Christopher Potter, You Are Here: A Portable History of the Universe, Harper, 2009
The title of this book, You Are Here, is derived from a common childhood activity of trying to write out one’s complete address: Planet Earth, The Solar System, The Milky Way Galaxy, The Universe. Potter begins his book with the assertion that science is an extension of the kinds of questions we all asked as children.i I can remember laying awake in bed at night, myself, as a child thinking about questions like, What does it look like just beyond the outer edge of the universe? If there is “nothing” beyond, then what does “nothing” look like? When I got older and went to college I attempted to revisit some of these same kinds of questions from a somewhat more sophisticated perspective. Questions like, What does it mean to contemplate my own existence and to confront my impending non-existence? In philosophy courses I did my best to slog through Sarte’s Being and Nothingness, and tried to courageously follow Kierkegaard as my guide through Fear and Trembling. However, science courses didn’t appear to even try to address these kinds of questions. Within science, as Potter puts it, the meaning of the universe often appears to be reduced to a set of index cards with facts: hydrogen has one neutron and one proton, mammals have a placenta, etc. The universe described by science comes across as immense, cold, and uncaring. In fact, for most of us it seems pretty bleak to contemplate that science might be all there is. What could science possible tell us about meaning, existence and non-existence? Well, actually, quite a bit, as it turns out.
Contained within the narrative of this book, the reader will encounter lots of facts discovered by science, many of them unappreciated by most non-scientists. I make a list of a few “amazing facts” I learned while reading this book below. However, embedded within this narrative one also encounters some pretty sophisticated philosophical ideas pertaining to Ontology, Metaphysics, Epistemology, and Philosophy of Science. And the book courageously pushes beyond the traditional boundaries separating science from religion, revealing that creation stories told from the perspectives of various religious traditions have a surprisingly close kinship with cosmology stories told by contemporary scientific theories.
This latter claim is not new. It is frequently put forth by authors writing from religious traditions, particularly from contemporary writers espousing a New Age theological perspective. However, it is rare to see these ideas discussed in a substantial manner from a scientific perspective.ii There is a theology encapsulated within this book, but probably not one that will be familiar to most readers. The theology is materialism, a concept that many will assume is too small to encompass large theological issues, but wait until you read the book before jumping to that conclusion. The materialism articulated in Potter’s book is large enough to compete with traditional theological systems in trying to provide answers to questions such as: Where did we come from? What is our ultimate fate? What is the Meaning of the Universe?
Show and Tell: Some Amazing Facts about Our Universe
Before delving into a discussion of some of the big issues discussed in the book, let me first engage in a “show and tell” session. Here is a list, in no particular order, of a few of the amazing facts about our universe that I learned about while reading Potter’s book:
- In 2004, a huge void was discovered in space. Some scientists have conjectured that this resulted from our universe having had a collision with another universe.
- Longest animal on the planet is the bootlace worm, about 180 feet long.
- Smallest known living organism is the nanoarchaum, an organism about 400 nm (billionths of a meter) in length that lives deep in the ocean under extreme conditions near hydrothermal vents.
- When a beam of light leaves the sun it has to travel for almost a year before it even gets out of our solar system.
- Our nearest neighbor galaxy, a dwarf galaxy named Canis Major, was only discovered in 2003. It is slowly being swallowed by our own galaxy, The Milky Way.
- Up until the 1920’s it was thought that our galaxy, The Milky Way, was the only galaxy – that it was the entire universe. Now we know that the Milky Way is part of a group of about 40 galaxies that make up a gravitationally held structure called the Local Group. This Local Group is only one of at least 100 other similar groups bound gravitationally into what is called the Virgo Supercluster, and this is only 1 of about 10 million superclusters in our Universe. And modern theories of physics propose that our universe might very well not be all there is; Our universe might be only one of many that collectively form a larger Multiverse.
- Aristotle, the founder of empiricism, asserted that men and women have different numbers of teeth, an assertion easily refuted by simply looking in the mouths of men and women.
- Our solar system orbits the center of the milky way galaxy every 225 to 250 million years.
- Bacteria have been found in rocks 1,000 meters underground that divide only once every thousand years or so.
- In the Newtonian world, the speed of approach for two beams of light traveling towards each other would be twice the speed of light; for Einstein it would be no faster than one times the speed of light because the speed of light cannot be exceeded.
