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Archive for the ‘scientists’ Category

The following is based on part seven of Jacob Bronowski’s BBC series on the history of science and invention, “The Ascent of Man” (1973). This part is about the physics of Newton and Einstein:

Newton was born on Christmas Day in the year that Galileo died, 1642.  He got his university degree at Trinity College, Cambridge  but then came the plague years: 1665 and 1666. He went to live with his mother in the country. There he made his great discoveries in physics and mathematics.

From his notebooks we know that he was badly taught: he had to work out mathematics for himself. But along the way he discovered a new form of mathematics: calculus. It became his secret weapon.

Copernicus and Kepler told us how the planets move but could not say why. Newton could: gravity. With his law of gravity he could work out how fast an apple fell from a tree and how many days it took the moon to go round the earth. Utterly amazing.

But none of it was made public till 20 years later. In the meantime Newton made his name in optics: he showed how white light is made out of coloured light. He became a professor at Cambridge and a leading light of science in Britain.

Then one day Edmund Halley came to Cambridge to ask Newton a question about physics. Halley loved his answer but then asked, “How do you know?” Newton said he would send him the proof. That proof took three years and was so long it became a book: the “Principia” (1687). It laid out his physics. Our idea that there are laws of nature comes from that book.

Newton’s physics was a wonder of the age, yet it assumed that time and space are absolute, that they are the same for all observers. Still it stood for 200 years. Then in 1881 Michaelson found the first hole in it: light always went at the same speed no matter what. No one knew what to make of it until Albert Einstein came up with his theory of special relativity in 1905.

Einstein would think about stuff like this: Suppose you get on the tram at the town clock to go to work and your tram went the speed of light. What would you see? If you looked back at the clock you would see that time had stopped – and yet for the people on the street the hands of the clock are still moving! Strange. That means the closer you get to the speed of light, the more time slows down. Time is not absolute. Nor is space: if you push the example further you find that the tops of the buildings will look like they are bending over the street and passers-by will look tall and thin.

Einstein worked out his physics along those lines and, while his conclusions were strange, he was proved right in the course of his life. Even the bit about the edge of a phonograph record ageing more slowly than the centre.

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Davy

Sir Humphry Davy (1778-1829) was a British scientist who discovered the elements potassium, sodium, barium, strontium, calcium and magnesium. He also discovered laughing gas, proved that iodine was an element and that diamonds are just a form of carbon.

But his greatest discovery was a man: Faraday, one of the greatest scientists of all time.

Davy’s big trick, the reason he discovered so many elements, was that he built the world’s biggest battery. That is why he could discover so many elements. With the electricity that it created he passed it through different substances to break them down into simpler ones. Some of these simpler substances were elements that no one had ever seen before.

For example, he thought potash had some kind of metal in it. He passed his electric current through the stuff and out came little shining balls of metal. He called the metal potassium.

Guy-Lussac was doing the same sort of thing in France. In one case he beat out Davy, finding boron nine weeks before he did.

When Davy was young he studied medicine and wanted to be a poet. He loved to fish and walk through the woods and look at the mountains. In one pocket he had his fishing hooks and in the other he had stones that he found along the way.

As a poet Davy was friends with Wordsworth, Coleridge and Southey, some of the best British poets of the time.

But he was not to become a famous poet: at age 19 he read Lavoisier’s book on chemistry. It hooked him for life. A friend of Davy’s let him use his library and chemistry laboratory, one of the best in England as it turned out.

Davy started out by trying to understand out how batteries work. Once he understood that he saw they could be used to break down substances into simpler ones.

Davy came to London. It turned out that he was a great speaker, even though his Cornish English sounded strange. The women liked his handsome looks. His talks on chemistry made him famous and helped to give science a good name. One person who came to see him was Faraday. Davy later hired him.

Davy did not believe in Dalton’s atoms. We take them for granted now, but it was a new idea then, one that was slow to catch on.

Davy was not all that careful: sometimes things blew up, one time he almost went blind.

He made a habit of breathing in any gas he created. He wanted to learn as much as possible about it. Once this paid off when he discovered laughing gas. Another time it almost killed him. But over the years it destroyed his health. He only lived to be 50.

