by Richard Dawkins

You could give Aristotle a tutorial. And you could thrill him to the core of his being. Aristotle was an encyclopaedic polymath, an all time intellect. Yet not only can you know more than him about the world. You also can have a deeper understanding of how everything works. Such is the privilege of living after Newton, Darwin, Einstein, Planck, Watson, Crick and their colleagues.

I'm not saying you're more intelligent than Aristotle, or wiser. For all I know, Aristotle's the cleverest person who ever lived. That's not the point. The point is only that science is cumulative, and we live later.

Aristotle had a lot to say about astronomy, biology and physics. But his views sound weirdly naive today. Not as soon as we move away from science, however. Aristotle could walk straight into a modern seminar on ethics, theology, political or moral philosophy. But let him walk into a modern science class and he'd be a lost soul. Not because of the jargon, but because science advances, cumulatively.

Here's a small sample of the things you could tell Aristotle, or any other Greek philosopher. And surprise and enthral them, not just with the facts themselves but with how they hang together so elegantly.

A Primer for Aristotle

The Earth is not the centre of the Universe. It orbits the Sun - which is just another star. There is no music of the spheres, but the chemical elements, from which all matter is made, arrange themselves cyclically, in something like octaves. There are not four elements but about 100. Earth, air, fire and water are not among them.

Species are not isolated types with unchanging essences. Instead, over a time scale too long for humans to imagine, they split and diverge into new species, which then go on diverging further and further. For the first half of geological time our ancestors were bacteria. Most creatures still are bacteria, and each one of our trillions of cells is a colony of bacteria. Aristotle was a distant cousin to a squid, a closer cousin to a monkey, a closer cousin still to an ape (strictly speaking, Aristotle was an ape, an African ape, a closer cousin to a chimpanzee than a chimp is to an orang-utan).

The brain is not for cooling the blood. It's what you use to do your logic and your metaphysics. It's a three-dimensional maze of a million million nerve cells, each one drawn out like a wire to carry pulsed messages. If you laid all your brain cells end to end, they'd stretch round the world 25 times. There are about 4 million million connections in the tiny brain of a chaffinch, proportionately more in ours.

What is Still to be Learnt?

Now, if you're anything like me, you'll have mixed feelings about that recitation. On the one hand, pride in what Aristotle's species now knows and didn't then. On the other hand an uneasy feeling of "isn't it all a bit complacent? What about our descendants, what will they be able to tell us?"

Yes, for sure, the process of accumulation doesn't stop with us. Two thousand years hence, ordinary people who have read a couple of books will be in a position to give a tutorial to today's Aristotles: to Francis Crick, say, or Stephen Hawking. So does this mean that our view of the Universe will turn out to be just as wrong?

Let's keep a sense of proportion about this! Yes, there's much that we still don't know. But surely our belief that the Earth is round and not flat, and that it orbits the Sun, will never be superseded. That alone is enough to confound those, endowed with a little philosophical learning, who deny the very possibility of objective truth: those so-called relativists who see no reason to prefer scientific views over aboriginal myths about the world.

Our belief that we share ancestors with chimpanzees, and more distant ancestors with monkeys, will never be superseded, although details of timing may change. Many of our ideas, on the other hand, are still best seen as theories or models whose predictions, so far, have survived the test. Physicists disagree over whether they are condemned forever to dig for deeper mysteries, or whether physics itself will come to an end in a final 'theory of everything', a nirvana of knowledge.

Meanwhile, there is so much that we don't yet understand, we should loudly proclaim those things that we do, so as to focus attention on problems that we should be working on.

The Wonder of Science

And there are misconceptions about science that we need to tackle. One is a public perception that science is 'difficult' or even dull. Recently I had a letter from a television viewer who poignantly began: "I am a clarinet teacher whose only memory of science at school was a long period of studying the Bunsen burner." Now, you can enjoy the Mozart concerto without being able to play the clarinet. You can be a discerning and informed concert critic without being able to play a note. Of course music would come to a halt if nobody learned to play it. But if everybody left school thinking you had to play an instrument before you could appreciate music, think how impoverished many lives would be.

Couldn't we treat science in the same way? Yes, we must have Bunsen burners and dissecting needles for those drawn to advanced scientific practice. But perhaps the rest if us could have separate classes in science appreciation, the wonder of science, scientific ways of thinking, and the history of scientific ideas, rather than laboratory experience.

Science is an uplifting subject. It is full of wonder. Einstein himself was openly ruled by an aesthetic scientific muse: "The most beautiful thing we can experience is the mysterious. It is the source of all true art and science."

Science vs Pseudoscience

There is mystery in the Universe, beguiling mystery, but it isn't capricious, whimsical, frivolous in its changeability. The Universe is an orderly place and, at a deep level, regions of it behave like other regions, times behave like other times. If you put a brick on a table it stays there unless something lawfully moves it, even if you meanwhile forget it's there. Poltergeists and sprites don't intervene and hurl it about for reasons of mischief or caprice. There is mystery but not magic, strangeness beyond the wildest imagining, but no spells or witchery, no arbitrary miracles.

This is not the impression given by many popular television programmes. In one ubiquitous type of programming, conjurers come on and do routine tricks. But instead of admitting they are conjurers, these performers claim genuine supernatural powers. In other programmes, disturbed people recount their fantasies of ghosts, poltergeists or reincarnation.

Now how can I be so sure that reincarnation doesn't happen and astrology doesn't work? How can I be so confident that the television 'supernaturalists' are ordinary conjurers, just because ordinary conjurers can replicate their tricks?

It really comes down to parsimony, economy of explanation. It is possible that your car engine is driven by psychokinetic energy, but if it looks like a petrol engine, smells like a petrol engine and performs exactly as well as a petrol engine, the sensible working hypothesis is that it is a petrol engine. Telepathy and possession by the spirits of the dead are not ruled out as a matter of principle.