- In Einstein’s special theory of relativity light beams travel through space, but they do not travel through time.iii
- There are some distances and times that are so small they do not exist as such.
- Einstein’s general theory of relativity predicts that a clock higher up from the surface of earth should tick slower and thus appear to slow down relative to a clock on the surface of the earth. This has been demonstrated empirically by measurements of two clocks at Harvard, one on the ground and one in a tower.
- Objects as large as Buckminsterfullerene molecules (made up of about 60 carbon atoms) can demonstrate quantum properties, such as passing simultaneously through both slits in a classic double slit experiment.iv
- One interpretation of quantum physics is that the universe we perceive and know is just one of many universes that collectively form The Multiverse. Schrodinger’s live cat and the dead cat v both exist in different universes. All the possibilities defined by the quantum physics equations exist simultaneously, but in any one universe, only the possibility that was brought into existence by an observation exists.
- The physicist David Deutsch asserts that we may soon have evidence in support of the many worlds (Multiverse) hypothesis. He states that we appear to be very close to inventing quantum computers that work. Once we have done that, he asks, Where is it that we propose quantum computing takes place?
- The Italian physicist Enrico Fermi is quoted as having responded to a student: “Young man, if I could remember the names of all those particles, I would have become a botanist.”
- Einstein worked with Podolsky and Rosen to formulate what is now referred to as the Einstein-Podolsky-Rosen (EPR) paradox.vi Their intent was to show that if quantum theory were correct, it would lead to a prediction that is ridiculous, a prediction they called spooky action at a distance. However, in 1982, an actual experiment was performed, turning the EPR thought experiment into a real experiment. The result confirmed spooky action at a distance.
- The materialism that results from modern quantum theory is now so bizarre that it is difficult to use the criterion of “bizarreness” to separate scientific theories from world views derived from mystics, religious perspectives, or crackpots.vii
- String theory is now so complex that there are about 10500 universes that it might be describing.
- When scientists measure how much mass there is in the universe, they discover that our current theories are only able to account for about 5% of what has to be present. Thus, 95% of the matter that we know makes up our universe is elusive Dark Matter, stuff that is hiding out there somewhere, but, to date, thwarting all of our methods of trying to find it.
- It was discovered in the 1990’s that about 5 billion years ago, our universe started expanding at an accelerating rate. A rate so fast that gravity will not ever be able to bring it back together. The ultimate fate of our universe is now known – it will continue to expand until it eventually loses all of its heat. We started with a big bang and will end in a big freeze.
- We are literally made of star dust. Prebiotic molecules (molecules that are essential to produce biological organisms of the kind found on earth) were not found in the universe until about 9 billion years after the big bang. These molecules are formed during the life cycles of stars, and there had to be several cycles of star births and deaths to produce enough of these molecules to make life possible in the universe.
- It is possible, perhaps even probable, that life on earth has cometary origins. If so, when we search for aliens, we might be searching in the wrong place – we are aliens. An example of a finding that makes this notion plausible is a massive rock called a chondrite that fell to earth in Australia in 1969. It contained 74 amino acids, seven of which are found in proteins in living organisms. These molecules were formed in outer space out of star dust long before life existed.
- For a long time it was thought that all living organisms depended on sunlight. Then in the 1970s, organisms living near hydrothermal vents in the ocean were found that use chemicals in the water for energy, and do not depend on sunlight.
- Until 1992, our solar system was the only multiplanetary system we were aware of. The first terrestrial planet outside of our solar system was not discovered until 2002, and the first Goldilocks planet (a planet similar enough to earth that we might be able to survive on it) not until 2007. For anyone who believes that our planet is unique in the universe, the window of opportunity for holding on to that belief is getting steadily smaller.
- Current theories of physics make a prediction that something called the Higgs particle, sometimes called the God particle by physicists, has to exist. The Large Hadron Collider (LHD) particle accelerator recently brought into operation in Europe should be able to find this particle if it does exist.
- There is increasing evidence that particle physics, based on observations of very small bits of matter, and astrophysics, based on observations of the universe as a whole, are describing the same reality. For example, particle physics predicts that there must be seven protons produced for every neutron under the high energy conditions that were present in early stages of the universe shortly after the big bang. Measurements of the constituents in our current universe confirm that ratio.
- Quantum theory states bubbles are constantly forming out of nothingness in the quantum foam. Most leave the foam for a short time and distance and then fall back into the foam. But when one happens to escape, a new universe is formed. This is what happened to form our own universe, and presumably many other universes that collectively form The Multiverse.