One of the best things he did was to make mines safer with his invention of the safety lamp. He worked out a way for the lamp’s flame to burn without being in danger of blowing up inside the mine.

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Dalton

John Dalton (1766-1844) was a British scientist who proved that ordinary matter is made up of atoms. It is an old idea that goes back to Democritus and the ancient Greeks. Many believed it to be true, but no one could prove it till Dalton.

The idea is this: take anything and cut it in half. Then cut it in half again and so on. Sooner or later you will get to a piece of it that you cannot cut no matter what. It is not a question of how good your cutting instrument is: the thing you are cutting has to be made of something, however small it might be. If you could go on cutting forever that would mean it was made of nothing, which is impossible.

Those small little bits that the thing is made out of, the bits you cannot cut no matter what, were called atoms by Democritus. Atom is Greek for “uncuttable“.

What Dalton called atoms are cuttable, as it turns out, but no one knew that for a hundred years, so the name stuck.

For a piece of bread, by the way, you would get to the level of Dalton’s atoms after cutting it in half about 80 times.

The Greeks thought atoms were different shapes: water atoms were round, fire atoms were sharp, etc. Dalton said atoms were all alike except for their weight. All gold atoms, for example, have the same weight and no other atom has that weight. It is how you tell them apart. That is what made Dalton’s atoms new and different. And provable.

Dalton noticed that when oxygen and hydrogen are put together to make water, the oxygen that goes to make up the water always has a weight eight times greater than the hydrogen.

And it was not just water. All the substances that scientists knew how to make back then out of elements were the same way. The weights were always the same for a given substance and the numbers were always small and simple, like 3 to 8 or 6 to 1.

Nothing made sense of this but Dalton’s atoms with their different weights. But it took a while for the idea to firmly take hold.

Earlier Dalton had studied the weather and wrote one of the first books about it. He made his own instruments and, like Benjamin Franklin, recorded the weather every day for nearly 60 years.

From studying the weather he became interested in the nature of air. That brought him to the work of Boyle, which in turn brought him to chemistry at age 30. Seven years later, in 1803, he came out with his ideas about atoms. The book followed in 1808.

Most groundbreaking ideas like that come to people when they are in their middle to late 20s, not their late 30s. But Dalton’s case shows that it is not age that matters but how long you have been in the field.

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Lavoisier

Antoine Lavoisier (1743-1794) was a French taxman and scientist. He did for chemistry what Galileo did for physics: he made it a hard science by putting ideas to the test with hard numbers.

By the 1700s chemistry had come a long ways from the days when it was called alchemy and men tried to turn lead into gold. But it was still not a proper science. Lavoisier made it one.

Lavoisier loved school as a child. When he grew up he gathered taxes for the king. He was not the one who knocked on your door, he was higher up than that. But everyone knew who he was and knew how he got so rich. He married a beautiful 14-year-old girl.

With his riches he built an amazing laboratory where he worked on his chemistry with the help of his wife. Jefferson, Franklin and Priestley and other leading lights of science visited him there.

But more important than his beautiful laboratory or his beautiful wife was his approach to chemistry:

  1. An element is any substance that cannot be broken down into simpler substances. Lavoisier listed 32 of them.
  2. Every substance is itself an element or made up of elements.
  3. A chemical reaction is when one substance changes into another. This comes from a change in the number or proportion of the elements that make up the substance.
  4. The conservation of matter: matter is neither created nor destroyed – it just becomes a different sort of substance.
  5. Measure the weight of everything that goes into a chemical reaction and everything that comes out of it, even the air.

Much of this is now common sense, but it was not in the 1700s. It was Lavoisier who made it so.

With this approach Lavoisier was able to tell which ideas were true and which were false.

One of these false ideas was phlogiston. For over a hundred years science said that things burned because they had phlogiston. Wood is full of phlogiston, which is why it burns so easily. The ash that is left over after the wood is burned has no phlogiston. It has been all used up. That is why you cannot burn ashes.

