Thinking Small and Large - Peter Forbes - E-Book

Thinking Small and Large E-Book

Peter Forbes

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The environmental crisis will not be solved by battery technology. We are looking for answers in the wrong places. Life began with the hydrogenation of CO2, and this is the process we must return to in order to heal the planet. Ground-breaking ongoing research into bacterial processes means our knowledge of bacterial processes is ever-expanding, and we can harness this new knowledge to develop a parallel carbon economy using engineered bacteria for fuel, food, and materials. This would enable rewilding on a vast scale, with the small land footprint of bacterial technologies solving the current conflict in land use between farming and fuel and materials production. In this fascinating and illuminating book, Peter Forbes shines a light on this crucial technology and offers a tantalising glimpse at what is possible. To solve the big problems, sometimes you have to think small.

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Also by Peter Forbes

The Gecko’s Foot: How Scientists Are Taking a Leaf from Nature’s Book

Dazzled and Deceived: Mimicry and Camouflage

Nanoscience: Giants of the Infinitesimal (co-authored with Tom Grimsey)

 

 

Published in the UK and USA in 2025 by

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email: [email protected]

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ISBN: 978-183773-170-1

ebook: 978-183773-171-8

Text copyright © 2025 Peter Forbes

The author has asserted his moral rights.

No part of this book may be reproduced in any form, or by any means, without prior permission in writing from the publisher.

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For Diana

CONTENTS

Prologue

1. Seeing Is Not Believing

How we creatures of the middle-size range get it wrong

2. Tornado in the Junkyard

How a simple equation has been at the heart of life for around four billion years

3. Infinitesimal Giants and the Global Cycles

How life has created and maintains balanced chemical cycles between the air, the soil, the waters and living things

4. The Great Engulfment

How the modern cell was born

5. Choanos, Sponges and Us

How life got out of single-cell gear

6. Beyond Sapiocentrism

How the Great Germ Theory obscured another truth

7. Fuel and Food from Air

How bacteria can create a parallel fossil-free carbon economy

Epilogue

Further Reading

Acknowledgements

PROLOGUE

Over around three decades, from time to time, my wife has suggested that I write a modern version of Microbe Hunters, a huge international bestseller by Paul de Kruif published in 1926. She possessed a 1940s American war-issue paperback – still does, in fact. It was a while before I actually read it; a quick look at the heroic stories of early medical science pioneers such as Pasteur, Koch and Ehrlich had revealed a style so far from the modern mode of science writing that it didn’t seem a likely model.

When I began to write on medical themes, among other biological topics, her message became more insistent. I protested that the flamboyantly dramatised approach of de Kruif is not the way medical and biological research are described for the general reader today.

But as the idea of what is now Thinking Small and Large became clearer to me, I was astonished to realise that, unintentionally, my topic really was a kind of ‘Microbe Hunters for our time’, but not as de Kruif had regarded microbes. For him, the point of hunting microbes was to kill them. But microbes are not primarily pathogenic predators on humans and other animals. How could they be? For over three billion years, microbes were the only living things on the planet: extensive fossil evidence for true animals begins only 538.8 million years ago. Microbes are single-celled organisms; bacteria and a related line called archaea, only recognised in 1977, were the earliest organisms on the planet; later came more developed unicellular organisms – the plankton of the oceans – that have modern cells like ours, with a nucleus, but for over a billion years never developed beyond being single celled. Although some claims for multicellular organisms go back more than a billion years, there were no land plants till around 500 million years ago, no proto-humans till around 6–7 million years ago, no Homo sapiens until some 300,000 years ago.

It is entirely understandable that in the late-nineteenth century the germ theory of disease – which had to be defended against widespread scepticism (as with climate change today) – was such a powerful idea it made looking beyond that to the deeper role of bacteria difficult. When people moved into cities in vast numbers as the world industrialised, the toll of infectious diseases was one of the world’s major problems. But for over 150 years, this focus totally obscured the prime role of bacteria in the environment.

