“[I]n truth there are only atoms and the void.” – Democritus

In the ancient Greek transition from mythos to logos, stories about the world and human lives being shaped by gods and goddesses gradually came to be replaced by new explanations from philosophers. Among these philosophers were the “atomists,” including Leucippus and Democritus. Later, the Roman philosopher and poet Lucretius expounded an atomist view of the universe. The atomists were regarded as being among the first atheists and the first materialists — if they did acknowledge the existence of the gods (probably due to public pressures), they argued that the gods had no active influence on the world. Although the atomists’ understanding of the atom was primitive and far from our modern scientific understanding — they did not possess particle accelerators, after all — they were remarkably farsighted about the actual workings of nature. To this day, the symbol of the American Atheists is a depiction of the atom:

However, the ancient atomists’ conception of how the universe is constructed, with solid particles of matter combining to make complex organizational structures, has become problematic given the findings of atomic physics in the past hundred years. Increasingly, scientists have found that reality consists not of solid matter, but of organizational principles and qualities that give us the impression of solidity. And while this new view does not restore the Greek gods to prominence, it does raise questions about how we ought to understand and interpret reality.

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Leucippus and Democritus lived in the fifth century BC. While it is difficult to disentangle their views because of gaps in the historical record, both philosophers argued that all existence was ultimately based on tiny, indestructible particles (“atoms”) and empty space. While not explicitly denying the existence of the gods, the philosophy of Leucippus and Democritus made it clear that the gods had no significant role in the creation or maintenance of the universe. Rather, atoms existed eternally and moved randomly in empty space, until they collided and began to form larger units, leading to the growth of stars and planets and various life forms. The differences between types of matter, such as iron, water, and air were due to differences in the atoms that composed this matter. Atoms could join with each other because of a variety of hooks or sockets in the atoms that allowed for attachments.

Hundreds of years later, the Roman philosopher Lucretius expanded upon atomist theory in his poem De rerum natura (On the Nature of Things). Lucretius explained that the universe consisted of an infinite number of atoms moving and combining under the influence of laws and random chance, not the decisions of gods. Lucretius also denied the existence of an afterlife, and argued that human beings should not fear death. Although Lucretius was not explicitly atheistic, his work was perceived by Christians in the Middle Ages as being essentially atheistic in outlook and was denounced for that reason.

Not all of the ancient philosophers, even those most committed to reason, accepted the atomist view of existence. It is reported that Plato hated Democritus and wished that his books be burned. Plato did accept that there were different types of matter composing the world, but posited that the particles were perfect triangles, brought together in various combinations. In addition, these triangles were guided by a cosmic intelligence, and were not colliding randomly without purpose. For Plato, the ultimate reality was the Good, and the things we saw all around us were shadows of perfect, ideal forms that were the blueprint for the less-perfect existing things.

For two thousand years after Democritus, atomism as a worldview remained a minority viewpoint — after all, religion was still an important institution in societies, and no one had yet seen or confirmed the existence of atoms. But by the nineteenth century, advances in science had accumulated to the point at which atomism became increasingly popular as a view of reality. No longer was there a need for God or gods to explain nature and existence; atoms and laws were all that were needed. The philosophy of materialism — the view that matter is the fundamental substance in nature and that all things, including mental aspects and consciousness, are results of material interactions — became increasingly prevalent. The political-economic ideology of communism, which at one time ruled one-third of the world’s population, was rooted in materialism. In fact, Karl Marx wrote his doctoral dissertation on Democritus’ philosophy of nature, and Vladimir Lenin authored a philosophical book on materialism, including chapters on physics, that was mandatory reading in the higher education system of the Soviet Union.

As physicists conducted increasingly sophisticated experiments on the smallest parts of nature, however, certain results began to challenge the view that atoms were solid particles of matter. For one thing, it was found that atoms themselves were not solid throughout but consisted of electrons orbiting around an extremely small nucleus of protons and neutrons. The nucleus of an atom is actually 100,000 times smaller than the entire atom, even though the nucleus contains almost the entire mass of the atom. As one article has put it, “if the nucleus were the size of a peanut, the atom would be about the size of a baseball stadium.” For that reason, some have concluded that all “solid” objects in the universe, including human beings, are actually about 99.9999999 percent empty space, because of the empty space in the atoms! Others respond that in fact it is not “empty space” in the atom, but rather a “field” or “wave function” — and here it gets confusing.

