## Monday, 27 September 2010

### What Makes You So Special?

[Edit. This article has now been greatly expanded into my book, What Makes You So Special? : From the Big Bang to You, available in paperback or ebook for Kindle]

Bear with me a while because yours is a long story but it's a story very much worth telling.

About 13.7 billion years ago the universe came into existence as a singularity. We know this because the universe is expanding in all directions at a measurable rate. Projecting this backwards leads to a time when the entire universe occupied a single point of nearly infinite density; a black hole or singularity.

We also know that time and space are part of the universe and do not exist independently of it, so there is no sense in which we can talk of where and when this singularity occurred in some pre-existing space-time dimension.

Quantum mechanics tells us that a single particle takes all possible paths through space-time. What we see as a wave is the resultant sum over histories for that particle. The shape of the wave is the probability distribution of that particle occupying any single point in space-time.

So it was for the singularity. It was not a single universe which came into existence but all possible universes, each with its own set of initial conditions – what scientists call quantum foam.

Some of these universes would have decayed immediately; some may have existed for a few milliseconds; some maybe for longer, and some, like our universe, would have had initial conditions which allowed it to expand rapidly under the outward pressure of forces from which gravity had been stripped.

We know that there is a minimum unit of space, (the Planck length). There is also a minimum length of time (the Planck time) 10-43 seconds (10 to the power of -43 or 0.0000000000000000000000000000000000000000001 of a second). This means that immediately the universe came into existence it was already 10-43 seconds old. This time, for our universe, was enough for gravity to be stripped off from the other three forms of energy – weak and strong nuclear forces and electromagnetic force – which are the forms of energy of which, in one manifestation or another our universe is composed.

Why did all this happen? Why did quantum foam form in the first place and so a universe in which we can ask questions arise? The answer need be nothing more complicated than a quantum fluctuation. At the quantum level there is no such thing as an absolute; all things fluctuate within a range of probabilities which is actually unbounded. At the quantum level all possible events will occur. If it is possible it WILL happen. And of course, in order for us to be asking these questions in the first place there MUST be a universe in which to ask them, and this universe MUST be capable of containing intelligent life capable of asking such questions.

In this universe all observations confirm that gravity is equal to the sum of the other three forms of energy and that, if gravity is the opposing form of the other three, the grand total of energy in the universe is zero. In total energy terms the universe is nothing.

And here we have answered three question which are often thrown at science by those who have never tried to understand it; by theologians and philosophers who struggle to understand why there is a universe instead of nothing, how a universe could come from nothing and why it appears to be 'fine tuned' for the existence of life.

Quantum foam explains all these things and removes any gaps in which those seeking to include one in the explanation can fit their favourite god. There is no need for a 'prime cause' and so no need for a prime causer.

Creationists may wish to breathe a huge sigh of relief at this point because it removes the obligation on them to explain the origins of their assumed creator without invoking a sub-prime cause, ad infinitum, so rendering absurd their prime cause hypothesis. Something which has caused them huge embarrassment and lead to all manner of increasingly ludicrous attempts to work around the problem and still retain the prime-cause hypothesis whilst simultaneously destroying it.

But let's leave creationists to come to terms with the destruction of their favourite hypothesis and the simultaneous relief from the embarrassment of it. Your story now moves on to what happened to all that energy which was made available.

About one ten thousandth of a second after the Big Bang, energy was electromagnetic radiation in the form of high-energy photons. At this stage the universe’s density would have been about a hundred trillion times as dense as water with a temperature of about 1 trillion degrees Celsius. In these extreme conditions, photons would have been moving with enormous energy but would hardly travel any distance before smashing into each other. The collision force would have been enough to create more elementary particles such as neutrons which would then have been smashed again to produce protons and electrons. But things were changing rapidly.

When the universe was just one second old its density had fallen to about 380,000 times that of water, its temperature was down to about ten billion degrees. The number of neutrons now being destroyed exceeded the number being created since photons were still powerful enough to smash them but lacked the energy to create new ones.

At about three minutes old the temperature was down to about a billion degrees (seventy times as hot as the sun) and the rate of change was also slowing.

If the universe had remained in that state for just a few more minutes, all the neutrons would have decayed to protons and electrons, and that would have been that. In some of the universe’s histories in the quantum foam, this is indeed what will have happened, but in this particular history, the one in which we live and ask questions about its origins, and maybe in an unknown number of other histories, the temperature cooled enough for some neutrons to stick to protons to form helium nuclei (or alpha particles). Neutrons had become stabilised and your universe entered its next phase.

We were just a few minutes away from never having existed!

