Is the Real World Really Real?
Is reality real? Such confusion!
Can it be that it's all just illusion?
Scientists speculate. But none of them reach a conclusion.
Abstract: The human imagination is a wonderful thing. Unfortunately, we have the ability to imagine many things that just aren't so. When we imagine the impossible, logic is useless, and science is helpless to deal with it. Impossible things need not follow the same rules that apply in the world of our sensory experience.
Scientific concepts are often derived from naive everyday concepts, and are even named using the same colloquial words, giving these words the status of technical terms. Such words as space, time, mass, force and theory are examples. When these words are given precise definitions as technical terms, their definitions are usually at variance from their colloquial meanings. Non-scientists sometimes deceive themselves into thinking that their colloquial meanings are sufficient to understand their scientific meanings. After, all, aren't these things "real", part of our everyday experience? Surely we can understand them in simple terms? The more we learn about nature, the more we strain this comfortable view.
For example: Einstein's relativity forced us to accept that space and time are not "absolute", and that measurements of time, distance, and even mass, give different values for different observers even when observers are measuring the same natural event or process. Reality suddenly became "elastic", but in a very precise and dependable way, because we learned the laws that allow us to precisely relate measured values from one observing frame to another.
Another example: Quantum mechanics upset our naive view that material things have a precise location in space and time, and can be counted upon to be found where they are predicted to be. But experiments showed that on the scale of photons, electrons and other tiny pieces of matter, we can not predict precisely where they are be found, but only the probability that they will be found in a particular place.
Still another: Matter, which we thought was something quite distinct from energy, was found to be sometimes converted to energy and vice versa.
These relatively recent developments still allow us to write equations for the behavior of things, and to deal with them quantitatively and precisely. But this new knowledge certainly shattered our naive view that the "real world" and the "real things" in that world behaved in the same manner as objects in the world of our direct sensory experiences.
We had been warned. Some philosophers, like Ernst Mach (1838-1916), questioned whether atoms were really real. Mach thought that the only real things were those that we could see, feel, hear and touch—things accessible directly to our unaided senses. Sense perceptions were the only reality, all else was hypothetical. Mach admitted, for example, that atoms and chemical formulae were a "useful fiction", but we shouldn't call them "real".
Other philosophers even suggested that nothing is real—all is illusion. Scientists ignored them. It didn't matter anyway, scientists said, for so long as the illusion is consistent and behaves in a reliable and regular manner, we can do physics on it. Leave it to philosophers to fuss about what's really real. 
Philosophy is something to think about, but you can tie your brain in knots doing it. Some branches of recent physics—cosmology and string theory come to mind—have become so far removed from what we used to call "real" that some non-scientists wonder whether physicists have lost all touch with reality. Some critics have even said that these theorists are only doing mathematics, not physics, and have challenged them to "come up with even one experimentally testable prediction of something we don't already know." 
Bookstore shelves contain many books trying to explain these new speculative ideas to laymen. Sometimes it's hard to distinguish some of these books from science-fiction. But even the best books, written by folks who really understand what they are talking about, bump up against the formidable obstacle of language. They try to explain esoteric mathematical theories without using mathematics. That can't be done. Something always gets lost in translation.
Probably the most funda- mental physical concepts are space and time. Surely we know what we are talking about when we use these words. Maybe not.
We now have good evidence that way back in time there was an "earliest" time for events in the universe. There was no earlier time. That particular time is sometimes called the moment of the "Big Bang". This is an unfortunate choice of words, for it suggests an explosion like that of a bomb. Some popular books even call it the "moment of creation" which carries theological implications that are also unfortunate. Already language is beginning to cause us problems. But it gets worse.
The word "beginning" suggests the start of something, or the emergence of something that wasn't there before. But "before" suggests an earlier time. Was there a time earlier than the big bang? How could there be, for this "earliest time" in the universe was the point where both time and space and energy were first in existence? Before this "event" there was no such thing as time. But even that's not accurate, for there was no "before". 
Thinking of the "big bang" as an explosion is misleading. A bomb explodes and releases energy, energy that was stored within the bomb before it exploded. The universe had no "before". This bothers people who find it hard to think that something (matter, energy and all the rest) can arise from nothing. They are thinking in the framework of the bomb analogy. Even to say there is "nothing" outside of and before the universe is saying too much, an assertion we cannot confirm experimentally. 
Didn't I warn you that thinking about these things, and the words we use, could tie your brain into knots? Every time we try to write a meaningful sentence we run against words that we thought we knew very well, that simply don't convey the intended meaning. Our natural language, developed to deal only with things in the universe of our everyday experience, is simply inadequate to talk about anything else that we might imagine.
