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There is, in old Athens, a bookshop. | 0:00:11 | 0:00:16 | |
It is the loveliest one I know. I discovered it 10 years ago | 0:00:16 | 0:00:21 | |
and within it I found something wonderful. | 0:00:21 | 0:00:25 | |
There, on a shelf, was a series of volumes, | 0:00:27 | 0:00:30 | |
the collected, translated, works of Aristotle. | 0:00:30 | 0:00:33 | |
Impressive, certainly. | 0:00:35 | 0:00:38 | |
But I wasn't much interested. | 0:00:38 | 0:00:41 | |
Philosophers and poets and playwrights may all worship | 0:00:41 | 0:00:45 | |
at the shrine of Aristotle, but not scientists. | 0:00:45 | 0:00:48 | |
And then I opened one. | 0:00:50 | 0:00:52 | |
The book was called Historia Animalium, | 0:00:55 | 0:00:58 | |
The Natural History of Animals. | 0:00:58 | 0:01:01 | |
It told of snakes, sharks, and sea urchins, how they are built, | 0:01:01 | 0:01:06 | |
where they live and what they do there. | 0:01:06 | 0:01:09 | |
Assertion followed assertion, fact followed fact, like hammer blows. | 0:01:09 | 0:01:13 | |
It was long, it was dense, it was impenetrable. | 0:01:13 | 0:01:18 | |
And yet, it was magnificent. | 0:01:18 | 0:01:22 | |
Aristotle, the man who gave us logic, poetics, political philosophy | 0:01:23 | 0:01:28 | |
had also known, loved and sought to understand the natural world. | 0:01:28 | 0:01:35 | |
Working by a lagoon on a Greek island, he investigated, | 0:01:37 | 0:01:40 | |
analysed and documented the world of animals and plants. | 0:01:40 | 0:01:46 | |
And did so in a wholly new way. | 0:01:46 | 0:01:49 | |
There he discovered order in the chaos of organic diversity | 0:01:53 | 0:01:57 | |
and there he invented a science. | 0:01:58 | 0:02:00 | |
And though it was my science, biology, I did not know it. | 0:02:04 | 0:02:09 | |
But then, hardly anyone does. | 0:02:09 | 0:02:12 | |
For Aristotle's biology, strange, difficult and yet wondrous, | 0:02:12 | 0:02:18 | |
is almost completely forgotten. | 0:02:18 | 0:02:20 | |
In the 10 years since I found that book in an Athens bookshop, | 0:02:23 | 0:02:28 | |
I've been living with Aristotle, | 0:02:28 | 0:02:30 | |
trying to understand the workings of his astonishing mind. | 0:02:30 | 0:02:34 | |
What did he do? | 0:02:34 | 0:02:36 | |
Why did he do it? And how? | 0:02:36 | 0:02:38 | |
And, most of all, why have we forgotten him, | 0:02:38 | 0:02:42 | |
the first, and perhaps the greatest, biologist ever? | 0:02:42 | 0:02:46 | |
The Scottish zoologist, | 0:02:57 | 0:02:59 | |
D'Arcy Thompson, who translated Historia Animalium, wrote that | 0:02:59 | 0:03:03 | |
the lagoon where Aristotle worked was on the Aegean island of Lesvos. | 0:03:03 | 0:03:08 | |
That same day, I boarded the evening ferry from Piraeus. | 0:03:10 | 0:03:14 | |
It's 347 BC and Aristotle is fed up. | 0:03:19 | 0:03:24 | |
For 20 years he has been at Plato's Academy, | 0:03:24 | 0:03:27 | |
first as a student, then as teacher. | 0:03:27 | 0:03:30 | |
But now Plato is dead and there's vacancy at the top. | 0:03:30 | 0:03:34 | |
Who should be the new head of the Academy? | 0:03:38 | 0:03:41 | |
"Well", thinks Aristotle, "obviously it should be me." | 0:03:41 | 0:03:45 | |
Intellectually voracious, | 0:03:45 | 0:03:47 | |
in the philosophical hothouse, he's the best. | 0:03:47 | 0:03:51 | |
Plato calls him The Reader. | 0:03:51 | 0:03:54 | |
And he's original. Perhaps excessively so. | 0:03:54 | 0:03:58 | |
In the event, the job goes to Plato's nephew. | 0:03:58 | 0:04:01 | |
"Very well", thinks Aristotle. | 0:04:01 | 0:04:04 | |
"I'll pack my bags and go where I'm appreciated." | 0:04:04 | 0:04:07 | |
And off he goes. | 0:04:10 | 0:04:12 | |
East, across the Aegean. | 0:04:12 | 0:04:15 | |
GREEK STYLE MUSIC | 0:04:15 | 0:04:18 | |
In the years that I have been searching for Aristotle, | 0:04:23 | 0:04:26 | |
I have come to know and love this island. | 0:04:26 | 0:04:29 | |
My dearest friend here is Giorgos Kokkoris, | 0:04:34 | 0:04:37 | |
an ecologist at the University of the Aegean, Mytilini. | 0:04:37 | 0:04:41 | |
It was he who first took me to the lagoon. | 0:04:41 | 0:04:45 | |
And it is he who takes me there now. | 0:04:47 | 0:04:49 | |
It was on the shores of this calm lagoon that, 23 centuries ago, | 0:04:54 | 0:04:58 | |
Aristotle did so much of his ground-breaking biology. | 0:04:58 | 0:05:03 | |
He knew it as Pyrrha. | 0:05:05 | 0:05:06 | |
Today they call it Kalloni. | 0:05:06 | 0:05:08 | |
But, for me, it is "Aristotle's Lagoon". | 0:05:08 | 0:05:13 | |
Lesvos is the perfect place for a naturalist. | 0:05:30 | 0:05:34 | |
In no other Greek island | 0:05:34 | 0:05:36 | |
is the natural world so endlessly present and richly seductive. | 0:05:36 | 0:05:42 | |
On the frontier of Europe and Asia, | 0:05:42 | 0:05:45 | |
Lesvos draws its creatures from both. | 0:05:45 | 0:05:48 | |
In spring and autumn, it is a resting place for millions of birds | 0:05:48 | 0:05:52 | |
migrating between Africa and the north. | 0:05:52 | 0:05:56 | |
What do we see over there? | 0:05:59 | 0:06:01 | |
There are avocets. | 0:06:01 | 0:06:03 | |
Filios Akriotis, Greece's leading ornithologist, lives on the island. | 0:06:03 | 0:06:09 | |
He takes me for an Aristotelian walk | 0:06:09 | 0:06:12 | |
in the marshes and woods that flank the lagoon. | 0:06:12 | 0:06:15 | |
For me, science is an endless conversation about the world. | 0:06:22 | 0:06:26 | |
Was it so for Aristotle? | 0:06:26 | 0:06:28 | |
He came here to Lesvos | 0:06:28 | 0:06:30 | |
at the invitation of a friend, Theophrastus. | 0:06:30 | 0:06:34 | |
-At least, that's what many scholars believe. -Yeah. | 0:06:34 | 0:06:37 | |
But who exactly was Theophrastus and what did he do? | 0:06:37 | 0:06:41 | |
He was a botanist, I gather. | 0:06:41 | 0:06:42 | |
Theophrastus was a botanist. | 0:06:42 | 0:06:47 | |
He was another very special person of those times | 0:06:47 | 0:06:53 | |
who has given us written descriptions | 0:06:53 | 0:06:57 | |
of a very big variety of plants. | 0:06:57 | 0:07:01 | |
Actually, many of the plants of today are named after Theophrastus, | 0:07:01 | 0:07:07 | |
have their scientific names based on his name. | 0:07:07 | 0:07:10 | |
Quite a remarkable person. | 0:07:10 | 0:07:14 | |
One imagines the two men, friends, dividing up the natural world. | 0:07:14 | 0:07:20 | |