This phase lasted for several hundred thousand years during which it was still too hot for the electrons to stick to the protons and alpha particles to form atoms. Instead they were free to zig-zag about in the expanding and slowly cooling universe, interacting with the electromagnetic radiation which still filled the universe. This final phase of the Big Bang continued until the next major change which occurred some 300,000 to 500,000 years after the beginning when the universe had cooled to a mere 6,000 degrees, or about the same temperature as the surface of the sun. At this temperature, negatively charged electrons become captured by positively charged protons and alpha particles to form electrically neutral atoms of hydrogen and helium respectively. Your universe had given birth to atoms.

The birth of atoms marks the end of the Big Bang and the beginning of atomic matter as we know and understand it. Moreover, since these neutrally charged particles hardly interact with electromagnetic radiation, the universe had become transparent. Photons were now free to stream almost uninterrupted through the universe and atoms were free to clump together under the influence of their own gravity, undisturbed by photons continually stirring them up and knocking them into different paths so ensuring a chaotic distribution of atoms. So clouds of gas could form in an otherwise amorphous universe. The universe was becoming grainy as centres of gravitational attraction were forming; structure was beginning to form under the influence of nothing more complicated than gravity.

Order was forming out of chaos and the whole process was inevitable. And now we have answered another question frequently asked of science, especially by Creationists pursuing a religious agenda. How did order come from chaos? The answer is quite simple - gravity.

Your story now moves on to the story of stars which are the end-point of collapsing clouds of hydrogen and helium, then the only atoms which exist in your still young universe. Under gravity, the gas clouds collapse and release some of the energy stored up in gravity to produce heat, so the collapsing gas clouds heat up. The rate of collapse increases as more and more atoms of gas are pulled towards the centre and, as more and more mass is added, so the gravity increases.

Clusters of stars form into galaxies of billions or trillions of stars which begin to spiral inwards towards a centre of gravity and, as the rate of collapse increases so the rate of rotation also increases until the centrifugal force tending to push bodies outwards equals the gravitational (centripetal) force tending to pull them inwards. Once again a degree of order is emerging in your universe from the chaos of unevenly distributed balls of collapsing gas clouds. A new structure is inevitably being imposed on the universe by the action of a simple forces on chaos and that force is once again gravity. And a third level or order is also emerging as galaxies form super-cluster.

But your story is still being written in the centres of these young suns. The precise details will depend on the size of the original gas cloud out of which the sun was formed. All suns will follow more or less the same process but what happens at the end of their life, and how quickly that end is reached will vary. Let us take a sun rather like our own in size and about which we know rather a lot and which is known to be a rather average sun. Gravity here has produced a temperature of around fifteen million degrees Celsius and hydrogen nuclei (or protons) are being forced together to form helium nuclei and releasing energy as they do so in a huge nuclear fusion reactor.

This process will continue until the star has used up all the hydrogen in its core, where the temperature is hot enough for the fusion reaction to proceed. At that point, with no energy being produced and so nothing pushing the helium outwards, the core will undergo a further collapse forcing helium atoms to fuse together to form carbon, and the temperature will rise to one hundred million degrees Celsius. The outer layer will swell enormously and dim so that the sun will become a red giant.

Eventually the helium supply will run out too and, in a final cataclysm, the core will collapse in one more time and carbon atoms will fuse to form larger atoms in a final, short-lived burst of activity, and a release of energy so violent it will force the sun to fly apart to form a super nova, the products of its reactor being thrown out into space to form interstellar dust and, together with hydrogen and helium, a new cloud out of which second generation suns will form, but clouds which now containing heavier elements than the hydrogen and helium out of which first generation stars were formed.

Not all suns have this ending. If they are large enough they will continue to collapse under their own gravity eventually forming a singularity with a gravity field so powerful that not even photons can escape it. They will form black holes and, at that local level, gravity will have regained control and that part of the universe will again be nothing. And it will be a suitable place for another quantum foam of universes to arise, each with its own space and time existing outside our universe.

Some stars may be too large to form red giants and supernovae and too small to become black holes. These will collapse to a density in which all atoms again break down and all electrons and protons are forced together to form neutrons. The neutron stars.

But your story continues not in a super-massive star destined to be a black hole or a massive star destined to become a spinning ball of super-dense neutrons. Your sun is a second or maybe third generation sun. It was formed from a collapsing cloud of gas and interstellar star dust formed in earlier suns and containing the elements with which you will be made; the carbon, nitrogen, sulphur and oxygen in your proteins; the iron in your blood, the phosphorus and calcium in your bones; the sodium and potassium in your cells. You are made of stardust, formed in nuclear fusion reactors and exploding supernovae out of the elementary particles formed out of pure energy during the Big Bang.

But we still have a few chapters of your story to tell. Your story now moves to the formation of this solar system centred on a rather ordinary star in an outer arm of an unremarkable galaxy in a cosmos containing perhaps a trillion galaxies each with maybe a trillion suns. This chapter begins about 4 billion years ago by which time the universe was about 10 billion years old.

