Today, a city falls. And the seeds of the
scientific method are sown. 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.
Do you remember Charlton
Heston playing the Spanish hero El Cid -- freeing
the city of Toledo from Moslem rule in AD 1085?
Never mind that the real El Cid was in fact a
murdering, looting barbarian. Never mind that he
wasn't even around when Toledo fell. Actually,
Toledo's Moslem ruler opened the gates to the
Christians so he could escape from enemies inside
the city.
Still, this was one of the great moments in Western
intellectual history. When they got to the library,
Christian scholars learned how far they'd fallen
behind the Moslems.
For four centuries Arab scholars had been the chief
preservers of the ancient Greek books. Plato and
Aristotle had become distorted echoes in the
Christian world. Now Europeans saw their legacy
first hand, and they were stunned by its
brilliance.
James Burke tells how the Arab and Jewish scholars
of Toledo graciously led academic tourists from the
North through their trove of literature. Those
visitors felt like primitive savages among the
mountains of newly discovered books.
The works of Aristotle presented them with a kit of
logical tools that opened a stunning array of
capabilities. They rediscovered the syllogism --
that miraculous means for using two facts to
generate a third. For example:
Skin gets wet with perspiration.
Moisture escapes from things through holes.
Therefore, skin must have small holes in it.
We've suddenly generated a third fact, seemingly
out of thin air.
The French scholar Pierre Abelard seized
on the new logic. He turned Aristotelian dialectic
loose on Holy Scripture. "By doubting we come to
inquiry," he said, and "by inquiring we perceive the
truth." And that, Burke reminds us, was revolution.
Abelard wrote four rules for inquiry:
Use systematic doubt and question
everything.
Learn the difference between rational proof and
persuasion.
Be precise in use of words, and expect precision
from others.
Watch for error, even in Holy Scripture.
It would be five centuries before
science would fully embrace this old logic in its new
wrapper. For the moment, theologians tried to ride
the shock waves Abelard had unleashed.
Medieval lawyers were first to arm themselves with
these new tools. By the mid-13th century the Church
finally acknowledged Aristotle. When they did,
Thomas Aquinas moved in and built a theology based
on Aristotelian logic.
Out of that came a new theological statement: No
longer "understanding can come only through
belief," but rather, "belief can come only through
understanding." And there, of course, was modern
science -- in its purest embryonic state.
I'm John Lienhard, at the University of Houston,
where we're interested in the way inventive minds
work.
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