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The sun, the moon, the planets and stars | 0:00:10 | 0:00:14 | |
have always fired our imaginations and fuelled our mythologies. | 0:00:14 | 0:00:19 | |
And studying the heavens - astronomy - is surely the oldest scientific discipline there is. | 0:00:19 | 0:00:25 | |
What's really unexpected, I guess, | 0:00:29 | 0:00:31 | |
is that astronomy has repaid our interest in it over the centuries. | 0:00:31 | 0:00:35 | |
Time after time it's been the place where new ideas have emerged, | 0:00:35 | 0:00:40 | |
and it's often led the rest of sciences. | 0:00:40 | 0:00:42 | |
I'm a Professor of Physics at the University of Surrey, | 0:00:47 | 0:00:51 | |
and the ideas and theories of the great European scientists | 0:00:51 | 0:00:54 | |
like Galileo, Newton and Einstein lie at the heart of my work. | 0:00:54 | 0:01:01 | |
But there's another side to me. | 0:01:01 | 0:01:02 | |
I'm half-Iraqi, and I'm keen to investigate stories I'd heard as a schoolboy in Baghdad | 0:01:02 | 0:01:09 | |
of great astronomers from the medieval Islamic world | 0:01:09 | 0:01:12 | |
whose work shaped the discoveries of these later, Western scientists. | 0:01:12 | 0:01:17 | |
So, I'm going on a journey through Syria and Egypt, to the remote mountains in northern Iran, | 0:01:19 | 0:01:25 | |
to discover how the work of these Islamic astronomers had dramatic and far-reaching consequences. | 0:01:25 | 0:01:32 | |
There, I'll discover how they were the first to attack seemingly unshakeable Greek ideas | 0:01:34 | 0:01:40 | |
about how the heavenly bodies move around the earth. | 0:01:40 | 0:01:44 | |
It was Islam that paved the way | 0:01:44 | 0:01:47 | |
for one of the greatest upheavals in the history of science. | 0:01:47 | 0:01:52 | |
This is the University of Padua in northern Italy. | 0:02:20 | 0:02:23 | |
I'm here to see incontrovertible evidence | 0:02:26 | 0:02:28 | |
that one of the greatest breakthroughs in European science | 0:02:28 | 0:02:32 | |
links back to the earlier work by Islamic scholars. | 0:02:32 | 0:02:36 | |
Astronomer Dr Luisa Pigotti and I | 0:02:41 | 0:02:43 | |
are climbing up to the 18th century observatory. | 0:02:43 | 0:02:47 | |
At the top she promises to show me one of the most important books in scientific history. | 0:02:49 | 0:02:54 | |
So, what do we have here? | 0:02:56 | 0:02:59 | |
OK... | 0:02:59 | 0:03:00 | |
This is the second edition of De Revolutionibus. | 0:03:00 | 0:03:04 | |
Ah, Copernicus. Yes. | 0:03:04 | 0:03:07 | |
This is De Revolutionibus Orbium Celestium, | 0:03:07 | 0:03:11 | |
which was published in 1543 by the Polish astronomer Nicolaus Copernicus. | 0:03:11 | 0:03:17 | |
The significance of this book is enormous. | 0:03:17 | 0:03:22 | |
In it, Copernicus argues for the first time since Greek antiquity | 0:03:22 | 0:03:26 | |
that all the planets, including the Earth, go around the sun. | 0:03:26 | 0:03:30 | |
For thousands of years, everyone had believed a very different view - | 0:03:34 | 0:03:39 | |
that the earth is static and everything - including the stars, | 0:03:39 | 0:03:44 | |
sun and planets - move around it. | 0:03:44 | 0:03:46 | |
And here there are...all his system, OK...? | 0:03:46 | 0:03:51 | |
Oh, here we go. | 0:03:51 | 0:03:53 | |
Sol. The sun in the middle. | 0:03:53 | 0:03:57 | |
Yes. | 0:03:57 | 0:04:00 | |
Oh, yes, there's Terra... | 0:04:00 | 0:04:01 | |
With the moon. With the moon going around it. Yes. | 0:04:01 | 0:04:05 | |
This is an astonishing book. | 0:04:05 | 0:04:07 | |
And many historians credit it with starting the European scientific revolution. | 0:04:07 | 0:04:14 | |
The first, crucial step in a journey that led to modern physics. | 0:04:14 | 0:04:19 | |
Well, I agree. | 0:04:21 | 0:04:23 | |
But it does seem a bit odd that one doesn't hear much | 0:04:23 | 0:04:25 | |
about where Copernicus got his ideas and information. | 0:04:25 | 0:04:29 | |
The impression is that they came out of nowhere. | 0:04:29 | 0:04:32 | |
The beginning... The beginning is all in Arabic. | 0:04:34 | 0:04:38 | |
It certainly is a real revelation to me | 0:04:38 | 0:04:41 | |
that he explicitly mentions a 9th century Muslim | 0:04:41 | 0:04:45 | |
for providing him with a great deal of observational data - | 0:04:45 | 0:04:49 | |
an astronomer who lived in Damascus, called Al-Battani. | 0:04:49 | 0:04:52 | |
Like all the great scientists of the Islamic Empire, | 0:04:54 | 0:04:57 | |
Al-Battani lived in a culture without portraiture. | 0:04:57 | 0:05:01 | |
All we have are later impressions of what he might have looked like. | 0:05:01 | 0:05:05 | |
And here he mentions Hipparchus, | 0:05:05 | 0:05:10 | |
Ptolemy and so on. | 0:05:10 | 0:05:13 | |
And he started to mention what he called Machometi Aracenfis, | 0:05:13 | 0:05:19 | |
he means Al-Battani. | 0:05:19 | 0:05:21 | |
OK. And then this second book here... This second book is... | 0:05:21 | 0:05:25 | |
We can look at the beginning in Latin... I see... | 0:05:25 | 0:05:29 | |
Copernicus, in fact, made extensive use of Al-Battani's observations | 0:05:29 | 0:05:33 | |
of the positions of planets, the sun, the moon and stars. | 0:05:33 | 0:05:37 | |
He worked with Latin translations, similar to this one, of the Syrian astronomer's data. | 0:05:37 | 0:05:43 | |
Kitab Al-Zij Al-Battani. | 0:05:43 | 0:05:45 | |
So this is Al-Battani's zij, his book of star charts. | 0:05:45 | 0:05:52 | |
So it has the Arabic on one side and... | 0:05:52 | 0:05:55 | |
Yes. And then the Latin version. | 0:05:55 | 0:05:58 | |
That's convenient. | 0:05:58 | 0:06:00 | |
But certainly he had the data, the observational data, by Al-Battani. | 0:06:02 | 0:06:07 | |
And Copernicus' book is full of clues | 0:06:10 | 0:06:12 | |
that hints at other past sources. | 0:06:12 | 0:06:14 | |
And though Al-Battani is the only Islamic astronomer Copernicus actually names, | 0:06:17 | 0:06:22 | |
recent detective work has uncovered clues that Copernicus based many of his ideas | 0:06:22 | 0:06:28 | |
on the work of other Islamic scholars. | 0:06:28 | 0:06:31 | |
The clearest example is Copernicus's use of a mathematical idea | 0:06:31 | 0:06:36 | |
devised by the 13th century Islamic astronomer Al-Tusi, called the Tusi Couple. | 0:06:36 | 0:06:42 | |
Back in England, I compared a copy of Al-Tusi's Tadhkirah Al-Hay Fi'ilm Sl-hay'ah | 0:06:46 | 0:06:52 | |
with another edition of Copernicus' Revolutionibus. | 0:06:52 | 0:06:57 | |
In it there's a diagram of the Tusi Couple - | 0:06:57 | 0:06:59 | |
and there's an almost identical diagram in Copernicus's book. | 0:06:59 | 0:07:05 | |
Even down to the letters that mark the points on the circles. | 0:07:05 | 0:07:09 | |
So, in Al-Tusi there is the Arabic Alif, which is A. | 0:07:09 | 0:07:13 | |
There's the Baa, which is B. Gheem, over here, is the G. | 0:07:13 | 0:07:17 | |
And the Dal at the centre, D. | 0:07:17 | 0:07:21 | |
It's a remarkable similarity. | 0:07:21 | 0:07:24 | |
Now this might just be coincidence, but it's pretty compelling evidence. | 0:07:24 | 0:07:29 | |
In fact, I truly believe that Copernicus | 0:07:29 | 0:07:33 | |
