Читать книгу The Davey Dialogues - An Exploration of the Scientific Foundations of Human Culture - John C. Madden - Страница 20

Knowledge, a rude unprofitable mass,

The mere materials with which wisdom builds,

Till smoothed and squared and fitted to its place,

Does but encumber whom it seems to enrich.

Knowledge is proud that he has learned so much;

Wisdom is humble that he knows no more.

WILLIAM COWPER, The Task, Book VI, “Winter Walk at Noon”

It was time for my next meeting with Davey.

I had had a head-crunching week of preparation. Some of the models of our universe are too much of a challenge for most or perhaps even all of us humans to grasp. What, I wondered, would it be like for Davey? I was soon to find out.

He arrived, seemingly full of vigour.

– Well, well, well. Here I am back in the schoolroom and ready for my next lesson.

Who had he just been visiting? Someone in England I surmised, judging from the “well, well, well”, which was a new turn of phrase for him.

– Shhhhhh! Not so loud, or my wife will come to find out who I am talking to. If she finds I am not talking to anyone, she may have me committed to an insane asylum!

– Ha, ha, ha! I wouldn’t worry about that.

– All very well for you. You probably don’t have a wife, or do you?

– Not really. At least not in your sense of the word. But don’t worry. Margaret won’t hear a word I say unless I open a talk channel with her.

– How on earth do you do that?

– Well, it is very easy if you know how. As I have already told you, I can locate any sounds in your universe with great precision. I can also direct my voice into your universe with similar precision, although there does tend to be a residual garble that can sometimes be heard by others.

– That’s just great. So, Margaret will hear me talking out loud intermixed with a garbled mumble from you. She will be absolutely certain I have gone mad!

– So, all you have to do is to speak in a whisper so she doesn’t hear you. I will still hear you quite distinctly. Or, if you like, you can go for a walk or a drive, and talk to me as we go along.

– That won’t work. I have to refer to my notes quite a bit today. It is a tough subject for a mere mortal like me to teach. Let’s just try the whispering routine. If it doesn’t work, we will meet another day.

– Fine. Let’s get started.

And start I did – in a whisper.

– There is an old story about a wise man from an Aboriginal tribe who was addressing a group of anthropologists. Like you when we first met, they were all anxious to know more about the “creation myth” of his tribe, so the man described in some detail how Earth as we know it is held up on the back of a turtle. “And what”, asked one of the anthropologists, “holds up the turtle?”

“Well”, the man replied, “the turtle is standing on the back of another turtle.”

“Hmmm”, said the anthropologist, who now had a bit of a glint in his eye, “and what do you suppose is holding up the second turtle?”

The man was quick to pick up the gist of the line of questioning.

“Oh”, he said. “It’s solid turtles all the way down!”

So, what does a modern “creation myth”, based on extensive research by a lot of scientists, really look like?

We believe that our Earth is a satellite of our sun, and that our sun is a part of the Milky Way galaxy, one of several billion galaxies in the universe. That’s a good start and is something we can see with our own eyes. But how was our universe created? Was it, as is currently believed, in one Big cosmic Bang? If so, might there be other universes? Are these other universes likely to obey the same physical laws as our own universe, or might they, for example, have a different value for the charge and mass of the electron, or of some other fundamental constants that have been the ultimate arbiters of the shape and structure of our universe? Some theoretical physicists believe that some fundamental constants were not so constant after all, having changed their values slightly over the life of our universe.

– Well, I told you last time we met that we have no unstable elements in our universe. From that you should have been able to conclude that some of our physical constants must be different, or we would have the same elements and the same chemistry that you have.

– I’m not yet totally certain that you exist. So, I can scarcely use your words as evidence!

You can tell I was feeling a little nettled! Davey noticed and immediately worked to calm me down.

– Quite right. I keep forgetting that the brains of you humans are subject to unbidden thoughts and visions, so you have to be very careful not to believe what you see and hear, unless it can be independently confirmed. Let’s proceed.