- A modern update on the original big bang model is referred to as the inflation model. In the original big bang model, it was assumed that the entire universe was present from the beginning, it was just compressed into a tiny point that exploded during the big bang to fill out our current universe. However, the inflation model allows the current universe to have emerged from only about 20 pounds of quantum stuff at the beginning. This opens the possibility that it might be possible for a scientist to create a brand new universe working with a few pounds of matter in a laboratory.
And on and on. I could easily double the size of this list. I hope this sample of a few of the gems in this book will motivate some to pick up a copy and read it. It is worth perusing simply as a catalog of many amazing scientific facts. However, the real strength of the book lies in the big ideas that are discussed, and it is to a few of those ideas that I turn my attention in the following sections of this essay.
Descarte’s Dualism: What is the relationship between the physical and nonphysical parts of the universe?
For more than 300 years, since at least the time Descartes’s proposed his ideas about dualism, Western Civilization has divided the world up into physical and non-physical. Science got the physical, and the rest, such as minds, souls, and deities, were allocated to philosophy and religion. The methods and laws of science, it is asserted, apply only to the physical universe, and have nothing to say about non-physical entities.viii
Individual scientists, though, have to live in the full-fledged universe, the universe populated by conscious minds and religious beliefs and multitudinous other non-physical stuff. Thus, every scientist has to come to grips with how to relate to these two worlds, the physical world described by science, and the rest of the world in which the scientist lives.
Some scientists deal with this situation by denying the existence of non-physical phenomena such as deities and souls. This is a common approach taken by scientists who adopt atheism as a belief system. Dawkins, for example, argues that beliefs in souls or in a God are simply delusions created by human minds.ix These entities have no real existence so there is no reason to ponder questions about what they might mean.
Other scientists are able, by compartmentalizing, to simultaneously hold the view that everything in the physical universe is accounted for by the laws of science, while at the same time maintaining a belief in a particular religious or metaphysical system. There is no inherent logical contradiction, for example, for a scientist to believe that all physical phenomena are subject to scientific laws, and all religious phenomena to tenets spelled out by specific religious dogma. An example would be the Judeo-Christian belief system in which the physical universe is treated as a creation of a preexisting nonphysical entity, God. The laws of science are interpreted as reflecting laws put in place by God to govern the physical universe, but only apply as long as the physical universe is present. God’s laws, however, are considered to be eternal reflections of a deeper reality.
Most philosophical systems that incorporate dualism, approach it, as Descartes did, from the perspective of realism. In other words, the perceptions of the world that are formed in our consciousness are assumed to be caused by the physical world. However, other philosophical systems, various forms of idealism, posit that the causal relationships go the other direction. It is our conscious perceptions that cause the existence of the physical reality. In other words, the non-physical entity called consciousness is the ultimate reality, and the physical world does not exist independently, but must be conjured up by consciousness.x The essence of idealism positions is captured by the riddle, How do you know that you are not simply someone’s dream, and as soon as that person wakes up, you will go out of existence? Quantum theory poses a similar riddle about the universe, If human observers disappeared tomorrow would the universe disappear? If there were no complex structures like our brains present in the universe, would properties of the universe such as the past, the present moment, and the future have any meaning?
For most of us raised and educated in Western Civilization, realism seems intuitively obvious and idealism too far fetched to take seriously. However, Potter points out that many aspects of quantum theory are perhaps more compatible with idealism than with realism. It is not at all clear from the quantum theory equations whether it makes more sense to adopt the point of view that the universe creates consciousness or that consciousness creates the universe. Only possibilities exist in the quantum world, and an act of observation is required in order to create a real physical particle out of these possibilities, a particle that has defined physical properties such as location and momentum. It is our consciousness of the moment that seems to be required to bring it into existence.
One problem that all metaphysical systems based on idealism have to deal with is how to avoid devolving into solipsism. The philosopher Bishop Berkeley, a proponent of idealism writing in the 18th Century, for example, posited that God constantly perceives the entire universe so as to keep it present when we humans are not observing it. A more modern solution discussed by Potter is to depend on other complex life forms living at various times in different parts of the universe to fill out the moments of the distant past before humans existed, and the distant future when we will no longer be present to bring it into existence. With enough telescopes aimed in all directions from far flung positions in the universe, every part of the universe could theoretically be seen by someone. We humans are, in this scenario, storytellers who get to tell a few parts of the story, and for only a scene or two, but the complete construction of the universe depends on other story tellers living at other times and places.
