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the medieval times are famous for being
a period of darkness in the history of
science
and in a lot of ways they were for the
western world but just
south and east of the mediterranean sea
the islamic world was in its golden age
between about 750
and 1250 ce the islamic empire made
incredible advances in science
and many of these discoveries have
shaped our modern world giving us things
like cataract surgery
and algebra but there's also another
major lesson that came out of this
period
diversity makes for better science at
this time the islamic empire stretched
all the way from the arabian peninsula
east into china as well as west across
north africa
and the iberian peninsula and there was
a lot about this empire that set it up
for this golden age of science like in
the early years of islam
the mission to understand the world was
a religious one and a scientific one
there was no difference so muslim
scholars translated hundreds of
thousands of manuscripts from greek
roman persian indian and egyptian
scientists into arabic
so they had the combined knowledge of
all these civilizations as a base but it
wasn't just the knowledge that was
diverse
it was a massive empire and it included
persians north africans spaniards
portuguese chinese and arabs and across
the region
all of these people with different
backgrounds were sharing translating and
exchanging ideas
one of the most famous scientists from
this period is the persian scholar known
as the father of algebra
muhammad ibn musa al-huarizmi al-hurismi
worked in a library in baghdad
called the house of wisdom where
academics from all different
backgrounds came together to work side
by side they included some of the most
famous scientists of the time
and they worked on all types of science
but while his colleagues poured over
ancient texts studied the stars and
invented medical treatments
al-horizmi wrestled with math and one of
the problems he took on
was the quadratic equation people had
been working on this equation
for thousands of years the ancient
egyptians
chinese babylonians and greeks all
recognized that if you have an area
enclosed by a square the amount of stuff
you can put in that area
is related to the length of one side in
other words the length squared
was related to area and any time you
have an equation with a certain value
and the square of that value
it's called a quadratic equation these
equations could be important for
practical reasons like
say you want to build a shed and it
needs to have a certain capacity
it would be useful to know exactly how
long to make the sides so you don't
overshoot or undershoot
various civilizations managed to solve
certain specific problems like this in
one way or another
so they might have been able to figure
out how long to make one particular shed
but they didn't have expressions that
would let them relate something like
length with area in a general way
al-horizmi was the first to do that
instead of solving problems with
specific numbers
he used variables as placeholders it's
not clear where he got that idea but it
made it possible for him to grasp the
universal form of the problem
and come up with a universal procedure
for solving it in doing this
all horizon essentially founded algebra
because that's what algebra is
manipulating symbols to find general
solutions that work with any numbers
all horizonte was familiar with a lot of
the work that had been done before him
he seems to have integrated knowledge
that indians babylonians and greeks
developed over centuries but by
introducing that concept of manipulating
variables
he gave us a whole new power while
al-horismi worked on algebra
three of his contemporaries worked on
another enormous accomplishment from the
house of wisdom
the book of ingenious devices the book
was written by three persian brothers
called the banu musa
and it documented about a hundred
automatic devices things like fountains
clocks and toys some of these were their
own inventions
but the book also compiled a bunch of
existing devices it included a bunch of
inventions documented by the greeks but
which likely came from various places
like iran
india and china even though they leaned
heavily on greek texts
the banu musa approached their work
differently while the greeks tended to
focus on the principles of mechanics the
brothers focused more on the
applications
in other words they wanted to build
something that worked they weren't as
worried about
how now many of their devices weren't
actually that useful but that wasn't
necessarily the point
because at the time engineering was seen
a lot like art
people may have collected these devices
the way they would collect paintings but
even if the brothers didn't intend to
revolutionize modern life
they did end up building some devices
that were kind of useful for instance
a handful of their devices used an
automatic crankshaft these were
contraptions that had a jar or water
trough that was designed to
automatically fill back up from some
reservoir anytime it was emptied they
used a floater to gauge the water level
and the floater was attached to a rod
as that rod went up and down it turned a
valve which controlled the flow of water
from a big bucket that served as a
reservoir this was the first
automatic crankshaft ever documented it
didn't make a full turn
so it didn't look exactly like today's
crankshafts but it did serve the same
general purpose
it turned linear motion into rotational
motion today
your basic engine does the same thing it
has pistons going up and down
and they attach to a crankshaft that
rotates a wheel no one is sure if
there's any direct connection between
the banomus brothers
and the crankshaft that emerged around
500 years later in europe which
eventually went on to be used in engines
but even if not
the brothers showed that they had a
grasp of some of the engineering
principles that still power the world
today
finally although both the banu musa
