around today.

They used arches and domes to create monumental buildings with big airy interiors that looked

truly Olympian—also still around.

And they moved thousands of tons of water using aqueducts to keep a bustling population

un-thirsty.

These old buildings?

Also still around!

But did the Romans come up with ideas about physics?

Like why arches support weight differently than right-angled structures?

Did they ask proto-chemistry questions—that is, “what is stuff?”—such as which tiny

things make up a good concrete?

Nope.

Let's look at what knowledge the Romans made in order to set up a debate that, spoiler

alert, is still going on: do you understand something when you can explain why it's

true, in the abstract?

Or do you understand something when you can do things with it, even if you can't explain why?

[Intro Music Plays]

The Romans inherited much of their knowledge from the Greeks.

From 323 to 31 BCE, the geometry, physics, astronomy, and other disciplines developed

by the Presocratics, Plato, and Aristotle spread throughout the Hellenistic world.

This “world” combined the parts of Asia, Africa, and Europe influenced by Greek thought

due in large part to Alexander's brief supervillain rampage.

In Alexandria, Egypt—the biggest of the seventy cities that Alexander named after

himself—the kings paid for the Museum, or “house of the muses.”

This wasn't a museum in the modern sense of the word but more like a research university.

In Pergamon, in what is now Turkey, the kings paid for the Library, which was—wait for

it—a really big collection of books.

These institutions lasted for centuries, drawing visitors from far and wide.

Alas, over the same period of time that these Greeks were supporting research, a tribe from

central Italy called the Romans went on a new supervillain rampage… that also lasted

for centuries.

The Romans would continue to spread classical Greek thought: we even call their culture

“Greco-Roman.”

But natural philosophy during Greco-Roman times didn't advance much.

Today, we remember the Romans for their engineering—or ability to improve some real-world system—not

their deep thoughts about why the world is the way it is.

Roman engineering built on Greek engineering.

Making knowledge is political, and most politicians really want the same thing: bigger catapults

and lots of ships.

So Greco-Roman leaders did what heads of state everywhere have always done: they paid smart

people to make bigger weapons.

In the ancient Mediterranean, the job of building warmachines was called architecton, or architect.

Most of these “architects” were anonymous and didn't write down theories.

But, a few of them did.

The most famous architecton, Archimedes of Syracuse, fought for the Greeks against the

Romans.

Archimedes is famous today as a mathematician: he worked out many geometrical proofs

including the area of a circle, and pioneered infinitesimals and exponents.

Archimedes also invented a lot of useful contraptions, including the water screw and compound pulley.

The water screw pumps water by turning a screw inside a pipe.

This was immediately useful in irrigation.

And a mechanical way to move water uphill is just plain cool!

Archimedes also designed various warmachines to kill the Romans who were trying to take

over his hometown.

He was so impressive that the Roman general ordered his troops to capture, not kill, him.

But one soldier particularly low on chill got frustrated when Archimedes wouldn't

stop working on a mathematical proof.

In a sense, Archimedes kept it so real that he got himself and, symbolically, an era of

Greek science killed.

Archimedes was interested in some of the natural philosophy that explained his machines, but

for most other thinkers of his time, astronomy, physics, and math were important for abstract,

quasi-religious reasons.

Making weapons was a matter of political power.

The heavens from which rain fell were perfect and abstract.

Shipbuilding was an art, something learned from practice.

It was not a matter of understanding hydrodynamics, or the chemical properties of wood that make

it bendy and floaty.

Aristotle came up with a handy division between these types of knowledge that we still use today.

He classified knowledge as either “useful” or “theoretical.”

Useful knowledge was called technē, which is where we get “technology.”

“Technology” has until recently, in historical terms, been connected to the idea of “art”—meaning

something you learn by doing, and can see in the real world.

Theoretical knowledge, on the other hand, was epistēmē—the root of our word epistemology,

the study of knowledge.

Epistēmē is the sort of knowledge we most associate with “science.”

Science is abstract, represented by formulas.

When historians of science talk about the possibilities of what we can know, they use

the word “epistemic.”

One of the most influential thinkers working on epistemic questions during the Greco-Roman

period was Claudius Ptolemy, a Greek or Greek-speaking southern Egyptian living in Roman-held Alexandria.

In addition to optics and the science of music, Ptolemy took up Plato's old problem of how

to fit the observed data about how the planets move to the theory of a cosmos made of perfect

circles with earth at its center.

He got really, really into this, mixing together three kinds of solutions in order to make

the math work: epicycles, for example, were the tiny circles that the planets moved along…

around bigger circles.

Ptolemy's version of the cosmos, a mathematically neater version of Aristotle's and Plato's,

became the basis of the understanding of the universe across much of the medieval Christian

and Islamic world.

His great astronomical work, the Mathematical Syntaxis, was renamed by Arabic scholars as

the Almagest, or The Greatest.

Fun fact: the Almagest may have been edited by one of the first recorded female natural

philosophers, Hypatia of Alexandria.

So we're on episode six of History of Science and, yes, this is the first mention of a woman...

Ptolemy was also pretty much the authority on earthly geography in the Greco-Roman world.

His book on the subject, called Geography, discusses the data he uses and why.