It takes about 9 billion years to evolve complex life of the type found on earth, so it might seem at first thought that this solution would not work for bringing the early universe into existence. However, there are many “nows” overlaid in the “now” any single one of us is experiencing at this moment. I can be looking at a distant star “now”, and see it as it existed billions of year ago. Astronomers are currently busy at work observing the cosmic radiation, a remnant of events that took place shortly after the big ban.
Potter also describes a modern approach to dealing with these kinds of issues that differs subtly from realism, idealism, atheism, and all of the other forms of dualism. This is the system he calls materialism. Like atheism, materialism rejects the major premise of dualism, that the universe is made up of two kinds of things, physical and non-physical. However, atheism arrives at this point by eliminating the nonphysical parts of the universe, by denying the existence of the non-physical entities. Materialism, on the other hand arrives at this monism position by expanding the idea of what is meant by the material universe such that it encompasses both what was traditionally meant by the term physical universe and what was traditionally referred to as the non-physical universe. Questions such as, “Where did we come from?, Where are we going?, What is the meaning of our existence?”, questions that have traditionally been considered to be metaphysical or religious in nature, are now addressable under the rubric of materialism.
In this modern version of materialism, our universe paradoxically sprung into existence out of “nothing”. The primordial quantum foam that gave rise to our universe is physical material, but it is not made of physical particles that exist in the dimensions of time and space. This assertion is based on some mysterious numbers that crop up in theories of physics. One is Plank distance, the smallest measure of length that can be said to exist. Another is Plank time, the smallest unit of time that can be said to exist. Times or distances less than these amounts have no existence, at least no existence that our current understanding of the physical universe can define. Physical materials whose properties are smaller than these numbers are nothing (“no thing”). The elements of the primordial quantum foam fall within this category. They are material that exists outside of time and space.
Occasionally bubbles form out of this quantum foam. Usually these bubbles get pulled back into the foam before they get very far. But occasionally one gets away, and when that happens, a physical universe is formed, a universe with separate particles that can exist in space and time. That is how our own universe got formed, and presumably many other universes that together form The Multiverse.
The laws that govern The Multiverse, of which our own universe is a part, are incorporated within this primordial quantum foam. These laws are mysterious and eternal, i.e., outside the realm of time. They are describable, in some mysterious way, as elaborated on in the next section, in the language of mathematics.
What name should we give to these immutable eternal laws that govern The Multiverse? It is easy to get hung up on the names of things, especially when the names have been associated historically with movements or policies with which one does not want to be associated. This is one of the reasons many scientists profess to be atheists or agnostics – They simply do not want to be associated with much of what has been done historically “in God’s name.” However, if you change the name from “God” to “Order”, many scientists affirm the concept associated with that word. Most scientists, even those who profess atheism, would agree with a statement along the lines, “there is order in the universe, and that order has been present since the big bang event that created our universe”.
In many theologies, the “Order” that is eternal (outside the realm of time), and out of which our universe was created, is given the name, “God”. Within the Christian tradition, for example, this is made explicit in the phrase “In the beginning was the word…”,xi where “word”, translated from the Greek “logos”, is better translated as “order”. Modern scientific theories that describe what is present in the primordial quantum foam play a similar role for the materialist. They are an eternal (outside the realm of time) set of laws that are responsible for the creation of our own universe and how it operates today. St. Augustine wrote that time was created when God created the universe. Modern physics has a similar assertion. Time did not exist until 10-43 seconds after the big bang. Our universe appears to have formed from spontaneous eruptions out of nothingness, but a nothingness that has order, and has the capacity to create physical universes governed by that order.
The state of the universe we currently live in evolved out of radiation, eventually forming large scale structures such as stars. But if that had been as far as the universe evolved, Potter reminds us, it would still perhaps be a rather boring place; just a number of remote fires burning in the vastness of space. And who would have appreciated them, or wondered where they came from, or what their ultimate fate would be, or even cared. It is hard to even know what it would mean to ask what the meaning would be of such a universe. But our material universe did not stop with stars and planetary bodies. It evolved more complicated material structures, such as humans with brains, that can contemplate its origins and ultimate fates, a consciousness that now allows our universe to become aware of itself.