 Relief Map of the Moon Showing Impact Craters
As the rotating cloud of gas and dust collapsed to form a new sun, the heavier elements would have been thrown outwards again as the nuclear fusion machine switched on. These would have formed a disc of debris consisting of atoms and molecules of heavier elements which would have begun to condense around stable centres orbiting the sun – a so-called accretion disc. Radiant energy from the sun would have driven the lighter gasses further out so that the outer planets are gas giants consisting mostly of gases with a rocky core and the inner planets are rocky. The accretion process was by no means a steady gradual process but, as clumps of matter grew larger so the impacts of accretion grew larger. On bodies like the moon and Mars with their stable outer layers, we can see the craters which resulted from the impacts of large bodies such as asteroids.

One collision involving Earth early in the life of the solar system was with a very large object, possibly a small planet, which tilted Earth on its axis of rotation and threw enough material out of Earth's gravity to give rise to a small accretion disc of its own. The relatively large Moon was formed out of this debris. For all practical purposes the Earth and Moon form a twin planet, formed out of the remains of these two earlier planets.

This event had huge significance for your story. The tilt of Earth’s axis has produced seasons and the close proximity of another relatively large body has produced tides. It is probable that both these contribute to Earth being a suitable place on which life could exist. But we still have another chapter in your story to tell.

About 3.5 billion years ago, on this little planet orbiting a very ordinary sun situated on an outer arm of a very ordinary galaxy, something quite extraordinary happened. We don’t know exactly how, though we have several theories, and we don’t know if it was unique. It might well have happened on other planets in other galaxies maybe a trillion times but, as the distances between galaxies and even across galaxies are so vast, we may never find out.

Here on our tiny bright blue dot, a replicator arose. A replicator is a chemical which can produce copies of itself. We don’t know exactly what the first replicator was; one theory is that it may have been crystalline structures in clay; another is that it may have been ribonucleic acid (RNA). It is generally agreed that RNA came into it fairly early on, maybe from the outset, maybe riding on the back of some other chemical in an evolutionary process in which those replicators better at replicating will produce more descendants. There are still some organisms like viruses which depend on RNA and RNA is certainly still involved even where the main genetic material is deoxyribonucleic acid (DNA). However this replicator started, it seems to have fairly quickly evolved into a DNA-based one.

For a general outline of what probably happened, see How Did Life Originate.

Each of your cells, with the exception of your red blood cells, contains DNA which contains all the instructions for making you and making the protein enzymes which control your body’s metabolism. DNA is organised into genes which carry instructions. Without going into detail (whole books are devoted to how DNA works as a store for information and how it is organised into genes, but the details are very well understood), these genes are the basic building blocks of life and are the replicators which carry your information from your parents, through you and into your children. Your story is the story of your genes which, over billions of years have built survival machines for replicating themselves through time. You are a gene survival machine with a body superbly fashioned to survive and reproduce and so pass on your genes to the next generation.

Consider again that dot. That’s here. That’s home. That’s us. On it, everyone you love, everyone you know, everyone you ever heard of, every human being who ever lived, lived out their lives. The aggregate of all our joys and sufferings, thousands of confident religions, ideologies and economic doctrines, every hunter and forager, every hero and coward, every creator and destroyer of civilizations, every king and peasant, every young couple in love, every mother and father, every hopeful child, every inventor and explorer, every teacher of morals, every corrupt politician, every superstar, every supreme leader, every saint and sinner in the history of our species, lived there on a mote of dust, suspended in a sunbeam.

Carl Sagan
Replicators are very good at replicating but occasionally they produce slightly different copies of themselves and these slight differences give rise to slight variations between individuals. Some of these will make the individual less fitted to survive and some will make it more fitted; the vast majority however will make no noticeable difference as they take place in the accumulated redundant DNA which all organisms contain.

Where the variation makes a difference, however, the environment will determine whether it gives an advantage or a disadvantage, or, in fact makes no difference in terms of success, even where there is a difference. It will tend to select for individuals carrying genes which make it more able to survive and against those less able. Those which tend to survive will tend to produce more descendants, in that environment, and those descendants will inherit the advantageous genes. Natural selection acts like a sieve at each generation tending to filter out those characteristics which act against survival and allowing through those which enhance it. In this way the gene pool of a species tends to adapt to its local environment and, where the gene pool is split amongst several different environments, tends to produce diversity. Diversity will eventually lead to speciation if separation is maintained for long enough.

So what does this mean for you and your story? You are the end-point of your own genes' evolution. You are the descendant of survivors, each of whom bred successfully and never once failed – for 3.5 billion years!

Think about that for a moment. In a world in which, for very many individuals, an early death and failure to breed were by far the most likely outcome, not one single one of your ancestors failed to produce at least one offspring. If they had failed, your gene-line would have ended there and then.