That microbes are principally something other than predators on human beings is well known to scientists but not to a wider public. Microbes, in the biological oceanographer Paul Falkowski’s words, ‘made the world habitable’; in other words, a world with the right conditions for plant and animal life to flourish, not just microbes. Some fine popular books have been written on this subject, especially by Falkowski, Lynn Margulis, James Lovelock and Nick Lane, but there is a reason that this book could only have been written now. In 2004, the British Astronomer Royal, Sir Martin Rees, wrote Our Final Century: Will Civilisation Survive the Twenty-first Century? For a long time I jibbed against this idea that we were living in quite such an unprecedented time. There have always been doom warnings and human civilisation has always survived. But the developing environmental crisis does pose a risk to human civilisation for reasons Thinking Small and Large will explain. And the current wave of research on bacteria is showing curious and fruitful connections between the way bacterial life began four billion years ago and the possibilities that are emerging for the use of microbes in mitigating our climate, fuel and materials crises.

Recently, the idea that the environmental crisis is casting all of human history in a new light has been voiced by several writers, most notably Simon Schama. A vastly energetic chronicler of the great European cultures, Schama, in his latest book Foreign Bodies: Pandemics, Vaccines and the Health of Nations (2023), is still writing history, but it is the history of medicine. In his prologue, Schama writes:

At this late point in the flash in the pan that is the paltry ten millennia of human civilisation, we have returned to this chastening truth: that the matter filling millions upon millions of pages of recorded history – wars and revolutions, the rise and fall of cities and empires, fevers of faith, the heating up and the emptying out of wealth – has been circumscribed by what we have done to nature and what it has done to us.

As a writer and thinker, Schama is very likely to be somewhat ahead of the curve, but this is surely a path we’re all going to follow. That a man whose life has been spent writing some of those millions of pages of recorded history should now refer to the entire chronicle of human civilisation in terms such as ‘paltry’ and ‘flash in the pan’ highlights the change in our perspective of time that the environmental crisis is forcing upon us.

Big History – which includes the history of the planet, the origin and evolution of life, ecological and climatic factors, as well as the cultural and technological development of humanity (with its 4,000-odd years of written history) – is in vogue; for this story we have to go very deep – in both time and place. Four billion years back and to the bottom of the primordial ocean. Then, warm alkaline currents containing hydrogen (H2) and various minerals welled up through mineralised chimney structures with tiny pores like a foamed plastic sponge. There they met cold acidic ocean water containing CO2. The conditions were right for the first organic molecules to form.

Four billion years later, our biggest challenge is to break our dependence on the four billion years’ worth of fossil energy trapped in oil, gas and coal that represents the stored carbon from ancient microbial and plant life and now, when released into the air, is the cause of global heating. This crisis cannot be solved by renewable electricity alone because the problem lies in nature and the disruption carbon emissions have caused to the global cyclic traffic of gases between the air, oceans, soil, rocks and living things.

Like the microbe hunters of the past, whose discoveries helped to conquer diseases such as rabies, anthrax and syphilis, current microbe hunters are on the cusp of finding solutions to the crises of the age: mitigating the environmental harm through carbon-saving microbial technologies for fuel, food, chemical and materials production that bypass fossil feedstocks, remove CO2 from the air, and take up a fraction of the land needed to create plant life and to rear livestock. In doing this, producing what we need to maintain our lifestyle no longer harms the planet, but actually addresses the problem of climate change at the same time. This is the win-win scenario we have been seeking.

Besides its enormous practical importance, there’s an Alpha and Omega feel to this four-billion-year odyssey that gives a rationale for Rees’ urgent question – whether civilisation might not survive this century – and also a potential programme for escaping that fate. Thinking Small and Large takes us through four billion years of life on earth from this novel perspective. It is a story of life coming uncannily full circle, a unique alignment of human history and nature at this critical time in the deep history of the earth.

1. SEEING IS NOT BELIEVING

How we creatures of the middle-size range get it wrong

Any river’s grand to one who’s seen no larger

And a tree or man may also seem gigantic;

The largest seen becomes the measure.

Though you add in the heavens, the earth and the ocean,

They shrink to nought against the cosmic frame.

LUCRETIUS,DE RERUM NATURA (‘ON THE NATURE OF THINGS’)

Beyond the level of resolution of the human eye there exists another world, parallel to ours and rich with life.