And where did this big bang happen? There was no "where" until it happened, for space and time have meaning only after it happened. And even now, all space is in the universe, and it's meaningless to ask what, if anything is "outside" the universe, if we even know what "outside" means in this context.
We, and all of our tools for observation and investigation, are part of this universe we inhabit. They do not permit us to see or study or even talk sensibly about anything else. So to wonder what is "outside" the universe or what was going on "before" the universe is idle fantasizing. It is an attempt to answer an unanswerable question. 
We have used these examples because they are ones that even non-scientists have heard about.
Physicists construct mathematical models of nature and its processes, usually expressed as equations. Sometimes these mathematical models may be visually displayed as graphs, plots or, nowadays, as three-dimensional computer displays. But the fact that we can visualize something doesn't guarantee that it's real, and often the visual presentation is not the whole picture, and can mislead. [Also, just because we can invent a name for a concept doesn't guarantee that the concept is something real. But even if it isn't real, it still may be useful.]
A good example from the history of physics is the 19th century concept of the field which had its roots in Newton's mechanics. Newton's gravitational theory described how bodies could exert forces on each other, even with nothing between them. This "action at a distance" was at first hard to accept. Many thought it an "occult" idea. But it worked so well that it was gradually accepted. In the 19th century when Faraday described interactions between charges he used a field concept, in which the forces between bodies were due to electric fields that were "in" the intervening space. Faraday's conception of these fields was a concrete one. He tought that field lines were elastic stresses in the "luminiferous ether" a tenuous medium that most scientists at that time supposed filled all of space, and even filled vacuums. A similar field theory was used for gravitational fields and magnetic fields. Well into the 20th century this conception of fields was used in textbooks, even after scientists realized that there was no such medium as the luminiferous ether. I can remember professors who used to tell us that "4π" field lines radiate from each unit of charge" (in the cgs unit system). They weren't asserting that as a "truth" but as a conceptual crutch. Yet, students often imagined field lines as if they were as real as a tree or a rock. Later, after taking higher level courses, we realized that this was just a conceptual model, convenient for visualization only. The field lines were only lines drawn on paper to make pictures of the situation.
Later, physics students learn that force, energy, and momentum are not really necessary for doing mechanics problems. Lagrangian and Hamiltonian methods accomplish the same results without those concepts. So were those concepts "real"? Apparently not. They were only convenient concepts, just as those field lines were.
Eventually we come to the realization that all concepts, time, space, mass, force, energy and all the rest are not something we "discover" in nature, not things that are "in" a real world, but concepts we invent in order to conveniently describe the behavior of things that we do observe in nature. We also realize that no particular set of concepts, even if they work perfectly, are "sacred". If we wanted to, we could replace them with an entirely different set of concepts that could work as well. But working out the details would be a huge task. We have seen that happen in the history of physics with Lagrangian mechanics, relativity, and quantum mechanics. Nature does what it must , without regard to the particular way we choose to describe it or the concepts we use in equations.
It takes a while, and lots of physics courses, to fully appreciate this. Non-scientists have a harder time of it, and prefer to "wallow in reality".
I'm not saying that "anything goes" in our descriptions of nature. Whatever clever models we invent, they must be grounded in observations and experiment. Any concept that has no precise and unambiguous connection at all to observations, or to experiments that we could perform, has no place in physics. It is useless. That's what killed the luminiferous ether. All of the clever experiments devised to detect the ether or to measure its properties failed miserably. Yet the concept of the ether was being used (somewhat successfully) in physicists' thinking. Then along came relativity theory, which answered many of the nagging questions in a new way, and relativity theory did not even mention the ether. The ether wasn't necessary! After a while that fact was accepted and realized, and the ether was abandoned. Today it only rates a footnote in textbooks. It was one of those concepts that had no connection to experiment, and was experimentally unverifiable. But even today there are folks who try to revive new versions of the old ether theory. We call them pseudoscientists—purveyors of eccentric ideas masquerading as science. Now, the notion that there is some barely tangible "stuff" filling space has returned into mainstream science. However these new hypotheses have no direct connection to the old concept of the luminiferous ether.
Modern physics models are generally many steps further removed from observation than they were a century ago. The observations on which they are based require sensitive, powerful and expensive equipment, trained observers and powerful data analysis. The experiments are no longer something anyone could do with simple equipment. The concepts are often subtle and require higher mathematics to express them and relate them to observations. Still, everything we do in science must relate back to experiment, and every prediction must be experimentally testable.