You are the product of billions of passes through the sieve of selection and at every pass your gene-line passed the fitness test. You are good at surviving; and you are unique in the history of the cosmos. The likelihood of you being alive at all is almost vanishingly small and yet here you are. Never before has anyone with your individual combination of genes, your individual collection of atoms and your history existed.

And you never will again.

Your ancestors were there when Europe and Africa split off from the Americas. They were there as small mammal-like reptiles when dinosaurs ruled the earth. They saw pterodactyls flying overhead. They survived the mass-extinction which ended the dinosaurs reign.

Your ancestors swam in the pre-Cambrian seas and crawled out onto the land as early air-breathing fish destined to become land-based animals. Your ancestors lived through the Carboniferous era when dense forests of tree ferns grew in steaming jungles where dragonflies with meter-wide wings flew. The trees then fell and formed the deposits destined to be coal as the climate changed. They saw the first flowering plants as plants and insects formed their mutual-benefit society.

Your ancestors lived through the first great toxic waste disaster when the blue-green algae produced oxygen and triggered a mass extinction; and they learned to turn it to their advantage by evolving aerobic respiration.

Your ancestors were bacteria; they were archaea; they may have been the strange Ediacarans which were the earliest known multi-cellular organisms. In almost every one of your cells, in your genes, you carry a record of your evolution, of the entire human evolution story, and of a great deal of the evolution story of every other living thing.

Your journey through space and time has been an adventure of disasters, adaptation, survival and recovery, many, many time you will have been on the brink of extinction - the fate of 99% of all known ancient species - yet your ancestors survived and because they were good at surviving you are here and now.

You will live for a mere flash in the time-scale of the universe but in the vast darkness of the cosmos there can surely be few flashes as bright as your bright spark of consciousness.

Be proud. Be very proud. But at the same time be humbled by the enormity of the events which produced you and the fragility of it all.

Stars died and because they died, you live. You are made by stars out of stardust and in a very real sense, because you are made of the same stuff the universe is made of and are a part of it, there is something even more wonderful about you. Through you, though not just through you, and maybe not just here on this small planet, the universe has gained self awareness and can begin to understand itself. Through you it can stand on the surface of this beautiful little jewel in the cosmos, can look up in awe at itself and think "Wow!"

You’re special. You are unique and you were nearly 14 billion years in the making.

That’s your story. Enjoy it while it lasts.

And please bear in mind also that every other human being; every mammal; every bird, insect, spider, fish, or worm; every plant; indeed, every other living thing, has made the same journey you have made. Each is unique and the descendant of survivors. Each has an unbroken gene-line going right back to the first replicator. They are your relatives. Like you they are part of the whole web of interdependent things we call life on earth.

To end their life will end their gene-line for the first and only time in the history of the universe. Something which has taken nearly 14 billion years to produce and 3.5 billion years to perfect will have been extinguished forever.

Each of them is worthy of respect and each of them deserves the one opportunity to experience life that chance has given them.

Life is too rare, precious and wonderful a thing to take lightly.

## Friday, 10 September 2010

### Reasons to Speak Out [Updated 16-April-2013]

A short collection of writings, poems and other stuff.

First they came...,

When the Nazis came for the communists,
I remained silent;
after all I was not a communist.

When they locked up the social democrats,
I remained silent;
after all I was not a social democrat.

When they came for the trade unionists,
I did not speak out;
after all I was not a trade unionist.

[When they came for the Jews and the Romani
I did not speak out;
after all I was not a Jew or a Roma]

When they came for me,
there was no one left to speak out.

Pastor Martin Niemöller (with additional verse by me)

Introduction to Age of Reason

TO MY FELLOW-CITIZENS OF THE UNITED STATES OF AMERICA:

I PUT the following work under your protection. It contains my opinions upon Religion. You will do me the justice to remember, that I have always strenuously supported the Right of every Man to his own opinion, however different that opinion might be to mine. He who denies to another this right, makes a slave of himself to his present opinion, because he precludes himself the right of changing it.

The most formidable weapon against errors of every kind is Reason. I have never used any other, and I trust I never shall.

THOMAS PAINE

Luxembourg, 8th Pluviose, Second Year of the French Republic, one and indivisible.

January 27, O. S. 1794.

I'll tell you what you did with Atheists for about 1500 years. You outlawed them from the universities, or any teaching careers, besmirched their reputations, banned or burned their books or their writings of any kind, drove them into exile, humiliated them, seized their properties, arrested them for blasphemy. You dehumanized them with beatings and exquisite torture, gouged out their eyes, slit their tongues, stretched, crushed, or broke their limbs, tore off their breasts if they were a woman, crushed their scrotums if they were men, imprisoned them, stabbed them, disembowelled them, hung them, burned them alive. And you have the nerve enough to complain to me that I laugh at you?