– Very soon now I shall address Charles Darwin’s monumental contribution to our quest to understand ourselves. As you almost certainly know already, Darwin believed that we have all evolved from the most primitive life forms through a process of natural selection, in which physical or mental capabilities that have species survival value are likely to be preserved, while changes that reduce the chances of survival have a tendency to die out.

It is difficult to see how understanding the origins of our universe will enhance our ability to survive. So, how could evolution through natural selection bestow on us, for example, the capacity to understand whether or not there are other parallel universes?

One answer is that it is well known that evolution frequently bestows properties that are peripheral to survival. Some genetic changes have no survival benefits, but neither do they materially reduce the odds of survival. Such changes simply alter our genetic makeup. It is to be expected that some such changes will subsequently prove to be advantageous. For example, it seems likely that our ability to write resulted from enhanced mental capacity more generally, combined with our manual dexterity, already a well-established inherited capacity. The upshot of our ability to record our thoughts and our progress has been nothing short of spectacular and has led many of us to view Homo sapiens as being in a class by itself relative to other animals. But we should not let this enormous success blind us to our probable limitations.

Let’s think small for a few minutes.

Consider the ant. Edward O. Wilson, the famous Harvard entomologist, did for many decades and at some length.[25]

It has been estimated that there are at least a million billion (10¹⁵) ants alive on Earth at any given point of time, and that there are thousands of different ant species, only some of which attend human picnics. Wilson describes ants as being “. . . in every sense of the word the dominant social insects”. Almost all, if not all, ant species have several different castes in their societies, including a queen, some males, soldiers (which can be much larger than their sisters and brothers), and smaller and medium-sized workers. Wilson describes the morning hunting activities of one particular species of ant, Eciton burchelli, in the following way:

When the light level around the ants exceeds 0.5 foot candle, the bivouac begins to dissolve. The chains and clusters break up and tumble down into a churning mass on the ground. . . . Then a raiding column emerges along the path of least resistance and grows away from the bivouac at a rate of up to 20 metres an hour. No leaders take command of the raiding column. Instead, workers finding themselves in the van press forward for a few centimetres and then wheel back into the throng behind them, to be supplanted immediately by others who extend the march a little farther. As the workers run on to new ground, they lay down small quantities of a chemical trail substance from the tips of their abdomens, guiding the others forward. A loose organization emerges in the columns, based on behavioural differences among the castes. The smaller and medium-sized workers race along the chemical trails and extend them at the points, while the larger, clumsier soldiers, unable to keep a secure footing among their nest-mates, travel, for the most part, on either side. . . . The smaller workers, bearing shorter, clamp-shaped mandibles, are the generalists. They capture and transport the prey, choose the bivouac sites, and care for the brood queen.[26]

Ants are not alone among insects in the highly developed innate nature of their social behaviour. Some species of termites build nests with special tunnels to provide air conditioning and heating as appropriate to keep termite larvae within a prescribed temperature range, and the dance of the honey bees to communicate the direction and distance to promising sources of nectar is now well known.

Change a few words here and there, and the quotation from Wilson could be a description of a raiding party by some remote human society, and yet experiments have conclusively established that almost all ant behaviour is inherited and not learned. It is enough to make us wonder just how many human activities are motivated more by innate behaviour than by our much-vaunted free will.

Ant societies have some definite boundaries to their understanding of the world about them. Exterior (and almost certainly, unimagined) forces can quite suddenly shatter the ant’s world – a bulldozer blade or an elephant’s foot on the nest, a sudden flood or a landslide.

So it is with humans and human societies, though our perception of just where those boundaries of understanding lie has undergone some very significant changes in recent years. We now think we understand how life evolved. We also understand the sources of earthquakes and violent storms. We know what fuels the sun and roughly how long the sun will continue as a benevolent source of energy. But there is still a lot that we don’t know.

For me, as for many others, some of the most perplexing and complex boundaries of our understanding lie in the physics of the universe.