must have been aware of Al-Tusi's work and other Islamic astronomers. | 0:07:33 | 0:07:38 | |
Further detective work also shows that Copernicus used mathematical ideas for planetary motion | 0:07:42 | 0:07:48 | |
that are remarkably similar to ones developed by another Islamic astronomer, | 0:07:48 | 0:07:53 | |
a 14th century Syrian called Ibn Al-Shatir. | 0:07:53 | 0:07:57 | |
For some historians this cannot be coincidence. | 0:07:57 | 0:08:01 | |
Copernicus, to me, I have no proof, I don't have a smoking gun. | 0:08:01 | 0:08:06 | |
But to me it looked like, and by analysing his own words, | 0:08:06 | 0:08:11 | |
it looks like he was working from diagrams. | 0:08:11 | 0:08:14 | |
Somebody gave him a geometric diagram of what was done by Ibn Shatir to solve the problem of the moon, | 0:08:14 | 0:08:21 | |
for example, to solve the problem of the upper planets, | 0:08:21 | 0:08:25 | |
to solve the problem of the movement of Mercury, he had diagrams, and he was genius enough | 0:08:25 | 0:08:29 | |
to be able to figure out from the diagrams what was the underlying theory behind those diagrams. | 0:08:29 | 0:08:35 | |
So, far from emerging from nowhere, | 0:08:39 | 0:08:42 | |
it seems Copernicus' work would be better described as | 0:08:42 | 0:08:46 | |
the culmination of the preceding 500 years of Islamic astronomy. | 0:08:46 | 0:08:51 | |
I wanted to investigate this story, | 0:08:51 | 0:08:54 | |
find out more about those astronomers and their ideas. | 0:08:54 | 0:08:57 | |
But before that, I wanted to investigate an even deeper question. | 0:08:59 | 0:09:03 | |
What actually motivated medieval Islamic scholars' interest in astronomy? | 0:09:03 | 0:09:09 | |
This is the Umayyad Mosque | 0:09:23 | 0:09:25 | |
in the heart of the Syrian capital, Damascus, | 0:09:25 | 0:09:28 | |
and is one of the oldest in the world. | 0:09:28 | 0:09:30 | |
And I'm here on a kind of treasure hunt. | 0:09:35 | 0:09:38 | |
Well, it says says in the books | 0:09:38 | 0:09:40 | |
that there is a sundial on the top of the Arus Minaret, | 0:09:40 | 0:09:44 | |
the bright minaret over there. | 0:09:44 | 0:09:46 | |
So we'll see whether it is there or not... | 0:09:46 | 0:09:48 | |
This is Dr Rim Turkmani, | 0:09:50 | 0:09:52 | |
an astrophysicist and medieval astronomy expert | 0:09:52 | 0:09:55 | |
from Imperial College London. | 0:09:55 | 0:09:57 | |
And we're looking for one of the most accurate sundials made in the medieval world. | 0:09:57 | 0:10:02 | |
And equally exciting for me | 0:10:02 | 0:10:04 | |
is the fact that it was made by one of the Islamic astronomers | 0:10:04 | 0:10:08 | |
who had so heavily influenced Copernicus, Ibn Shatir. | 0:10:08 | 0:10:12 | |
Let's see... | 0:10:14 | 0:10:16 | |
Officials in the mosque claim that the sundial was removed in the 19th century, | 0:10:19 | 0:10:25 | |
but Rim's research suggests that an exact replica might still exist, | 0:10:25 | 0:10:30 | |
high in one of the minarets, hidden from view. | 0:10:30 | 0:10:33 | |
It's not quite the lost of arc of the covenant, | 0:10:33 | 0:10:36 | |
but the idea of discovering a 150-year-old artefact is still quite something. | 0:10:36 | 0:10:40 | |
Would you recognise anything if you...? Yeah, I need to look out of the other window, I'm sorry. | 0:10:42 | 0:10:46 | |
Nope. No, it is further up... | 0:10:49 | 0:10:51 | |
Yeah. | 0:10:51 | 0:10:53 | |
Marking time accurately is essential to Islam. | 0:10:53 | 0:10:57 | |
The Qur'an requires the faithful to pray five times a day, | 0:10:59 | 0:11:04 | |
at five very precise times. | 0:11:04 | 0:11:06 | |
At the exact moment of dawn, when the sun is overhead, | 0:11:10 | 0:11:14 | |
in the afternoon, at sunset, | 0:11:14 | 0:11:17 | |
and then again at the moment of nightfall. | 0:11:17 | 0:11:21 | |
So for early Islam, an accurate sundial was an extremely important fixture in many mosques. | 0:11:21 | 0:11:28 | |
That's it. That's it, I've found it! I've found it! | 0:11:34 | 0:11:38 | |
Here it is, that's it, look! | 0:11:38 | 0:11:41 | |
Just as described in the book. Wow! It's hidden by the pillar. | 0:11:41 | 0:11:46 | |
Yeah. No wonder they didn't know that it exists here. | 0:11:46 | 0:11:48 | |
It's all covered with the pigeons' filth. | 0:11:48 | 0:11:52 | |
Pigeon crap. Yeah. Try that. Oh, great, thank you. | 0:11:52 | 0:11:56 | |
Now, this consists of three sundials. | 0:12:01 | 0:12:05 | |
The main, big one. | 0:12:05 | 0:12:06 | |
And there's the northern one and the southern one. | 0:12:06 | 0:12:10 | |
There is a line here for Dhuhr, | 0:12:10 | 0:12:12 | |
the midday prayer, and there is one for the afternoon prayer. | 0:12:12 | 0:12:15 | |
Ibn Al-Shatir had calculated the arrangement of these lines | 0:12:17 | 0:12:21 | |
so that the sun dial remains accurate all through the year, | 0:12:21 | 0:12:26 | |
even though length of the days change. | 0:12:26 | 0:12:28 | |
They will have a timekeeper. | 0:12:28 | 0:12:31 | |
You know, it's a very important job. | 0:12:31 | 0:12:33 | |
Yeah. So he would sit here watching the shadow... Exactly. | 0:12:33 | 0:12:36 | |
And the precise moment for prayer, he'd signal to the muezzin to start the call for prayer. Exactly. | 0:12:36 | 0:12:42 | |
Ibn Al-Shatir's sundial, accurate to within minutes, | 0:12:55 | 0:12:59 | |
really showed me how Islam required its scholars | 0:12:59 | 0:13:02 | |
to make meticulously accurate observations of heavenly bodies. | 0:13:02 | 0:13:06 | |
And I began to understand why Copernicus was so impressed by the work of his Islamic predecessors. | 0:13:17 | 0:13:23 | |
They really brought standards of accuracy and precision to astronomy that were unheard of before. | 0:13:24 | 0:13:30 | |
They had calculated the size of the Earth to within 1 per cent. | 0:13:32 | 0:13:36 | |
And created trigonometric tables accurate to three decimal places. | 0:13:36 | 0:13:41 | |
And when I met up with Rim Turkmani again on Mount Qassioun outside Damascus, | 0:13:44 | 0:13:49 | |
I was to hear about the Islamic astronomer who personified accurate observation, | 0:13:49 | 0:13:55 | |
the man whose astronomical tables and measurements | 0:13:55 | 0:13:58 | |
Copernicus explicitly makes reference to - Al-Battani. | 0:13:58 | 0:14:02 | |
Born in 858 in southern Turkey, | 0:14:03 | 0:14:06 | |
Al-Battani made accurate astronomical measurement a personal obsession. | 0:14:06 | 0:14:12 | |
And the story goes that Al-Battani used to observe on this mountain here in this observatory... | 0:14:12 | 0:14:20 | |
Over 40 years from 877 - both here and in the town of Raqqah - | 0:14:20 | 0:14:26 | |
Al-Battani's great project was to work to out, | 0:14:26 | 0:14:29 | |
as accurately as possible, the length of the year. | 0:14:29 | 0:14:33 | |
This is a copy of the original manuscript. | 0:14:33 | 0:14:37 | |
OK. I'll show you the chapter at which he explains the length of the year, OK? | 0:14:37 | 0:14:42 | |
Mm-hmm. The Chapter 27. | 0:14:42 | 0:14:45 | |
So he first started by citing the ancient values of the Egyptians and the Babylonians. | 0:14:45 | 0:14:51 | |
And he gives their length of the year. | 0:14:51 | 0:14:52 | |