Facebook Status following the Boston Marathon Bombing:

Boston. Fucking horrible.

I remember, when 9/11 went down, my reaction was, "Well, I've had it with humanity."

But I was wrong. I don't know what's going to be revealed to be behind all of this mayhem. One human insect or a poisonous mass of broken sociopaths.

But here's what I DO know. If it's one person or a HUNDRED people, that number is not even a fraction of a fraction of a fraction of a percent of the population on this planet. You watch the videos of the carnage and there are people running TOWARDS the destruction to help out. (Thanks FAKE Gallery founder and owner Paul Kozlowski for pointing this out to me). This is a giant planet and we're lucky to live on it but there are prices and penalties incurred for the daily miracle of existence. One of them is, every once in awhile, the wiring of a tiny sliver of the species gets snarled and they're pointed towards darkness.

But the vast majority stands against that darkness and, like white blood cells attacking a virus, they dilute and weaken and eventually wash away the evil doers and, more importantly, the damage they wreak. This is beyond religion or creed or nation. We would not be here if humanity were inherently evil. We'd have eaten ourselves alive long ago.

So when you spot violence, or bigotry, or intolerance or fear or just garden-variety misogyny, hatred or ignorance, just look it in the eye and think, "The good outnumber you, and we always will."

Patton Oswalt, American Comedian

From "Pale Blue Dot"

 Earth is a bright pixel when photographed from "Voyager 1" six billion kilometres out (past Pluto).
From this distant vantage point the earth might not seem of any particular interest. But for us it’s different. Consider again that dot. That’s here. That’s home. That’s us. On it, everyone you love, everyone you know, everyone you ever heard of, every human being who ever lived, lived out their lives. The aggregate of all our joys and sufferings, thousands of confident religions, ideologies and economic doctrines, every hunter and forager, every hero and coward, every creator and destroyer of civilizations, every king and peasant, every young couple in love, every mother and father, every hopeful child, every inventor and explorer, every teacher of morals, every corrupt politician, every superstar, every supreme leader, every saint and sinner in the history of our species, lived there on a mote of dust, suspended in a sunbeam.

The earth is a very small stage in a vast cosmic arena. Think of the rivers of blood spilled by all those generals and emperors so that in glory and in triumph they could become the momentary masters of a fraction of a dot. Think of the endless cruelties visited by the inhabitants of one corner of this pixel on scarcely distinguishable inhabitants of some other corner of the dot. How frequent their misunderstandings, how eager they are to kill one another, how fervent their hatreds. Our posturings, our imagined self-importance, the delusion that we have some privileged position in the universe, are challenged by this point of pale light.

Our planet is a lonely speck in the great enveloping cosmic dark. In our obscurity — in all this vastness — there is no hint that help will come from elsewhere to save us from ourselves…… It is up to us. It’s been said that astronomy is a humbling, a character-building experience. To my mind, there is perhaps no better demonstration of the folly of human conceits than this distant image of our tiny world. To me, it underscores our responsibility to deal more kindly with one another and to preserve and cherish that pale blue dot, the only home we’ve ever known.

The late, great Carl Sagan. (November 9, 1934 – December 20, 1996)

"All that is necessary for the triumph of bad people is that good people do nothing."

(with apologies to Edmund Burke)

No man is an island,
Entire of itself.
Each is a piece of the continent,
A part of the main.
If a clod be washed away by the sea,
Europe is the less.
As well as if a promontory were.
As well as if a manner of thine own
Or of thine friend's were.
Each man's death diminishes me,
For I am involved in mankind.
Therefore, send not to know
For whom the bell tolls,
It tolls for thee.

John Donne 1624

"We do not need magic to change the world, we carry all the power we need inside ourselves already: we have the power to imagine better."

JK Rowling

Finally, brothers and sisters, whatever is true, whatever is noble, whatever is right, whatever is pure, whatever is lovely, whatever is admirable—if anything is excellent or praiseworthy—think about such things.

Philippians 4:8

Dear fellow-unbelievers,

Nothing would have kept me from joining you except the loss of my voice (at least my speaking voice) which in turn is due to a long argument I am currently having with the specter of death. Nobody ever wins this argument, though there are some solid points to be made while the discussion goes on. I have found, as the enemy becomes more familiar, that all the special pleading for salvation, redemption and supernatural deliverance appears even more hollow and artificial to me than it did before. I hope to help defend and pass on the lessons of this for many years to come, but for now I have found my trust better placed in two things: the skill and principle of advanced medical science, and the comradeship of innumerable friends and family, all of them immune to the false consolations of religion. It is these forces among others which will speed the day when humanity emancipates itself from the mind-forged manacles of servility and superstition. It is our innate solidarity, and not some despotism of the sky, which is the source of our morality and our sense of decency.