Lavoisier disproved phlogiston. He heated different kinds of metal inside closed containers until they started to burn and change. When he measured the weight of the containers before and after, there was no change. But the burned metal was now heavier. Instead of losing phlogiston, whatever that is, something from the air must have been added to the metal.

For most this put an end to the idea of phlogiston.

In 1789 he came out with his “Elements of Chemistry”, one of the great works of science.

But that year the king was overthrown and the country went mad, wanting to kill all the king’s men. Lavoisier was one of the king’s men. In 1794 they sent him to the guillotine and cut off his head.

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Priestley

Joseph Priestley (1733-1804), a British scientist, discovered oxygen. He was the first to make and drink soda water, which soft drinks are now made from, and the first to call that stuff that comes from inside trees in South America “rubber” (because he rubbed out pencil marks with it).

He was a friend of Benjamin Franklin and later moved to America where spent the last ten years of his life. There he became friends with Thomas Jefferson.

The Americans claim him as one of their own and France made him a citizen, but he did all his best work while still in Britain.

He favoured both the Americans and the French in overthrowing their kings. This made him hated in Britain, which still believed in kings. His house was burned down once. He was very forgiving about the whole thing, but thought it best to spend his old age in America.

As part of the Lunar Society, which met on the night of the full moon, he knew James Watt and Erasmus Darwin, grandfather of Charles Darwin. He also belonged to the French Academy of Sciences even before he discovered oxygen.

He discovered oxygen in 1775. He was not the first: as he later found out, Scheele in Germany had beat him by a few months. But Priestley gets the credit because he made it public first.

He made oxygen by burning mercury till it turned into a red powder and then heated the powder till it turned back into mercury. The stuff that came out of the red powder into the air made wood burn brighter and made mice move and jump more. He found out the same stuff was coming from plants.

Priestley thought that breathing oxygen would become a fashionable vice among the rich.

Priestley did not call it oxygen, a name we get from Lavoisier. He called it dephlogisticated air because it had no phlogiston.

For over a hundred years science said that things burned because they had phlogiston. Wood is full of phlogiston, so it burns easily. Dephlogisticated air, said Priestley, lacked phlogiston and so took it up readily from things that were burning. This made them burn more strongly.

Priestley did not make a living from science. No one did before the late 1800s when German universities started hiring scientists. Science was just something he did on the side. He worked as a Unitarian minister.

Unitarians are Christians who do not believe in the Holy Trinity. They follow the teachings of Jesus but do not think he is divine. It was the latest thinking in those days and some thought that America would become Unitarian by 1900.

It suited Priestley who thought for himself and was up on all the newest ideas.

Priestley never studied science at university: he studied philosophy and languages. He knew Hebrew and Arabic. It was Benjamin Franklin who later got him interested in science. Franklin was in Britain trying to prevent the coming war between America and Britain.

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Herschel

Sir William Herschel (1738-1822) was a German-born British scientist who discovered Uranus, the first planet discovered since ancient times. He also discovered two moons of Uranus (Oberon and Titania) and two moons of Saturn (Mimas and Enceladus).

We take new discoveries in science for granted. We expect to read about a new one every few months in the newspaper. But in the 1700s people thought Newton was the last word in science, that everything had been discovered already. Uranus was a breath of fresh air.

Herschel was the greatest astronomer of his day. He became that by making the best telescopes in the world and studying every single part of the night sky with them, not knowing what he would find there.

He came to England from Germany at age 19, not wanting to fight in the German wars, even though his father was in the army. Instead he taught music in the English town of Bath.

He taught himself Latin and Italian and read Newton’s book on optics, about how glass lenses bend light. He started making lenses of his own and then, in the 1770s, telescopes. He brought over his sister Caroline from Germany and she helped him.

One by one he looked at each star in the sky with his telescope. Then in 1781 he came upon a star that was not a star. It was a small little circle of light.

At first he thought it was a comet, but when he and Laplace worked out its orbit, they found out it circled the sun beyond Saturn. It was a planet like Saturn!

You can see it with the naked eye if you know where to look. It looks like a very faint star and had been appearing on star maps, but it moved so slowly no one knew it was a planet. Not till Herschel.