I am almost certain that if my science teacher had not taught me about Newton’s law of gravity, it would never have occurred to me to wonder why it was I walked around on Earth and did not float up into the sky. Just like the vast majority of our ancestors, and, one supposes, all the other mammals and life forms, I would have lived my life without ever imagining such concepts as force and gravity. Furthermore, when I learned about Newton’s equations, they came to me as just another item on a long list of things to learn about, and, if need be, parrot back during an exam.

Now I look at what Isaac Newton discovered in wonder. How is it that he looked about him – perhaps triggered by the famous apple he is reputed to have seen falling to the ground – and asked the simple question I would never have thought to ask: “Why did the apple fall down?” Of course, Newton went even further. He integrated the force of gravity into his laws of motion, identifying the gravitational force as identical in principal to the force felt in one’s back arising from the acceleration of a plane down a runway, or, in his case, more likely a trotter moving a carriage swiftly away from a curb. What a stroke of genius!

Einstein, too, addressed questions it would not have occurred to most human beings to ask. Some famous experiments by distinguished scientists were showing that the speed of light is constant no matter what the relative motion is between the observer and the observed object. This is counterintuitive. If I throw a ball out of a speeding car in the direction of the car’s motion, I expect that the initial velocity of the ball relative to the ground will be the sum of the velocity I give the ball by throwing it, and the velocity of the car. This is true for the ball I throw (though air friction rapidly slows it down), but, as you may know, not for the light in a flashlight beam I point in the direction of travel. In that instance, the speed of the light in the beam as measured by a stationary observer is the same as the speed measured by someone on a passing car going in the opposite direction, or indeed, as measured by me while speeding along in the car. In exploring the consequences of this very strange fact, Einstein evolved the Special Theory of Relativity in 1905.[27]

Figure 6.1 – Two Geniuses, Two Theories of Gravity. Sir Isaac Newton in middle age on the left; Albert Einstein aged sixty-eight at Princeton in 1947 on the right.

Eleven years later, he pushed much further into the realm of questions I would not have thought to ask, in the process adding new meaning and accuracy to Newton’s gravitational equation. Gravity, he concluded, can be thought of as the curvature in space resulting from the presence of mass.

I beg your pardon? Space is curved? What kind of a concept is that? To most of us, space is space, stretching out in three dimensions. Curvature of space, unless in only one or two dimensions – such as the surface of a sphere, or the curvature of a line – has no obvious meaning.[28] Unnoticed by me, as well as by most others, was the unanswered question of what is really meant by the “force” of gravity. What is it that causes the force to be observable? We know it is not a piece of elastic tying two bodies together, so what can it be? And while we are on the subject, what causes oppositely charged bodies to attract each other, and similarly charged bodies to show mutual repulsion?[29] And what about the strange forces that hold the nucleus together? As you are quite likely aware, Einstein was only one of many who spent their lives endeavouring unsuccessfully to devise a coherent theory that would explain all these forces in what came to be called a “Theory of Everything”.[30]

Now, in my later years, we are told that Einstein’s four dimensions (three spatial dimensions plus time) are really only a convenient approximation of reality, although useful for almost all practical purposes. Some theoretical physicists now tell us that we live in a world of eleven dimensions, one of which is time, with the rest being spatial. Only three of the spatial dimensions are large, and thus visible to us. The other seven are very, very small strings (whose dimensions are of the order of the [tiny] Planck length of 10^-33 cm) and are tightly curled up on themselves. In a wonderful book for the layman, The Elegant Universe, Brian Greene explains why he and his colleagues believe that ten spatial dimensions is the correct number, how the space can be described mathematically (Calabi-Yau space) and envisioned. He also explains how he expects pursuit of the very complex mathematics that are required to provide numerical rigour to the theory may lead us to be able to describe what the gravitational, electro-weak and strong nuclear forces actually are, thus at last realizing the dreams of Einstein, Newton and many others of explaining all forces using a single theory.[31]

Even a dim understanding of ten spatial dimensions is hard for most of us to imagine. I found one of Greene’s many analogies especially helpful in this regard.

