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 system remains crucial
for the scientific revolutions to come.