Potter informs us that materialism, as expressed in current theories of physics, probably needs a poet to do it justice. The poetry is in the mathematics.
Mysterious relationships between mathematics and empirical science?
There are two kinds of science that are quite different, but often not appreciated by the public. Empirical science has to do with making observations of the universe and summarizing those observations. Theoretical science has to do with ideas, often expressed in the language of mathematics, that describe physical reality. The origins of these two approaches to science are often traced back to Plato and Aristotle. Plato was interested in trying to discover universals that applied to the entire world. Plato also believed that ultimate reality exists only in the world of ideas. He described the physical universe as being analogous to dim shadows being projected onto the walls of a cave. It only appears to us that these dim shadows are reality because that is all we can see. But ultimate reality exists only in the unseen world of ideas that is casting the shadows. It was Plato’s student Aristotle who emphasized the role of the empirical method, making observations of the actual physical world, in science.
A major part of theoretical science has to do with making evaluations of ideas. Evaluations along the lines that this particular theory is “beautiful” and thus likely to be a correct description of physical reality while some other theory, one that perhaps can explain the same number of observations, is ugly, and thus should be jettisoned. Einstein, for example, was often quoted as being convinced that his theoretical ideas were correct, long before there was any empirical evidence to support them, because he found them to be beautiful.
Evaluations of scientific theories based on the attribute of beauty also have a historical relationship with mathematics. Going back to the Pythagorean School in ancient Greece, there was a belief that what is ultimately real has to do with perfect mathematical ideas, not the physical universe. There are many historical examples of the mysterious operation of mathematics in making predictions about properties of the universe that later turn out to be correct. Here are a couple of examples taken from Potter’s book.
Maxwell formulated some equations to describe properties of light, but discovered that these equations could only be solved mathematically if light was considered to be invariant. This idea is so counter-intuitive that Maxwell assumed this was simply a mathematical statement of truth, not a statement about the true nature of the physical universe. Einstein took the truths expressed by those equations as being descriptions of the physical world and gave us the scientific theory of relativity.
Dirac found solutions to a set of mathematical equations that were thought to represent physical reality, but his solutions required negative values. This mathematical solution seemed too strange to correspond to physical reality. In fact the conjecture by some physicists that these mathematical solutions might actually apply within the realm of physics was said by Heisenberg to be “the saddest day in the history of physics.” Then antimatter was discovered.
Why mathematical solutions should be able to describe physical reality is a complete mystery. Mathematical equations are pure (non-physical) ideas. They are not derived by making observations of the universe. A mathematician does not observe the world to solve equations, he or she simply thinks.
The opposite would seem to make more sense. Scientists, one would think, should first observe some properties of the physical universe, and then set out to see if there are mathematical equations that can be used to describe those relationships. However, what actually happens is often quite different. Mathematicians, working in isolation from the physical world, simply sitting and thinking about mathematical ideas, first come up with solutions to certain equations, sometimes solutions whose properties appear too bizarre to apply to the physical world, and discover later that these equations made predictions about properties of the physical universe that turned out to be true.
I suppose it is a logical possibility that this is a total coincidence. But a more parsimonious explanation would seem to be that there is order in the universe, and this order can be described in the language of mathematics. Divvying up the universe into Descartes’ realms of the physical and the nonphysical, mathematics has to fall within the nonphysical realm of ideas. Where did the mathematical equations that happen to describe our physical universe come from? Some traditional religions would attribute them to the mind of God; a materialist to the Order that is eternally present in the primordial quantum foam.
Science’s Creation Story: Cosmology
Modern scientific theories are similar to many religious theologies in that they describe a creation story for the universe that has a beginning (the big bang) and an ultimate fate (the big freeze). This was not always the case. Newton saw the universe as being eternal in space and time with universal laws that applied to all parts of the universe and at all times. Similarly, up until the 1920s most scientists believed that the world is eternal, infinite, and uncaused, in need neither of an act of creation nor a creation story. Einstein’s general theory of relativity, published in 1915, did not describe a stable universe, but he was so troubled by this that he added a cosmological constant to his theory that had only one purpose, to make the universe stable.
Other theoretical physicists in examining the implications of Einstein’s general theory of relativity realized that the theory actually described an expanding universe. But if the universe is expanding, expanding from what? Mathematicians discovered that if one uses the equations to run the universe backwards in time, it is contracting towards a point. Modern science now accepts a world view much different from what was accepted prior to Einstein. Our universe had a starting point (the big bang) out of which the current state of our universe was created, and it has a future.