Their estimate of the year | 0:14:55 | 0:14:57 | |
was 365 days, 6 hours and just over 10 minutes. | 0:14:57 | 0:15:03 | |
To improve on this, Al-Battani used his ingenuity and a device like this, an armillary sphere. | 0:15:03 | 0:15:09 | |
He used it to measure how the length of shadows varied over the course of the year. | 0:15:09 | 0:15:14 | |
With this information he worked out the precise day | 0:15:14 | 0:15:17 | |
on which it's both light and dark for exactly the same time - | 0:15:17 | 0:15:21 | |
the so-called equinox. | 0:15:21 | 0:15:23 | |
And he repeated his measurements over the course of 40 years. | 0:15:23 | 0:15:27 | |
Now here's the clever bit. | 0:15:27 | 0:15:29 | |
He then examined a Greek text that was written 700 years earlier, | 0:15:29 | 0:15:33 | |
and discovered the precise day on which its author had also measured the equinox. | 0:15:33 | 0:15:38 | |
He now had two vital pieces of data - | 0:15:38 | 0:15:40 | |
the number of days between the two observations, and the number of years. | 0:15:40 | 0:15:45 | |
He divided the first number by the second to arrive at an astonishing result - | 0:15:45 | 0:15:53 | |
a year is 365 days, five hours, 46 minutes and 24 seconds. | 0:15:53 | 0:15:59 | |
He gets the new number, which was only two minutes off the modern observations. | 0:15:59 | 0:16:04 | |
The length of the year to an accuracy of just two minutes. | 0:16:04 | 0:16:08 | |
Exactly, the one he calculated. | 0:16:08 | 0:16:09 | |
What's astonishing about the accuracy of Al-Battani's measurements | 0:16:15 | 0:16:20 | |
is that he had no telescope. | 0:16:20 | 0:16:21 | |
He used an armillary arm, his naked eye, and devices like this - an astrolabe. | 0:16:24 | 0:16:29 | |
So you move the pointer, and you move this disc with it, to point towards the North Star. | 0:16:29 | 0:16:34 | |
And then these small pointers here, | 0:16:34 | 0:16:37 | |
they will give you the location of the rest of the stars and the planets. | 0:16:37 | 0:16:41 | |
Despite this, among his many other observations | 0:16:43 | 0:16:46 | |
is an incredibly accurate figure for the Earth's tilt, | 0:16:46 | 0:16:51 | |
of just under 24 degrees - about a half a degree from the figure we now know it to be. | 0:16:51 | 0:16:57 | |
And he didn't stop there. | 0:16:59 | 0:17:01 | |
He measured variations in the sun's diameter with such accuracy | 0:17:01 | 0:17:06 | |
that it lead him to astonishing conclusion. | 0:17:06 | 0:17:10 | |
This distance, the furthest point the sun reaches from the Earth during the year, | 0:17:10 | 0:17:15 | |
known as its apogee, actually changes from one year to another. | 0:17:15 | 0:17:19 | |
Also, his tables showing the position of the sun and moon, | 0:17:22 | 0:17:26 | |
which is what Copernicus refers to some 600 years later, | 0:17:26 | 0:17:31 | |
set a new standard in precision and accuracy. | 0:17:31 | 0:17:34 | |
So, Al-Battani and his fellow Islamic astronomers were clearly good observers. | 0:17:37 | 0:17:42 | |
But so what, you might ask. | 0:17:44 | 0:17:47 | |
Well, the answer is that their observations began to suggest to them | 0:17:47 | 0:17:51 | |
that the prevailing Greek theory that described how everything | 0:17:51 | 0:17:56 | |
in the heavens revolved around the Earth had some serious flaws. | 0:17:56 | 0:18:00 | |
This Greek tradition, which had been unquestioned for over 700 years, | 0:18:03 | 0:18:09 | |
was based primarily on the work of one of the greatest astronomers of the ancient world. | 0:18:09 | 0:18:15 | |
Claudius Ptolemaeus, or Ptolemy, | 0:18:19 | 0:18:22 | |
was a Greek astronomer based in Alexandria in the 2nd century AD. | 0:18:22 | 0:18:27 | |
He wrote one of the greatest texts in astronomy, the Alamgest, | 0:18:27 | 0:18:31 | |
which was basically a distillation of all the Greek knowledge on the celestial world. | 0:18:31 | 0:18:37 | |
Ptolemy believed that the sun, the moon, the planets and the stars | 0:18:37 | 0:18:42 | |
all sat on crystal spheres that rotated around the Earth. | 0:18:42 | 0:18:46 | |
So, the moon sits on the innermost sphere, | 0:18:46 | 0:18:49 | |
followed by the sun and the planets, | 0:18:49 | 0:18:52 | |
and finally, a patchwork of stars on the outermost sphere. | 0:18:52 | 0:18:56 | |
So, we human beings sit at the very centre of the universe, | 0:18:56 | 0:19:00 | |
with the rest of the universe rotating around us. | 0:19:00 | 0:19:03 | |
But, as Ptolemy himself realised, | 0:19:03 | 0:19:06 | |
there's a problem with trying to describe the heavens | 0:19:06 | 0:19:09 | |
as a place of mathematically-idealised perfect spheres. | 0:19:09 | 0:19:14 | |
And that is that the planets don't really play ball. | 0:19:15 | 0:19:19 | |
As they move across the night sky, they change speed, | 0:19:19 | 0:19:23 | |
appear to get bigger and smaller and even go back on themselves. | 0:19:23 | 0:19:28 | |
Ptolemy tried to explain this away by arguing that the planets sat on small spheres called epicycles, | 0:19:28 | 0:19:35 | |
which rotated around a bigger sphere called a deferent. | 0:19:35 | 0:19:39 | |
This explained why they might look as though they were changing size | 0:19:42 | 0:19:45 | |
and why they sometimes even changed direction. | 0:19:45 | 0:19:47 | |
Unfortunately, that still didn't fit all the facts. | 0:19:49 | 0:19:53 | |
It didn't easily explain why the planets appear to speed up and slow down. | 0:19:53 | 0:19:58 | |
So rather desperately, Ptolemy fudged his model further | 0:19:58 | 0:20:03 | |
by moving the Earth away from the centre of the deferent, | 0:20:03 | 0:20:08 | |
and having the deferent rotate around an arbitrary point in space - the equant. | 0:20:08 | 0:20:14 | |
But now the works of astronomers like Al-Battani | 0:20:14 | 0:20:18 | |
started to strain Ptolemy's ideas to breaking point. | 0:20:18 | 0:20:22 | |
Their careful observations began to suggest that even with Ptolemy's unwieldy equants and deferents, | 0:20:22 | 0:20:30 | |
the actual behaviour of the heavens didn't fit the data. | 0:20:30 | 0:20:34 | |
So, what do you do if you were an astronomer living in Baghdad | 0:20:34 | 0:20:38 | |
and you have all these results on your table? | 0:20:38 | 0:20:41 | |
The very first requirement is to say, | 0:20:41 | 0:20:44 | |
this Greek tradition is not as trustworthy as it is advertised to be. | 0:20:44 | 0:20:51 | |
And now of course they begin to say, | 0:20:51 | 0:20:53 | |
"If the fundamental values of the astronomical measurements of the Greeks, | 0:20:53 | 0:20:59 | |
"which we could double-check and we found them to be in error, what else is in error?" | 0:20:59 | 0:21:04 | |
They began to question now the more basic foundational | 0:21:04 | 0:21:10 | |
astronomical, cosmological foundations of the Greek tradition. | 0:21:10 | 0:21:16 | |
And question they did. | 0:21:16 | 0:21:18 | |
What's absolutely striking about the writings of Islamic scholars by the 9th century | 0:21:23 | 0:21:30 | |
is the increasing use of the word "shukuk", which in English means "doubts". | 0:21:30 | 0:21:36 | |
They showed it's sometimes necessary to doubt an idea that everyone around you believes unquestioningly. | 0:21:36 | 0:21:42 | |
