No. 334:

Today, 19th-century atomic theory -- 2000 years too soon. The University of Houston's College of Engineering presents this series about the machines that make our civilization run, and the people whose ingenuity created them.

The Epicurean philosopher Titus Lucretius lived in the last century BC, but he held late-19th-century ideas about the nature of things. Lucretius didn't leave many tracks. Contemporaries mention him here and there, and St. Jerome wrote about him in the 4th century. We have only one of Lucretius's writings, but it tells us what we really need to know about him. It's a 200-page poem, De Rerum Natura -- On the Nature of Things.

Two things mark Lucretius's writing: Epicurean simplicity and a very clear mind. He scorned the mystery-laden polytheism of Rome. Epicureans believed that things are what they seem to be -- that our senses don't deceive us. What Lucretius did with that belief was astonishing.

He watched matter dividing, subdividing, and rejoining. So, he concluded, matter must be made of very small building blocks, of atoms, that form and reform. The Greeks had flirted with atomism, but Aristotle's continuous elements, earth, air, fire, and water, had ended all that 300 years before. And his ideas flew in the teeth of Aristotle's.

Lucretius couldn't win -- not then. The 2000-year dominance of Aristotle had just begun. Lucretius's work survived only because it had another dimension. He was a superb poet. Writing in Latin was an uphill battle. It was a simple, direct language -- not good for handling complex ideas. But he made it work. He reshaped Latin and created beauty on the way. Listen to him as he paints a modern picture of atoms moving in solids and gases.

... no rest is allowed the atoms moving through the depths of space. Driven along in an incessant but variable movement. Some of them bounce far apart after a collision [while others] recoil but little. Entangled by their own close-coupled shapes, they make strong rooted rock or the bulk of iron.

When 19th-century physicists talked about large sets of atoms, some called them "assemblies." That was pure Lucretius. He used the Latin word for the Greek citizens' assembly when he talked about aggregate atomic behavior.

His poem was standard classical literature when Aristotle's science began crumbling in the 1600s. Finally a French cleric named Pierre Gassendi broke with Aristotle in 1658. He began creating a modern kinetic theory of gases. His work began right where Lucretius's poem left off.

The poem is a rich trove of ideas -- ideas out of place in time -- modern ideas of heat -- Galilean ideas about falling -- ideas that would've been bypassed and forgotten. In the end, Lucretius's ideas were handed down to us, not on their merits as ideas, but because they were so beautifully said.

I'm John Lienhard, at the University of Houston, where we're interested in the way inventive minds work.

(Theme music)

This episode has been greatly revised as Episode 2662.

Two translations of Lucretius:

Lucretius, Lucretius on the Nature of Things (Trans. by C. Bailey). London: Oxford University Press, 1929.

Lucretius, Lucretius on the Nature of Things (Trans. by R.E. Latham). Baltimore: Penguin Books, 1968.

See also the Encyclopaedia Britannica and Dictionary of Scientific Biography articles on Lucretius.