That essential sense of decency is outraged every day. Our theocratic enemy is in plain view. Protean in form, it extends from the overt menace of nuclear-armed mullahs to the insidious campaigns to have stultifying pseudo-science taught in American schools. But in the past few years, there have been heartening signs of a genuine and spontaneous resistance to this sinister nonsense: a resistance which repudiates the right of bullies and tyrants to make the absurd claim that they have god on their side. To have had a small part in this resistance has been the greatest honor of my lifetime: the pattern and original of all dictatorship is the surrender of reason to absolutism and the abandonment of critical, objective inquiry. The cheap name for this lethal delusion is religion, and we must learn new ways of combating it in the public sphere, just as we have learned to free ourselves of it in private.

Our weapons are the ironic mind against the literal: the open mind against the credulous; the courageous pursuit of truth against the fearful and abject forces who would set limits to investigation (and who stupidly claim that we already have all the truth we need). Perhaps above all, we affirm life over the cults of death and human sacrifice and are afraid, not of inevitable death, but rather of a human life that is cramped and distorted by the pathetic need to offer mindless adulation, or the dismal belief that the laws of nature respond to wailings and incantations.

As the heirs of a secular revolution, American atheists have a special responsibility to defend and uphold the Constitution that patrols the boundary between Church and State. This, too, is an honor and a privilege. Believe me when I say that I am present with you, even if not corporeally (and only metaphorically in spirit...)

Resolve to build up Mr Jefferson's wall of separation. And don't keep the faith.

Sincerely
Christopher Hitchens
Letter to American Atheist Conference, 2011

When the Christian missionaries came to Africa we had the land and they had Bibles.  They taught us to pray with our eyes closed. When we opened them, we saw they had the land and we had the Bibles.

Jomo Kenyatta, first president of post-colonial Kenya.

As you grow up, always tell the truth, do no harm to others, and don't think you are the most important being on earth. Rich or poor, you then can look anyone in the eye and say, "I'm probably no better than you, but I'm certainly your equal."

Harper Lee (Letter to a young fan,07 July 2006)

Once you start asking yourself questions like, ‘How do I really know there is a God?’ you are already on the path to unbelief. During my documentary on St Paul, some experts raised the possibility that his spectacular conversion on the road to Damascus might have been caused by an epileptic fit. It made me realise that I had taken things for granted that were taught to me as a child without subjecting them to any kind of analysis. When you think about it rationally, it does seem incredibly improbable that there is a God.”

Jonathan Edwards, Olympic Gold Medallist, Atheist.
Former Evangelical Christian and presenter of BBC TV religious programmes.

When I became convinced that the Universe is natural-that all the ghosts and gods are myths, there entered into my brain, into my soul, into every drop of my blood, the sense, the feeling, the joy of freedom. The walls of my prison crumbled and fell, the dungeon was flooded with light, and all the bolts, and bars, and manacles became dust. I was no longer a servant, a serf, or a slave. There was for me no master in all the wide world-not even in infinite space. I was free: free to think, to express my thoughts; free to live to my own ideal; free to live for myself and those I loved; free to use all my faculties, all my senses; free to spread imaginations wings; free to investigate, to guess and dream and hope; free to judge and determine for myself; free to reject all ignorant and cruel creeds, all the "inspired" books that savages have produced, and all the barbarous legends of the past; free from popes and priests; free from all the "called" and "set apart"; free from sanctified mistakes and holy lies; free from the fear of eternal pain; free from the winged monsters of the night; free from devils, ghosts, and gods. For the first time I was free. There were no prohibited places in all the realms of thought, no air no space, where fancy could not spread her painted wings; no chains for my limbs; no lashes for my back; no fires for my flesh; no masters frown or threat; no following another's steps; no need to bow, or cringe, or crawl, or utter lying words. I was free. I stood erect and fearlessly, joyously, faced all worlds.

And then my heart was filled with gratitude, with thankfulness, and went out in love to all the heroes, the thinkers who gave their lives for the liberty of hand and brain-for the freedom of labor and thought-to those who fell in the fierce fields of war, to those who died in dungeons bound with chains-to those who proudly mounted scaffold's stairs-to those whose bones were crushed, whose flesh was scarred and torn-to those by fire consumed-to all the wise, the good, the brave of every land, whose thoughts and deeds have given freedom to the sons of men. And then I vowed to grasp the torch that they had held, and hold it high, that light might conquer darkness still.

Robert G. Ingersoll (1833-1899)

To my dearest daughter,

Now that you are ten, I want to write to you about something that is important to me. Have you ever wondered how we know the things that we know? How do we know, for instance, that the stars, which look like tiny pinpricks in the sky, are really huge balls of fire like the Sun and very far away? And how do we know that the Earth is a smaller ball whirling round one of those stars, the Sun?
The answer to these questions is ‘evidence’.