Imagine a hose stretched across a canyon that you can see off in the distance. The hose will appear to you as a line that is slightly curved.[32] This is a one-dimensional space. The position of an ant walking along the hose can be described by a single number, such as its distance from the left-hand end of the hose. Now imagine that you raise your powerful binoculars to peer at the hose, and you see that the ant can also walk around the diameter of the hose, although this second dimension is small and curled up, and not at all like the dimension along the length of the hose. You might even look again, and realize that ants are emerging from inside the hose. You might then conclude that there must be at least one more dimension curled up inside. Now, says Greene, consider the fundamental nuclear particles and imagine that in addition to the three spatial dimensions in which they observably exist, there are other tightly curled up and very small dimensions associated with these particles.

It still sounds pretty wild, doesn’t it? But then these dimensions are so very small that none of our senses could possibly detect them, nor, if you believe that our senses are the product of an evolutionary development where only those faculties that had survival value predominated, is it to be expected that survival would depend on anything remotely close to an understanding of string theory and ten spatial dimensions. Just like the ants, for whom, from our perspective, there is so much of the world that is beyond their ken, is it not possible that there are some spatial dimensions that are likely irrelevant to our survival, and for which we have therefore not evolved any capacity to observe? Although these dimensions may be inaccessible to us by direct observation, is it possible that we could come across a few hints and clues occasionally providing scraps of evidence of dimensions we cannot properly ken?

This last proposition seems reasonable to me, based partly on some of the key non-intuitive discoveries of scientists, such as Einstein, Newton and Planck, but also based on what sensors one might expect humans and other animals to have evolved in their fight for survival over evolutionary time periods. Hence my admiration for those amongst us who have supplied verifiable answers to scientific questions I would never have thought to ask!

During my lifetime I have seen the theory of the universe evolve from an essentially static model in which stars were born, “lived” and died, to a model that posited our universe was spontaneously created 13.8 billion years ago, has been expanding ever since and may or may not, at some time in the future, reach a point of maximum expansion, followed by a compression stage leading to annihilation – or, on the other hand (as is currently believed), may go on expanding forever. Spontaneous creation from a point source has always seemed to me to be a bit of a stretch, as it has to Arthur Eddington (who was quoted on this subject during our fourth dialogue) and to Einstein. String theory relieves some of the mental stretch implied by the Big Bang, by immersing our particular Big Bang in a “turbulent cosmic ocean called the multiverse” so that, in Eddington’s (previously quoted) words, “the implied discontinuity of the divine nature” derived from the Big Bang can at least potentially be satisfied at a higher level as one of many Big Bangs in a “cosmic ocean”.

String theory is by no means the only theory in contention to explain the workings of the universe at a fundamental level. Thus far the theory has been jigged so that it can explain most observed phenomena. However especially after Einstein’s experience inserting a cosmological constant to explain what turned out to be an incorrect assumption that the universe is stable, physicists are slow to accept a theory unless it can also make some predictions that can be tested. String theorists have so far been unable to meet this challenge in a manner that is widely accepted.

Some other leading theories do not require us to envision extra spatial dimensions that are inaccessible to us, but no theory has yet provided a widely accepted explanation of the observed properties of the universe. As our ability to explore the outer reaches of our universe has increased with the availability of scientific satellites, some challenging new phenomena demanding explanation have come to light.

Intense efforts to understand how galaxies formed have led to widespread acceptance of the existence of dark matter, matter which is undetectable by our available instruments, but which is needed to provide enough gravitational force to account for the formation of galaxies. Dark matter is believed to comprise 22 per cent of the total mass and energy in the universe. Recall that energy [e] can be equated to an equivalent mass [m] using Einstein’s famous equation, e=mc², where “c” is the speed of light.

Even harder to comprehend is the likely existence of dark energy. Without it, the existing theoretical framework cannot otherwise explain the recently determined fact that the expansion of our universe is accelerating, when our best theories predict that gravitational forces should be slowing the expansion. Nor is dark energy a minor factor, as current estimates are that it comprises about 73 per cent of the total mass and energy in the universe. Between them, dark matter and dark energy thus comprise 95% of all matter and energy, leaving only 5% for the matter and energy that we know about and can explain!