"I'll do the animals", says Aristotle. | 0:07:20 | 0:07:23 | |
"You, Theophrastus, do the plants". | 0:07:23 | 0:07:26 | |
And so zoology and botany were born. | 0:07:26 | 0:07:30 | |
Aristotle describes the forms, habits and habitats | 0:07:35 | 0:07:38 | |
of hundreds of animals. | 0:07:38 | 0:07:40 | |
He says that tortoises have shells, hiss, lay eggs and hibernate. | 0:07:41 | 0:07:46 | |
That snakes copulate by entwining themselves. | 0:07:48 | 0:07:51 | |
He describes the life cycle of the cicada. | 0:07:53 | 0:07:56 | |
He tells of a bird with steel blue plumage, a long and slender beak, | 0:07:58 | 0:08:04 | |
short legs that lives on rocks, obviously a rock nuthatch. | 0:08:04 | 0:08:08 | |
He turns his attention to the water's edge. | 0:08:19 | 0:08:22 | |
"In the shallows", he says, | 0:08:22 | 0:08:24 | |
"the vegetation is more delicate and lush than any garden. | 0:08:24 | 0:08:28 | |
"There is a kind of crab that has flattened hind limbs | 0:08:30 | 0:08:34 | |
"with which it swims". | 0:08:34 | 0:08:36 | |
He says that ibises, herons and egrets | 0:08:40 | 0:08:43 | |
use their beaks as fishing spears. | 0:08:43 | 0:08:46 | |
And that stilts are very quarrelsome and do not have a hind toe. | 0:08:50 | 0:08:55 | |
And he describes the loveliest of the spring migrants, | 0:08:58 | 0:09:02 | |
the European bee-eater. | 0:09:02 | 0:09:04 | |
Aristotle notes their voracious appetite for bees, how they nest | 0:09:04 | 0:09:09 | |
in holes that they dig in riverbanks and how they breed. | 0:09:09 | 0:09:14 | |
And so, each year by the Lagoon, | 0:09:14 | 0:09:17 | |
the bee-eaters still do. | 0:09:17 | 0:09:20 | |
This is the philosopher discovering nature. | 0:09:20 | 0:09:25 | |
He was not prejudiced by anything. | 0:09:27 | 0:09:29 | |
He was not influenced by somebody who wrote about the same thing | 0:09:29 | 0:09:32 | |
some time ago and had read about it when he was young. | 0:09:32 | 0:09:36 | |
Yes, a freshness. That's what I admire in his writing. | 0:09:36 | 0:09:41 | |
Everything he writes seems to be his own observations. | 0:09:41 | 0:09:44 | |
In a wonderful passage known as the Invitation to Biology he says, | 0:09:48 | 0:09:51 | |
"It's not good enough simply to study the stars, | 0:09:51 | 0:09:55 | |
"no matter how perfect and divine they may be. | 0:09:55 | 0:09:58 | |
"Rather we must also study the humblest creatures, | 0:09:58 | 0:10:02 | |
"even if they seem repugnant to us. | 0:10:02 | 0:10:04 | |
"And that is because all animals have something of the good, | 0:10:04 | 0:10:09 | |
"something of the divine, something of the beautiful". | 0:10:09 | 0:10:12 | |
But make no mistake, | 0:10:17 | 0:10:19 | |
Aristotle is no mere naturalist. | 0:10:19 | 0:10:22 | |
He collects facts, lots of facts, and arranges them. | 0:10:22 | 0:10:27 | |
He's systematic, relentlessly so. | 0:10:27 | 0:10:31 | |
He classifies. | 0:10:42 | 0:10:43 | |
In Historia Animalium alone, | 0:10:43 | 0:10:46 | |
he names and distinguishes 110 kinds of animals. | 0:10:46 | 0:10:50 | |
And he's especially good on fish. | 0:10:51 | 0:10:54 | |
Oh, nice. | 0:10:57 | 0:10:58 | |
What is this beautiful thing? | 0:10:58 | 0:11:00 | |
-Melanis. -Melanis. Melania. | 0:11:00 | 0:11:02 | |
-Tsipouris. -Tsipouris. | 0:11:02 | 0:11:04 | |
So, right here, we have about seven, eight, nine species of fish | 0:11:04 | 0:11:10 | |
and they're all the fish that Aristotle describes. | 0:11:10 | 0:11:14 | |
And he does so in wonderful detail. | 0:11:14 | 0:11:16 | |
He talks about their forms and their proportions, | 0:11:16 | 0:11:20 | |
where they live and how they breed and how they come into the lagoon, | 0:11:20 | 0:11:25 | |
in and out every year. | 0:11:25 | 0:11:26 | |
But Aristotle also notices that some species resemble each other. | 0:11:32 | 0:11:37 | |
Aristotle classifies many of the creatures he finds in the lagoon | 0:11:43 | 0:11:50 | |
into larger groups and you can see them here. | 0:11:50 | 0:11:55 | |
Such as these things which I am trying to get. | 0:11:59 | 0:12:04 | |
Which are sea squirts. | 0:12:04 | 0:12:07 | |
He puts "sea squirts", so called because they squirt, | 0:12:12 | 0:12:20 | |
and snails and sea urchins all in the same group, the ostracoderma, | 0:12:20 | 0:12:25 | |
because they all have rather hard exteriors. | 0:12:25 | 0:12:29 | |
He puts crabs, which also have hard exteriors, | 0:12:29 | 0:12:32 | |
into a different group because they have legs. | 0:12:32 | 0:12:36 | |
It's the beginning of the great classifications that we know today. | 0:12:36 | 0:12:41 | |
Not all of his classifications have stood the test of time. | 0:12:45 | 0:12:49 | |
Sea squirts, snails and sea-urchins are, in fact, | 0:12:49 | 0:12:52 | |
quite unrelated to each other. | 0:12:52 | 0:12:54 | |
But the 19th Century discovered that. | 0:12:54 | 0:12:58 | |
And he's superb on dolphins. | 0:13:03 | 0:13:06 | |
Aristotle notices that although dolphins live in water | 0:13:07 | 0:13:11 | |
and look a bit like fish, they breathe air and suckle their young | 0:13:11 | 0:13:16 | |
just as many land quadrupeds do. | 0:13:16 | 0:13:18 | |
He therefore puts whales and dolphins, cetaceans, | 0:13:18 | 0:13:22 | |
in a group of their own. | 0:13:22 | 0:13:23 | |
His successors ignored him and just called them fish. | 0:13:23 | 0:13:28 | |
What makes a scientist turn to the study of the natural world? | 0:13:32 | 0:13:36 | |
So often, it is a place. | 0:13:36 | 0:13:39 | |
And whatever that place is, it stays with him for the rest of his life, | 0:13:39 | 0:13:43 | |
for it is where he first sees the beauty and delight of living things, | 0:13:43 | 0:13:47 | |
begins to understand their mysterious order and glorious | 0:13:47 | 0:13:50 | |
confusion and it is where he first begins to wonder why. | 0:13:50 | 0:13:57 | |
And that is Aristotle's question. | 0:13:59 | 0:14:02 | |
For he's in search of the deepest causes of things. | 0:14:02 | 0:14:06 | |
And to do that, he knows that he can't simply go about | 0:14:06 | 0:14:10 | |
pressing wild flowers and check listing birds. | 0:14:10 | 0:14:13 | |
He has to get into the guts of things. | 0:14:13 | 0:14:17 | |
But to do that, Aristotle first had to find a friendly fisherman. | 0:14:21 | 0:14:25 | |
-Hey, Dimitri. -Hi, Armando. | 0:14:25 | 0:14:27 | |
-Kalimera. -Kalimera. | 0:14:27 | 0:14:29 | |