In fact, subatomic particles do not have a precise location in space; they behave like a fuzzy wave until they interact with an observer— and then the wave “collapses” into a particle. The bizarreness of this activity confounded the brightest scientists in the world, and to this day, there are arguments among scientists about what is “really” going on at the subatomic level.

The currently dominant interpretation of subatomic physics, known as the “Copenhagen interpretation,” was developed by the physicists Werner Heisenberg and Niels Bohr in the 1920s. Heisenberg subsequently wrote a book, Physics and Philosophy to explain how atomic physics changed our interpretation of reality. According to Heisenberg, the traditional scientific view of material objects and particles existing objectively, whether we observe them or not, could no longer be upheld. Rather than existing as solid objects, subatomic particles existed as “probability waves” — in Heisenberg’s words, “something standing in the middle between the idea of an event and the actual event, a strange kind of physical reality just in the middle between possibility and reality.” (Physics and Philosophy, p. 41 — page numbers are taken from the 1999 edition published by Prometheus books). According to Heisenberg:

The probability function does . . . not describe a certain event but, at least during the process of observation, a whole ensemble of possible events. The observation itself changes the probability function discontinuously; it selects of all possible events the actual one that has taken place. . . Therefore, the transition from the ‘possible’ to the ‘actual’ takes place during the act of observation. If we want to describe what happens in an atomic event, we have to realize that the word ‘happens’ can apply only to the observation, not to the state of affairs between two observations. It applies to the physical, not the psychical act of observation, and we may say that the transition from the ‘possible’ to the ‘actual’ takes place as soon as the interaction of the object with the measuring device, and thereby with the rest of the world, has come into play. (pp. 54-55)

Later in his book, Heisenberg writes: “If one wants to give an accurate description of the elementary particle — and here the emphasis is on the word ‘accurate’ — the only thing that can be written down as a description is a probability function.” (p. 70) Moreover,

In the experiments about atomic events we have to do with things and facts, with phenomena that are just as real as any phenomena in daily life. But the atoms or the elementary particles themselves are not as real; they form a world of potentialities or possibilities rather than one of things or facts. (p. 186)

This sounds downright crazy to most people. The idea that the solid objects of our everyday experience are made up not of smaller solid parts but of probabilities and potentialities seems bizarre. However, Heisenberg noted that observed events at the subatomic level did seem to fit the interpretation of reality given by the Greek philosopher Aristotle over 2000 years ago. According to Aristotle, reality was a combination of matter and form, but matter was not a set of solid particles but rather potential, an indefinite possibility or power that became real only when it was combined with form to make actual existing things. (pp. 147-49) To provide some rough analogies: a supply of wood can potentially be a table or a chair or a house — but it must be combined with the right form to become actually a table or a chair or a house. Likewise, a block of marble is potentially a statue of a man or a woman or an animal, but only when a sculptor shapes the marble into that particular form does the statue become actual. In other words, actuality (reality) equals potential plus form.

According to Heisenberg, Aristotle’s concept of potential was roughly equivalent to the concept of “energy” in modern physics, and “matter” was energy combined with form.

All the elementary particles are made of the same substance, which we may call energy or universal matter; they are just different forms in which the matter can appear.

If we compare this situation with the Aristotelian concepts of matter and form, we can say that the matter of Aristotle, which is mere ‘potential,’ should be compared to our concept of energy, which gets into ‘actuality’ by means of the form, when the elementary particle is created. (p. 160)

In fact, all modern physicists agree that matter is simply a form of energy (and vice versa). In the earliest stages of the universe, matter emerged out of energy, and that is how we got atoms in the first place. There is nothing inherently “solid” about energy, but energy can be transformed into particles, and particles can be transformed back into energy. According to Heisenberg, “Energy is in fact the substance from which all elementary particles, all atoms and therefore all things are made. . . .” (p. 63)