Islamic doubting of Greek astronomy | 0:21:42 | 0:21:44 | |
began the slow process of undermining the notion | 0:21:44 | 0:21:47 | |
that the Earth is at the centre of the universe. | 0:21:47 | 0:21:50 | |
To doubt takes great courage and imagination, | 0:21:50 | 0:21:54 | |
but if the great dialogue between Islamic and European astronomers shows anything, | 0:21:54 | 0:22:00 | |
it's that doubt, or shukuk, is the engine that drives science forward. | 0:22:00 | 0:22:04 | |
One of the first great shukuk scientists was called Ibn Al-Haytham. | 0:22:11 | 0:22:17 | |
He was born in the Iraqi city of Basra in 965AD. | 0:22:17 | 0:22:23 | |
And was among the first to argue passionately | 0:22:23 | 0:22:27 | |
that scientific ideas are only valid | 0:22:27 | 0:22:29 | |
if they're mathematically consistent and reflect reality. | 0:22:29 | 0:22:34 | |
And when he applied his fierce, rigorous intelligence to Greek astronomy, | 0:22:34 | 0:22:39 | |
he immediately spotted that there was a fundamental contradiction at its heart. | 0:22:39 | 0:22:45 | |
On the one hand, Greek cosmology argued that everything in the heavens revolves around the Earth. | 0:22:45 | 0:22:52 | |
On the other hand, Ptolemy, in his Almagest, | 0:22:52 | 0:22:55 | |
argued that if you want to mathematically predict how the sun and planets move, | 0:22:55 | 0:23:01 | |
you have to pretend that they go around an arbitrary point in space - the so-called equant. | 0:23:01 | 0:23:06 | |
This is clearly a contradiction - | 0:23:08 | 0:23:10 | |
the heavens can't both go around the Earth and not go around it at the same time. | 0:23:10 | 0:23:16 | |
Ibn Al-Haytham hated this nonsensical contradiction. | 0:23:16 | 0:23:20 | |
In the early 11th century, he wrote a paper, Al-Shukuk Ala-Batlamyus, or Doubts On Ptolemy. | 0:23:22 | 0:23:29 | |
In it, he writes with barely contained frustration, | 0:23:29 | 0:23:33 | |
"Ptolemy assumes an arrangement that cannot exist." | 0:23:33 | 0:23:37 | |
Ibn Al-Haytham says, "That is a total absurdity. We cannot accept that." | 0:23:37 | 0:23:42 | |
And furthermore he says, "It's not a slip of the tongue. | 0:23:42 | 0:23:46 | |
"Ptolemy knew that it was absurd." | 0:23:46 | 0:23:48 | |
And he shows us where Ptolemy himself was embarrassed by having to introduce it. | 0:23:48 | 0:23:52 | |
So, he says there is a fundamental reasoning problem, | 0:23:52 | 0:23:56 | |
meaning that the Greeks knew, that Ptolemy knew he was making a mistake, | 0:23:56 | 0:24:02 | |
but he couldn't do any better, | 0:24:02 | 0:24:04 | |
and hints, now the challenge is to do much better and hints to be able to fix this... | 0:24:04 | 0:24:09 | |
That, in my explanation, | 0:24:09 | 0:24:12 | |
begins to be the programme of research for all astronomers to come. | 0:24:12 | 0:24:16 | |
In order to achieve that project, you had to be convinced - | 0:24:16 | 0:24:22 | |
you had to be convinced - | 0:24:22 | 0:24:24 | |
that it was possible to make high-precision mathematical models | 0:24:24 | 0:24:30 | |
of the way in which planets and stars move, | 0:24:30 | 0:24:34 | |
that would really capture how they are in the heavens. | 0:24:34 | 0:24:39 | |
Ibn Al-Haytham, in effect, | 0:24:47 | 0:24:48 | |
laid down the challenge for all astronomers who followed, | 0:24:48 | 0:24:52 | |
which was to come up with an explanation for how the heavens move | 0:24:52 | 0:24:57 | |
that is both mathematically consistent, and agrees with what we observe. | 0:24:57 | 0:25:01 | |
The final answer to this would come from far-away Europe, with Copernicus and others. | 0:25:05 | 0:25:10 | |
But the next and crucial breakthrough came somewhat closer. | 0:25:10 | 0:25:14 | |
The top of this mountain in northern Iran | 0:25:33 | 0:25:36 | |
was the adopted home of the man who was the next of Copernicus' Islamic influences, | 0:25:36 | 0:25:43 | |
Nasir Al-Din Al-Tusi. | 0:25:43 | 0:25:44 | |
He would succeed in rewriting Ptolemy's theory, | 0:25:44 | 0:25:48 | |
which would ultimately lead to the overthrow of the geocentric view of the universe, | 0:25:48 | 0:25:55 | |
and so the birth of the modern scientific age. | 0:25:55 | 0:25:58 | |
This is the remote castle of Alamut, | 0:26:02 | 0:26:07 | |
Al-Tusi's adopted home. | 0:26:07 | 0:26:10 | |
For many years, it was the home of a Muslim sect called the Ismailis. | 0:26:10 | 0:26:14 | |
It's a lovely secluded spot, | 0:26:17 | 0:26:19 | |
and it was the centre of the Ismaili movement. | 0:26:19 | 0:26:23 | |
It's not surprising that Al-Tusi would find a home here. | 0:26:23 | 0:26:27 | |
And it wasn't just him. | 0:26:27 | 0:26:29 | |
Many other scholars were gathered here | 0:26:29 | 0:26:31 | |
and there seems to have been a library - | 0:26:31 | 0:26:33 | |
it was a centre for learning as well as a military stronghold. | 0:26:33 | 0:26:37 | |
Here, this is the main gate, northern gate of the upper castle... | 0:26:45 | 0:26:52 | |
A new archaeological dig is now revealing under the castle, hewn into the living rock, | 0:26:54 | 0:26:59 | |
a warren of rooms and studies, a mosque and living quarters | 0:26:59 | 0:27:04 | |
for this extraordinary community of soldiers and scientists. | 0:27:04 | 0:27:09 | |
This is the court of mosque, | 0:27:09 | 0:27:12 | |
or centre of headquarters of castle. | 0:27:12 | 0:27:18 | |
And it was within these cramped conditions | 0:27:21 | 0:27:25 | |
that Al-Tusi started his masterwork of the shukuk, | 0:27:25 | 0:27:29 | |
or the doubts - the Tadhkirah. | 0:27:29 | 0:27:31 | |
In it he finds an answer to Ibn Al-Haytham's first challenge - | 0:27:31 | 0:27:36 | |
how to eliminate Ptolemy's equant. | 0:27:36 | 0:27:39 | |
Instead of a sphere rotating around an arbitrary point in space, | 0:27:42 | 0:27:47 | |
Al-Tusi devised a series of two nested circles, | 0:27:47 | 0:27:50 | |
which rotate around each other in such a way that they eliminate the equant. | 0:27:50 | 0:27:56 | |
The nested circles became known as a Tusi Couple. | 0:27:58 | 0:28:03 | |
This is the mathematical system that finds it way into Copernicus' work some 300 years later. | 0:28:05 | 0:28:12 | |
Having found a solution to the equant problem, | 0:28:17 | 0:28:20 | |
Al-Tusi now wanted to complete the task Ibn Al-Haytham had started 200 years earlier - | 0:28:20 | 0:28:26 | |
to find a consistent mathematical description of the movement of the celestial bodies. | 0:28:26 | 0:28:33 | |
But to do that he needed better data, | 0:28:33 | 0:28:36 | |
which meant bigger and better equipment than he was ever going to find here at Alamut. | 0:28:36 | 0:28:40 | |
And then something happened which changed Al-Tusi's life forever - the Mongols. | 0:28:40 | 0:28:48 | |
Streaming in from the East, an army of Mongols led by Hulagu Khan | 0:28:56 | 0:29:02 | |
marched into Iran, crushing everything before them. | 0:29:02 | 0:29:05 | |
By 1255, they had reached the foothills of Alamut, intent on its destruction. | 0:29:08 | 0:29:15 | |
Then, in a brilliant piece of diplomacy, | 0:29:18 | 0:29:20 | |
Al-Tusi managed to both save his own skin | 0:29:20 | 0:29:24 | |
and satisfy his scientific ambition. | 0:29:24 | 0:29:27 | |