One of the great attractions of pursuing research on dark matter and dark energy is that if we do succeed in understanding them, they lend further credibility to our current best theories about the known forces. These theories have gained a lot of credibility due to their ability to predict phenomena such as hitherto undiscovered particles and the mechanisms fueling the movement of stars, planets and galaxies in the universe. One of the very basic conundrums this research faces is that the Standard Model predicts the existence of a particle called a Higgs boson after a British physicist named Peter Higgs who was prominent amongst those who proposed in 1964 that such a particle was required if observed phenomena are to be consistent with the Standard Model.

At the time, a major problem with this proposal was that the likelihood of ever seeing and identifying such a particle seemed very remote because of the huge energy output required of any particle accelerator that could make a Higgs boson identifiable.

However, in 2008 a new ultra powerful particle accelerator called the Large Hadron Collider (LHC) was commissioned at the European Centre for Nuclear Research (CERN) in Geneva, after more than ten years of construction. The single most important reason for the LHC was to search for the Higgs boson.

On July 4, 2012, two competing research groups, both based at CERN, announced that each had discovered a boson “consistent with” a Higgs boson. The wording was appropriately cautious. The Higgs boson is estimated to have a lifetime of about one zeptosecond (10^-21 seconds) and would be accompanied by vast showers of unrelated particle interactions which obscure the event of interest. The discovery of the Higgs boson opens up new realms of exciting research. Some theories imply the existence of a whole family of Higgs-like bosons, some or all of which may interact with dark matter. Other theories implicate Higgs particles in a posited rapid expansion of the universe immediately following the Big Bang.[33]

An intriguing alternative explanation for the unexplained expansion of our universe is put forward by string theorists. They think that gravity may not be confined to the three spatial dimensions we are familiar with, and may be “leaking” into some of the other dimensions postulated by string theory, thus having a reduced effect in the dimensions we can observe. In this scenario, it is the reduced impact of gravity, rather than the countervailing force of the dark energy, that is driving the accelerated expansion of the universe. Yet others believe that our galaxy may inhabit a part of the universe that is much less dense than average, so that the velocity of expansion of the universe will vary from place to place, instead of being uniform throughout the universe, as most current theories assume. Clearly there is much yet to understand about our universe!

The Big Bang itself continues to be an intriguing enigma. While theories which explain the behaviour of the universe after the Big Bang are relatively well developed, the cause of the Big Bang itself is still unexplained.

One promising approach described by Neil Turok[34], the Director of the Perimeter Institute for Theoretical Physics in Waterloo, Canada, envisages the universe as a cyclic process which, after its expansion phase then contracts down to a very small (but not infinitely small) size, followed by another expansion phase. Whether or not there is more than one universe, the idea that our universe might be oscillating between two extremes has some intuitive appeal, though the complex mathematics involved in all these cosmological theories render further enquiry forbidding for all but the highly trained expert.

Another enduring challenge to our understanding lies in the field of quantum physics. Quantum theory seems like an essential component to our understanding of our world, since it is an integral part of the Standard Model, which provides an excellent explanation, accurate to many decimal places, of observed phenomena. In particular, it is brilliant in explaining the strong and weak nuclear forces, as well as the electromagnetic forces, but, as already mentioned, it has yet to be reconciled with what we know about gravitational force. In this latter domain, it is still Einstein’s theories of Special and General Relativity that govern. Attempts to reconcile the two approaches into a combined “Theory of Everything” have failed miserably thus far.

For most of us, the most confusing aspect of quantum theory is the concept of non-locality, that is, the prediction, confirmed by experiment, that two widely separated particles can be “entangled” in such a way that changes in the state of one particle immediately affect the other, without there being any observable force to effect such a change. Furthermore, the changed states seem to take place simultaneously, which is to say that the communication between the two seems to be faster than the speed of light, which, according to relativity theory, is the fastest speed at which such communication can occur.[35]

This property of quantum entanglement is currently being vigorously investigated by researchers intent on developing, for example, ultra-high-speed quantum computers, but even the most brilliant minds (notably including Einstein and Niels Bohr) seem to have had the same difficulty the rest of us more intuitively experience in reconciling the observed fact that particle entanglements over very large distances really occur, perhaps even extending right across the universe, with the lack of any observable force to give effect to the entanglement.