The big bang theory has gone through some revisions in recent years. Originally, it was not assumed that the universe originated out of nothing. It was simply that the universe was compressed into a very small size. Then at some particular moment (perhaps this statement is meaningless since time did not exist at that moment), an explosion occurred and this small point of unimaginable high intensity started to expand, and has continued ever since, based on the same laws of physics that have been present since the big bang.
The story of the big bang being told by current scientific theories is somewhat different. Now we have the universe being formed out of nothing, a bubble forming out of primordial quantum foam, at the moment of the big bang; Perhaps only one of a number of universes that have, or will, be created, known collectively as The Multiverse. The transitions from the original idea of a stable, unchanging universe; to that of a universe that has always contained the same amount of stuff, but is changing in size as that stuff expands starting with the big bang; to the current notion that our universe might have formed out of “nothing”, came gradually as scientists and mathematicians explored the implications of the theories of relativity and of quantum theories. Potter tells a story of a meeting between Goerge Gamow and Einstein. As they were walking Gamov revealed to Einstein an insight he had derived from Einstein’s own theories, that the universe could have come into existence out of nothing. Einstein was so struck as the implications of this insight began to sink in that he stopped in the street where they were walking, causing several cars to have to come to a halt.
Over the past several decades there has also been an evolving understanding about the ultimate fate of our universe. Until recently, some scientists thought it would expand only up until a certain point, and and would then (due to gravity) begin to contract again, ending in a big crunch. Others thought it would arrive at a steady state and then stay in this state forever. A third possibility, and the one favored by current scientific theories, is that the universe will continue to expand forever, the big freeze. The evidence on which this current understanding of our fate is based comes from measurements showing that our universe is not only expanding, it is expanding at an accelerating rate. In fact it is expanding so fast that there is not enough gravitational force present in the universe to stop the expansion. So our universe will continue to expand until it reaches absolute zero, the big freeze.
Einstein originally added his cosmological constant to his theory of relativity because he could not accept the idea that space is not constant. Later, he stated that adding this constant was the biggest blunder of his career. So he took the constant out of his theory after resigning himself to the fact that the universe is in fact expanding. Now, modern theories have had to put a constant back in, this time with a new value, to account for inflation faster that predicted by Einstein’s theory. So, Potter suggests, perhaps Einstein was not wrong to insert a cosmological constant into his theory after all; he just put it in for the wrong reason.
As the universe continues to expand, eventually the nighttime sky (whatever that means at that point in time) will gradually empty out into complete blackness. After that comes the dark era, which for our universe lasts forever. Hope, if that term is to have any meaning, must lie in The Multiverse.
Technology, The Advantage of Materialism over other Theologies
Potter informs us that what science does is measure the universe and its contents, and by measurement he means any systematic observation of what we take to be the outside world. In order to measure something, it is first necessary to separate it out from the rest of the universe. Thus science involves separating the universe into measurable parts and then describing relationships between those separate parts. But, Potter cautions us, science itself is not divisive – this is a confusion between the methods of science (observation and measurement of parts) with scientific theories that attempt to describe a unified reality.
If science can be said to search for “truth” at all, is in the sense of always moving towards theories that have “greater truth” than those that came before, not in the sense of seeking absolute truth. Science is always provisional; something along the lines, “This is the best guess we have about how the universe operates based on the experiments that have been performed to date. But we will throw our theory out tomorrow if new evidence supports a new theory better than the current one.”
The advantage of the scientific method as opposed to other ways of relating to the world is that the scientific method gives rise to progress based on technology. Technology is the evidence that science is getting somewhere. The name Potter gives to this world view based on progress is materialism.
