void. Electricity is not some continuous field moving from place to place but is best modeled as a beam of electrons streaming through the void. (A copper wire is mostly void.)

Nevertheless, strong dissenting voices can be found among scientists in other fields, as well as religious apologists and New Age gurus, that claim phenomena exist that cannot be reduced to elementary particle physics. These phenomena are called emergent.9

The dissenters correctly point out that the equations of particle physics cannot be used to derive the properties of most complex systems of atoms and molecules, such as the structure of DNA or the behavior of an ant colony. I say “most” because there are several examples from physics where collective properties can be derived from basic particle interactions. This includes all the laws of classical thermodynamics that were originally discovered from macroscopic observation of mundane machines such as heat engines. For example, the ideal gas equation is easily derived in freshman physics from simple particle collisions. The same is true for fluid mechanics, while solids are now also well understood using quantum physics. And, it needs to be pointed out, the physics of classical waves such as sound can also be derived from particle mechanics. There is no wave-particle duality in either classical mechanics or quantum mechanics.

Nevertheless, it is true that the principles that describe most complex systems cannot be derived from particle physics. Chemists, biologists, neuroscientists, sociologists, political scientists, and economists never need to learn about quarks and gauge bosons but develop their own descriptions based on their own observations. You don't need to consult with a quantum mechanic to fix your car. Yet the car and automotive mechanics are still made of material particles.

However, these facts do not imply that emergent properties cannot arise from particle interactions alone—that some new laws of nature operating on the collective scale must come into play. While accepting that we have “bottom-up causality” in which collective properties of complex objects emerge from the interactions of their constituent particles, many authors wishfully seek out an additional “top-down causality,” operating in the opposite direction, in which some overarching, universal force acts down to control the behavior of particles at the lowest levels.

Some scientists imagine a natural force akin to Aristotle's principle of final cause.10 Theologians imagine God as that top-down force.¹¹ In both cases, we see a strong desire to find purpose in the universe that is absent in both ancient and modern atomism. However, if top-down causality existed, we would expect to see some evidence at all levels of complexity—in social systems, brain processes, biological mechanisms, chemical reactions, and on down to subatomic events. The fact is, we don't. Based on the absence of evidence that should be there but is not, we can rule out beyond a reasonable doubt the existence of top-down emergence. The universe remains reducible to it parts, just as the ancient atomists predicted.

THE ROLE OF CHANCE

Physics from Aristotle to Pierre-Simon Laplace (1749–1827) was marked by the notion of logical principles governing the behavior of matter, with every outcome predetermined by what went on before. Atomism also envisaged atoms moving in a determined direction, “downward” toward some center of attraction, which need not necessarily be the center of Earth. However, on top of that motion was a random “swerve” that causes atoms to deviate from their paths so that they could come in contact with other atoms and stick together to form objects.

Although random motion had been utilized in the nineteenth century by Maxwell, Boltzmann, Gibbs, and others to derive the macroscopic (emergent) laws of thermodynamics from the statistical mechanics of atomic motions, the physics governing these motions was still classical and, thus, deterministic. It was assumed that the laws of Newtonian mechanics ultimately predetermined atomic motions. However, because of the large number of atoms involved, physicists had no hope of calculating individual motions directly, nor really any need for knowing them. By using statistical methods, they were able to calculate various average properties of the whole system, such as pressure and temperature, that sufficed for all practical applications.

With the rise of quantum mechanics and the Heisenberg uncertainty principle in the early twentieth century, the “true” randomness inherent in the motion of all bodies became built into the structure of physics.

Physicists had (almost) no trouble giving up the determinism of the Newtonian world machine. The one exception was Bohmian quantum mechanics, which still has some supporters but is largely dismissed by most physicists because of its implication of superluminal connections for which no evidence exists.12 However, theists cannot abide events happening outside the supervision of God. We see this in the rejection of Darwinian evolution by virtually all Christians and Muslims. Oh, Catholics and moderate Protestants claim they accept evolution, but only if it is God-guided. But Darwinian evolution is unguided. The Darwinian conclusion that humanity is an accident rather than a divine creation contradicts fundamental teachings of all the major religions on Earth.

Similarly, the role of randomness in the physical universe is irreconcilable with the theistic belief that God created and sustains the universe. Some Christian apologists have tried to make the best of this by suggesting that God operates through the medium of chance.¹³ Others have attempted to find a way for God to act in the universe without violating the laws of physics by calling upon quantum mechanics and chaos theory. In my 2009 book, Quantum Gods, I show why these arguments all fail.¹⁴

Put simply, I admit that the god these scholars propose is not ruled out by any current empirical or theoretical knowledge. However, it simply isn't the Judaic-Christian-Islamic God but rather a special deist god who creates the universe, rolls the dice to create complete randomness, and then leaves it alone. It's the god Einstein refused to accept, the “god who places dice.” Furthermore, it's not the Enlightenment deist God, who created the fully deterministic Newtonian World Machine. Also, note that by starting up the universe in total chaos, the god who plays dice leaves no memory of its existence or intentions. In short, we humans have no way to infer its existence except to say it is the only god consistent with the data.

