Speculations of Atoms: Ancient Theories of Matter

This is an excerpt from The Cosmic Machine: The Science That Runs Our Universe and the Story Behind It

By Scott Bembenek, PhD

The first “atomic theories” focused on a “primary element” responsible for creating all other matter. Heraclitus said it was fire, Thales of Miletus (c. 624 BC–c. 546 BC) said it was water, Anaximenes (c. 585 BC–c. 528 BC) thought it was air, and Empedocles finally unified these, declaring there to be four elements: air, earth, fire, and water. Later, Aristotle adopted Empedocles’ four elements, and so it remained until about the seventeenth century.

Born in Acragas, in present-day Sicily, Empedocles (c. 492 BC–c. 432 BC) was an interesting character, who has been described as a philosopher, prophet, healer, democratic politician, mystic, charlatan, fraud, and scientist. His main contribution to the physical sciences was his four-element theory.

These fundamental elements, which he called “roots,” combined in varying amounts to form all other matter: plants, animals, humans, rocks – everything. And while the elements mixed together to form other things, they still maintained their own individual characteristics. Indeed, Empedocles envisioned the four elements as changeless, eternal, and indestructible. Empedocles believed in two eternal metaphysical forces: Love and Strife. Love was responsible for bringing the elements together in the process of creation, whereas the opposing force of Strife was responsible for the separation of the elements, ultimately leading to the process of decay. The cosmic battle between Love and Strife represented the natural cycle of change in the universe; Love built things up and Strife tore them back down, and they struggled against each other, each one trying to gain dominance over the other.

In Empedocles’ theory, we clearly see the concept of a changing universe similar to that described by Heraclitus, although where Heraclitus only believed in Strife, Empedocles softened his theory with the addition of Love as its cosmic counterpart. Perhaps less clear is that Empedocles also embraced a bit of the doctrine of Parmenides. While he didn’t believe in a changeless universe, as Parmenides’ monistic dogma had demanded, he did attribute changelessness to his fundamental elements. To be sure, this was a deliberate attempt to reconcile the opposing doctrines of Heraclitus and Parmenides, and he was not the only one to do so. Nonetheless, he abandoned Parmenides’ monistic view in favor of a pluralistic one governed by his four elements (roots), two forces, and the ensuing comingling thereof. A contemporary of Empedocles and fellow early atomic theorist was Anaxagoras.

Anaxagoras (c. 500 BC–c. 428 BC) was born in the town of Clazomenae in Ionia, located in present-day Turkey. He was the first to bring philosophy to Athens (most likely convinced to come by Pericles (c. 495 BC–c. 429 BC) who became his student) and spent thirty years there but eventually left. It seems his teachings on the Earth, the Sun, and the Moon might have gotten him into a bit of trouble (apparently Galileo wasn’t the first to suffer this fate). Specifically, he was in violation of a law permitting the impeachment of anyone who didn’t practice religion and taught theories about the heavenly bodies. He was charged for impiety. Rather than stay and face his sentence, which was execution, with the assistance of Pericles he left Athens for Lampsacus (in Asia Minor), where he remained for the rest of his life.

Like Empedocles, Anaxagoras attempted to meet the challenge of Parmenides’ demand of a changeless world while accounting for the apparent change we experience in everyday life. Whereas Empedocles singled out air, earth, fire, and water as the fundamental building blocks of everything in existence, Anaxagoras, seeing no reason for such discrimination, declared that everything contains a bit of everything else.

For Anaxagoras, things such as bone, skin, and hair were just as real as Empedocles’ fundamental elements of air, earth, fire, and water, and as such there’s no reason one would choose some in favor of others. So he decided not to choose, but instead included a “portion of everything in everything.” While it’s not known for sure, it might be that he arrived at his theory of matter from his rather insightful studies in nutrition. Anaxagoras noted that food provided nourishment for animals that, in turn, caused certain things to occur, such as their hair to grow and their skin to heal. He concluded that food must then have the constituents of hair and skin already in it to be able to convey these effects.

Moreover, Anaxagoras considered matter to be infinitely divisible. Thus, if one cut a piece of hair again and again, it would still contain the essence of hair. He says, “For of the small there is no smallest, but always a smaller (for what is cannot not be). But also of the large there is always a larger, and it is equal in amount to the small. But in relation to itself, each is both large and small.”

However, despite this, Anaxagoras considered these components of matter, often referred to as “seeds,” or “stuffs,” as eternal and indestructible, albeit more loosely so than envisioned by Empedocles. This still raises the question that if everything contains everything else (in varying proportions nonetheless), then what is it that makes something what it is? To this Anaxagoras replies: “each single thing is and was most plainly those things of which it contains most.” In other words, something is what it is because it contains most of that “stuff.” More precisely, something is what it appears to be macroscopically because it contains most of that “stuff” microscopically.

So we see in both the theories of Empedocles and Anaxagoras the attempt at producing intelligible theories of matter. Each tried to combine ideas that would account for the changing world that we all experience, while still allowing for certain components to remain fundamental, and as such changeless. In effect, each was trying to include simultaneously, in his unique way, the dogma imparted by Heraclitus and Parmenides.

Today, their ideas may sound strange and metaphysical to us, yet one can find the similarity between them and current atomic theory. This is perhaps best exemplified in the theory put forth by Democritus, who is undoubtedly the most important ancient Greek atomic theorist.

Dr. Scott Bembenek is a principal scientist in the Computer-Aided Drug Discovery group at Johnson & Johnson Pharmaceutical Research & Development in San Diego. He is also the author of The Cosmic Machine: The Science That Runs Our Universe and the Story Behind It. To learn more about Dr. Bembenek and his work, visit http://scottbembenek.com and connect with him on Twitter

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