Why the metric system matters - Matt Anticole

What does the French Revolution

have to do with the time NASA accidentally
crashed a $200 million orbiter

into the surface of Mars?

Actually, everything.

That crash happened due to an error

in converting between
two measurement systems,

U.S. customary units,

and their S.I, or metric, equivalence.

So what's the connection to
the French Revolution?

Let's explain.

For the majority of recorded
human history,

units like the weight of a grain
or the length of a hand weren't exact

and varied from place to place.

And different regions didn't just use
varying measurements.

They had completely different
number systems, as well.

By the late Middle Ages,
the Hindu-Arabic decimal system

mostly replaced Roman numerals
and fractions in Europe,

but efforts by scholars like John Wilkins
to promote standard decimal-based measures

were less successful.

With a quarter million different units
in France alone,

any widespread change would require
massive disruption.

And in 1789, that disruption came.

The leaders of the French Revolution
didn't just overthrow the monarchy.

They sought to completely
transform society

according to the rational principles
of the Enlightenment.

When the new government took power,

the Academy of Sciences convened
to reform the system of measurements.

Old standards based on arbitrary authority
or local traditions

were replaced with mathematical
and natural relationships.

For example, the meter,
from the Greek word for measure,

was defined as 1/10,000,000
between the Equator and North Pole.

And the new metric system was,
in the words of the Marquis de Condorcet,

"For all people, for all time."

Standardizing measurements
had political advantages

for the Revolutionaries, as well.

Nobles could no longer manipulate local
units to extract more rent from Commoners,

while the government could collect
taxes more efficiently.

And switching to a new Republican Calendar
with ten-day weeks

reduced church power
by eliminating Sundays.

Adoption of this new system wasn't easy.

In fact, it was a bit of a mess.

At first, people used new units
alongside old ones,

and the Republican Calendar
was eventually abandoned.

When Napoléon Bonaparte took power,

he allowed small businesses
to use traditional measurements

redefined in metric terms.

But the metric system remained standard
for formal use,

and it spread across the continent,
along with France's borders.

While Napoléon's empire
lasted eight years,

its legacy endured far longer.

Some European countries reverted
to old measurements upon independence.

Others realized the value
of standardization

in an age of international trade.

After Portugal and the Netherlands
switched to metric voluntarily,

other nations followed,

with colonial empires spreading the system
around the world.

As France's main rival,

Britain had resisted revolutionary ideas,
and retained its traditional units.

But over the next two centuries,
the British Empire slowly transitioned,

first approving the metric system
as an optional alternative

before gradually making it offical.

However, this switch came too late
for thirteen former colonies

that had already gained independence.

The United States of America stuck with
the English units of its colonial past

and today remains one
of only three countries

which haven't fully embraced
the metric system.

Despite constant initiatives
for metrication,

many Americans consider units like feet
and pounds more intuitive.

And ironically, some regard the once
revolutionary metric system

as a symbol of global conformity.

Nevertheless, the metric system is almost
universally used in science and medicine,

and it continues to evolve according
to its original principles.

For a long time,

standard units were actually defined by
carefully maintained physical prototypes.

But thanks to improving technology
and precision,

these objects with limited access
and unreliable longevity

are now being replaced with standards
based on universal constants,

like the speed of light.

Consistent measurements are such
an integral part of our daily lives

that it's hard to appreciate what a major
accomplishment for humanity they've been.

And just as it arose
from a political revolution,

the metric remains crucial for
the scientific revolutions to come.