LYNN MARGULIS,GARDEN OF MICROBIAL DELIGHTS, 1988

As human beings, we are creatures of the middle zone, medium-sized animals who, until the Scientific Revolution of the seventeenth century, had only ever perceived and recognised phenomena on a scale similar to our own. But to see is not to believe: to see, in the naïve sense of registering what our unaided eyes reveal, is to be deceived. We are in our naturally restricted, unaided visual sense so unadapted to understand the world of tiny living things linked to the enormous chemical cycles that pulse through the atmosphere, the oceans and soil of the planet, that we are no better than the moles in Miroslav Holub’s poem ‘Brief Reflection on Cats Growing in Trees’. The moles decided to investigate the world above. Depending on the time of day, intrepid voyager moles reported that ‘birds grew on trees’; the next saw only mewing cats; the third ventured forth in utter darkness and reported: ‘In fact, things above/Were the same as things below, only the clay was less dense …’ As David Waltham put it in his book Lucky Planet (2014): ‘Our view of what is really there has been misled by the accident of what we’re able to see’.

As sentimental, visually orientated beings, we are irresistibly drawn to the animals and plants that make the most striking visual impression on us: doleful soulful-eyed dogs, cuddly kittens, the chromatically glorious hues of flowers. But nature has achieved these delights after four billion years of evolution and her means, unlike these late products, are not pretty. To get to now, nature has dealt in grubby transactions among primeval muds, stinking hot gases at the floor of the ocean in strange liaisons between alien bits of chemistry. Nature is the bricoleur cobbling together bits of old microbes to make the cells from which all these animals and plants are made, even co-opting an ancient virus to create the placenta, without which mammals like us wouldn’t be possible.

So perhaps the real hero, the source of all this useless beauty, is the environment. All of the lovely creatures we cherish have a niche in the world of the rocks, the soil, the waters and the air; and the chemistry and physics in the universe had to be right to enable all this. If the earth were not alive in its core, still molten and pumping up lava after 4.54 billion years, life would not have been possible; if the planet had not kept an atmosphere, life would not have been possible. There is a whole suite of features of the earth that are not to be taken for granted. To fully grasp that, we need to focus on both the very small and the very large – those ends of the size spectrum that are not revealed directly to our vision.

This skewed view of the world that results from being middling-sized creatures in a world of enormous scales on either side of us, is what I call sapiocentrism. It begins, at least textually, in Genesis:

And God said, Let us make man in our image, after our likeness: and let them have dominion over the fish of the sea, and over the fowl of the air, and over the cattle, and over all the earth, and every creeping thing that crept upon the earth.

The idea that this bizarre ex-nihilo power had been granted to us could and should have been supplanted 2,000 years ago by the vision of the Roman poet Titus Lucretius Carus (c. 99–55 BCE; usually known as Lucretius) who divined the true course of the human animal’s civilising process:

When man built huts, wore skins, tamed fire,

And man and woman established a household,

Teaching their children the arts of living,

Then was the time that the savage was tamed.

And Darwin, in The Descent of Man, 1871, took it further:

The following proposition seems to me in a high degree probable – namely, that any animal whatever, endowed with well-marked social instincts, the parental and filial affections being here included, would inevitably acquire a moral sense or conscience, as soon as its intellectual powers had become as well, or nearly as well developed, as in man.

But the emergence of secular rationality did nothing to alter the sense of human exceptionalism. The Renaissance, a triumphalist secular project if ever there was one, took the human proportions of Leonardo da Vinci’s drawing Vitruvian Man to be the yardstick by which fine creations in architecture should be created and judged: man the measure of all things. Indeed, centuries before, the chronicler William of Malmesbury (c. 1095–1143) claimed that the yard was standardised by King Henry I of England as the length of his own arm. Of course, the Vitruvian principle is fruitful in the world of human constructs meant to please and satisfy human needs, but it isn’t the measure of nature, which does its vital work on the nanoscale, about one billionth of that other human yardstick, the metre.

Although God might be forgotten by many of those who continue to exercise this licence, the essential idea of unchallengeable right has persisted. In the Novum Organon (1620), Francis Bacon wrote: ‘Let the human race recover that right over nature which belongs to it by divine bequest.’ And, of course, from that point on, Bacon’s ‘New Instrument’ – science and technology – never shrank from bending nature to its will.

The eighteenth century Enlightenment doubled down on sapiocentrism. Alexander Pope, in An Essay on Man (1733-34), wrote:

Know then thyself, presume not God to scan;

The proper study of mankind is man.

But, in fairness to Pope, he then went on:

Plac’d on this isthmus of a middle state,

A being darkly wise, and rudely great:

With too much knowledge for the sceptic side,

With too much weakness for the stoic’s pride,

He hangs between; in doubt to act, or rest;

In doubt to deem himself a god, or beast . . .