So what do you say? Let's do some fishing. | 0:14:29 | 0:14:33 | |
Historia Animalium | 0:14:33 | 0:14:34 | |
is so filled with observations about the creatures that live | 0:14:34 | 0:14:38 | |
in and around the lagoon that they cannot all be Aristotle's own. | 0:14:38 | 0:14:43 | |
He must have interrogated people who knew about animals. | 0:14:43 | 0:14:48 | |
As Darwin wrote to pigeon fanciers, so Aristotle spoke to fishermen. | 0:14:48 | 0:14:53 | |
So roughly where are we going? Are we going over there to the right? | 0:14:55 | 0:14:58 | |
That direction. About in the middle. About in the middle. | 0:14:58 | 0:15:01 | |
About half way down the lagoon. | 0:15:01 | 0:15:03 | |
-Yeah. -The lagoon cuts the island of Lesvos nearly in two. | 0:15:03 | 0:15:10 | |
It is one of the most productive stretches of water | 0:15:10 | 0:15:13 | |
in the Eastern Aegean. | 0:15:13 | 0:15:14 | |
And it contains an animal to which Aristotle was particularly devoted, | 0:15:17 | 0:15:23 | |
the cuttlefish. | 0:15:23 | 0:15:24 | |
The first few traps are empty. | 0:15:26 | 0:15:29 | |
But there are cuttlefish down there. | 0:15:29 | 0:15:31 | |
These are the eggs. | 0:15:31 | 0:15:33 | |
Yeah. | 0:15:33 | 0:15:35 | |
The net's just covered in them. | 0:15:35 | 0:15:37 | |
-Exactly. -That's fantastic. | 0:15:37 | 0:15:39 | |
God, there must be thousands and thousands of cuttlefish down there. | 0:15:42 | 0:15:45 | |
You can see the embryo. Look. | 0:15:50 | 0:15:53 | |
-Yeah. -You can see the embryo! | 0:15:53 | 0:15:55 | |
I didn't expect that. | 0:15:55 | 0:15:57 | |
I thought they stayed black all along, throughout their development. | 0:15:57 | 0:16:03 | |
No, some of them, they haven't been sprayed. | 0:16:03 | 0:16:05 | |
-Not all of them. Very few. -You mean they haven't been fertilised? | 0:16:05 | 0:16:09 | |
Yeah. No, no, they have. But they are, usually when they are finished, | 0:16:09 | 0:16:13 | |
-they spray with the ink to protect. -Oh, I see. I see. | 0:16:13 | 0:16:18 | |
The ink is the last thing they do. | 0:16:18 | 0:16:21 | |
But, the pale ones, you can see right inside them. | 0:16:21 | 0:16:26 | |
And you can see the little baby cuttlefish. | 0:16:26 | 0:16:30 | |
-Yeah, they're moving. -And they're moving, you're absolutely right. | 0:16:30 | 0:16:33 | |
You can see its eyes. You can see exactly as Aristotle describes it. | 0:16:33 | 0:16:37 | |
My god, they're gorgeous. They're amazing. | 0:16:44 | 0:16:47 | |
In a week or two, they all will be gone. | 0:16:49 | 0:16:52 | |
And then we see movement, | 0:16:54 | 0:16:57 | |
cuttlefish, dozens of them. | 0:16:57 | 0:17:00 | |
These weird, wonderful animals infest the lagoon | 0:17:07 | 0:17:10 | |
and Aristotle has a lot to say about them. | 0:17:10 | 0:17:12 | |
He describes how they change colour | 0:17:12 | 0:17:15 | |
and how they eject ink when they're afraid. | 0:17:15 | 0:17:19 | |
How they breed. How they hunt with these amazing long tentacles. | 0:17:19 | 0:17:23 | |
And the fact that they only live for about a year. | 0:17:23 | 0:17:26 | |
One of Aristotle's masterpieces is the dissection of the cuttlefish. | 0:17:40 | 0:17:46 | |
Aristotle describes the anatomy of a cuttlefish in detail. | 0:17:56 | 0:18:01 | |
He describes its gills over here, | 0:18:01 | 0:18:04 | |
he describes its reproductive organs. This is a female. | 0:18:04 | 0:18:07 | |
These are the glands with which it produces the shell. | 0:18:07 | 0:18:11 | |
He knows that cuttlefish have a very unusual anatomy insofar that | 0:18:11 | 0:18:16 | |
the guts are bent around such that, in effect, it defecates on its head. | 0:18:16 | 0:18:22 | |
Its rectum is located very close to its brain and its eyes, | 0:18:22 | 0:18:27 | |
underneath the mantle cavity, unlike most creatures whose rectums | 0:18:27 | 0:18:31 | |
are at the opposite ends of their bodies from their mouths. | 0:18:31 | 0:18:34 | |
The mouth, the beak, | 0:18:34 | 0:18:38 | |
which is hard, with which it bites, | 0:18:38 | 0:18:43 | |
over there. | 0:18:43 | 0:18:45 | |
He looks inside of the cuttlefish and he sees that the biggest organ | 0:18:45 | 0:18:49 | |
is a big orange thing, which he calls the mytis. | 0:18:49 | 0:18:54 | |
And it's right in the middle of the body. | 0:18:54 | 0:18:57 | |
He thinks that this is the heart | 0:18:57 | 0:18:59 | |
or at least the equivalent of a cuttlefish heart. | 0:18:59 | 0:19:02 | |
It isn't. It's the liver. But because it's centrally located | 0:19:02 | 0:19:06 | |
and our hearts are centrally located, he, in effect, | 0:19:06 | 0:19:10 | |
argues that they are the same thing. | 0:19:10 | 0:19:12 | |
It's an easy mistake to make. And it must be said that | 0:19:12 | 0:19:15 | |
everything else he does is just incredibly impressive. | 0:19:15 | 0:19:19 | |
Aristotle's description of the anatomy of the cuttlefish | 0:19:25 | 0:19:29 | |
was not bettered until the 17th Century when a Dutchman, | 0:19:29 | 0:19:33 | |
Jan Swammerdam, found the cuttlefish's hearts, | 0:19:33 | 0:19:37 | |
all three of them. | 0:19:37 | 0:19:40 | |
You might expect that a book like this would be ordered by species, | 0:19:47 | 0:19:51 | |
that there would be a chapter on insects and another chapter | 0:19:51 | 0:19:55 | |
on the cuttlefish and lizards and so on and so forth. | 0:19:55 | 0:19:58 | |
But it isn't. In fact, it's ordered by system. | 0:19:58 | 0:20:01 | |
There are sections on digestion and reproduction and life cycles. | 0:20:01 | 0:20:07 | |
Really, it's ordered like any modern invertebrate zoology textbook. | 0:20:07 | 0:20:12 | |
And it's that that tells us that Aristotle | 0:20:12 | 0:20:14 | |
isn't simply accumulating natural history knowledge. | 0:20:14 | 0:20:18 | |
He's doing something much more systematic. | 0:20:18 | 0:20:20 | |
He's doing science. | 0:20:20 | 0:20:22 | |
And therein lies a paradox. | 0:20:26 | 0:20:28 | |
The way in which Aristotle structured this book | 0:20:28 | 0:20:31 | |
is so familiar to us, so very much a part of the way we think about | 0:20:31 | 0:20:35 | |
the natural world and how we do biology, that it's almost impossible | 0:20:35 | 0:20:40 | |
for us to understand just how original he was. | 0:20:40 | 0:20:44 | |
And yet, when he came down to this lagoon, | 0:20:44 | 0:20:48 | |
saw the creatures in it, cut them up and wrote down what he saw, | 0:20:48 | 0:20:53 | |