He visited the Mongol leader, and played on his deep astrological superstition. | 0:29:28 | 0:29:34 | |
Convincing him he could tell the future if only he had new equipment, Al-Tusi persuaded the Khan | 0:29:37 | 0:29:43 | |
to make him his head scientist and to build him, just a few hundred miles away, | 0:29:43 | 0:29:48 | |
perched on a hilltop where the air was clear, | 0:29:48 | 0:29:51 | |
the largest observatory the world had ever seen. | 0:29:51 | 0:29:55 | |
This is all that remains of the Maragheh Observatory. | 0:30:04 | 0:30:10 | |
The main instrument is hidden is under this protective dome. | 0:30:10 | 0:30:13 | |
Al-Tusi's new astronomical centre was based around a single large building. | 0:30:16 | 0:30:22 | |
Inside was an enormous metal arc, | 0:30:23 | 0:30:27 | |
an armillary arm, ten metres across. | 0:30:27 | 0:30:30 | |
On its circumference were marked angles in degrees and minutes. | 0:30:32 | 0:30:37 | |
The scientists would line up the celestial object under study | 0:30:37 | 0:30:41 | |
with a central point on the arc, and then make a reading from the markings on the arc, | 0:30:41 | 0:30:47 | |
giving them the definitive, accurate position of the object in the sky. | 0:30:47 | 0:30:51 | |
The building was also surrounded by smaller astronomical equipment, | 0:30:55 | 0:30:59 | |
libraries, offices and accommodation. | 0:30:59 | 0:31:02 | |
The observatory even had its own dedicated mosque. | 0:31:04 | 0:31:08 | |
I suppose it is a little disappointing that there's not much left of the place now, | 0:31:15 | 0:31:20 | |
so you really have to imagine what it must have been like back in its heyday. | 0:31:20 | 0:31:24 | |
After all, what Al-Tusi built here | 0:31:24 | 0:31:27 | |
was nothing less than the world's greatest observatory for 300 years. | 0:31:27 | 0:31:32 | |
And like any modern-day international research institute, | 0:31:32 | 0:31:37 | |
he brought together the world's greatest astronomers from as far away as Morocco and even China. | 0:31:37 | 0:31:43 | |
I mean, it really must have been a great buzzing atmosphere to work here. | 0:31:43 | 0:31:48 | |
With his new observatory and world-class team, | 0:31:55 | 0:31:58 | |
Al-Tusi was now ready to fulfil Ibn Al-Haytham's dream - | 0:31:58 | 0:32:02 | |
to try to make Ptolemy's model scientifically rigorous. | 0:32:02 | 0:32:07 | |
First they attacked the mathematics. | 0:32:07 | 0:32:11 | |
As well as the Tusi Couple, they invented other systems of planetary movement. | 0:32:11 | 0:32:16 | |
And with these new systems, they were able to calculate | 0:32:16 | 0:32:19 | |
mathematically-consistent models for many of the celestial bodies. | 0:32:19 | 0:32:24 | |
Mercury, Venus, Mars, Jupiter, Saturn and the sun and moon. | 0:32:24 | 0:32:30 | |
Al-Tusi and the astronomers he brought together created what became known as the Maragheh revolution, | 0:32:38 | 0:32:45 | |
which was a complete paradigm shift in astronomy, overthrowing the old Ptolemaic view. | 0:32:45 | 0:32:51 | |
What Islamic scholars and astronomers like Al-Tusi do | 0:32:51 | 0:32:56 | |
is to organise and make sense of mathematical astronomy | 0:32:56 | 0:33:02 | |
at a level of unprecedented accuracy, | 0:33:02 | 0:33:05 | |
using instruments more precise than had been built before, | 0:33:05 | 0:33:09 | |
over longer timescales, with predictions | 0:33:09 | 0:33:13 | |
of the positions of planets and stars that no-one had previously reached - | 0:33:13 | 0:33:17 | |
that at Maragheh or at Alamut | 0:33:17 | 0:33:21 | |
we see, I think, genuine revolutions in the level, scale and intensity of mathematical astronomy. | 0:33:21 | 0:33:28 | |
But there was still a problem. | 0:33:35 | 0:33:37 | |
The new models were mathematically coherent and they dispensed with Ptolemy's unwieldy equant. | 0:33:37 | 0:33:44 | |
But they still firmly placed the earth at the centre of the universe, | 0:33:44 | 0:33:49 | |
and that inevitably meant that their descriptions of the heavens were intricate and complicated, | 0:33:49 | 0:33:55 | |
with epicycles, deferents and couples - it was like some great cosmic gearbox. | 0:33:55 | 0:34:01 | |
It would require a huge leap of imagination to make the next step in our story. | 0:34:08 | 0:34:13 | |
And that next step would take place 2,000 miles from where I am now. | 0:34:13 | 0:34:18 | |
In my view, the last phase of the Maragheh revolution took place | 0:34:33 | 0:34:37 | |
not in Iran or anywhere in the Islamic Empire, but here in Northern Italy. | 0:34:37 | 0:34:43 | |
Based on the work of Muslim scholars, places like | 0:34:43 | 0:34:46 | |
the University of Padua were already starting a new scientific movement - | 0:34:46 | 0:34:51 | |
the Renaissance. | 0:34:51 | 0:34:52 | |
Back in Padua, where I began my journey, | 0:34:56 | 0:34:59 | |
I now understand why Islamic astronomers were so important to Copernicus. | 0:34:59 | 0:35:05 | |
They gave him his motivation. | 0:35:05 | 0:35:07 | |
He's the first European to share Ibn Al-Haytham's deep aversion to Ptolemy's cosmology. | 0:35:08 | 0:35:15 | |
And that's what makes Copernicus not the first great astronomer | 0:35:15 | 0:35:19 | |
of a new European tradition, but the last of the Islamic tradition. | 0:35:19 | 0:35:23 | |
As we've seen, many of the complex mathematical models Copernicus uses in his new heliocentric model, | 0:35:27 | 0:35:34 | |
like the Tusi Couple, are copied from Islamic astronomers. | 0:35:34 | 0:35:38 | |
But more importantly, it's Copernicus's deep desire | 0:35:38 | 0:35:42 | |
to bring mathematical consistency to cosmology that he really owes to his Islamic predecessors. | 0:35:42 | 0:35:49 | |
Copernicus' ideas set in motion a train of scientific revelations | 0:35:51 | 0:35:57 | |
that would eventually lead to Isaac Newton and the discovery of gravity. | 0:35:57 | 0:36:02 | |
In Newton's hands, Ibn Al-Haytham's dream of an astronomy with rigorous | 0:36:02 | 0:36:07 | |
and coherent mathematics which agrees with experimental observation finally took place. | 0:36:07 | 0:36:13 | |
But this begs two crucial questions - | 0:36:23 | 0:36:26 | |
why was the great astronomical project which Islamic astronomers began | 0:36:26 | 0:36:30 | |
completed in Europe and not in the Middle East? | 0:36:30 | 0:36:35 | |
And how did knowledge of Islamic science get to Europe in the first place? | 0:36:35 | 0:36:39 | |
The answers to these questions lie in one of the most beautiful cities on earth, | 0:36:45 | 0:36:49 | |
the Queen of the Adriatic - Venice. | 0:36:49 | 0:36:53 | |
Venice was founded on a swamp off the coast of Italy, | 0:37:08 | 0:37:13 | |
and felt itself separate from Europe, and not bound by its laws and traditions. | 0:37:13 | 0:37:18 | |
And as Shakespeare famously pointed out, the two most important aspects | 0:37:18 | 0:37:22 | |
of Venice were its merchants and its longstanding links with the Arabs, or Moors. | 0:37:22 | 0:37:30 | |
It was a rich and complicated relationship, sometimes based on piracy and theft. | 0:37:30 | 0:37:37 | |
The story goes that in 828, | 0:37:37 | 0:37:40 | |