In locating humans as beings between god and beast, he does acknowledge human weakness, but the Enlightenment was entirely a project of unfettered human scope. I realise that the accusation of sapiocentrism will sound too harsh, too species self-flagellatory. Of course, as an animal we’ve always put ourselves first: that’s what all animals do. As W.H. Auden put it:

Bee took the politics that suit a hive,

Trout finned as trout, peach moulded into peach,

….

Till, finally, there came a childish creature

On whom the years could model any feature,

But besides our infinite capacity for deception, we have intelligence and a moral sense, and when we realise that we’ve been led astray in plundering the world, and that this threatens our own existence, we need to recognise the error. Some of us have, but in terms of the scale of our remodelling of the world already achieved, it has come so late in the day.

Life’s processes – trapping sunlight to create biomass, synthesising proteins, operating DNA’s magical peeling apart to replicate – operate many orders of magnitude below our vision. Despite our inbuilt bias, and long before we had microscopes of any kind to help us, some brilliant minds, using reason alone, imaginatively recognised that nature must work at this scale: figures such as the Greek pre-Socratic philosopher Democritus, his later advocate Lucretius and, in the seventeenth century, the English poet Richard Leigh.

Lucretius observed:

Mark, when the sun’s rays pour into the shadowy room

How many tiny scintillations contend with the rays:

Dust motes in fretful motion without pause,

Massed troops clashing in endless disputation.

De rerum natura (‘On the Nature of Things’)

Lucretius used only beautifully clear logical thinking to deduce that behind the tiny, jinking dust motes lay bombardment by much smaller bodies: atoms. Something like his idea was taken up in the modern era in 1828 with the work of the Scottish botanist Robert Brown (1773–1858). Brown noticed a similar random motion of pollen grains suspended in water seen through a microscope, but without citing molecular motion as the cause. Brownian Motion, as it is known, was later developed by Einstein in one of his key papers of 1905 (see page 14). Lucretius’ anticipation of Brownian Motion was one of the key insights in his remarkably prescient poem. Taking seriously such an apparently unpromising topic – specks of dust bobbing in the air – is the royal route to knowledge.

In terms of actually seeing a chink into this world, nothing happened until the 1660s, when the Dutchman Antonie van Leeuwenhoek (1632–1723) invented a microscope and reported the existence of tiny ‘animalcules’ in scrapings from his mouth and in pond waters. But despite the early flush of interest prompted by the illustrations of microscopic entities in Robert Hooke’s (1635–1703) Micrographia (1665), very few of us have ever really grasped the fact that biology, with all its secrets, operates on a scale very far beneath our unaided vision.

Lucretius drew remarkably modern conclusions in many areas of life: he had some inkling of evolution, both biological and social, and he realised – without any of our knowledge of the deep roots of life on earth – that human civilisation must have been quite a recent phenomenon. We now, as a rule of thumb, reckon this as 10,000 years ago, when the domestication of crops and animals ushered in the break with the hunter-gatherer lifestyle. Lucretius was 2,000 years closer to this discontinuity than we are now. But his bracingly rational vision has remained an outlier to this day, despite some very distinguished advocates, including Leonardo, Machiavelli, Galileo, Einstein and the twentieth century Jewish-Italian writer and chemist Primo Levi.

Thinking about the 10,000 years of technologically improvisatory humanity against the background of the big numbers of the development of life on earth, it’s hard to resist the notion that human civilisation is still in its infancy, sapiocentrism being a species-level equivalent of a baby’s assumption that the whole world is all about them.

Perhaps we did not want to grow up? The attempts of the pioneers to enlighten us were met, as often as not, by ridicule and abuse, as Leeuwenhoek observed: ‘the idea that small things could be important seems to make many people angry’. A century or so after Leeuwenhoek, many people seemed to be angry about those who peered down microscopes. In Citizen of the World (1762), the poet and dramatist Oliver Goldsmith kicked off the Two Cultures debate (are art and science irreconcilably opposed?), two centuries before C.P. Snow’s famous 1959 polemic, by mocking the supposed pedantry of all who study tiny creatures. Commenting on naturalists such as Abraham Trembley (1710–84), who wrote a paper on that creature now familiar from school biology, the hydra, Goldsmith wrote:

… their fields of vision are too contracted to take in the whole of any but minute objects … Thus they proceed, laborious in trifles, constant in experiment, without one single abstraction, by which alone knowledge may be properly said to increase.