Potter ends his book with a metaphor attributed to the physicist Robert Jastrow. I will paraphrase the essence of the metaphor. A group of theologians are climbing a mountain of ultimate truth. Each step as they ascend the mountain they are getting closer to the ultimate truth of the universe, and know that they will have attained this ultimate truth once they reach the summit. Nearby, a group of scientists are also climbing a mountain, this one a mountain of scientific truths. When the two groups each cross the threshold of the summit, they meet up with each other and realize they have been climbing the same mountain the entire time, just coming up from opposite sides. They had both thought they were climbing a dual set of mountains, one containing theological truths and the other scientific truths. Now they realize that there is only one mountain, and it is made of material.
i During our book club discussion of You Are Here, Neil related a story about a group of school children who went on a field trip. They encountered one of those maps with an arrow pointing to a spot labeled, “You Are Here”. One of the students asked the teacher, How do they know that?, a question with enough levels of profundity to fill a book, which is essentially what Potter has done here.
ii I do not have enough background in mathematics to be able to evaluate the mathematical underpinnings of theoretical physics that are discussed in Potter’s book. However, a former colleague of mine from Emory University who has a background in theoretical physics informs me that Potter has gotten most of the physics right.
iii This is a fact that I already knew, but the description Potter gives about this fact provided me with new insights that allow me to now have a much more intuitive understanding of what this fact means.
iv In the classic slit experiment, a beam of light passes through two narrow slits and then illuminates a screen located behind the slits. Looking at the light on the screen, one sees a pattern of light and dark regions called interference patterns. The traditional explanation for interference patterns was that photons of light exhibit wave properties such that two photons that pass simultaneously through the two slits can interact with one another, analogous to the way waves on water passing through two tunnels side by side interact when they emerge into a reservoir. More recently, this explanation has had to be modified. The screen behind the slits can be replaced with film that is exposed when the photons of light reach it. Then the beam of light that is passing through the slits is made so dim that no more than one photon ever passes through the slits at one time. Nevertheless, if this is allowed to continue for a long enough period, an interference pattern is seen when the film is developed. This means that , in some real sense, a single photon of light passes through both slits and interacts with itself. The dual nature of light, exhibiting simultaneously wave-like and particle-like properties, is paradoxical, but is consistent with quantum theory equations. The Buckminsterfullerene molecule experiments demonstrate that this quantum weirdness is not limited to photons of light, but also applies to small molecules of matter.
v Schrodinger used the example of a cat to demonstrate one of the paradoxes created by quantum theory. He imagined a cat locked inside a box with a radioactive particle. If the particle has decayed, the cat is dead, otherwise it is alive. According to the standard Copenhagen interpretation of the implications of quantum mechanics (formulated by Bohr, Heisenberg and others in the years 1924-1927), it is impossible to state whether the radioactive particle has decayed or not until the box is opened and a measurement has been made. So Schrodinger’s cat is not allowed to exist in a state of being dead nor in a state of being alive. While in the unopened box it only exists in a state of possibilities, dead or alive. Potter also discusses a different interpretation (formed more recently than the standard Copenhagen interpretation) that eliminates the need for consciousness. According to this new interpretation, a quantum object that exists only as a waveform of superimposed possibilities can be collapsed into a particular reality through interactions with classical material objects (clumps of matter too large to have quantum properties). By this interpretation, the very presence of the cat within the box would be sufficient to collapse the waveform of the radioactive particle and cause it to be either decayed or not-decayed.
vi In the EPR paradox, one imagines that two particles have been entangled such that they are guaranteed to have opposite properties, such as opposite spin. Then the two particles are released and allowed to travel different directions in space. It is impossible to know which particle has which spin until a measurement has been made. But once a measurement has been made on one particle, one instantly knows the spin of the other particle, even if the other particle is at that moment located light years away in the far reaches of space. This would seem to violate one of the fundamental tenets of Einstein’s special theory of relativity, that information can never travel through space faster than the speed of light. The seemingly instant transfer of information regarding the state of the distant particle is what EPR meant by spooky action at a distance.
vii Einstein, even though many of his ideas went into the formulation of quantum theory, could never accept many of the bizarre implications of the theory such as the idea that electrons only exist if someone observes them. Until his death Einstein held out hope that a new theory could be obtained that maintained objectivity – laws that describe the nature of the universe whether or not it is being observed by anyone.
viii This is the position adopted by my own discipline, psychology. The textbook I use when I teach Introductory Psychology makes this position explicit in the opening chapter by differentiating what it refers to as scientific questions and metaphysical questions. Questions such as, “Does God exist?”, or, “Is there an afterlife?”, are listed as examples of questions that are metaphysical in nature, and thus fall outside the realm of what can be addressed by the science of psychology.
ix R. Dawkins, The God Delusion, 2006.
x I discuss various philosophical positions regarding relationships between consciousness and the physical world in my own book: R. G. Boothe, Perception of the Visual Environment, Springer-Verlag, 2002.
xi The opening sentence from the book of John in the Christian New Testament.