He named it George’s Star, after the king. Others called it Herschel. Someone else named it Uranus, after Saturn’s father. That is the name that caught on.

Herschel thought there was life on the other planets, even on the sun. He did not think the sun was a huge ball of fire like we do: he thought its clouds were on fire, that sunspots were holes through the clouds where you could see a world below.

He tried to find out how far away the stars were but had no luck. But he did find out that the sun is moving among the stars. It is headed for the constellation of Hercules.

He also found out that the sun is in a huge wheel made of stars, what we now call the Milky Way Galaxy. He saw other such wheels of stars through his telescope, other galaxies, very far away.

Uranus takes 84 years to go round the sun. When it returned to the place where it was when Herschel was born, he died.

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Tycho

Tycho Brahe (1546-1601), a Danish nobleman, was one of the greatest astronomers of all time. Before Tycho’s time only Hipparchus was better. Tycho tried to prove Copernicus wrong but his work, continued by Kepler after his death, only proved Copernicus right once and for all.

Copernicus said that the planets went round the sun. Ptolemy said they went round the earth. Tycho said something in between: yes, the planets went round the sun, but the sun went round the earth!

Tycho turned to astronomy when he saw an eclipse while at university. He once got in a fight there in the middle of the night over a point of mathematics. He lost his nose and later got a metal nose made to put in its place.

Although he was a nobleman who was often full of himself, he did fall in love with a simple country girl and married her.

In the universities they taught Aristotle: the earth was the centre of the world, a place of endless change, but the heavens above the moon were perfect and unchanging. What about comets? Aristotle said they were below the moon, part of the earth’s weather.

Tycho proved the heavens were anything but unchanging. He became famous when he found a new star that was not there before. It was called Tycho’s star (we call it a nova). It soon became brightest star in the sky.

Tycho also proved that comets were not part of the weather but farther than the moon. By gathering observations from different parts of Europe he could tell that its position in the sky against the stars changed less than the moon’s, meaning it was farther away.

The king built an observatory for Tycho on the island of Ven in between Denmark and Sweden. There Tycho studied the stars with the best instruments in the world. He carefully recorded the motion of the sun and the planets. His measurements were five times better than anything ever made. He even took into account the effects of the air and the limits of his own instruments. He wanted to prove Copernicus wrong.

Tycho wrote a letter to Galileo and told him that if Copernicus were right, then we should be able to measure how far away the stars were. Galileo had no answer for that. What neither of them knew was how unimaginably far away the stars were.

When the king died Tycho had to leave the island. He travelled to Prague. There he met Kepler. Kepler knew what a gold mine Tycho’s tables of numbers were. He promised Tycho to continue his work after he died and prove Copernicus wrong once and for all.

Kepler did continue his work, but in the end he had to admit that Copernicus, with a few changes, was right after all.

Later in the 1600s Tycho’s old observatory was burned down by war. Riccioli, who named the craters of the moon, named the brightest one Tycho in his honour.

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Hipparchus (190-120 BC) was the greatest astronomer of ancient times. He took astronomy almost as far as it would go before the invention of the telescope.

Ptolemy is more famous but most of his astronomy is warmed-over stuff he got from Hipparchus, whom he called a great “lover of truth”.

A Greek from Nicaea, Hipparchus lived on the island of Rhodes where he studied the sun, the moon and the stars.

Hipparchus was the first to find out how far away the moon is. In order to work out the answer, he came up with a new field of mathematics: trigonometry.

Hipparchus made the best star map of ancient times, with some 2000 stars.

It was so good that his practice of using latitude and longitude has been used to map the heavens and the earth ever since.

It was so good that it had Uranus on it, a planet that was not discovered till 1900 years later.

It was so good that he discovered the precession of the equinoxes: that the sun does not appear in quite the same position on the first day of spring every year. Instead it moves backwards against the background of the stars, going all the way round in 26,700 years.

He started his map in 134 BC after seeing a new star in the constellation of Scorpio. He thought it was new, but could not be sure. He checked the star maps of Eudoxus and Erastosthenes. They did not have the star, but then he saw how bad their maps were. So he made his own.