It’s curious that even today most can contemplate a flying insect only just large enough to see and not wonder at the machinery it must contain to enable the feat of directed flight. Technologists today are still struggling to make autonomous flying robots much smaller than a standard drone, although they aspire to make, among other things, pollinating robot bees (to replace pollinators decimated by our ecological vandalism).

Lucretius’ insight that behind his dust motes lay the motion of the fundamental particles of matter – atoms, as the Ancient Greeks termed these then only notional bodies – entered science with the modern atomic theory, first proposed in Isaac Newton’s Opticks, 1704:

It seems probable to me that God, in the beginning, formed matter in solid, massy, hard, impenetrable, moveable particles, of such sizes and figures, and with such other properties, and in such proportions to space, as most conduced to the end for which He formed them; and that these primitive particles, being solids, are incomparably harder than any porous bodies compounded of them, even so very hard as never to wear or break in pieces; no ordinary power being able to divide what God had made one in the first creation.

Notice that Newton has not dispensed with God, but this is deism: the creed according to which God started the world, after which it ran like clockwork according the laws of physics and chemistry.

Newton’s work heralded the beginning of modern science, with the physics that could explain the motion of the planets and the earth’s moon and the tides that the force of gravity produced. But the nature of the material of the world did not achieve a similar breakthrough for another half-century: the time of Goldsmith.

As Goldsmith wrote, modern chemistry was being born. The breakthrough came from experiments that showed that ‘air’ – one of the classic Greek four elements – was a mixture, not an elementary substance.

In 1754 the Scottish doctor and experimenter Joseph Black investigated a gas produced by the effect of acids on chalk or limestone. The fizzing gas, heavier than air, and unable to support combustion or respiration, is what we now know as the notorious carbon dioxide (CO2). Hydrogen followed in 1762, and oxygen in 1766, and these discoveries quickly led to knowledge of nature’s great system of chemistry that underlies the entire material world.

Until this point, there was highly ingenious craft – trial-and-error knowledge of materials like glass, metals, ceramics, cement and the secondary products of nature such as wool, leather, timber and fibres – but there was no knowledge of the nature of all the deep matter of the physical world. Every substance – mineral or organic – has a precise, detailed atomic structure, which can only be understood from the bottom up: the irreducible chemical elements and the laws governing their combination. The discovery of the elemental gases opened the road that would eventually lead to the deciphering of DNA with its three billion bases precisely ordered. And to a true understanding of bacteria which, on an atomic scale, are not tiny, primitive bugs too small to be seen, but giant assemblies of protein nanomachines that are almost identical to those that power all the living things today we can see. The essential metabolism of life was developed in bacteria – they possess the secrets of life. Knowledge like this could not have been achieved without the chemical discoveries of the mid-eighteenth century; the scale of nature that sees atoms organised into giant nanomachines is the true scale of life that science has opened up for us.

Nanomachines are at the heart of life’s processes and also this book. You might be surprised to hear the word associated with life, because isn’t nanotechnology all about computer chips and other hard silicon devices? No, because it is biology that is the ur-nanoscience. If you’ve heard a bit about nanotechnology, Eric Drexler and his ‘molecular assemblers’, the threat from ‘Grey Goo’, or read Michael Crichton’s apocalyptic novel Prey, please forget all that. The nanomachines of life are wet, biological molecules, giant protein assemblies in every cell – the beating heart of all life forms, performing all life’s essential tasks.

We call them nanomachines because they are machines, with moving parts. It was always obvious that life had to employ such devices. No one imagines that a car or any machine manufactured by humans is made out of some generalised moving-around stuff, or heavy-lifting stuff. Cars have to have pistons and crankshafts, and gears, and clutches and steering gear and brakes. They have to have moving parts. Animals move around, so why would they be any different? It’s just that a lot of what makes this happen takes place inside every cell, and these are extremely small on our scale, around a millionth of a metre across, but still giants compared to the very many nanomachines they contain, which are around a thousand times smaller. All the large actions of the body, like flexing your muscles, come from the coordinated activity of nanomachines in the billions of muscle cells in your limbs. And they are also the chemical processing centres of the cell. We will see the nanomachines in action throughout this book, and especially in the next two chapters.

But to return to the simple chemistry of the eighteenth century which had to be understood before we could know anything about life’s nanomachines: that oxygen was essential for animal life was soon demonstrated, becoming a parlour game wonderfully illustrated by Joseph Wright’s (1734–97) great painting An Experiment on a Bird in the Air Pump (1768), which showed that in a sealed container the air would, after a time, no longer support life. The same volume of oxygen substituted for ordinary air would further prolong life.