Scientific progress requires creative speculation, and in the process many hypotheses are developed into full-blown theories before their consequences have been tested experimentally. These cannot qualify as "established science" before they have been fully and skeptically tested. Many appealing and wonderful speculative notions are killed by troublesome experimental facts. Sometimes years elapse before such speculative physics ideas are tested and accepted. But during that time they are "hot news" in the popular science magazines and in popular books. The non-scientist cannot easily separate established science from speculation and hypothesis. In fact, to the non-scientist, the speculation is more fun to read about.
The reader may be quite willing to accept that fields, wave functions, quantum strings and superstrings may be conceptual constructs that are somewhat less than real, yet still linked to experimental observations. But what about time, space and mass? Surely those are more concrete, being more closely linked to sense impressions.
How do we "sense" time? Perhaps we should ask instead "How do we measure time?" Clocks depend on the motion of something: a pendulum swinging, a spring turning an escapement wheel, or a tiny vibrating tuning fork. They all have some material object moving in space, and they depend on a natural regularity of some mass in motion. Even more modern timekeepers rely on motion: the natural vibrations of a crystal, or the natural vibrations of atoms. Without motion (and motion requires space) we'd have no way to measure time.
How do we measure space? Rulers, meter sticks, surveying, and laser beams are used. These measurement processes do not occur instantaneously; they require time. A laser beam needs time to get from one point to another, in order to measure the distance between those points. Even a meter stick measurement requires that the endpoints of the length being measured are observed simultaneously. That requires signals to be compared from each of the endpoints, and all signals travel through space at no more than the finite speed of light. So, again, there are time delays to be considered. Without time, we could not measure distances.
How do we measure mass? With a balance scale we can compare the gravitational force on two masses. When doing that, the two masses are at different places, with distance separating them.  Or a spring balance can be used, and the spring moves up and down in response to the weight. Distance is again necessary, and time is required. Or we could apply a force to a mass and see how much it accelerates, using Newton's law F=ma. To measure acceleration, the body must move through a distance. Without distance, we could not measure mass. And, time is required as well.
How do we measure force? Every method we use to measure force requires measurement of the motion the force causes of some material object. Even pressure and force transducers work by very small compression of a tiny sensor element. Without the motion a force produces, we could not assign a value to the force.
These simple considerations should convince us that space, time and matter are inextricably linked, and each concept would be meaningless without the others. That ought to have been clear even before relativity was formulated, but in fact the idea received little notice in the early history of physics. 
Special relativity, formulated in the early 20th century, is now well-tested and accepted. It showed that the concepts of time and space are inseparably bound into "space-time". Space is meaningless without time and vice versa. And matter and all else would be inconceivable without space and time.
Science fiction has often played with the idea that our sense impressions may be quite different from what's "really" out there that's causing those sense impressions. But that, of course, raises the question of whether we are real in the way we think we are. Could all of reality, ourselves included, be only virtual reality constructs formed in a giant cosmic computer-like brain? Such science-fiction concepts fascinate, but perhaps they are still too rooted in our limited ability to imagine. Even the idea of a vast computer of this sort is derived from our own mental models built from our sensory experiences with computers. We may suppose the truth to be "out there", but can we comprehend it with our limited intelligence?
The bottom line for such speculation is that we don't know, and even worse, we cannot know, the answers to such questions. Nor can we know whether the questions are even meaningful. Earlier we raised the question of determinism vs. free will. We think we have free will to make decisions that can affect our future and that of the universe. But we can't know whether that is true, and all we can do is behave "as if it is true". To attempt, through thought or experiment, to determine whether we have free will is simply futile, a waste of effort. But if we decide whether or not to waste time on such questions, did we really have any choice in the decision?
We often speak of the continuum of time from past to present to future. If space and time are bound together, and the universe includes space and time, then outside of the universe these words have no meaning. Let's fantasize for a moment that there really was an "outside" intelligence that fabricated the whole thing. And I mean the whole thing, from beginning to end of time. The whole history of the universe and everything in it is "there" in the creator's mind (if we even can use that term). The creator could examine it in detail, and see every point in the continuum of time. To this creator there's no mystery about past or future events; they are all an open book, completed as a work of art. We thinking creatures in this universe see only our present instant of time and the evidence left by events in a past time. Of course, because of the finite speed of light, when we look out to very distant parts of the universe we are seeing light that originated in past time, but that is far removed from the space path we traverse. We have no way to examine future time; we just have to coast along in time until we get there. To this hypothetical creator, there's no mystery about the future, for it is right there freely accessible for examination, a part of the completed creation.
We have ventured into speculative theology to make a point. Our human preoccupations with the future, and with free will, seem pathetic and pointless from the broader viewpoint. We see things with very constraining blinders. We are trapped like insects in amber, unable to break from the confines of our niche in space-time to gain this larger viewpoint. We are limited to sense impressions that allow us to form concepts that serve us well enough in everyday life, but prevent us from ever knowing what's "really" out there—if anything.