It provided a resource for other scholars to use in more accurately picturing and drawing

the world, for centuries.

Oh, and none of these thinkers thought that the earth was flat.

Flat earth theory may have more proponents today than it did in Greco-Roman times.

As Ptolemy shows, epistemic work was important to a few Greco-Romans.

But what they're really remembered for is their technē, their engineering.

For example, people had been mixing together water and rocks to make cement for generations.

But by 150 BCE, the Romans began mixing volcanic ash, rocks, water, and lime to make Roman

concrete, or opus caementitium, which is one of those technologies that the smarty-pants like

to call "a big freakin' deal.”

This new stuff was super durable and could be poured into weird shapes like domes.

The Pantheon or Really Big Temple in Rome is capped by a 143-foot diameter dome of concrete

that has stood for almost two thousand years.

But the Romans found out that arches support more weight than straight joints.

This matters when you're trying to move something really heavy, like water.

Thus the Romans were able to move water long distances using arch-y aqueducts.

This in turn allowed Roman cities to grow in population, mines to run, and dry lands

to be irrigated.

The Romans changed their lands in other ways, too: they drained the marshes of their home

city using an innovative sewer system called the Cloaca Maxima, which literally means “Biggest

Sewer.”

Great name, my dudes.

The politician and civil engineer Sextus Julius Frontinus wrote a landmark, comprehensive,

two-volume report on the design for the aqueducts and sewers of Rome… which luckily a Renaissance

scholar found a copy of, just as the city recovered from a roughly one thousand year

downturn in population.

Yes, that's right: Roman infrastructural engineering lasted through a millennium of

neglect and still worked!

But as great as gigantic open rooms, fresh drinking water, and big-big sewers are, the

most important feat of Roman engineering may have been their highways.

We hear a lot about “infrastructure” today.

And states have always made roads to foster trade and move troops.

But Roman road builders took the art of logistics to another level.

Show us what a big deal this was, Thought Bubble!

Consider the Appian Way: running from Rome southeast through the “heel” of Italy,

it connected several not very urbanized regions of the peninsula.

Its first leg was built in 312 BCE—before Roman concrete was perfected...

...using cement over layers of fitted stones and gravel.

Drainage ditches lined its sides, and the road was cambered to allow water to drain

off.

The Appian Way allowed Roman troops to efficiently crush their enemies.

It was expanded over the centuries.

And the Appian Way is still around!

The cement has eroded away, but you can still see many long, very straight sections.

It's lined by trees, marked by monuments, and haunted by history.

And the Appian Way is only one of several well-preserved, two-thousand-year-old Roman

roads crisscrossing Africa, Asia, and Europe.

Metaphorically, all of these roads led to Rome.

Her citizens paid taxes toward many large-scale public works such as highways.

Perhaps the most important technology the Romans optimized was the state itself: they

developed a complicated legal system, a well-supplied army, public food assistance, and massive

public games.

One site of these games was the Flavian Amphitheater, AKA the Colosseum.

It had a retractable roof that was staffed by sailors who used complicated rigging to

move the canvas coverings around, and it was sometimes flooded to allow for naval war games.

How many engineers today know how to properly rig a giant sun-sail?

Or safely flood a public venue—without using plastic?

Thanks, Thought Bubble, but these public works were intended for Romans, not their property…

Before the industrial revolution, public works such as aqueducts, sewers, and roads required

quarrying lots of materials and lots and lots of labor.

And “labor” meant slaves.

Some estimates hold that one in three people in Roman Italy were enslaved.

These people were involved in knowledge creation, if against their will, by building and maintaining

all those great roads and other structures.

Roman slavery was a little different than plantation slavery in the American South.

Slaves could be highly educated.

Many physicians were even slaves.

They could buy their freedom and become voting citizens.

But most remained chattel—meaning property.

In 73 BCE, the gladiator Spartacus famously led a slave revolt in Italy.

The freed slaves fought the army for two years, but they were eventually defeated.

The survivors of the rebellion were crucified along the Appian Way, from Rome to Capua,

over a hundred miles to the south.

Brutal story, but worth telling in the context of Roman engineering.

Because the technologies that engineers make are, like the sciences, political—only as

good or as bad as the humans who use them.

Roman thinkers left behind written sources including histories, plays, proto-novels,

poems, legal manuals, and religious texts.

But only a few Roman texts deal with natural philosophy.

Frontius's guide to aqueducts was one exception.

Another was the Architecture of Vitruvius.

He wrote about buildings, but also urban planning and even the plan of the human body.

By linking the limbs of the human body to mathematical principles, Vitruvius inspired

Da Vinci's “Vitruvian man.”

Vitruvius's Architecture sums up the concepts about knowledge common to the Hellenistic

and Greco-Roman worlds: it's a technical manual also concerned with the beautiful harmonies

of form inherent to bodies as well as the efficient management of cities—the “body

politic.”

Next time—we'll meet mechanical wonders and the wonder of public healthcare in the

Abbasid Caliphate's great capital, Baghdad.

Crash Course History of Science is filmed in the Dr. Cheryl C. Kinney studio in Missoula,

Montana and it's made with the help of all this nice people and our animation team is

Thought Cafe.

Crash Course is a Complexly production.

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