That plants illuminated by light produced oxygen was also recognised at the same time. And that water was simply the result of hydrogen combining with oxygen. So, 250 years ago, the vital links that lie at the heart of the chemistry of life and run through this book had been found: those between carbon, hydrogen, oxygen and water.

Many of Wright’s paintings are remarkable for their artistic engagement with science. He was not alone in this: for a period between the 1760s and 1820s there was a rapprochement between art and science – what I call, after the cultural club the Lunar Society of Birmingham, the Lunar Moment – in which scientists like Joseph Priestley (1733–1804), co-discoverer of oxygen, artists like Wright and entrepreneurs like Wedgwood, Boulton and Watt mixed. Emblematic of the time was the friendship between Coleridge – a poet who kept a chemical laboratory – and Humphry Davy (1778–1829), prolific chemist, the public face of science at the time, and an amateur poet; Davy’s lectures at the Royal Institution were thronging social occasions.

In the intellectual ferment of this time, the basis of chemistry, the apparently irreducible building blocks, our familiar carbon, oxygen, hydrogen, nitrogen (and eventually a further 88 in nature), was established. In 1789 the French chemist Antoine Lavoisier (1743–94) systematised the elements, and in 1800 the North of England nonconformist John Dalton (1766–1804) took Newton’s atomic hypothesis further by mathematicising it, identifying each element with an atom of a certain size and weight.

That atoms are very small, as Lucretius had intuited, was confirmed ingeniously in the mid-nineteenth century. But it was still hard to imagine them; they are far too small, at less than a nanometre, a billionth of a metre, to grasp. But if we mostly can’t do this, life and the chemists could, and from the simple chemistry of the nineteenth century a picture was gradually built up that brought us today to the atom-by-atom structure of DNA and the other giant molecules of life.

But the work of chemists and physicists in probing the properties and dimensions of Lucretius’ atoms remained hidden to most. Until 1905, even some scientists remained sceptical about the real existence of atoms. In a sense, they still wanted to be able to ‘see’ atoms before they could believe in them. The physicist Ernst Mach (1838–1916) wrote that ‘Atoms and molecules … from their very nature can never be made the objects of sensuous contemplation’. Mach believed that the realm of science should include only phenomena directly observable by the senses, and rejected theories of invisible hypothetical entities.

Seeing is believing is one of our deepest rules of thumb. And it is wrong. As was Mach. The question was resolved by Einstein in one of his three great papers of 1905 (the other two being the theory of relativity and the photoelectric effect). Einstein developed the idea of Brownian Motion (which of course was also Lucretian Motion) in his third 1905 paper ‘On the Movement of Small Particles Suspended in Stationary Liquids required by the Molecular Kinetic Theory of Heat’. The kinetic theory of heat, one of the triumphs of nineteenth-century physics, allowed the behaviour of gases to be understood mathematically in terms of just the kind of molecular motion first observed by Lucretius.

Einstein believed that particles large enough to be ‘easily observed in a microscope’ in suspension in a liquid would behave just as the gas molecules did:

[A] dissolved molecule is differentiated from a suspended body solely by its dimensions, and it is not apparent why a number of suspended particles should not produce the same osmotic pressure as the same number of molecules.

Here was a link between the worlds of the seen and the unseen. And it wasn’t just, as it had been for Lucretius, a conceptual link, a thought experiment. Einstein knew that numerically, mathematically, by observing the motion of suspended particles much larger than molecules, the actual size of atoms and molecules could be deduced (an atom is the single particle irreducible by normal chemical means; a molecule is a combination of atoms; the gases oxygen, hydrogen and nitrogen actually exist as molecules containing two atoms). A section heading in the paper read: ‘A New Method of Determining the Real Size of the Atom’.

But Einstein was no experimenter. The paper ended with a plea: ‘It is to be hoped that some enquirer may succeed shortly in solving the problem suggested here …’ Einstein’s paper was widely noticed and in 1908 the French physicist Jean Perrin set out to perform the experiment that Einstein had proposed. For the importance of the topic, as Einstein’s biographer Abraham Pais has written, the experimental technique seemed laughably simple: ‘prepare a set of small spheres which are nevertheless huge compared with simple molecules, use a stopwatch and a microscope, and find A’s [Avogadro’s] number’. Avogadro’s number is a fundamental constant of nature: the number of molecules in the gram molecular weight of any element. There are 6.022 x 1023 atoms in 1 gram of hydrogen or 16 grams of oxygen. Ten to the power of 23 is a very large number, which shows just how small atoms are.