It's been suggested that if the supernaturalists really had the powers they claim, they'd win the lottery every week. I prefer to point out that they could also win a Nobel Prize for discovering fundamental physical forces hitherto unknown to science. Either way, why are they wasting their talents doing party turns on television?

By all means let's be open-minded, but not so open-minded that our brains drop out. Let's not go back to a dark age of superstition and unreason, a world in which every time you lose your keys you suspect poltergeists, demons or alien abduction.

Magic in the Sky

Enough, let me turn to happier matters. The popularity of the paranormal, oddly enough, might even be grounds for encouragement . I think that the appetite for mystery, the enthusiasm for that which we do not understand, is healthy and to be fostered. It is the same appetite which drives the best of true science, and it is an appetite which true science is best qualified to satisfy. Perhaps it is this appetite that underlies the ratings success of the paranormalists.

I believe that astrologers, for instance, are playing on - misusing, abusing - our sense of wonder. I mean when they hijack the constellations, and employ sub-poetic language like "the Moon moving into the fifth house of Aquarius". Real astronomy is the rightful proprietor of the stars and their wonder. Astrology gets in the way, even subverts and debauches the wonder.

To show how real astronomical wonder can be presented to children, I'll borrow from a book called Earthsearch by John Cassidy, which I brought back from America to show my daughter Juliet. Find a large open space and take a soccer ball to represent the Sun. Put the ball down and walk ten paces in a straight line. Stick a pin in the ground. The head of the pin stands for the planet Mercury. Take another nine paces beyond Mercury and put down a peppercorn to represent Venus. Seven paces on, drop another peppercorn for Earth. One inch away from Earth, another pinhead represents the Moon, the furthest place, remember, that we've so far reached. Fourteen more paces to little Mars, then 95 paces to giant Jupiter, a ping-pong ball. Another 112 paces on, Saturn is a marble. No time to deal with the outer planets except to say that the distances are much larger. But, how far would you have to walk to reach the nearest star, Proxima Centauri? Pick up another soccer ball to represent it, and set off for a walk of 4200 miles. As for the nearest other galaxy, Andromeda, don't even think about it!

Who'd go back to astrology when they've sampled the real thing - astronomy, Yeats's "starry ways", his "lonely, majestical multitude"? The same lovely poem encourages us to "remember the wisdom out of the old days" and I want to end with a little piece of wonder from my own territory - evolution.

Ancient Wisdom in our Cells

You contain a trillion copies of a large, textual document written in a highly accurate, digital code, each copy as voluminous as a substantial book. I'm talking, of course, of the DNA in your cells. Textbooks describe DNA as a blueprint for a body. It's better seen as a recipe for making a body, because it is irreversible. But today I want to present it as something different again, and even more intriguing. The DNA in you is a coded description of ancient worlds in which your ancestors lived. DNA is the wisdom out of the old days, and I mean very old days indeed.

The messages that have come down to us are the ones that have survived millions, in some cases hundreds of millions, of generations. For every successful message that has reached the present, countless failures have fallen away like the chippings on a sculptor's floor. That's what Darwinian natural selection means. We are the descendants of a tiny »lite of successful ancestors. Our DNA has proved itself successful, because it is here. Geological time has carved and sculpted our DNA to survive down to the present.

There are perhaps 30 million distinct species in the world today. So, there are 30 million distinct ways of making a living, ways of working to pass DNA on to the future. Some do it in the sea, some on land. Some up trees, some underground. Some are plants, using solar panels - we call them leaves - to trap energy. Some eat the plants. Some eat the herbivores. Some are big carnivores that eat the small ones. Some live as parasites inside other bodies. Some live in hot springs. One species of small worms is said to live entirely inside German beer mats. All these different ways of making a living are just different tactics for passing on DNA. The differences are in the details.

The DNA of a camel was once in the sea, but it hasn't been there for a good 300 million years. It has spent most of recent geological history in deserts, programming bodies to withstand dust and conserve water. Like sandbluffs carved into fantastic shapes by the desert winds, camel DNA has been sculpted by survival in ancient deserts to yield modern camels. At every stage of its geological apprenticeship, the DNA of a species has been honed and whittled, carved and rejigged by selection in a succession of environments. If only we could read the language, the DNA of tuna and starfish would have 'sea' written into the text. The DNA of moles and earthworms would spell 'underground'. Of course all the DNA would spell many other things as well. Shark and cheetah DNA would spell 'hunt', as well as separate messages about sea and land.

We can't read these messages yet. Maybe we never shall, for their language is indirect, as befits a recipe rather than a reversible blueprint. But it's still true that our DNA is a coded description of the worlds in which our ancestors survived. We are walking archives of the African Pliocene, even of Devonian seas, walking repositories of wisdom out of the old days. You could spend a lifetime reading in this ancient library and die unsated by the wonder of it.

Feeding the Appetite

There is an appetite for wonder, and isn't true science well qualified to feed it?

It's often said that people 'need' something more in their lives than just the material world. There is a gap that must be filled. People need to feel a sense of purpose. Well, not a bad purpose would be to find out what is already here, in the material world, before concluding that you need something more. How much more do you want? Just study what is, and you'll find that it already is far more uplifting than anything you could imagine needing.

You don't have to be a scientist - you don't have to play the Bunsen burner - in order to understand enough science to overtake your imagined need and fill that fancied gap. Science needs to be released from the lab into the culture.

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This is an abridged version of the Richard Dimbleby Lecture originally entitled Science, Delusion and the Appetite for Wonder and delivered on 12 November 1996. Parts of the lecture have been expanded in the book Unweaving the Rainbow, now available in paperback (Penguin).