he was the very first person to have ever done so. | 0:20:53 | 0:20:57 | |
What he does next is revolutionary. Having sorted his data, | 0:21:02 | 0:21:07 | |
having arranged his facts, he begins to explain. | 0:21:07 | 0:21:11 | |
He pits theory against observation. | 0:21:11 | 0:21:14 | |
He invents a new way of understanding the world. | 0:21:16 | 0:21:21 | |
A COCK CROWS | 0:21:27 | 0:21:30 | |
He applies this method to one of biology's deepest problems... | 0:21:32 | 0:21:37 | |
..how life originates in the egg and in the womb. | 0:21:38 | 0:21:43 | |
He wants to know how, the words are his, living things "come to be". | 0:21:43 | 0:21:49 | |
If you really want to understand development, | 0:21:55 | 0:21:59 | |
you have to do what Aristotle did. | 0:21:59 | 0:22:01 | |
You have to go to a farmyard | 0:22:01 | 0:22:02 | |
and get yourself some fertilised chicken eggs. | 0:22:02 | 0:22:05 | |
One of the charms of this is that you just don't know | 0:22:18 | 0:22:21 | |
what you are actually going to see until you open the egg. | 0:22:21 | 0:22:24 | |
Sometimes, when you do, | 0:22:26 | 0:22:28 | |
you see exactly what Aristotle saw. | 0:22:28 | 0:22:32 | |
Aristotle would have looked inside the egg with the naked eye. | 0:22:33 | 0:22:37 | |
But we can do a bit better with this handy microscope, | 0:22:38 | 0:22:43 | |
which attaches to my computer. It's a little bit tricky, | 0:22:43 | 0:22:48 | |
but if you focus it just right... | 0:22:48 | 0:22:51 | |
..you can see what I'm seeing. | 0:22:53 | 0:22:56 | |
It's an embryo, not more than a few days old, lying there, minute, | 0:22:58 | 0:23:05 | |
on its bed of albumen and yolk. With the blood vessels, | 0:23:05 | 0:23:11 | |
the vitelline arteries and veins ramifying into its surroundings. | 0:23:11 | 0:23:16 | |
You can see its head. | 0:23:16 | 0:23:18 | |
You can see its eye. | 0:23:20 | 0:23:21 | |
And above all, you can see its little heart, just beating there. | 0:23:23 | 0:23:28 | |
Even Aristotle's detractors, and he does have them, | 0:23:30 | 0:23:33 | |
have to give him credit for this. | 0:23:33 | 0:23:35 | |
He's the first person to open an egg and describe the embryo of a chick. | 0:23:35 | 0:23:41 | |
He's the first person to describe the origin of a living thing. | 0:23:41 | 0:23:47 | |
Aristotle describes the growth of an apparently inanimate egg | 0:24:00 | 0:24:04 | |
into a living, breathing, copulating creature. | 0:24:04 | 0:24:09 | |
Had he done just this, | 0:24:09 | 0:24:11 | |
he would be worthy of our admiration. | 0:24:11 | 0:24:14 | |
But I think he did much more. | 0:24:14 | 0:24:16 | |
I think he attempted to, and largely succeeded in, | 0:24:16 | 0:24:21 | |
penetrating to the very deepest secrets of life. | 0:24:21 | 0:24:25 | |
Why do chicks hatch from chicken eggs? | 0:24:29 | 0:24:32 | |
Why not tortoises, fish or snakes? | 0:24:32 | 0:24:35 | |
It sounds like a trivial question, but it isn't. | 0:24:35 | 0:24:38 | |
It's a question about why progeny look like their parents. | 0:24:38 | 0:24:42 | |
It's a question about inheritance. | 0:24:42 | 0:24:45 | |
Aristotle argued that the properties of matter, the elemental building | 0:24:50 | 0:24:55 | |
blocks of the world, cannot explain how an embryo constructs itself. | 0:24:55 | 0:24:59 | |
Something else is needed. | 0:24:59 | 0:25:02 | |
Something that it gets from its parents, something that shapes it. | 0:25:02 | 0:25:07 | |
And he called that thing eidos. | 0:25:10 | 0:25:13 | |
Which is what, exactly? | 0:25:16 | 0:25:19 | |
Well, this is where Aristotle gets hard. | 0:25:19 | 0:25:23 | |
This is where he we hit his metaphysics. | 0:25:23 | 0:25:27 | |
We need a classical philosopher. | 0:25:29 | 0:25:32 | |
This is what one looks like. | 0:25:32 | 0:25:34 | |
Richard King and I have been talking Aristotle for years. | 0:25:34 | 0:25:40 | |
Aristotle takes a comparison between | 0:25:40 | 0:25:42 | |
the material constituents of things, the elements, as he calls them, | 0:25:42 | 0:25:48 | |
and the form or eidos. And he says, | 0:25:48 | 0:25:51 | |
"The elements are like letters A and B and you can combine | 0:25:51 | 0:25:57 | |
"them in various ways. | 0:25:57 | 0:25:59 | |
"So you can either have the syllable AB or the syllable BA, | 0:25:59 | 0:26:05 | |
"AB or BA, and the arrangement, | 0:26:05 | 0:26:07 | |
"well, that's the form and the form is different in each case. | 0:26:07 | 0:26:10 | |
"So the form is different from the material constituents". | 0:26:10 | 0:26:15 | |
So what he seems to be saying is that it's not the stuff of which | 0:26:16 | 0:26:20 | |
it's made that matters, it's the way in which that stuff is ordered. | 0:26:20 | 0:26:24 | |
Exactly, exactly. It's the order of the material constituents | 0:26:24 | 0:26:29 | |
just as the order of the letters makes the two different syllables. | 0:26:29 | 0:26:33 | |
So what eidos really is is something like information? | 0:26:33 | 0:26:37 | |
That's right. Information or a kind of activity. | 0:26:37 | 0:26:42 | |
And the really remarkable thing is, | 0:26:42 | 0:26:45 | |
he's using a metaphor for information, | 0:26:45 | 0:26:49 | |
the order of the letters that is almost exactly like the metaphor | 0:26:49 | 0:26:53 | |
that we use when we speak about the genetic code, about DNA. | 0:26:53 | 0:26:57 | |
After all, it's not the material constituents of DNA that matter, | 0:26:57 | 0:27:01 | |
rather it's the order of the elements of which DNA is made up, | 0:27:01 | 0:27:04 | |
the molecules, the nucleotides, that's the information. | 0:27:04 | 0:27:08 | |
That's right. | 0:27:08 | 0:27:09 | |
One of Aristotle's methods for studying living things | 0:27:17 | 0:27:20 | |
was simplicity itself. He cut them open while still alive. | 0:27:20 | 0:27:26 | |
Aristotle has an enthusiasm for vivisection | 0:27:32 | 0:27:37 | |
that today seems excessive. | 0:27:37 | 0:27:40 | |
He describes how, if you cut an insect such as this in half, | 0:27:40 | 0:27:45 | |
it lives for a surprisingly long time. | 0:27:45 | 0:27:47 | |
Well, lots of modern biologists vivisect insects. | 0:27:57 | 0:28:01 | |
But few vivisect chameleons. | 0:28:01 | 0:28:03 | |
Aristotle did. | 0:28:03 | 0:28:06 | |
"After being cut open", he observes, | 0:28:06 | 0:28:08 | |
"the chameleon continues to breathe for a considerable time." | 0:28:08 | 0:28:13 | |
