Source: Science News

Long before there was a periodic table of the elements, there was no need for a table — just four chairs.

From ancient through medieval into early modern times, natural philosophers could count the known elements with the fingers of only one hand (with no need for the thumb). All material reality, nearly every authority concurred, was built from only four elements. And those four elements had been identified in the fifth century B.C. by the imaginative and somewhat idiosyncratic Greek philosopher known as Empedocles of Acragas. 

Even though Empedocles had the true number of elements wrong, and the substances he identified aren’t actually elements anyway, he had more or less (less, I guess) the right idea. In fact, stripped of the literary embellishment in his poetic metaphors (and ignoring a few really weird ideas that didn’t make much sense), Empedocles articulated much of what passes today for sound scientific concepts. He basically identified the essence of modern notions of matter and force, and he dreamed up a theory of the universe that shares features with some current cosmological speculations.

Empedocles was born in Sicily around 490 B.C., apparently into a prominent family (his grandfather, legend has it, was an Olympic champion chariot racer). By some accounts Empedocles promoted democracy (despite his aristocratic status) and supposedly declined an offer to be king of Acragas, his home city-state. His oratorical ability and skillful writings inspired Aristotle to declare Empedocles the founder of rhetoric. Empedocles may also have been a physician (he wrote a lot about physiological topics at any rate), he dabbled in magic, and even described a primitive notion of natural selection’s role in shaping the forms of organisms. But most of all, he deserves recognition as one of the great natural philosophers of antiquity.

Empedocles is most well-known for his theory that all matter consists of four elements — he called them “roots” — and named them for the Greek gods Zeus, Hera, Aidoneus and Nestis. They personified (or godified) the physical forms known as fire, earth, air and water (although experts do not agree about which god stood for which element). These elements, Empedocles declared, persist throughout recurring cycles of creation and destruction. That is, the various forms of matter and life and the structures of the everyday world are just mixtures of the elements in varying proportions.

Empedocles declared that sensible objects come into being as the elements are melded together or pulled apart by two opposing forces: “love” and “strife” (sometimes translated as “hate” or “conflict”). Love impelled the combination of elements into a unified whole; strife was the destructive agitator that ripped the elements asunder.

Remarkably, virtually all the Greek philosophers seemed to buy this story — at least the four elements part — and it persisted throughout the educated Western world until well after the Middle Ages. It wasn’t inescapably obvious, though. Ancient Chinese scholars agreed on just three of those four elements and identified a total of five: earth, fire, water, metal and wood. But the rest of the world didn’t care what the Chinese thought the elements were. In the West, Aristotle adopted Empedocles’ classification and therefore so did the rest of educated Europe.

Empedocles developed his element theory in response to the philosophy of Parmenides, who was a couple of decades or so older than Empedocles. Parmenides argued that nothing came from nothing, and therefore nothing new could be created. Matter, and all existence, was therefore everlasting and never changing. In the face of all the obvious change in the world, it might seem an odd philosophy, but it gained wide acceptance in the philosophical era preceding Socrates. In an attempt to preserve Parmenidean logic while still accounting for the apparent change in the universe, Empedocles proposed that his four elements “never cease their continual interchange,” but “they exist always changeless in the cycle.” So no element ever comes into being or is ever destroyed. Elements just get mixed up in different ways, either while merging into one under the influence of love, or while dissembling during the predominance of strife.

Cosmologically, then, love forced everything into unity, a huge homogeneous sphere. But then strife attacked, mixmastering the sphere’s innards to create diversity, ultimately reaching a state of utter chaos. When chaos triumphed, strife’s work was done. Then love reasserted its influence to rebuild the harmonious sphere. A diverse world like the one we live in, Empedocles averred, could exist either during the phase of love’s ascendancy, pulling things together, or during the opposite side of the cycle, while strife strove for chaos. (Take a guess which phase he would think we are in today.)

Life emerges during love’s assembly phase, when body parts emerge from earth and are randomly connected. But some mixes, like a beast’s head on a man’s body, don’t work well and die out, Empedocles believed, leaving only those creatures who are fit to survive. (Empedocles perhaps thought he had special knowledge about life-forms, as he believed in reincarnation and stated that he had previously been a bird and a fish.)

Apart from the poetic and mythological metaphor of gods at work in this process, Empedocles’ cycle of creation and destruction of the cosmos resembles a modern theory of cosmology proposing a cyclic universe. That idea isn’t widely approved of today, but is a legitimate scientific proposal.

On the other hand, Empedocles’ basic notion of unalterable elements governed by fundamental forces echoes today’s physics textbooks. Unchangeable forms of matter create the phenomena of nature through interactions governed by forces, he asserted, as do present-day experts. 

Empedocles’ elements are not, of course, quite the same thing as the fundamental particles of matter that physicists talk about now. Nor are his elements the same kind of things as the elements that Dmitrii Mendeleev so carefully organized in his periodic table in 1869. Water is a compound of two elements, hydrogen and oxygen; air is a mixture of oxygen, nitrogen and a few other gases (such as an ever increasing amount of carbon dioxide); earth is a bunch of stuff; and fire is a manifestation of stuff getting burned up by combining with oxygen. 

But that’s not the point. Empedocles may not have known a real element from an elephant. But he grasped the central feature that makes an element an element: It’s something that stays the same despite all sorts of change. Chemical reactions take elements and combine and splice them, arrange and rearrange them, but in the end an element retains its identity and can be recovered from whatever mess any force, or chemist, got it into. Implicit in Empedocles’ beliefs is the law of conservation of mass, which modern scientists articulated only a couple of hundred years ago. The footnotes added to this story by modern nuclear physics do not detract from its conceptual validity for everyday life.

Empedocles not only attributed god status to the elements, but also believed he was a god himself. When it was time to die, one ancient account claims, he jumped into a volcano to demonstrate his confidence that he would live again. Perhaps he thought he would be reincarnated millennia later. Maybe as Mendeleev.