Confirming the atomic size theory required a researcher to sit watching sediments in a jam jar with a microscope – a bathetic contrast not only in physical scale but in apparent grandeur. But Einstein was a master of the universe at both ends of the size scale and knew that the very small was just as grand as the cosmos. And like Einstein, Perrin was sure the link between what we can see with our eyes and the atomic realm could be made:

If the agitation of the molecules is really the cause of the Brownian movement, and if that phenomenon constitutes an accessible connecting link between our dimensions and those of the molecules, we might expect to find therein some means for getting at these latter dimensions.

Perrin confirmed Einstein’s results and finally laid to rest all doubts about the atomic theory. In 1909 he wrote: ‘The atomic theory has triumphed’.

Atoms range in size from 0.1 to 0.4 of a nanometre in diameter (1 nanometre – 1nm – is one billionth of a metre). For comparison, living cells vary widely in size but are typically around one millionth of a metre or around five to ten thousand times bigger than atoms. In 1959 Richard Feynman (1918–88) gave a lecture entitled ‘There’s Plenty of Room at the Bottom’. This is usually taken to signal the beginning of the nanotechnology revolution, seen as purely mineral materials technology typified by the silicon chip. But in explaining this nano kingdom, Feynman took his examples from biology:

A biological system can be exceedingly small. Many of the cells are very tiny, but they are very active; they manufacture various substances; they walk around; they wiggle; and they do all kinds of marvellous things – all on a very small scale.

Having said, ‘It is very easy to answer many of these fundamental biological questions; you just look at the thing’, he went on to lament that the really important work in nature was still beyond the power of our microscopes. Feynman was a great inspirational figure, but his insistence on naïve looking was slightly misleading. Science is not just ‘looking at the thing’, even with powerful microscopes.

Take the Einstein/Perrin experiment to find the size of the atom. It involved logical and lateral thinking rather than simply ‘looking’. Indirectness – putting nature to a test to reveal itself – is very much the standard mode of science. Of course, the latest imaging techniques – not available when Feynman wrote – do produce actual pictures of the micro and nano world, but even these are most useful when combined with indirect evidence.

Sadly, despite the brilliant clarity of the reasoning that has revealed the size scale at which nature works in its deepest processes, the gap between science and a ‘seeing is believing’ worldview is still with us. In 1992 the embryologist Lewis Wolpert wrote a book called The Unnatural Nature of Science in which he pointed out that science was not remotely the extension of common sense that many people want it to be. Science is deeply counter-intuitive – we feel sure that a cannonball must fall faster than a feather because, even if we don’t have access to cannonballs, any heavy object dropped alongside a feather will prove the point: seen, believed, sorted! But Galileo deduced that common sense was wrong in this instance. Wolpert referred to the problem of scale:

Science also deals with enormous differences in scale and time compared with everyday experience. Molecules, for example, are so small that it is not easy to imagine them.

But whatever difficulties we have in grasping it, the world disclosed by science is the deepest truth of all; to deny it courts the ultimate disaster.

If the fact that atoms are so small creates problems in understanding life, the great physicist Erwin Schrödinger (1887–1961) highlighted another problem in his little book What is Life? (1944), which inspired so many great minds, like Francis Crick (1916–2004), to turn from physics to biology after the Second World War, and laid the course for modern thinking about life in philosophical reasoning highly reminiscent of Lucretius.

Schrödinger’s arguments go something like this. Thought is an orderly process: we grasp perceptions and thoughts and hold them in our minds so there must be something stable in our minds to be able to do this. But chemical substances of the kind you find on lab benches or in the environment are buzzing and darting about with heat motion. You grasp the perception of a still glass of water – it appears to be motionless but every molecule of it is in random turbulent Brownian motion. As is the air at all times, even when we don’t perceive a wind.

Schrödinger’s idea was that the chemical basis of the key components of living cells cannot be the kind of small buzzing assemblages of atoms in water or air or in the bottles on lab shelves, which only have stable form when seen en masse with their billions of molecules. There must be some molecules in living cells that are stable, not just in the here and now but over many years and, indeed, in evolution over millennia and billennia.