And tortoises. "They", he says, "continue to wiggle their legs | 0:28:16 | 0:28:21 | |
"even after their hearts have been removed." | 0:28:21 | 0:28:23 | |
I don't know how long a tortoise would survive without its heart. | 0:28:25 | 0:28:30 | |
And I am not, I think, inclined to find out. | 0:28:30 | 0:28:33 | |
And yet Aristotle's belief that some creatures can survive | 0:28:33 | 0:28:37 | |
for a surprisingly long time when eviscerated strikes | 0:28:37 | 0:28:40 | |
to one of the deepest parts of his research programme. | 0:28:40 | 0:28:43 | |
For when Aristotle cut out the heart of a tortoise, | 0:28:43 | 0:28:48 | |
he was in search of nothing less | 0:28:48 | 0:28:53 | |
than its soul. | 0:28:53 | 0:28:54 | |
The ancient Greeks allegorised the soul as butterfly. | 0:29:06 | 0:29:11 | |
They used the same name for both, psyche. It's easy to see why. | 0:29:11 | 0:29:16 | |
The butterfly clambers from the dark chrysalis just as the soul, | 0:29:22 | 0:29:27 | |
immaterial and immortal, flees a corpse at death, | 0:29:27 | 0:29:30 | |
yet lives on in Hades. It's the soul as spirit. | 0:29:30 | 0:29:35 | |
Aristotle's view of the soul is very different. | 0:29:40 | 0:29:43 | |
He thinks that all living creatures, not just humans, have one. | 0:29:43 | 0:29:49 | |
He thinks that mussels and clams and lobsters and crabs all have souls. | 0:29:49 | 0:29:54 | |
Or at least they did when they were alive. | 0:29:54 | 0:29:58 | |
For, Aristotle thinks, when a living thing dies, its soul dies with it. | 0:29:58 | 0:30:04 | |
This is the soul as biology. | 0:30:09 | 0:30:13 | |
Yet when you read Aristotle on the soul, it seems rather mysterious. | 0:30:13 | 0:30:17 | |
It's not material, yet it controls matter. | 0:30:17 | 0:30:21 | |
It's not an organ that you can dissect out and hold in your hand. | 0:30:21 | 0:30:25 | |
It's something much more abstract. | 0:30:25 | 0:30:29 | |
The soul is the network of command and control that makes a creature. | 0:30:30 | 0:30:35 | |
It's the flow of nutrients throughout its body, | 0:30:35 | 0:30:39 | |
it's the workings of its organs, | 0:30:39 | 0:30:41 | |
it's the senses with which it perceives the world. | 0:30:41 | 0:30:44 | |
And in the case of a man, it's the thoughts he thinks. | 0:30:44 | 0:30:49 | |
It is what 21st century biologists simply call The System. | 0:30:56 | 0:31:01 | |
It is a creature's metabolism | 0:31:03 | 0:31:05 | |
and the circuitry of genes and proteins that control it. | 0:31:05 | 0:31:08 | |
It is all the devices that stave off entropy and stop living things | 0:31:11 | 0:31:17 | |
collapsing into heaps of inert matter. | 0:31:17 | 0:31:20 | |
What Aristotle calls the soul, we call the system. | 0:31:23 | 0:31:27 | |
What he calls eidos, we call genes. | 0:31:27 | 0:31:30 | |
The language is very different but the concepts are much alike. | 0:31:30 | 0:31:34 | |
At the heart of both theories of life | 0:31:34 | 0:31:36 | |
is the idea that information handed down from parent to child, | 0:31:36 | 0:31:40 | |
generation upon generation, shapes living matter. | 0:31:40 | 0:31:45 | |
Aristotle believes that every species has a unique eidos, | 0:31:49 | 0:31:54 | |
its own particular soul. | 0:31:54 | 0:31:56 | |
Why, then, are there so many species? | 0:31:57 | 0:32:01 | |
For us, there are two explanations, | 0:32:01 | 0:32:04 | |
a religious one, God made them, and a scientific one, they evolved. | 0:32:04 | 0:32:10 | |
Aristotle has a relentlessly scientific mind, | 0:32:18 | 0:32:22 | |
but he lived 23 centuries before Darwin. | 0:32:22 | 0:32:24 | |
So is he a creationist? | 0:32:24 | 0:32:27 | |
His teacher Plato certainly was. | 0:32:27 | 0:32:30 | |
Plato gives an account of the origin of animals, | 0:32:32 | 0:32:35 | |
and it's a frank Creationist myth with a moralising twist. | 0:32:35 | 0:32:40 | |
God made the cosmos and then, | 0:32:40 | 0:32:42 | |
as punishment for various misdemeanours, | 0:32:42 | 0:32:45 | |
turned some humans into animals. The frivolous became birds, | 0:32:45 | 0:32:49 | |
the low-minded became lizards, snakes and things that crawl. | 0:32:49 | 0:32:53 | |
Others became fish. | 0:32:53 | 0:32:56 | |
Only the sober-minded remained human. | 0:32:56 | 0:32:59 | |
Aristotle thinks all of this is nonsense. | 0:32:59 | 0:33:03 | |
He has no time for creation myths, all that talk of the ancient Gods. | 0:33:03 | 0:33:07 | |
"I love Plato", he said, "but I love truth even more". | 0:33:07 | 0:33:12 | |
So is he an evolutionist? | 0:33:15 | 0:33:19 | |
He has Darwin's sense of how creatures are fitted to | 0:33:19 | 0:33:22 | |
the environments in which they live. | 0:33:22 | 0:33:24 | |
He describes how the beaks of birds are suited to their food. | 0:33:26 | 0:33:30 | |
"Creatures are", he says, "designed to survive and reproduce". | 0:33:30 | 0:33:36 | |
And, he's quite clear, | 0:33:36 | 0:33:37 | |
there isn't a celestial designer. | 0:33:37 | 0:33:41 | |
Nature designs living things and does so beautifully. | 0:33:41 | 0:33:48 | |
He thinks that some animals are more advanced than others. | 0:33:56 | 0:34:02 | |
There is a scale of complexity. | 0:34:02 | 0:34:05 | |
Most remarkably, he tells us that apes are intermediate in form | 0:34:08 | 0:34:12 | |
between quadrupeds and humans, which is certainly true. | 0:34:12 | 0:34:16 | |
It all sounds terribly Darwinian. | 0:34:18 | 0:34:21 | |
But it isn't. | 0:34:21 | 0:34:22 | |
For Aristotle isn't an evolutionist. | 0:34:22 | 0:34:24 | |
He's something much stranger. | 0:34:24 | 0:34:27 | |
Aristotle thinks that the world | 0:34:30 | 0:34:32 | |
that we see before us has simply always been there, unchanging. | 0:34:32 | 0:34:37 | |
He is, in other words, an eternalist. | 0:34:37 | 0:34:41 | |
It's a difficult idea to understand. | 0:34:43 | 0:34:46 | |
Our conceptual world is constructed on a Manichean conflict | 0:34:46 | 0:34:50 | |
between Creation and Evolution and Eternity simply isn't an option. | 0:34:50 | 0:34:55 | |
Eternity denies history. | 0:34:55 | 0:34:59 | |
It says that the past is not a very different place, | 0:34:59 | 0:35:04 | |
but the same place forever and forever and forever. | 0:35:04 | 0:35:10 | |
Which brings us to one of the most puzzling gaps in his science, | 0:35:12 | 0:35:17 | |
the fact that he doesn't say anything about fossils. | 0:35:17 | 0:35:21 | |