two Venetian merchants stole the bones of a famous Christian saint | 0:37:40 | 0:37:44 | |
from Venice's rival city across the water, Alexandria. | 0:37:44 | 0:37:47 | |
The bones belonged to St Mark the Evangelist, and they brought them back to here to St Mark's Square. | 0:37:47 | 0:37:53 | |
But without doubt, trade with the East brought to Venice great wealth | 0:37:59 | 0:38:04 | |
and an exchange of ideas, customs and people, as Venice expert Vera Costantini showed me. | 0:38:04 | 0:38:11 | |
So this is called the Campo dei Mori because as you can see | 0:38:11 | 0:38:14 | |
at the corners, there are statues of what were called Moors. | 0:38:14 | 0:38:21 | |
There's another... Yeah, there's another one with a turban. | 0:38:21 | 0:38:24 | |
The beard was recommended to many Venetian merchants even when they went to the East. | 0:38:24 | 0:38:29 | |
There were manuals written for Venetian merchants. | 0:38:29 | 0:38:33 | |
How to blend in? | 0:38:33 | 0:38:35 | |
Yes. How to be respected in the East. | 0:38:35 | 0:38:38 | |
As Venetians traded more and more with their Muslim neighbours, | 0:38:41 | 0:38:45 | |
the influence of Islam was more strongly felt. | 0:38:45 | 0:38:49 | |
Arabic coffee culture became hugely popular. | 0:38:51 | 0:38:54 | |
As did Islamic styles of architecture, | 0:38:57 | 0:38:59 | |
with their characteristic arches and decorations. | 0:38:59 | 0:39:02 | |
So, the next thing I want to show you is the Palace of the Camel. | 0:39:06 | 0:39:09 | |
When Venetians traded in the East, the unit of measurement, | 0:39:09 | 0:39:15 | |
of a load that could be loaded on a dromedary was called a carrico. | 0:39:15 | 0:39:21 | |
And it was exactly the same unit of measurement | 0:39:21 | 0:39:24 | |
they had in the East. And it was called yook. | 0:39:24 | 0:39:28 | |
So it's not coincidence that | 0:39:28 | 0:39:30 | |
they actually imported that unit of weight. | 0:39:30 | 0:39:33 | |
Yes, of measurement, of weight. | 0:39:33 | 0:39:36 | |
And with the Arabic trade came the Arabic books. | 0:39:39 | 0:39:44 | |
The great 9th century Arabic text on algebra appeared in Latin in the 12th century. | 0:39:44 | 0:39:50 | |
The same century saw the arrival of Arabic astronomical tables, | 0:39:50 | 0:39:55 | |
and in the 15th century, the famous canon of medicine was first published in the West. | 0:39:55 | 0:40:01 | |
And this influx of learning seems to coincide with a great historical shift. | 0:40:10 | 0:40:15 | |
The engine of science begins to move west, from the Islamic world to Europe. | 0:40:15 | 0:40:21 | |
That's where the great breakthroughs from the 1500s would mainly take place. | 0:40:21 | 0:40:26 | |
I encountered an astonishing and very tangible symbol of this shift, and a really surprising clue | 0:40:36 | 0:40:43 | |
as to why it happened, thanks to Professor Angela Nuovo, from the University of Udine. | 0:40:43 | 0:40:49 | |
20 years ago, in this library on one of the islands of Venice, | 0:40:53 | 0:40:57 | |
Angela discovered the only surviving version of a 500-year-old book. | 0:40:57 | 0:41:03 | |
And what did it feel like? This is a big, big discovery! | 0:41:03 | 0:41:07 | |
Yes, yes. It was a great emotion. | 0:41:07 | 0:41:10 | |
I remember it was July, very hot, like today - even hotter. | 0:41:10 | 0:41:13 | |
And I felt cold. | 0:41:13 | 0:41:15 | |
Wow! | 0:41:15 | 0:41:17 | |
Yes, it was a great emotion. | 0:41:17 | 0:41:19 | |
What she found was the very first printed copy of Islam's holy book, the Qur'an. | 0:41:22 | 0:41:29 | |
This is the first time she has seen her Qur'an since she discovered it 20 years ago. | 0:41:38 | 0:41:45 | |
But it struck me as strange that world's first printed Qur'an | 0:41:45 | 0:41:49 | |
was produced in Venice, and not in the Islamic world. | 0:41:49 | 0:41:53 | |
And it's obvious at first glance that it was printed by people who didn't speak Arabic very well. | 0:41:53 | 0:42:00 | |
HE READS ALOUD | 0:42:00 | 0:42:04 | |
What strikes me is that | 0:42:08 | 0:42:10 | |
it's written in what I would regard as almost childlike handwriting. | 0:42:10 | 0:42:17 | |
It's clumsy. | 0:42:17 | 0:42:19 | |
Yeah. Well, it's the first attempt to reproduce the handwriting in moveable types, | 0:42:19 | 0:42:26 | |
and as you know, the language has an enormous amount of different sorts. | 0:42:26 | 0:42:31 | |
Every letter changes according to ligatures and the position. | 0:42:31 | 0:42:36 | |
Of course, so it's difficult. | 0:42:36 | 0:42:38 | |
Yeah, the word meaning "for that", | 0:42:38 | 0:42:41 | |
the dash should be underneath the L, but it's above it, so it says the wrong thing. | 0:42:41 | 0:42:49 | |
Probably there were not people of mother language in the press. | 0:42:49 | 0:42:56 | |
So there were some errors in the text, which are of course sins. | 0:42:56 | 0:43:01 | |
Yes, of course, as the Qur'an, every Muslim believes it's the word of God, you can't change it. | 0:43:01 | 0:43:08 | |
So when you change it, it's a sin. | 0:43:08 | 0:43:11 | |
How was it first received when it was published? | 0:43:11 | 0:43:14 | |
Well, yes, the hypothesis is, and I think it's true, | 0:43:14 | 0:43:18 | |
that it was an enormous failure from the business point of view. | 0:43:18 | 0:43:23 | |
The Muslims didn't accept the printing press for centuries, | 0:43:23 | 0:43:28 | |
and probably the whole copies of this book were destroyed. | 0:43:29 | 0:43:33 | |
So we don't have any other copy. | 0:43:33 | 0:43:36 | |
Probably the only one that remained in the Western world is this book. | 0:43:36 | 0:43:41 | |
'I felt that the failure of this printed Qur'an to catch on in the Islamic world spoke volumes.' | 0:43:41 | 0:43:48 | |
800 years earlier, one reason for Islamic science's success | 0:43:53 | 0:43:58 | |
had been the precision of the Arabic language - with over 70 different ways | 0:43:58 | 0:44:03 | |
of writing its letters and many extra symbols to define pronunciation and meaning, | 0:44:03 | 0:44:08 | |
it allowed scholars of many different lands to communicate in a single, common language. | 0:44:08 | 0:44:14 | |
Now, with the arrival of the printing press, | 0:44:18 | 0:44:21 | |
scientific ideas should have been able to travel even more freely. | 0:44:21 | 0:44:26 | |
In the West, books printed in Latin accelerated its scientific renaissance. | 0:44:26 | 0:44:32 | |
But because of its symbols and extra letters, | 0:44:32 | 0:44:37 | |
Arabic was much harder to set into type than Latin, | 0:44:37 | 0:44:40 | |
and so a similar acceleration in the Islamic world failed to materialize. | 0:44:40 | 0:44:45 | |
I believe this rejection of the new technology - the printing press - | 0:44:46 | 0:44:52 | |
marks the moment in history when Arabic science undergoes a seismic shift. | 0:44:52 | 0:44:57 | |
Europe has embraced Greek and Arabic knowledge and the new technology. | 0:44:57 | 0:45:02 | |
And Galileo and his ilk are poised at the cusp of the Renaissance. | 0:45:02 | 0:45:07 | |
It has been a turning point both in the history | 0:45:07 | 0:45:11 | |
of the Venetian printing press, who used to be extremely powerful. | 0:45:11 | 0:45:15 | |