So what exactly is energy? Oddly enough, physicists have a hard time stating exactly what energy is. Energy is usually defined as the “capacity to do work” or the “capacity to cause movement,” but these definitions remain somewhat vague, and there is no specific mechanism or form that physicists can point to in order to describe energy. Gottfried Leibniz, who developed the first formula for measuring energy, referred to energy as vis viva or “living force,” a concept which is anthropomorphic and nearly theological.  In fact, there are so many different types of energy and so many different ways to measure these types of energy that many physicists are inclined to the view that energy is not a substance but just a mathematical abstraction. According to the great American physicist Richard Feynman, “It is important to realize that in physics today, we have no knowledge of what energy ‘is.’ We do not have a picture that energy comes in little blobs of a definite amount. It is not that way. It is an abstract thing in that it does not tell us the mechanism or the reason for the various formulas.” The only reason physicists know that energy exists is that they have performed numerous experiments over the years and have found that however energy is measured, the amount of energy in an isolated system always remains the same — energy can only be transformed, it can neither be created nor destroyed. Energy in itself has no form, and there is no such thing as “pure energy.” Oh, and energy is relative too — you have to specify the frame of reference when measuring energy, because the position and movement of the observer matters. For example, if you move toward a photon, its energy in that frame of reference will be greater; if you move away from a photon, its energy will be less.

In fact, the melding of relativity theory with quantum physics has further undermined materialism and our common sense notions of what it is to be “real.”  A 2013 article in Scientific American by Dr. Meinard Kuhlmann of Bielefeld University in Germany, “What is Real,” lays out some of these paradoxes of existence at the subatomic level. For example, scientists can create a vacuum in the laboratory, but when a Geiger counter is connected to the vacuum container, it will detect matter. In addition, a vacuum will contain no particles according to an observer at rest, but will contain many particles from the perspective of an accelerating observer! Kuhlmann concludes: “If the number of particles is observer-dependent, then it seems incoherent to assume that particles are basic. We can accept many features to be observer-dependent but not the fact of how many basic building blocks there are.”

So, if the smallest parts of reality are not tiny material objects, but potentialities and probabilities, which vary according to the observer, then how do we get what appears to be solid material objects, from rocks to mountains to trees to houses and cars? According to Kuhlmann, some philosophers and scientists say that we need to think about reality as consisting entirely of relations. In this view, subatomic particles have no definite position in space until they are observed because determining position in space requires a relation between an observer and observed. Position is mere potential until there is a relation. You may have heard of the old puzzle, “If a tree falls in a forest, and no one is around to hear it, does it make a sound?” The answer usually given is that sound requires a perceiver who can hear, and it makes no sense to talk about “sound” without an observer with functional ears. In the past, scientists believed that if objects were broken down into their smallest parts, we would discover the foundation of reality; but in the new view, when you break down larger objects into their smallest parts, you are gradually taking apart the relations that compose the object, until what you have left is potential. It is the relations between subatomic particles and observers that give us solidity.

Another interpretation Kuhlmann discusses is that the fundamental basis of reality is bundles of properties. In this view, reality consists not of objects or things, but of properties such as shape, mass, color, position, velocity, spin, etc. We think of things as being fundamentally real and properties as being attributes of things. But in this new view, properties are fundamentally real and “things” are what we get when properties are bundled together in certain ways. For example, we recognize a red rubber ball as being a red rubber ball because our years of experience and learning in our culture have given us the conceptual category of “red rubber ball.” An infant does not have this conceptual category, but merely sees the properties: the roundness of the shape, the color red, the elasticity of the rubber. As the infant grows up, he or she learns that this bundle of properties constitutes the “thing” known as a red rubber ball; but it is the properties that are fundamental, not the thing. So when scientists break down objects into smaller and smaller pieces in their particle accelerators, they are gradually taking apart the bundles of properties until the particles no longer even have a definite position in space!

So whether we thing of reality as consisting of relations or bundles of properties, there is nothing “solid” underlying everything.  Reality consists of properties or qualities that emerge out of potential, and then bundle together in certain ways. Over time, some bundles or relations come apart, and new bundles or relations emerge. Finally, in the evolution of life, there is an explosion of new bundles of properties, with some bundles containing a staggering degree of organizational complexity, built incrementally over millions of years. The proper interpretation of this organizational complexity will be discussed in a subsequent post.