The Greeks thought the heavens were perfect and unchanging, so finding a new star was a serious matter.

Hipparchus was the first to measure stars by their brightness. The 20 brightest stars he called first magnitude stars, the next brightest stars he called second magnitude and so on.

Most of what you see in Ptolemy comes from Hipparchus. Those circles within circles (the epicycles) and even most of the numbers. Hipparchus put the earth in the centre because that is what the best science of the day said: Aristotle’s.

The earth-centred model of Hipparchus was so good at working out where planets would be on any given day that few doubted it.

His model was just that: a model. But it worked so well that most mistook it for the truth.

Hipparchus and many others knew that Aristarchus had put the sun in the centre, but it went against common sense (the earth does not seem to be moving), the best science (Aristotle) and, besides, no one had worked it up into a model as good as that of Hipparchus. Not Aristarchus, not even Copernicus himself over 1600 years later.

Hipparchus was not overthrown till the 1600s when Aristotle was overthrown by Newton. And not until Kepler made some changes to the model of Copernicus.

All but one of his books is lost. Most of what we know of his work comes through Ptolemy.

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Archimedes

Archimedes (287-212 BC) was a Greek mathematician from Syracuse, Italy, back when the city was still Greek. He was one of the greatest minds of the ancient world. He gave us the word “Eureka!” and worked out how levers work, but most of all he showed us how you could use numbers to do science.

His use of numbers in science did not catch on in his own time, but it did later when his writings came out in Latin in 1544. Galileo read them and used the same approach, which led to the rise of Western science and our faith in numbers.

Even today Archimedes is worth reading because of how sees and understands the world through number and shapes, through geometry.

He used number and measurement to work out how levers work and how strong they are in different cases. From this he knew there was no limit to what they could do. He said he could move the whole world if he had a place to stand.

Archimedes worked out pi to two places: 3.14. He knew it was somewhere between 3.141 and 3.143.

The word “Eureka!” comes from the time when the king asked Archimedes to find out whether his crown was made of pure gold.

Gold was the heaviest metal known in those days: for a given size, nothing else was so heavy.

The easy way to find out if the crown was pure gold would be to melt it down to a block and compare it to a block of pure gold of the same weight. If the melted down crown was larger, then something was added to the gold. It was not pure.

But Archimedes could not destroy the crown. So he had to find out how much space it took up some other way.

But how?

One day as he was getting into his bath he saw the water flow over the sides.

When he saw that he jumped out of his bath and ran through the streets naked shouting “Eureka! Eureka!”, which is Greek for “I have found it! I have found it!”

Meaning he had found out how to measure the size of the crown: by putting it in water and seeing how much water it pushes out. The water it pushes out had to be the same size as the crown.

Archimedes found out the crown was not made of pure gold and the king put the goldsmith to death.

Later the Romans made war on Syracuse for siding with Carthage. To defend the city Archimedes came up with different inventions, like one that turned over ships. It came from his work with levers. The Romans grew to fear him.

When Syracuse was falling, Archimedes was drawing circles in the sand, working on something in geometry. He asked a Roman soldier not to mess up his circles. In spite of orders to take him alive, the soldier killed him.

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Thales

Thales (640-562 BC) was the first Greek philosopher and scientist. He was the first to try to find out how the world works through observation and reason, not through old stories about the gods.

Thales said everything comes from water in the end, just as we say everything is made of atoms in the end.

He was wrong about the water bit, but that style of thinking, of looking for a root natural cause of everything, is still with us and it started with him.

He was on everyone’s list as one of the seven wise men in ancient Greece. So was Solon, the great lawmaker of Athens, who lived at the same time across the Aegean sea. We still have a letter that Thales wrote to him.

Thales was the first to say “Know yourself”. He said it was the hardest thing in the world to do. The best way to make yourself better is to avoid the faults you see in others. Time was the wisest thing of all because it brought all to light.

But Thales was less interested in men than in the stars. He was the first Greek to know when an eclipse would take place. He said there would be one on May 12th 585 BC. On that day, right in the middle of a battle, the moon covered the sun just like he said it would. It made him a wonder in the Greek world.