It's hard to see how Aristotle missed this. | 0:35:24 | 0:35:27 | |
We're on the western end of the island amid the remains | 0:35:27 | 0:35:32 | |
of a vast forest, but the trees are now stone. | 0:35:32 | 0:35:36 | |
It is one of the world's great petrified forests. | 0:35:36 | 0:35:41 | |
Some people say that theory blinkers scientists. | 0:35:46 | 0:35:51 | |
I don't think that's true, at least not in any strong sense. | 0:35:51 | 0:35:56 | |
And yet, | 0:35:56 | 0:35:58 | |
if you don't believe that the past is a different place, | 0:35:58 | 0:36:01 | |
it's easy to see how you could mistake a forest | 0:36:01 | 0:36:05 | |
for a field of stones. | 0:36:05 | 0:36:07 | |
An ancient volcano covered them in ash. | 0:36:09 | 0:36:12 | |
Now, 20 million years later, | 0:36:12 | 0:36:13 | |
you can still see their leaves, bark and tissues. | 0:36:13 | 0:36:17 | |
Aristotle's friend, Theophrastus, | 0:36:20 | 0:36:23 | |
the founder of botany, lived just a few kilometres away in Erissos. | 0:36:23 | 0:36:28 | |
Did he see them? | 0:36:28 | 0:36:30 | |
I asked Nicholas Zouros, | 0:36:32 | 0:36:34 | |
the Director of the Lesvos Petrified Forest, about it. | 0:36:34 | 0:36:38 | |
We know that Theophrastus was born just next to Erissos | 0:36:40 | 0:36:44 | |
and I am sure that once he visited this site. | 0:36:44 | 0:36:49 | |
So, for me, it is quite obvious | 0:36:49 | 0:36:52 | |
that he would have seen these silicified trees. | 0:36:52 | 0:36:57 | |
For me, it's absolutely unbelievable that a person like Aristotle, | 0:36:57 | 0:37:03 | |
or like Theophrastus, have not seen this. | 0:37:03 | 0:37:08 | |
Perhaps he just missed the entire forest. | 0:37:12 | 0:37:15 | |
Perhaps it was covered up. | 0:37:15 | 0:37:17 | |
But I suspect that the real reason Aristotle doesn't mention this | 0:37:17 | 0:37:22 | |
or any other fossil is not because he didn't see them, | 0:37:22 | 0:37:25 | |
but because he didn't believe in them. | 0:37:25 | 0:37:28 | |
Still, the question remains. | 0:37:37 | 0:37:41 | |
If species weren't created and did not evolve, | 0:37:41 | 0:37:44 | |
why then are there so many of them? | 0:37:44 | 0:37:48 | |
Aristotle understands that species | 0:37:48 | 0:37:51 | |
are connected to each other in very complex ways. | 0:37:51 | 0:37:54 | |
He compares the world to a house, | 0:37:54 | 0:37:56 | |
the Greek is oikos, from which we get our "ecology". | 0:37:56 | 0:38:00 | |
And in the household of the world, every species has its own role. | 0:38:00 | 0:38:07 | |
Aristotle knows that households are not always harmonious. | 0:38:12 | 0:38:17 | |
He understands, as Darwin would, that there is a war of nature. | 0:38:17 | 0:38:22 | |
But where in Darwinian wars some species flourish while others | 0:38:22 | 0:38:27 | |
go extinct, in Aristotelian wars the combatants simply fight forever. | 0:38:27 | 0:38:34 | |
But earthly creatures are not the only inhabitants of | 0:38:46 | 0:38:49 | |
Aristotle's household, the sun, the planets and the stars are as well. | 0:38:49 | 0:38:54 | |
His ecology embraces the cosmos. | 0:38:57 | 0:39:00 | |
And regulating it all is God, a God who simply thinks. | 0:39:00 | 0:39:06 | |
And though his God is the ultimate, remote intellectual, | 0:39:06 | 0:39:11 | |
he is also the reason for life on earth. | 0:39:11 | 0:39:15 | |
It's a beautiful, if slightly mystical, doctrine. | 0:39:18 | 0:39:23 | |
For it says that the nature that Aristotle described, | 0:39:23 | 0:39:26 | |
dissected and classified is, in fact, sacred. | 0:39:26 | 0:39:30 | |
Had I a God... | 0:39:34 | 0:39:36 | |
HAD I a God, | 0:39:36 | 0:39:38 | |
he would surely be Aristotle's. | 0:39:38 | 0:39:41 | |
Aristotle's world is very different from ours. | 0:39:50 | 0:39:54 | |
Our world does have a history, | 0:39:54 | 0:39:57 | |
one that can be seen in this very lagoon. | 0:39:57 | 0:40:01 | |
Had Aristotle ever sat at this spot, | 0:40:08 | 0:40:11 | |
he wouldn't have been by the water's edge. | 0:40:11 | 0:40:14 | |
That's because tectonic movements | 0:40:14 | 0:40:16 | |
have been shifting the islands beneath the Aegean. | 0:40:16 | 0:40:20 | |
And for millions of years the shoreline has been rising. | 0:40:20 | 0:40:24 | |
The ecology of the lagoon has changed, too. | 0:40:29 | 0:40:33 | |
The most enchanting creatures that live here are surely the flamingos. | 0:40:33 | 0:40:39 | |
For all their flamboyance, Aristotle does not mention them at all. | 0:40:39 | 0:40:45 | |
They are newcomers and only arrived here a few decades ago. | 0:40:47 | 0:40:50 | |
Other changes to the lagoon's ecology are more disturbing. | 0:40:55 | 0:40:59 | |
Giorgos Kokkoris and his colleagues from the University of the Aegean | 0:41:04 | 0:41:08 | |
have been monitoring the lagoon. They have found that pollution | 0:41:08 | 0:41:12 | |
and over fishing are taking their toll on its creatures. | 0:41:12 | 0:41:15 | |
I asked him about the lagoon's future. | 0:41:15 | 0:41:18 | |
The problems that we have faced | 0:41:20 | 0:41:22 | |
in this lagoon, these are the problems that we face | 0:41:22 | 0:41:27 | |
in the entire Aegean. And actually, in the entire world, I would say. | 0:41:27 | 0:41:32 | |
Biodiversity is threatened, fish catches have lowered. | 0:41:32 | 0:41:37 | |
I think the situation will deteriorate and some day | 0:41:37 | 0:41:41 | |
the fishermen will come and say that | 0:41:41 | 0:41:44 | |
there is nothing else to fish down there. | 0:41:44 | 0:41:48 | |
You know, | 0:41:48 | 0:41:50 | |
I know that what's happening here is happening right across the Aegean | 0:41:50 | 0:41:55 | |
-and the world. -It is. | 0:41:55 | 0:41:57 | |
And as such, the lagoon is really just a microcosm | 0:41:59 | 0:42:04 | |
of that larger picture of ecological devastation. | 0:42:04 | 0:42:10 | |
And yet, for me, | 0:42:10 | 0:42:13 | |
the fact that Aristotle worked here and that this | 0:42:13 | 0:42:17 | |
is where biology began, | 0:42:17 | 0:42:19 | |
makes the destruction of this lagoon a thing of unutterable sadness. | 0:42:19 | 0:42:26 | |
If this lovely lagoon inspired Aristotle's vision | 0:42:27 | 0:42:31 | |
of an eternal and harmonious world, then there is bitter irony | 0:42:31 | 0:42:37 | |
in the fact that history has now caught up with it. | 0:42:37 | 0:42:41 | |
GREEK STYLE MUSIC | 0:42:41 | 0:42:47 | |
