The Great Conversation: Element
By Gabriel Blanchard
Are we "such stuff as dreams are made on"?
When we heard the word element, we generally think of the periodic table (or possibly Captain Planet). Elements refer to the indivisible building-blocks that other things are made of—which is why they became the term for the chemical elements. But other usages survive, as in Euclid’s Elements or Strunk and White’s Elements of Style, or the word elementary. Though it isn’t common now, letters used to be called elements, because they are the building blocks of writing; in ancient and Medieval astronomy, the planets were sometimes called the elements; the word was also used to refer to what we now call an atom.
The four classical elements stood closer to what we generally mean by an element today. Fire, air, water, and earth were understood to be the stuff out of which everything was made—everything, that is, from the Moon’s orbit downwards. Since things on Earth change, grow, and decay, but the heavens remain constant and appeared perfectly regular in their movements, it was reasonable to assume they were made of a different kind of stuff, which was called aether. Plato assigned geometric shapes (the so-called Platonic solids) to the base particles of all five of these elements: the cube for earth, the icosahedron for water, the octahedron for air, the tetrahedron for fire, and the dodecahedron for aether.
The classical elements were also understood to be related to the four humors, i.e. blood, yellow bile, black bile, and phlegm; the terms sanguine, choleric, melancholy, and phlegmatic originally referred to these substances. This theory was formulated by ancient doctors such as Hippocrates and Galen. The interrelations of the humors governed not only health, but also temperament and psychology. Indeed, the word temperament, related to temperance, referred originally to the balance of humors in a given person—and thus eventually also gave us the meaning “anger” for temper.
Atomist theory, which is principally connected with the fifth-century BC author Democritus, often used the word element (or its Greek equivalent στοιχει̂ον) for the smallest, indivisible pieces of matter. The term atom itself comes from a Greek word meaning “uncuttable.” There were extensive debates between those on the one hand who believed that the world was made of particles moving through a void, and those on the other who thought that the different kinds of stuff were continuous rather than spaced apart, or infinitely divisible, or both. Aristotle famously rejected atomism, while the Epicureans championed it; Lucretius’ portrait of the universe became one of the most famous expressions of atomism in the classical world. Some versions of atomism considered not only matter, but space and time as well: Nicholas of Autrecourt, a fourteenth-century French scholar, suggested that matter, space, and time were composed of atoms, points, and instants that were themselves all indivisible.
Modern chemistry has of course proven the atomists right—and wrong. Atoms themselves turned out to exist, but not to be the most elementary particles of matter; even subatomic particles themselves have turned out to be composites, made of tinier particles still. And of course, we discovered that, how, and with what terrible consequences, the atom can itself be split.
Galen, On the Natural Faculties
Lucretius, On the Nature of Things
Antoine Lavoisier, Elements of Chemistry
Werner Heisenberg, Philosophical Problems in Quantum Physics