He wrote little. We know of only two books, both on the motion of the sun: “On the Solstices” and “On the Equinox”. Both are lost.

Perhaps he wrote so little because he was too busy going all over the known world to learn all he could. He went to Crete, Egypt, Asia and throughout the Greek-speaking world.

Although to the Greeks he seems to have made great discoveries about the sun, the moon and the stars, it is likely that he “discovered” most of them not in the skies but in talking to the priests of Egypt, who even then had records going back thousands of years.

Even so Thales did not find philosophy and science being practised anywhere in the world. They are his invention. He certainly did not find it in Egypt, a land ruled by priests.

Thales came from Miletus, a town Athens settled on the other side of the Aegean sea. It was then a part of Ionia, which ran down the west coast of what we now call Turkey. It produced most of the early Greek thinkers, even Pythagoras who later moved to Italy. Athens did not become the centre of Greek thought till 200 later in the time of Plato and Socrates.

He once measured the height of a pyramid: he waited till his shadow was as long as he was tall. Then he measured the shadow of the pyramid.

Some say he died by falling into a hole while looking up at the stars.

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Chomsky

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Chomsky in 2011

Noam Chomsky (1928- ) is an American intellectual. Along with the likes of Cicero and Marx, he is one of the authors most cited by university professors. He has written many books on the nature of language and the evils of American power abroad.

In the 1950s he helped to make the study of language into something more like a real science. He studied English syntax – the rules English has for putting words together in a certain order. But he was not so much interested in English as in the nature of language itself and what it can tell us about the inner workings of the human mind.

He pushed beyond the mere rules of English to the deeper rules that govern every language in search of the universal grammar. Such a universal grammar, he said, could not be universal unless it was built into the human brain from birth.

This has set him against fashionable thought in two quarters.

First, against those who think they can build a computer that possesses more intelligence than man. Both computers and languages work by applying a set of rules. But the rules a computer can apply are much simpler than the sort that govern human language. That means that no matter how much memory or power you give a computer, it can never match the human mind. Its design is too simple for that.

Second, it put Chomsky against left-wing thinking about human nature. Although Chomsky himself is a leading intellectual on the left, he thinks that much of what makes us human is built into the brain – it is not largely a matter of upbringing and education as most on the left believe.

Chomsky is good at following a line of argument to the bitter end, using reason alone where most are guided by received wisdom instead.

He applies this style of thinking to everything, including foreign affairs and the use of American power abroad. He believes in democracy as well as world justice as the equality of nations: America should not do unto other countries what it does not want to have done unto itself. When America breaks this rule, as it often does, he calls it immoral.

Such talk delights those who hate America, like Hugo Chavez and Nasrallah.

Chomsky is not only against the war in Iraq, he was even against the American war in Afghanistan after 9/11. In the 1960s he was against the Vietnam war. He is also against Israel, even though he is Jewish.

He reads the New York Times, the Guardian and other such newspapers, but he reads between the lines, noting what is not being said as much as what is. He even has a propaganda model to account for what gets reported.

His writing style is dreadful. While it is the common style among American professors, you would think he would know better, with his understanding of language. Nevertheless, you are willing to make your way through it because his arguments are good, sometimes even surprising.

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Darwin

Charles Darwin (1809-1882) was a British scientist who discovered the theory of evolution by natural selection, explaining the history of life on earth. He wrote about it in the “Origin of Species” (1859) and the “Descent of Man” (1871).

The Bible says God created the species – all the kinds of plants and animals. Darwin said no: all life belongs to the one large family, each branch developing or “evolving” into different creatures. Over time fish came from worms and men from monkeys. His theory shook – and still shakes – the West.

The son of a rich family, Darwin went to Cambridge but he had no direction in life. The only thing he seemed to love was nature, especially beetles. Then he heard the HMS Beagle was about to sail round the world. Darwin signed up.

Along the way they came to the Galapagos islands. Each island had its own kind of finch. Yet they were all similar to the same bird found nearby in South America. How did this happen? Did God create a finch for each island? If not, how did they change or evolve for each island?