Sometimes evidence means actually seeing (or hearing, feeling, smelling….) that something is true. Astronauts have traveled far enough from the Earth to see with their own eyes that it is round. Sometimes our eyes need help. The ‘evening star’ looks like a bright twinkle in the sky but with a telescope you can see that it is a beautiful ball – the planet we call Venus. Something that you learn by direct seeing (or hearing or feeling…) is called an observation.

Often evidence isn't just observation on its own, but observation always lies at the back of it. If there’s been a murder, often nobody (except the murderer and the dead person!) actually observed it. But detectives can gather together lots of other observations which may all point towards a particular suspect. If a person’s fingerprints match those found on a dagger, this is evidence that he touched it. It doesn't prove that he did the murder, but it can help when it’s joined up with lots of other evidence. Sometimes a detective can think about a whole lot of observations and suddenly realize that they all fall into place and make sense if so-and-so did the murder.

Scientists – the specialists in discovering what is true about the world and the universe – often work like detectives. They make a guess (called a hypothesis) about what might be true. They then say to themselves: if that were really true, we ought to see so-and-so. This is called a prediction. For example, if the world is really round, we can predict that a traveler, going on and on in the same direction, should eventually find himself back where he started. When a doctor says that you have measles he doesn’t take one look at you and see measles. His first look gives him a hypothesis that you may have measles. Then he says to himself: if she really has measles, I ought to see… Then he runs through his list of predictions and tests them with his eyes (have you got spots?), his hands (is your forehead hot?), and his ears (does your chest wheeze in a measly way?). Only then does he make his decision and say, ‘I diagnose that the child has measles.’ Sometimes doctors need to do other tests like blood tests or X-rays, which help their eyes, hands and ears to make observations.

The way scientists use evidence to learn about the world is much cleverer and more complicated than I can say in a short letter. But now I want to move on from evidence, which is a good reason for believing something, and warn you against three bad reasons for believing anything. They are called ‘tradition’, ‘authority’, and ‘revelation’.

The trouble with tradition is that, no matter how long ago a story was made up, it is still exactly as true or untrue as the original story was. If you make up a story that isn't true, handing it down over any number of centuries doesn’t make it any truer!

Most people in England have been baptized into the Church of England, but this is only one of many branches of the Christian religion. There are other branches such as the Russian Orthodox, the Roman Catholic and the Methodist churches. They all believe different things. The Jewish religion and the Muslim religion are a bit more different still; and there are different kinds of Jews and of Muslims. People who believe even slightly different things from each other often go to war over their disagreements. So you might think that they must have some pretty good reasons – evidence – for believing what they believe. But actually their different beliefs are entirely due to different traditions.

I’ll come back to tradition at the end of my letter, and look at it in another way. But first I must deal with the two other bad reasons for believing in anything: authority and revelation.

Authority, as a reason for believing something, means believing it because you are told to believe it by somebody important. In the Roman Catholic Church, the Pope is the most important person, and people believe he must be right just because he is the Pope. In one branch of the Muslim religion, the important people are old men with beards called Ayatollahs. Lots of young Muslims are prepared to commit murder, purely because the Ayatollahs in a faraway country tell them to.

When I say that it was only in 1950 that Roman Catholics were finally told that they had to believe that Mary’s body shot off to Heaven, what I mean is that in 1950 the Pope told people that they had to believe it. That was it. The Pope said it was true, so it had to be true! Now, probably some of the things that Pope said in his life were true and some were not true. There is no good reason why, just because he was the Pope, you should believe everything he said, any more than you believe everything that lots of other people say. The present Pope has ordered his followers not to limit the number of babies they have. If people follow his authority as slavishly as he would wish, the results could be terrible famines, diseases and wars, caused by overcrowding.

Of course, even in science, sometimes we haven’t seen the evidence ourselves and we have to take somebody else’s word for it. I haven’t with my own eyes, seen the evidence that light travels at a speed of 186,000 miles per second. Instead, I believe books that tell me the speed of light. This looks like ‘authority’. But actually it is much better than authority because the people who wrote the books have seen the evidence and anyone is free to look carefully at the evidence whenever they want. That is very comforting. But not even the priests claim that there is any evidence for their story about Mary’s body zooming off to Heaven.

The third kind of bad reason for believing anything is called ‘revelation’. If you had asked the Pope in 1950 how he knew that Mary’s body disappeared into Heaven, he would probably have said that it had been ‘revealed’ to him. He shut himself in his room and prayed for guidance. He thought and thought, all by himself, and he became more and more sure inside himself. When religious people just have a feeling inside themselves that something must be true, even though there is no evidence that it is true, they call their feeling ‘revelation’. It isn’t only popes who claim to have revelations. Lots of religious people do. It is one of their main reasons for believing the things that they do believe. But is it a good reason?