Aristotle continued the work that he began on Lesvos. | 0:42:55 | 0:42:58 | |
He wrote books about the anatomy, | 0:42:58 | 0:43:00 | |
physiology and development of animals. | 0:43:00 | 0:43:03 | |
There is a book about breathing, | 0:43:03 | 0:43:05 | |
another on ageing, another on movement. | 0:43:05 | 0:43:08 | |
There is a book on the soul. | 0:43:08 | 0:43:11 | |
The scientific legacy he left is not vast, | 0:43:11 | 0:43:15 | |
it is monumental. | 0:43:15 | 0:43:17 | |
It was read, copied and plagiarised by Roman encyclopaedists, | 0:43:20 | 0:43:26 | |
Muslim physicians and Medieval scribes. | 0:43:26 | 0:43:28 | |
By the 13th century | 0:43:28 | 0:43:30 | |
it was being taught throughout the universities of Europe. | 0:43:30 | 0:43:36 | |
In the Renaissance, scholars rearranged his books | 0:43:40 | 0:43:43 | |
into catalogues with exquisite illustrations | 0:43:43 | 0:43:47 | |
depicting the creatures that Aristotle had seen. | 0:43:47 | 0:43:51 | |
They founded museums full of natural wonders, | 0:43:55 | 0:43:58 | |
not unlike this one in a small village near the lagoon. | 0:43:58 | 0:44:01 | |
In fact, it's no exaggeration to say | 0:44:04 | 0:44:07 | |
that modern biology was founded on Aristotle. | 0:44:07 | 0:44:11 | |
Which raises the question, | 0:44:15 | 0:44:18 | |
why have we forgotten him? | 0:44:18 | 0:44:20 | |
Why has he no place in the pantheon of great scientists next to, say, | 0:44:20 | 0:44:27 | |
Pasteur or Darwin? | 0:44:27 | 0:44:29 | |
One reason is that some of his biology was, very simply, wrong. | 0:44:31 | 0:44:37 | |
He was very wrong about eels. | 0:44:40 | 0:44:44 | |
Whoa! It's a big one. | 0:44:48 | 0:44:50 | |
What a gorgeous fish. | 0:44:54 | 0:44:57 | |
Which kind is it? Is it leptocephalous? | 0:45:02 | 0:45:04 | |
-Leptocephalous. -Leptocephalous. | 0:45:04 | 0:45:06 | |
Aristotle says that the eels grow from the mud | 0:45:07 | 0:45:10 | |
at the bottom of the rivers. | 0:45:10 | 0:45:12 | |
-Why would he say that? -Because basically he sees eels, | 0:45:12 | 0:45:18 | |
even big ones, but especially small ones, | 0:45:18 | 0:45:21 | |
they hide in the mud, they can easily just | 0:45:21 | 0:45:24 | |
in the mud, just go... Go directly inside and disappear inside. | 0:45:24 | 0:45:29 | |
In the mud. | 0:45:29 | 0:45:31 | |
See, all this time, we never saw an eel with eggs. | 0:45:31 | 0:45:35 | |
So what do you think that tells us? | 0:45:35 | 0:45:38 | |
I don't know. This is a mystery. | 0:45:40 | 0:45:43 | |
This is a eel mystery. Nobody knows. | 0:45:43 | 0:45:46 | |
Well, marine biologists do know, but Aristotle certainly didn't. | 0:45:46 | 0:45:52 | |
-See, he turns? -Yes. | 0:45:54 | 0:45:57 | |
So when they bite they turn like that... | 0:45:57 | 0:46:00 | |
I think we've got enough, don't you? | 0:46:03 | 0:46:05 | |
Yeah. | 0:46:05 | 0:46:07 | |
Aristotle noticed that eels are very unusual creatures. | 0:46:13 | 0:46:19 | |
If you do a ventral incision, | 0:46:21 | 0:46:25 | |
if you make a ventral incision of this sort, | 0:46:25 | 0:46:28 | |
in order to look at its internal organs... | 0:46:28 | 0:46:31 | |
..through to the rectum, | 0:46:33 | 0:46:38 | |
down beyond, | 0:46:38 | 0:46:41 | |
what you see are all the regular organs | 0:46:43 | 0:46:46 | |
that you would find in any fish. | 0:46:46 | 0:46:49 | |
But, in a regular fish, | 0:46:51 | 0:46:56 | |
the reproductive organs would be somewhere right around here, | 0:46:56 | 0:47:01 | |
the gonads, the sperm and the eggs. | 0:47:01 | 0:47:03 | |
However, in eels, you simply never find them. Aristotle noticed this, | 0:47:03 | 0:47:07 | |
and for him, it raised the obvious question, | 0:47:07 | 0:47:10 | |
how, if an eel doesn't have eggs or sperm, does it reproduce? | 0:47:10 | 0:47:16 | |
It's a reasonable question. | 0:47:18 | 0:47:22 | |
He could, of course, not know that the European eel develops its gonads | 0:47:22 | 0:47:27 | |
in the course of a 9,000 km swim | 0:47:27 | 0:47:30 | |
to its spawning grounds in the Sargasso Sea. | 0:47:30 | 0:47:34 | |
He seems to think that some kinds of creatures don't reproduce. | 0:47:39 | 0:47:44 | |
They just appear from nowhere. | 0:47:44 | 0:47:48 | |
-They "spontaneously generate", to use his term. -That's right. | 0:47:48 | 0:47:53 | |
-What's all that about? -He noticed that some animals | 0:47:53 | 0:47:58 | |
don't come about from animals of the same kind. | 0:47:58 | 0:48:03 | |
So humans can produce tapeworms or fleas | 0:48:03 | 0:48:06 | |
and he extends this to other animals, in other parts of nature, | 0:48:06 | 0:48:12 | |
in the sea above all, but also with almost all insects. | 0:48:12 | 0:48:16 | |
Quite why he does that is a very peculiar question. | 0:48:19 | 0:48:22 | |
For nearly 2,000 years after Aristotle, | 0:48:23 | 0:48:27 | |
as a consequence of Aristotle, | 0:48:27 | 0:48:29 | |
people believed that lots of different creatures, | 0:48:29 | 0:48:33 | |
insects, snails, clams, spontaneously generated, | 0:48:33 | 0:48:36 | |
that they didn't actually ever reproduce. | 0:48:36 | 0:48:38 | |
It had immense influence on biology. | 0:48:38 | 0:48:40 | |
A disaster. | 0:48:40 | 0:48:43 | |
One of Aristotle's less happy theories. | 0:48:43 | 0:48:46 | |
Less happy theories? | 0:48:46 | 0:48:47 | |
One of his catastrophic mistakes, I would say. | 0:48:47 | 0:48:50 | |
Aristotle observed that putrefying flesh | 0:48:54 | 0:48:57 | |
often seems to breed other creatures. | 0:48:57 | 0:49:01 | |
Take this European glass lizard, which we have conveniently | 0:49:03 | 0:49:07 | |
found dead at the side of a road. | 0:49:07 | 0:49:12 | |
I'm cutting it up in order to see what's inside. | 0:49:14 | 0:49:18 | |
The lizard has become rather mummified in the intense heat. | 0:49:24 | 0:49:29 | |
We see, perhaps unsurprisingly, | 0:49:32 | 0:49:37 | |
that it's crawling with maggots. | 0:49:37 | 0:49:42 | |
Now, Aristotle knows that | 0:49:45 | 0:49:49 | |
flies come from maggots | 0:49:49 | 0:49:52 | |
and he knows that maggots come from | 0:49:52 | 0:49:56 | |
putrefying flesh. | 0:49:56 | 0:49:59 | |
And so he concludes, | 0:49:59 | 0:50:01 | |
not unreasonably, | 0:50:01 | 0:50:04 | |
that flies are, in his words, "spontaneously generated" | 0:50:04 | 0:50:09 | |
from dead things. | 0:50:09 | 0:50:13 | |