On the ship Darwin read Charles Lyell’s “Principles of Geology”. Lyell said that the mountains, the rivers and so on were not created suddenly, either by God or some sudden natural calamity. Instead everything was created bit by bit, by slow, everyday change that is still going on.

This is called uniformitarianism. It makes for great science: Science is not about one-off changes like acts of God but about what can be observed to happen over and over again.

So Darwin thought that if the finches had changed for each island, it was a slow change that was going on all the time right under his nose. But what was it?

One night years later when Darwin was back from sea he read a book by Malthus. Malthus said that more children are born than can be fed, so some die, chiefly among the poor.

That was it: too many finches are born. Only those best suited for the island would live long enough to give birth to the next generation. Over time the fit would multiply and the unfit die out. That is how each island got its own finch. That is how evolution happened. No acts of God were required.

For over 20 years Darwin kept the theory to himself and some close friends. But then one day Darwin got a letter from Alfred Russell Wallace. Wallace had also sailed around the world, he had also read Malthus and he had also come up with the same theory. He asked Darwin what he thought of it.

This forced Darwin’s hand. In 1858 they jointly made the theory public. A year later Darwin explained the theory in his book, the “Origin of Species”.

The theory destroyed Darwin’s Christian faith, but not Wallace’s. Wallace did not see how evolution could explain man, especially his mind. Darwin thought it could and wrote about it in the “Descent of Man”.

Darwin died rich and famous but without hope of heaven.

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Einstein

Albert Einstein (1879-1955) was one of the top minds in physics in the 1900s, if not since Newton himself. He was widely regarded as the definition of genius. His theories in physics made possible the atom bomb, which can destroy a whole city in a moment. He was a kindly, humble man who rarely combed his hair and often had a sad look on his face.

Einstein discovered the theory of relativity. He came out with it in two parts: special relativity in 1905 and general relativity in 1915.

He came up with his theory while riding the train to work at the patent office in Berne, Switzerland. He looked at the town clock and wondered what would happen if he moved away from it on a beam of light. He asked the kind of simple questions a child would ask. But then he would tirelessly follow the physics and the numbers to the breaking point till he found the answer.

The most famous bit of his theory is this:

E=mc²

This means that matter (m) can be converted into energy (E). Energy is the force needed make something move faster or change its course. The c is for how fast light moves. In an atom bomb matter is converted into energy at an incredible rate. Which is how such a small thing can destroy a city. It is also how the sun and the stars shine.

The theory also says that nothing can move faster than light. And as you move faster time slows down. But for time to slow down by a lot, you need to be going almost as fast as light itself.

This leads to the Twin Paradox: one twin stays on Earth while the other goes to the stars in a ship that moves almost as fast as light. When he gets back from the stars he will find that his twin brother is much older than he is. Because what had seemed like months on the ship was years on Earth.

Just as matter and energy are two sides of the same coin, so are space and time. Gravity, which we know as the force that pulls things down to earth, is a fold in space. The gravity of the earth is like a deep well in the structure of space.

When the second world war broke out in 1939 Einstein knew the Germans could use his theories to build an atom bomb and win the war. He wrote a letter to President Roosevelt to tell him the horrible news. Taking no chances America built the bomb.

When Einstein died they burned his body but kept his brain. His genius had become a legend by then. But when they looked at his brain, it seemed completely ordinary. Years later, however, when they knew more about brains, they noticed that the part that thinks about space and number is larger than most people’s. He was probably born that way.

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Rene Descartes (1596-1650) was a French philosopher. In Latin his name is Renatus Cartesius, from which we get the word “Cartesian.” He moved Western philosophy beyond Aristotle, created analytic geometry by applying algebra to geometry and was a leading light of the new science.

Descartes is the one who said “Cogito, ergo sum”, Latin for “I think, therefore I am”.

Descartes said that if you really want to know the truth, then at least once in your life you must doubt everything. From this universal doubt he knew that he existed because he doubted! “I think, therefore I am.” From there he proved that God exists, using the proofs of Anselm and Aquinas. But God would not deceive us, therefore we can trust our senses too. And so on.

