Keith Devlin
speaker
76 appearances
2 recordings
1 series
first heard Dec 2011
last heard Apr 2012
Keith Devlin’s voice in public audio — every appearance, attributed to the second.
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Appearances
The beginning of the 13th century, nobody in Europe had ever seen that kind of thing before.
It really was the first comprehensive, actually the first coverage at all, of what we now call Hindu Arabic arithmetic, the kind of arithmetic that we all learn when we're in the elementary school.
Counting with the ten digits from zero through nine, all the algorithms, all of the methods we learn at school, that had been invented by Indian mathematicians in about the first six or seven centuries of the current era.
Then the Arabic speaking traders in the Muslim world who were trading between North Africa and Europe
and the Orient, they discovered these methods, and they started using them in their trade, and then some of their scholars started developing them, and one of the offshoots was what we now call algebra.
And so for several hundred years, it was those traders that were sort of developing it and using it, and it was in North Africa when Leonardo, who was a teenager, who'd gone over to join his father, who was a customs official in Bougie, Leonardo sees these traders in the coffee shops using this incredible method, and he recognises at once that,
this can change the world.
If I can package this and make it accessible to ordinary people, then anyone can do their own arithmetic.
Roman numerals are fine for adding and subtracting, but that's not very useful when you're working out volumes of things that you want to buy.
And so,
You need multiplication and division, and Roman numerals are hopeless for that.
So when people did calculations, they did one of two things.
Either they counted on their fingers.
The other way they used to calculate was with a board on which lines were ruled, on which you move pebbles around.
Then you record the answers in Roman numerals.
So, first of all, you couldn't do your own calculations.
You had to have someone who'd spent many years becoming efficient at using one of these two physical calculating methods.
Another drawback was there's no audit trail.
If you carry out a long calculation and then one of the two parties disputes the answer, you can't just go back over the working like we would today.
The working's disappeared.
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