-You find these just here in Kalloni? -Just here in port. | 0:50:16 | 0:50:20 | |
The fish from Kalloni, are they nice? | 0:50:20 | 0:50:22 | |
-They are the very best. -The best. And I'll take one of these guys. | 0:50:22 | 0:50:26 | |
Aristotle's belief in spontaneous generation wasn't, however, | 0:50:26 | 0:50:31 | |
the real reason he became discredited. | 0:50:31 | 0:50:33 | |
Rather, it was the failings in his method that this belief exposed. | 0:50:33 | 0:50:38 | |
When I read Aristotle, it's like reading the work | 0:50:38 | 0:50:40 | |
of a brilliant, albeit eccentric, colleague. | 0:50:40 | 0:50:44 | |
There are the same detailed observations, | 0:50:44 | 0:50:47 | |
the closely argued theory, | 0:50:47 | 0:50:50 | |
the same invidious references to predecessors. | 0:50:50 | 0:50:54 | |
But there's one thing that's missing, | 0:50:54 | 0:50:58 | |
the thing that defines modern science... | 0:50:58 | 0:51:04 | |
..experiment. | 0:51:07 | 0:51:09 | |
I place two fresh fish in two jars, | 0:51:13 | 0:51:15 | |
cover one with gauze and leave the other exposed. | 0:51:15 | 0:51:20 | |
It's the kind of experiment that Aristotle might have done, | 0:51:20 | 0:51:23 | |
but didn't. | 0:51:24 | 0:51:25 | |
A week later, I look at the results. | 0:51:25 | 0:51:29 | |
This fish has been left open | 0:51:30 | 0:51:33 | |
and exposed to the elements. | 0:51:33 | 0:51:36 | |
And it is | 0:51:40 | 0:51:43 | |
crawling with maggots. | 0:51:43 | 0:51:47 | |
Such as this one here. | 0:51:51 | 0:51:54 | |
And the fish that has been covered in gauze, by contrast, | 0:52:04 | 0:52:07 | |
there's plenty of rotting meat, | 0:52:07 | 0:52:10 | |
but there aren't any maggots. | 0:52:10 | 0:52:13 | |
And that proves that in order to get maggots in rotting meat | 0:52:15 | 0:52:19 | |
you first have to get flies that lay eggs in them. | 0:52:19 | 0:52:23 | |
And that, in all its simplicity, | 0:52:23 | 0:52:25 | |
was the experiment that Francesco Redi did in 1668. | 0:52:25 | 0:52:30 | |
It demolished Aristotle's theory of spontaneous generation. | 0:52:30 | 0:52:33 | |
And his reputation never recovered. | 0:52:33 | 0:52:37 | |
At the heart of this story lies a tragic paradox. | 0:52:58 | 0:53:01 | |
For nearly 2,000 years, when men inquired about the natural world, | 0:53:01 | 0:53:06 | |
they first asked, "What did Aristotle think?" | 0:53:06 | 0:53:10 | |
And such was the force of his mind and the scope of his investigations | 0:53:10 | 0:53:14 | |
that invariably he had an answer. | 0:53:14 | 0:53:16 | |
And that was the problem. | 0:53:23 | 0:53:25 | |
Aristotle, or rather his epigones, became an impediment to progress. | 0:53:25 | 0:53:30 | |
The battle cry of modern science was sounded, | 0:53:30 | 0:53:33 | |
"Study nature, not books" and by that, they meant Aristotle's books. | 0:53:33 | 0:53:39 | |
He was turned into a symbol of the muddleheaded past | 0:53:42 | 0:53:47 | |
and with some reason. | 0:53:47 | 0:53:49 | |
He was the giant who had to be slain | 0:53:49 | 0:53:52 | |
so that we could pass through the gates of philosophy | 0:53:52 | 0:53:56 | |
and reach the green fields of scientific truths that lay beyond. | 0:53:56 | 0:54:01 | |
Aristotle stayed in Lesvos for just two years. | 0:54:06 | 0:54:11 | |
He was offered a job, tutor to a princeling called Alexander, | 0:54:11 | 0:54:17 | |
whom history would call the Great. | 0:54:17 | 0:54:20 | |
Later, he returned to Athens, | 0:54:20 | 0:54:23 | |
where he founded his own philosophical school. | 0:54:23 | 0:54:28 | |
He thought, wrote and, in 322 BC, died. | 0:54:28 | 0:54:34 | |
What, then, are we to make of Aristotle? | 0:54:41 | 0:54:44 | |
Should we praise him for his prescience, | 0:54:44 | 0:54:47 | |
or condemn him for his errors? | 0:54:47 | 0:54:50 | |
I think he gives us this. He tells us that creatures | 0:54:52 | 0:54:56 | |
are exquisitely fitted to their environments. | 0:54:56 | 0:54:59 | |
That they are adapted and that adaptation requires an explanation. | 0:54:59 | 0:55:05 | |
He also says that complex things such as creatures cannot simply | 0:55:05 | 0:55:08 | |
self assemble from their constituent parts, | 0:55:08 | 0:55:11 | |
but rather that they need something else. | 0:55:11 | 0:55:14 | |
They need information. | 0:55:14 | 0:55:17 | |
And he tells us that if we want to understand living things, | 0:55:17 | 0:55:21 | |
we have to take them apart, we have to reduce them down | 0:55:21 | 0:55:25 | |
to their individual bits and pieces. But that once we have done so, | 0:55:25 | 0:55:29 | |
we also have to put them back together again. | 0:55:29 | 0:55:32 | |
For only when we do so will we really understand how they work. | 0:55:32 | 0:55:36 | |
And it is this that, I think, makes Aristotle speak to us today. | 0:55:36 | 0:55:40 | |
For if taking things apart was the task of 20th Century biology, | 0:55:40 | 0:55:45 | |
putting them back together again is the task of the 21st. | 0:55:45 | 0:55:50 | |
He is important because he gives us the very structure of our thought, | 0:55:53 | 0:55:58 | |
even when we do not know it ourselves. | 0:55:58 | 0:56:01 | |
His thought flows like a subterranean river | 0:56:01 | 0:56:05 | |
through the history of our science, surfacing now and then as a spring, | 0:56:05 | 0:56:09 | |
with ideas that are apparently new but are, in fact, very old. | 0:56:09 | 0:56:14 | |
Is this view of Aristotle anachronistic? | 0:56:22 | 0:56:27 | |
I don't think so. | 0:56:27 | 0:56:29 | |
He is so vast, so protean, that each generation must read him anew. | 0:56:29 | 0:56:35 | |
For when they do, | 0:56:35 | 0:56:36 | |
they always find things in him that their predecessors have missed. | 0:56:36 | 0:56:42 | |
Aristotle wrote thousands of sentences, but one, | 0:56:48 | 0:56:53 | |
the first in his Metaphysics, defines him. | 0:56:53 | 0:56:57 | |
"All men", he says, "desire to know. | 0:56:57 | 0:57:01 | |
"But not all forms of knowledge are equal, the best is | 0:57:01 | 0:57:07 | |
"the pure and disinterested search for the causes of things". | 0:57:07 | 0:57:11 | |
And, he has no doubt, | 0:57:11 | 0:57:13 | |
"Searching for them is the best way to spend a life". | 0:57:13 | 0:57:17 | |
It's a claim for the beauty and worth of science. | 0:57:17 | 0:57:24 | |
Subtitles by Red Bee Media Ltd | 0:57:44 | 0:57:48 | |
E-mail [email protected] | 0:57:48 | 0:57:51 |