In the circumstances, the idea that the force or forces from which the entanglement results might operate in one or more dimensions inaccessible to us has some attraction.

So, how about you, Davey? Do you have entanglement in your universe? And if so, do you understand it? Is it possible that entanglement can happen between particles in different universes, and if so, is that perhaps how you are able to communicate with me?

– That’s a lot of questions to ask all at once!

First of all, yes, I am familiar with the idea of entanglement. Indeed I observe it all the time. It is an important phenomenon in my universe. I may lack your ability to review past history, since we lack radioactive isotopes, but we do have useful features in our universe that you seem to lack.

For example, you could not have known that in my universe we live in six spatial dimensions, and entanglement works in only three of them. It is very hard for me to imagine anyone living in only three spatial dimensions, and of course, since I can hear but not see you, my imagination gets no help from just listening to you talk. As far as I know, entanglement of particles between universes is possible between some, but not all universes. Indeed, I believe it is quite rare. However, it is possible between your universe and mine, a situation that has made communication with you humans possible for me.

Our universe is undoubtedly much more stable than yours, possibly as a result of having those three extra dimensions. I believe our past was very like our present.

– You come with very exciting news today! What is it like in your universe?

– What do you mean? It all seems pretty normal to me.

I was dumbfounded by his answer! Six dimensions! Everyday particle entanglement similar to what we call quantum entanglement! This hardly seemed normal to me. It took me a few seconds to see my question from his perspective, and even then, I was a little surprised that he had failed to see it from mine.

– Sorry, but you have to understand that what is normal for you is not at all normal for me.

– If only I could see you, it would probably be obvious, but sadly I cannot.

– Okay. Try this! Do you have weather? Trees? Sunlight? Nighttime? Animals?

– I think we have some, or possibly all, of these things. But it is sometimes hard for me to figure out what is our equivalent of those things you call weather, trees and sunlight, for example. It is harder still to understand how they might resemble what may be our equivalents. With no electromagnetic radiation and six spatial dimensions, when you have only three, resemblance is a hard word to define.

But I might be able to help you understand what you call non-locality. Let’s go back to your example of the hose suspended in the distance on which, with binoculars, you are able to see ants crawling. Instead, let’s assume that you see two trains approaching each other from opposite ends of the suspended hose, and apparently running on tracks on the hose. A head on collision seems certain to be about to occur.

But what you are looking at (essentially) is a one-dimensional hose. However, unseen by you are two pairs of tracks on a flat ribbon, rather than what looks to you like a (one-dimensional) hose. To your amazement, the trains roll right past each other. Ah, you may say to yourself, this is amazing. The trains just passed right through each other without any impact! The second spatial dimension is unobservable by you, though it can be inferred as one explanation for the fact that the trains passed each other without colliding. I can tell you that the quantum non-locality observation is the result of you not being able to envisage other dimensions through which a local force can operate.

– An interesting idea. I wonder if what you say is correct. Maybe our two universes have no relevance at all to each other.

– I totally disagree. Several things you have said already have helped me to understand the plight of my superhumans, as I have already told you. That is what makes what you are telling me so very important!

I can tell that this subject was a difficult one for you to try to explain to me. From listening in on conversations on Earth I have learned that many humans do yearn to know more about their origins.

And now you even have me wondering how I came about, and why our universe is the way it is! Alas we don’t seem to have any easy way of finding out about our origins.

By this time I was tired. All I could think of to say was, “How very odd!”

But then I realized that I needed to summarize for Davey what conclusions I thought he should draw, even though they may not be the conclusions he would wish to draw.