Suppose I told you that your dog was dead. You’d be very upset, and you’d probably say, ‘Are you sure? How do you know? How did it happen?’ Now suppose I answered: ‘I don’t actually know that Pepe is dead. I have no evidence. I just have this funny feeling deep inside me that he is dead.’ You’d be pretty cross with me for scaring you, because you’d know that an inside ‘feeling’ on its own is not a good reason for believing that a whippet is dead. You need evidence. We all have inside feelings from time to time, and sometimes they turn out to be right and sometimes they don’t. Anyway, different people have opposite feelings, so how are we to decide whose feeling is right? The only way to be sure that a dog is dead is to see him dead, or hear that his heart has stopped; or be told by somebody who has seen or heard some real evidence that he is dead.

People sometimes say that you must believe in feelings deep inside, otherwise you’d never be confident of things like ‘My wife loves me’. But this is a bad argument. There can be plenty of evidence that somebody loves you. All through the day when you are with somebody who loves you, you see and hear lots of little tidbits of evidence, and they all add up. It isn’t purely inside feeling, like the feeling that priests call revelation. There are outside things to back up the inside feeling: looks in the eye, tender notes in the voice, little favors and kindnesses; this is all real evidence.

Sometimes people have a strong inside feeling that somebody loves them when it is not based upon any evidence, and then they are likely to be completely wrong. There are people with a strong inside feeling that a famous film star loves them, when really the film star hasn’t even met them. People like that are ill in their minds. Inside feelings must be backed up by evidence, otherwise you just can’t trust them.

Inside feelings are valuable in science too, but only for giving you ideas that you later test by looking for evidence. A scientist can have a ‘hunch’ about an idea that just ‘feels’ right. In itself, this is not a good reason for believing something. But it can be a good reason for spending some time doing a particular experiment, or looking in a particular way for evidence. Scientists use inside feelings all the time to get ideas. But they are not worth anything until they are supported by evidence.

I promised that I’d come back to tradition, and look at it in another way. I want to try to explain why tradition is so important to us. All animals are built (by the process called evolution) to survive in the normal place in which their kind live. Lions are built to be good at surviving on the plains of Africa. Crayfish are built to be good at surviving in fresh water, while lobsters are built to be good at surviving in the salt sea. People are animals too, and we are built to be good at surviving in a world full of … other people. Most of us don’t hunt for our own food like lions or lobsters, we buy it from other people who have bought it from yet other people. We ‘swim’ through a ‘sea of people’. Just as a fish needs gills to survive in water, people need brains that make them able to deal with other people. Just as the sea is full of salt water, the sea of people is full of difficult things to learn. Like language.

It’s a pity, but it can’t help being the case, that because children have to be suckers for traditional information, they are likely to believe anything the grown-ups tell them, whether true or false, right or wrong. Lots of what grown-ups tell them is true and based on evidence or at least sensible. But if some of it is false, silly or even wicked, there is nothing to stop the children believing that too. Now, when the children grow up, what do they do? Well, of course, they tell it to the next generation of children. So, once something gets itself strongly believed – even if its completely untrue and there never was any reason to believe it in the first place – it can go on forever.

Could this be what happened with religions? Belief that there is a god or gods, belief in Heaven, belief that Mary never died, belief that Jesus never had a human father, belief that prayers are answered, belief that wine turns into blood – not one of these beliefs is backed up by any good evidence. Yet millions of people believe them. Perhaps this is because they were told to believe them when they were young enough to believe anything.

Millions of other people believe quite different things, because they were told different things when they were children. Muslim children are told different things from Christian children, and both grow up utterly convinced that they are right and the others are wrong. Even within Christians, Roman Catholics believe different things from Church of England people or Episcopalians, Shakers or Quakers, Mormons or Holy Rollers, and all are utterly convinced that they are right and the others are wrong. They believe different things for exactly the same kind of reason as you speak English and someone speaks German.

Both languages are, in their own country, the right language to speak. But it can’t be true that different religions are right in their own countries, because different religions claim that opposite things are true. Mary can’t be alive in the Catholic Republic but dead in Protestant Northern Ireland.

What can we do about all this? It is not easy for you to do anything, because you are only ten. But you could try this. Next time somebody tells you something that sounds important, think to yourself: ‘Is this the kind of thing that people probably know because of evidence? Or is it the kind of thing that people only believe because of tradition, authority or revelation?’ And, next time somebody tells you that something is true, why not say to them: ‘What kind of evidence is there for that?’ And if they can’t give you a good answer, I hope you’ll think very carefully before you believe a word they say.