Although the god who plays dice is possible, it is certainly not needed. The universe can toss its own dice, which leads us nicely into a discussion of the atomists’ atheistic view of an infinite, eternal cosmos and how it contrasts with the traditional religious teaching of a finite, created universe.

THE COSMOS

The multiverse, as we now conceive it, is unlimited in space and eternal in time. It had no beginning and will have no end. It did not come from nothing. It did not have to come from anything because it always was. The discovery of the big bang encouraged theologians to argue that science supports a supernatural creation a finite time ago, although far more distant in the past and far different in details than any scriptural account of creation ever imagined. What's more, the universe revealed by astronomy is incredibly larger than what was supposedly revealed in sacred books.

Today, physicists and cosmologists have shown that while our universe undoubtedly began with the big bang 13.7 billion years ago, mathematically precise models based on general relativity and quantum mechanics suggest that it may have quantum-tunneled from an earlier universe. Furthermore, these models also imply that our universe is just one of an enormous, if not unlimited, number of other universes in a vast multiverse.

Now, theologians have argued that this proposal is unscientific. First, they say we have no evidence for other universes, which is true, but such evidence is not beyond our reach. The presence of another universe is in principle detectable by its gravitational effect on ours, for example, by producing an anisotropy in the cosmic background radiation.

Second, the multiple-universe hypothesis is said to be non-parsimonious, in violation of Ockham's razor. This is untrue. Ockham's razor applies to the hypotheses of a theory, not the number of entities in the theory. The atomic theory multiplied the number of entities physicists had to deal with by a trillion-trillion, yet it was more parsimonious than previous theories because it involved fewer hypotheses. It takes an additional hypothesis to assume that only one universe exists when the current theory, with fewer hypotheses, predicts many. That is, it is the single-universe theory that violates Ockham's razor.

The multiverse is also unlimited in spatial extent, again in agreement with the atomist picture. Furthermore, our visible universe, all 100 billion galaxies, may be only a grain of sand on the Sahara of galaxies that arose from the original big bang and now continues far beyond our light horizon. While the ancient atomists, of course, had none of this knowledge, their original intuition continues to be right on the mark as we progress in our knowledge of the cosmos.

THE MIND

The notion that only atoms are real contradicted the teaching of Aristotle, who regarded sense impressions as constituting an intrinsic reality.15 To Aristotle, redness is a real property of a tomato and sweetness is a real property of sugar, while the atomists maintained these qualities are “conventions”—mental perceptions that describe human reactions to the messages of their senses.

Modern cognitive science fully supports the atomists’ view. The intrinsic properties of elementary particles, such as mass and energy, are now referred to as primary properties. Objectively observed secondary properties, such as color and wetness, arise from the interactions of particles and are not intrinsic to the objects that are assigned these properties. The subjective sense impressions that arise from secondary properties I have termed secondary qualities.

I have not said much about the human mind in this book, which has focused on the physical evidence that supports the model of atoms and the void. I have asserted (many times now) that all we observe with our senses and scientific instruments can at least plausibly, and in most cases explicitly, be explained without the inclusion of immaterial elements. In this, I expect to get disagreement from dualists who will say that because we still don't have a consensus material explanation of consciousness, the door is still open for there to be a nonmaterial component to the human mind.

I claim I can make a similar statement about those phenomena conventionally labeled “mental”: all we observe concerning mental phenomena with our senses and scientific instruments can at least plausibly, and in most cases explicitly, be explained without the inclusion of immaterial elements. As I covered in detail in God and the Folly of Faith, neuroscience has provided convincing evidence that the mind is what the brain does, and the brain is fully material.16 Furthermore, our current knowledge of the brain is consistent with atomism. Indeed, neurons act, in a way, as the “atoms” of the brain.

Of course, debate still rages on the nature of conscious experience, the qualia mentioned in chapter 3. But the very subjective nature of that experience makes it difficult to even talk about it scientifically. About the only objective data we have is the correlation between subject reports on types of such experiences and the observed increase in activities in local areas of the brain, along with other physiological measurements.

Models that introduce immaterial elements into the human cognitive process have failed to produce any supportive evidence comparable to materialistic brain science. That would seem to make a pretty good case for the physical source of conscious experiences even though, as yet, there is no received philosophical/scientific explanation of how the brain gives rise to consciousness. So far, brain science, which is very much based on atomism, has been making steady progress in explaining the features of consciousness. Dualism has made none.

NO HIGHER POWER

No doubt, many religious apologists will argue that nothing in the success of the atomic theory of matter, as exemplified by modern elementary particle physics and cosmology, is necessarily inconsistent with the belief in a “higher power.” However, we have seen throughout this book that the atomism of Democritus, Epicurus, and Lucretius was very closely based on a worldview in which no such higher power exists. The total absence of empirical facts and theoretical arguments to support the existence of any component to reality other than atoms and the void can be taken as proof beyond a reasonable doubt that such a component is nowhere to be found. The scientific triumph of atomism represents a philosophical triumph for the recognition by the ancient atomists that the world can be understood without calling upon any forces from outside the world—no wood sprites, no fairies, no angels, no devils, no gods or spirits of any sort.