– Well, Davey, this pretty well concludes what I wanted to tell you about our knowledge of the physical world we live in. We have two underlying theories that explain the actions of the physical forces we are aware of. The Standard Model very accurately describes the actions of the strong and weak nuclear forces and the electro-magnetic force, Einstein’s theories of Special and General Relativity describe the way that the gravitational force behaves. The Standard Model, for the most part, does an excellent job of describing nature in the small, while Einstein’s theories, again for the most part, do an excellent job of describing nature where the force of gravity predominates, i.e. over large distances. Neither approach, however, explains everything even within its own domain. Perhaps most notably, in the domain of the small, we have yet to comprehend and explain the phenomenon of non-locality. In the domain of the large, perhaps the greatest remaining mysteries are the apparent existence of dark matter and dark energy. Despite extensive efforts by some of our brightest minds labouring over many decades, we have yet to arrive at a satisfactory “Theory of Everything” that might unify these two theoretical approaches and clean up the mysteries at their fringes.

In his summary at the end of The Elegant Universe, Brian Greene wrote:

Already . . . we have seen glimpses of a strange new domain of the universe lurking beneath the Planck length, possibly one in which there is no notion of time or space. At the opposite extreme, we have also seen that our universe may merely be one of the innumerable frothing bubbles on the surface of a vast and turbulent cosmic ocean called the multiverse. These ideas . . . may presage the next leap in our understanding of the universe.[36]

Eight years after Greene wrote those words, the beginnings of what may turn out to be the next leap were posited by a physicist named Lisi who used some advanced geometry to construct a plausible family of new particles and forces that could explain dark matter and dark energy and encompass both the Standard Model and Einstein’s General Relativity theory. He calls his theory E8 Theory, where E8 refers to an E8 Lie Group. It is particularly of interest that the theory predicts that the newly constructed European particle accelerator, the LHC, will be able to generate some of the new particles that the theory predicts.[37]

Davey, I cannot tell you what an E8 Lie Group is, but I can tell you that it is vital to know that there appears to be a way to test whether or not it has promise. You might be surprised to learn how many theories in this domain are essentially untestable.

Perhaps one of the most wonderful phenomena of our history as a species is that we humans have been able to adapt the brains that evolved to enhance the survival chances of our forebears when they were hunter-gatherers into engines that have not only allowed many of us to experience a much better, longer and pleasanter life, but also has allowed us to contemplate the laws that govern our universe.

It is a source of wonder that scientists have been able to formulate testable theories about the origins of the universe and thus create a credible knowledge base about worlds undreamt of only a hundred years ago. However, an important part of self-knowledge lies in an understanding that humans, like ants, may never be able to see and understand all of the real world.

There is a useful corollary to this statement. The history of science clearly demonstrates that it is neither useful nor helpful to accept without question unverifiable explanations for those things we do not understand. If a satisfactory science-based explanation is not available, wait a while. There may be one in the making!

– Bravo, Peter! I know it was a lot of work for you to prepare for this, but that wasn’t so bad was it? I do hope though that your brilliant researchers will continue to explore the use of additional spatial dimensions to help explain what they do not now understand. I can assure you from personal experience that it is a promising avenue to pursue.

Let’s meet again at the same time next week.

– Well thank you Davey. I was afraid that you might find my discussion either much too simple or totally incomprehensible! It is very helpful to get your reactions to what I say, especially as I know you have a habit of talking to others who may know a lot more than I do about any given subject.

You should find our next discussion much easier to understand, though many humans get a headache as soon as the word “statistics” is mentioned.

In much of human experience we encounter potential events that either cannot happen (i.e. have zero probability) or that are certain to occur. Of course we often have to deal with situations that might or might not occur, though we seldom feel impelled to understand in numerical terms just how likely it is that a particular event will occur. Our distant forebears didn’t have the tools available to make such calculations, and we clearly have little innate drive to calculate probabilities. In many fields of science it is important to place a value on the likelihood or probability that a particular event will take place.

So, next week I will try to give you a feel for the human fascination with lotteries, and other statistical marvels, and show you how knowledge of statistics can help us to better understand our origins.

Before I could say another word I sensed that he had withdrawn to another universe.