It's the limit of expansion, let's say. | 0:45:15 | 0:45:18 | |
And in the history of the general and cultural relationship between the East and the West. | 0:45:18 | 0:45:24 | |
As acceptation of printing would have meant | 0:45:24 | 0:45:28 | |
the acceptation of the first important technology, | 0:45:28 | 0:45:31 | |
so the two histories started to differ very much. | 0:45:31 | 0:45:37 | |
This initial rejection of printing was one of the many reasons | 0:45:41 | 0:45:45 | |
that caused science in the Islamic world to fall behind the West. | 0:45:45 | 0:45:50 | |
It coincided with a host of global changes, all of which affected the way science developed. | 0:45:50 | 0:45:58 | |
The first and most obvious reason for the slowdown in Islamic science | 0:46:06 | 0:46:09 | |
is that the Islamic empire itself | 0:46:09 | 0:46:13 | |
falls into decline from the mid-1200s. | 0:46:13 | 0:46:17 | |
One reason for this is that it's under attack from all sides. | 0:46:17 | 0:46:21 | |
From the east are the Mongols. | 0:46:21 | 0:46:23 | |
In 1258, they invaded the capital, Baghdad, and it's said that | 0:46:28 | 0:46:32 | |
the waters of the Tigris and Euphrates rivers | 0:46:32 | 0:46:35 | |
ran black for days with the ink of the books they'd destroyed. | 0:46:35 | 0:46:40 | |
But trouble was also brewing in the far west of the empire. | 0:46:40 | 0:46:44 | |
Islamic Spain, already fragmented into separate city states, now faced a new threat - | 0:46:48 | 0:46:55 | |
a united and determined onslaught from the Christian north. | 0:46:55 | 0:47:00 | |
The re-conquest, as it was called, raged for hundreds of years, | 0:47:03 | 0:47:07 | |
but culminated in the 15th century, when Ferdinand II and Isabella | 0:47:07 | 0:47:12 | |
led an army which forced the last of the Muslims in Grenada to surrender in 1492. | 0:47:12 | 0:47:19 | |
The Christians were intent | 0:47:19 | 0:47:21 | |
on removing every last vestige of Islamic civilization and culture from Spain. | 0:47:21 | 0:47:26 | |
In 1499, they ordered the burning in this square in Granada | 0:47:26 | 0:47:31 | |
of all Arabic texts from Granada's libraries... | 0:47:31 | 0:47:34 | |
except for a small number of medical texts. | 0:47:34 | 0:47:38 | |
Within about 100 years, every Muslim in Spain | 0:47:38 | 0:47:42 | |
had either been put to the sword, burnt at the stake or banished. | 0:47:42 | 0:47:46 | |
And Christians from the east of Europe were intent on reclaiming the Holy Land - | 0:47:49 | 0:47:56 | |
the Crusades. | 0:47:56 | 0:47:57 | |
Bent on carving out a wholly Christian Levant | 0:47:59 | 0:48:03 | |
and claiming the holy city of Jerusalem, | 0:48:03 | 0:48:05 | |
the Crusaders launched a massive attack on Northern Syria. | 0:48:05 | 0:48:09 | |
They quickly captured this castle and turned it into one of their strongholds. | 0:48:09 | 0:48:14 | |
Then, with ruthless and missionary zeal, they marched on Jerusalem. | 0:48:14 | 0:48:19 | |
And as the empire fought with its neighbours, it collapsed into warring fiefdoms. | 0:48:19 | 0:48:26 | |
The Mamluks, slaves who originally belonged to the state of Egypt, | 0:48:26 | 0:48:30 | |
became its leaders. | 0:48:30 | 0:48:32 | |
The Bourbon Almohads ruled Morocco and Spain in the 13th century. | 0:48:32 | 0:48:38 | |
And the north of Syria and Iraq splintered into a series of city states. | 0:48:38 | 0:48:43 | |
But for many historians of science, the biggest single reason | 0:48:46 | 0:48:50 | |
for the decline in Islamic science was a rather famous event that took place in 1492. | 0:48:50 | 0:48:56 | |
That year, the entire political geography of the world | 0:48:56 | 0:49:01 | |
changed dramatically when a certain Christopher Columbus arrived in the Americas. | 0:49:01 | 0:49:08 | |
I explain it with the phenomena of | 0:49:08 | 0:49:11 | |
the discovery of the New World in 1492. | 0:49:11 | 0:49:14 | |
The immediate result is that you got immense amounts of gold and silver | 0:49:14 | 0:49:18 | |
coming to the royal houses of Europe at the time and all the adventurers, | 0:49:18 | 0:49:23 | |
empires and royal houses of the time were setting colonies all over the world. | 0:49:23 | 0:49:27 | |
And science always follows the money. | 0:49:27 | 0:49:31 | |
As the 16th and 17th centuries came and went, that money, | 0:49:31 | 0:49:36 | |
power and hence scientific will, moved through Italy, Spain and onto Britain. | 0:49:36 | 0:49:42 | |
By the 17th century, England, sitting at the centre | 0:49:42 | 0:49:45 | |
of the lucrative Atlantic trade route, could afford big science. | 0:49:45 | 0:49:50 | |
And that ultimately explains why the greatest book in world science, | 0:49:50 | 0:49:54 | |
Sir Isaac Newton's Principia Mathematica, | 0:49:54 | 0:49:57 | |
the book that ultimately explains the motion of the sun, moon and planets, | 0:49:57 | 0:50:01 | |
was not published in Baghdad, but in London. | 0:50:01 | 0:50:06 | |
It was necessary for him to have data of astonishing accuracy | 0:50:06 | 0:50:11 | |
gathered from across the world. | 0:50:11 | 0:50:15 | |
Global inventories of numbers, observations, positions. | 0:50:15 | 0:50:22 | |
The heights of tides, the positions of comets and planets, the rate at which pendulums beat... | 0:50:22 | 0:50:28 | |
It's a global project, it's big science. | 0:50:28 | 0:50:32 | |
And many of those observations, many of those mathematical models | 0:50:32 | 0:50:37 | |
were of course models initially developed | 0:50:37 | 0:50:40 | |
by Islamic astronomers in Egypt and the Near East and Central Asia. | 0:50:40 | 0:50:47 | |
But there's a final twist in the tale. | 0:50:50 | 0:50:54 | |
As the wealth of the Islamic nations subsided through war, | 0:50:56 | 0:51:00 | |
political and religious entrenchment and the loss of its lucrative trade, | 0:51:00 | 0:51:04 | |
so its science declined. | 0:51:04 | 0:51:08 | |
But what this doesn't explain is why their scientific achievements have been so forgotten. | 0:51:08 | 0:51:13 | |
And that's partly because as Europeans colonised great swathes of the Middle East and Asia, | 0:51:15 | 0:51:21 | |
they actively encouraged the idea | 0:51:21 | 0:51:23 | |
that the civilizations they encountered were moribund and in decline. | 0:51:23 | 0:51:28 | |
It seems the English and the French were uncomfortable with subjugating people | 0:51:28 | 0:51:35 | |
whose knowledge and science might be as sophisticated as their own. | 0:51:35 | 0:51:39 | |
So it became important to portray the Islamic world | 0:51:39 | 0:51:42 | |
in a very specific way, | 0:51:42 | 0:51:45 | |
namely that yes, they once were very sophisticated and had great scientists and philosophers, | 0:51:45 | 0:51:50 | |
but of course now, they've fallen into decay. | 0:51:50 | 0:51:52 | |
Somehow this point of view made the whole colonial enterprise seem much more palatable. | 0:51:52 | 0:51:59 | |
One of the most fascinating developments, I think, | 0:51:59 | 0:52:03 | |
in the history of the encounter between western Europeans and other cultures | 0:52:03 | 0:52:09 | |
is a kind of shift which has got fundamental and terrible consequences | 0:52:09 | 0:52:17 | |
amongst western Europeans, | 0:52:17 | 0:52:19 | |