Descartes reasoned from truths he could not doubt to new truths and then reasoned from these new truths to derive yet other truths and so on through a process of deduction.

Descartes did to philosophy what Euclid had done to geometry, building it from the ground up. So had Aristotle, but Descartes was far more thorough. It was quite unlike Bacon’s science by induction.

Descartes founded the school of rationalism. It said that man’s knowledge is based on reason and certain inborn ideas. This was later opposed by the empiricism of Locke.

Descartes saw the body and all of nature as matter in motion, as moving parts working together. The human mind, on the other hand, was something completely different. The mind was not material, it was not an ordinary part of nature. You could not see it or touch it. We only know about minds because we all experience them.

This is known as mind/body dualism, where the world is divided into mind and body. Most philosophers in the English-speaking world see it as a false distinction.

Descartes wondered where the mind was connected to the body. So he cut open dead animals and he cut open dead men and looked. Only man had a pineal gland, so he thought that was it. Years later, however, the pineal gland was found in other animals.

Descartes was a pious Catholic and, like Galileo, saw himself as helping the Church into the new age of thought. The Church did not see it that way.

While Descartes was writing his master work on science, “Le Monde”, the Church condemned Galileo for teaching the theory of Copernicus as true. That is just what Descartes had done in “Le Monde”! He stopped writing the book and never put it out. Instead he came up with his theory of vortices. It had some following till Newton proved Copernicus right once and for all.

In 1649 he went to Sweden to teach philosophy to the queen. The cold was too much for him and he died of pneumonia a year later.

His best books:

  • Discourse on Method (1637)
  • Meditationes de prima philosophia (1641)
  • Principia philosophiae (1644)

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Ptolemy

Claudius Ptolemy (about 100-170) of Alexandria is the inventor of the Ptolemaic system, a theory of the heavens that said the stars, sun, moon and planets went round the earth. The earth did not move, it did not even turn. In the early 1600s this was replaced by the theory of Copernicus and Kepler that held that the earth and everything else went round the sun.

Ptolemy also wrote about music, astrology, optics and geography. He was among the first to apply trigonometry to science.

He wrote about his theory of the heavens in the “Almagest” (150) and other works. With it you can get the position of the sun, moon and planets on any given day, past, present or future.

Ptolemy built his theory on 25 years of his own observations and the work of Hipparchus — and probably the work of others (now lost).

The Almagest is a work of genius and beauty that stood for over a thousand years, but it is hardly perfect:

  • We now know some of his observations were made up.
  • It contains arithmetic errors that just happen to let his proofs come out right.
  • It was based on Aristotle’s physics, some of which was easy to prove wrong if anyone took the trouble to check it out against the real world. Someone finally did: Galileo.

Ptolemy takes Aristotle’s physics as a given and then comes up with a theory that fits both Aristotle and his observations.

The root trouble with his theory is not what you think – where he put the earth – but his use of circles.

According to Aristotle heavenly bodies were made up of something called quintessence. Quintessence, being perfect moved in perfect circles. Aristotle said that was the perfect motion.

And so Ptolemy manfully stuck to circles. But to get his circles to match his observations, he needed circles within circles – the dreaded epicycles.

Planets move in stretched-out circles called ellipses, as Kepler later found out. It is not that Ptolemy could not do ellipses – it was just the sort of thing he was good at. It was his physics that held him back.

Copernicus used circles and epicycles too, so he was not that much better. It was not till the work of Galileo, Kepler and Newton that Copernicus’ theory won the day. Galileo proved it true, Kepler made it usable and Newton provided the physics.

Astrology: Ptolemy believed that the movements of the heavens affect us. In his book “Tetrabiblios” he shows how in terms of Aristotle’s physics.

Geography: his book on geography was not known in the West till 1300. In it he gives the latitude and longitude of over 8000 places from Spain to China, making possible a detailed map of the world as it was known in Alexandria in his day. It is from Ptolemy that we get the idea of north being “up.”

Ptolemy knew the earth was round but thought it was smaller than it really is. That is why Columbus thought that he could easily get to Asia by sailing west across the ocean.

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