brothers and al-horizmi
were based at the house of wisdom in
baghdad that wasn't the only hub for
academics another was at bukhara
a persian city in what's now uzbekistan
like baghdad
bukhara was right along the major
east-west trade route called the silk
road so there were always people
circulating through
and it became a hub for arts and
sciences during islamic times that was
the home and workplace of scientist abu
ali al-hussein ibn abdullah ibn sina ibn
sinah was a persian philosopher
physician and physicist
known for uniting ideas from the east
and west and really
it's hard to decide what to even focus
on because the guy had a hand in just
about every kind of science
like he worked on principles of motion
and figured out the concept of linear
momentum centuries before isaac newton
he also observed a supernova and
wrestled with problems like
consciousness and the concept of
infinity but what he's most famous for
is writing a book called
the canon of medicine which outlined
principles for treating illness and
injury
and feels surprisingly modern for
instance it outlined a procedure for
cataract surgery cataracts
are clumps in the eye's lens that form
as proteins in the eye break down they
get worse over time
and can cloud a person's vision but ibn
cena came up with a procedure to restore
vision in people with cataracts a
surgeon would insert an instrument into
the
eye and just nudge the cataracts down
out of the line of sight
it didn't look much like today's
surgeries where cataracts are typically
broken up by a laser or
ultrasound and then removed but it did
the trick the canon also spells out a
process for testing
and administering new drugs that isn't
so far off from what we do today
for instance ibn cena highlighted how
important it is to isolate the illness
to understand whether or not a drug
works in other words you can't reliably
test a drug on someone with multiple
illnesses
he also emphasized that it's necessary
to test drugs in human bodies
not just other animals today these
concepts sound basic
but they don't go without saying and the
principles that ibn cena laid out around
a millennium ago
are still relevant in drug trials today
but although he was precocious
the practices and procedures outlined in
ibn cena's books
weren't just born out of his own
brilliance starting as a kid he had lots
of wide-ranging influences he learned
indian arithmetic from a local grocer
and read the texts of many scientists
who'd come before him he also adopted
certain practices from indian and
chinese medicine
like the use of medicinal herbs and he
pulled theories and principles from
greek medicine
and integrated them into his own
teachings thanks to these influences
he created a powerful holistic practice
of medicine that he's still known for
today
in a lot of ways this history speaks for
itself it shows that the science that
defined the golden age
grew out of the connections between
people with totally different social and
academic backgrounds and sure
some of that is because they were in the
right place at the right time to take
advantage of centuries worth of
knowledge from different civilizations
but what we know about diversity today
suggests that wasn't the whole story
even now diversity still produces better
science
even though we have the internet and
don't need cross-cultural collaborations
to exchange knowledge and that strongly
suggests that diversity itself
plays a role one major study on this
came out of harvard in 2015. the authors
were curious
if there was any relationship between
the quality of a study and the ethnic
diversity of a research team so they
examined 2.5 million
scientific papers published by teams
based in the us
between 1985 and 2008. they used the
author's last names as a way to gauge
the amount of ethnic diversity and they
used the number of citations
and place of publication as markers of
success these are
crude approximations and of course last
names aren't perfect or exclusive
signals of diversity
but even so a couple trends jumped out
for instance
teams with authors of four or five
different ethnic backgrounds
got five to ten percent more citations
than non-diverse teams they also
published
in more reputable journals the study
authors acknowledged that you could
interpret these findings in a few ways
like maybe more diverse teams have
broader professional networks
so their work has a broader reach even
if it's not necessarily better but other
research lends weight to the idea that
diversity improves the quality of
research itself
because study after study shows that
diversity is linked with creativity
research has shown that when we're in a
diverse setting we make fewer
assumptions
because we're less likely to take it for
granted that our peers will agree with
us
we also anticipate pushback which makes
us craft better arguments in the first
place that may be why studies have found
that people who work
outside their home countries are more
creative or why they found people in
cross-cultural relationships make better
entrepreneurs the authors of one such
study concluded that relationships that
broaden our horizons
actually change the way we think and
make us better at coming up with
creative ideas overall
the islamic golden age with all of its
intersecting cultures was the perfect
place for this kind of creativity to
take hold many of the ideas that emerged
changed how things worked at the time
and some of them
laid the foundation for research we're
still doing today and along the way
these discoveries continue to remind us
what happens when different minds
come together thanks for watching this
episode of scishow and special thanks to
this month's president of space
charles zazz and thanks to the amazing
community that supports us on patreon
we couldn't make these videos without
you and if you're not a patron but would
like to help us make science education
free on the internet
you can find out more at patreon.com
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scishow