when they start to reflect on why they are superior. | 0:52:19 | 0:52:25 | |
It doesn't often cross western Europeans' minds that they might not be superior to everybody else. | 0:52:25 | 0:52:31 | |
For a very long time after all, western Europeans in general, | 0:52:31 | 0:52:36 | |
the British, for example, supposed that their superiority lay in their religion. | 0:52:36 | 0:52:40 | |
But then I think around the 1700s, we begin to see a shift. | 0:52:40 | 0:52:46 | |
And the shift is from claiming that the reason for European superiority is its religion | 0:52:46 | 0:52:52 | |
to the reason for European superiority is its science and technology. | 0:52:52 | 0:52:57 | |
Eventually it ends up with the famous phrase, "We have the Gatling gun, and they do not." | 0:52:59 | 0:53:04 | |
Europeans in that period were quite prepared to acknowledge that in ancient times, | 0:53:04 | 0:53:12 | |
Islam for example had achieved great things in the sciences. | 0:53:12 | 0:53:17 | |
But they weren't doing so now. | 0:53:17 | 0:53:21 | |
So even recent Islamic and Sanskrit astronomy | 0:53:21 | 0:53:26 | |
was imagined to be very old, | 0:53:26 | 0:53:28 | |
because if it was very old, it meant that the culture the British were conquering was declining. | 0:53:28 | 0:53:34 | |
And for the British, that was clearly good news. | 0:53:34 | 0:53:37 | |
And some experts believe that the effect of this on Islamic scientific history | 0:53:40 | 0:53:45 | |
is still felt in the Islamic world today. | 0:53:45 | 0:53:50 | |
The Islamic part and the Arab part have not yet discovered their history | 0:53:50 | 0:53:54 | |
because their history was obliterated intentionally | 0:53:54 | 0:53:58 | |
by the colonisation period. And unfortunately when they rediscover it now, | 0:53:58 | 0:54:03 | |
they are rediscovering it in bits and pieces. | 0:54:03 | 0:54:05 | |
So today, for many different reasons, the great observatories | 0:54:09 | 0:54:14 | |
of the medieval Islamic world are ruined husks. | 0:54:14 | 0:54:19 | |
And it's true to say that most of the great scientific breakthroughs | 0:54:19 | 0:54:23 | |
of the last four centuries have taken place in the West. | 0:54:23 | 0:54:28 | |
But that's not to say that science has completely ground to a halt in the Islamic world. | 0:54:28 | 0:54:34 | |
Now, in the 21st century, | 0:54:34 | 0:54:36 | |
there are many examples of cutting-edge research being carried out. | 0:54:36 | 0:54:40 | |
I've arrived at the Royan Institute here in Tehran, | 0:54:40 | 0:54:43 | |
where they carry out stem cell research, | 0:54:43 | 0:54:46 | |
infertility treatment and cloning research. | 0:54:46 | 0:54:49 | |
I was surprised to learn that here in Iran, an Islamic state, | 0:54:53 | 0:54:57 | |
potentially controversial science like genetic modification | 0:54:57 | 0:55:01 | |
and cloning is condoned, even funded by a theocratic government. | 0:55:01 | 0:55:07 | |
One of the uses is when a small part of the heart stops working, | 0:55:07 | 0:55:10 | |
which is finally going to lead to heart failure... | 0:55:10 | 0:55:13 | |
Right. So the cells from that part of the heart are actually replaced with the cells that have been cloned. | 0:55:13 | 0:55:19 | |
Another use of cloning in therapeutics | 0:55:19 | 0:55:23 | |
is actually creating an animal which has the medicine in their milk, for example. | 0:55:23 | 0:55:29 | |
So when we drink the milk, we actually receive the medicine we need. | 0:55:29 | 0:55:35 | |
Considering genetic research has many vociferous opponents in Christian communities, | 0:55:35 | 0:55:40 | |
I was intrigued to see that here in Tehran, | 0:55:40 | 0:55:43 | |
they have their own in-house imam to offer support and advice | 0:55:43 | 0:55:48 | |
on this sometimes quite controversial research. | 0:55:48 | 0:55:51 | |
TRANSLATION: We have got this medical ethic committee here in Royan Institute, | 0:55:55 | 0:56:01 | |
and every project which is proposed is investigated | 0:56:01 | 0:56:07 | |
in this committee, and we see different aspects of it, | 0:56:07 | 0:56:11 | |
and they have got to justify the project for us. | 0:56:11 | 0:56:15 | |
I'm not enough of an expert in genetics to truly assess the quality of the work here. | 0:56:15 | 0:56:20 | |
But one thing I can say is how at home I felt. | 0:56:20 | 0:56:24 | |
Whatever cultural and political differences we have with the Iranian state, | 0:56:24 | 0:56:28 | |
inside the walls of the lab, | 0:56:28 | 0:56:31 | |
it was remarkably easy to find common ground with fellow scientists. | 0:56:31 | 0:56:36 | |
Nature's rules are refreshingly free of human prejudice. | 0:56:38 | 0:56:42 | |
That's something the scientists of the medieval Islamic world understood and articulated so well. | 0:56:42 | 0:56:48 | |
In the 9th century, Al-Khwarizmi synthesised Greek and Indian ideas | 0:56:51 | 0:56:56 | |
to create a new kind of mathematics, algebra. | 0:56:56 | 0:57:01 | |
The polymath Ibn Sina brought together the world's traditions | 0:57:02 | 0:57:06 | |
of healthcare into one book, contributing to the creation of the subject of medicine. | 0:57:06 | 0:57:12 | |
In remote Iranian mountains, | 0:57:12 | 0:57:15 | |
astronomers like Al-Tusi paved the way for scientists working hundreds of years later in Western Europe. | 0:57:15 | 0:57:22 | |
These scientists' quest for truth, wherever it came from, | 0:57:22 | 0:57:27 | |
were summed up by the 9th century philosopher Al-Kindi, who said, | 0:57:27 | 0:57:31 | |
"It is fitting for us not to be ashamed of acknowledging truth, | 0:57:31 | 0:57:35 | |
"and to assimilate it from whatever source it comes to us. | 0:57:35 | 0:57:39 | |
"There is nothing of higher value than truth itself. | 0:57:39 | 0:57:42 | |
"It never cheapens or abases he who seeks." | 0:57:42 | 0:57:47 | |
One moral emerges from this epic tale of the rise and fall | 0:57:52 | 0:57:56 | |
of science in the Islamic world between the 9th and 15th centuries. | 0:57:56 | 0:58:01 | |
And that is that science is the universal language of the human race. | 0:58:01 | 0:58:06 | |
Decimal numbers are just as useful in India as they are in Spain. | 0:58:06 | 0:58:10 | |
Star charts drawn up in Iran speak volumes to astronomers in northern Europe. | 0:58:10 | 0:58:15 | |
And Newton's Principia is as true in Arabic as it is in Latin or English. | 0:58:15 | 0:58:21 | |
What medieval Islamic scientists realised and articulated | 0:58:21 | 0:58:25 | |
so brilliantly is that science is the common language of the human race. | 0:58:25 | 0:58:31 | |
Man-made laws may vary from place to place, | 0:58:31 | 0:58:34 | |
but nature's laws are true for all of us. | 0:58:34 | 0:58:38 | |
Subtitles by Red Bee Media Ltd | 0:58:51 | 0:58:54 | |
Email [email protected] | 0:58:54 | 0:58:56 | |
When I think of the world we inhabit, everyone will think, | 0:59:17 | 0:59:20 | |
"Oh, this was done digitally." | 0:59:20 | 0:59:21 | |
Yeah. And it wasn't, it was done by hand | 0:59:21 | 0:59:23 | |
over days and weeks and months and years. | 0:59:23 | 0:59:26 | |
It was always a very, very deep love affair | 0:59:27 | 0:59:31 |