All of this suggests a deterministic universe. (But that, too, is a naive simplification.) This causes some to say "Why should I agonize over choices, for what happens is what must happen?" This notion of the inevitability of "fate" has been a common theme throughout history. It even appears in some religions, rephrased as "What happens is what the gods choose to make happen, and we are powerless to change that." At this point you may hope that I will say something encouraging and uplifting to give people hope and purpose. Nothing I could say of that sort would make any difference, would it?
Writers and philosophers have explored such questions throughout human history, and nothing has come of it. None of my rambling ruminations in this document are original with me. I have not referenced them, for to do so would double the length of this document. Besides, these themes have been freely borrowed by others many times before, from Plato to Thomas Aquinas to Douglas Adams. They are part of the common currency in the history of ideas.
In this short document I have illustrated the difficulties, paradoxes and impossibilities that arise when we try to invent answers to unanswerable questions. The human mind is capable of imagining many things that aren't so, and even things that couldn't possibly be so. But we also have an unfortunate tendency to believe in such invented fantasies.
It is perfectly possible for a clever person to construct a fantasy that is untestable and unprovable, yet seems perfectly logically consistent on casual examination. But when skeptically examined, all such fantasies invented and passionately believed by mankind, such as religions, contain logical contradictions that make them easy to discredit. Could this fact tell us something about the way our brains are wired? Or is it a trick played by a spiritual supernatural intelligence, to remind us that we haven't got it right—and never can? Could it be that true truths (as distinct from imagined truths) must necessarily have internal logical contradictions? Or could there be multiple truths, all mutually contradictory? Inquiring minds would like to know.
 Even though relativity, quantum mechanics and other recent developments of physics go beyond naive views of reality, they are still grounded in experiment, on things we can observe with the aid of sophisticated precise instrumentation. Any notion that has no experimental connection to the observable world is considered inadmissible in physics. It is considered science-fiction, pseudoscience, or philosophy.
 Most non-scientists imagine time as something that always existed and that the universe came into existence either by the "big bang" or an "act of God" at some particular point in time, and time may even continue if at some future time the universe ceases to exist. But those who think more deeply, philosophers, scientists and even theologians, aren't satisfied with this naive view. Even the religious philosopher and theologian St. Augustine of Hippo (354–430), who wrote a lot about such matters, concluded that there was no time "before creation", since "time itself was God's creation."
Yet some current cosmologists propose that time (or something timelike) might have existed before the beginning of the universe, and that space (or something like space) might exist outside of the universe. However, even they admit there's no direct way to test this assumption. They use this mathematical hypothesis to make predictions of things that we can observe.
 I leave for another time the issue of "cause and effect". In everyday life we see events as connected in time, and for many processes is makes sense to say that one event is the cause and a related event is its effect. To say this does not tell us how the relation works, just that we never observe these two events unconnected. In many cases, we never observe such connected events to be reversed in time. So we naively suppose that there is something like a universal law of cause and effect. It may be—within the observable universe. But when someone poses the question of "What caused the big bang" we are asking an unanswerable question, for it supposes we must connect two events, one "outside" of the universe in both space and time, when we have just argued that space and time have no meaning outside of the observable universe. We have created this paradox by our habits of thought and the inadequacy of our language. Or as H. L. Mencken observed of philosophers "They are always creating mysteries."
 Some theoretical physicists view the events since the earliest time to be happening in an even larger space-time continuum. This is at present a hypothesis, which may have testable consequences, but is not yet an established scientific conclusion. At present we have no evidence of such a larger space-time. If we should ever discover such evidence, that will simply expand our definition of the natural universe, but that will not affect the arguments here. But even then, the model of events before the big bang will not be anything more than a useful fictitious concept, not to be confused with what we think of as reality. It would be something like the concept of force fields. From a logical viewpoint, such a "cause" outside of the space and time of the observable universe would lead to the classic recursion problem. If X caused the universe, then what caused X? If Y caused X, tnen what caused Y? And so on, in infinite regression. As soon as we realize this, we see it is the same as the question "If God created the universe, what created God?"
This leads us into science-fantasy. Perhaps, as our universe runs merrily along, some civilization within it advances to the point where it has figured out how to initiate a "big bang" creation event. They do the experiment, and their event is the very one that led to us. A nice, neat closed loop of events. But the civilizations within it will still ask "What is outside of this loop?" and "Where did its matter, energy, entropy, etc. come from?" Some questions we can easily invent seduce us into imagining that we can find answers for them. We'd be wise to recognize them as impossible and leave them alone, but they continue to suck us in. It is like an addiction.
 "What is is what must be." (Gottfried Wilhelm von Leibnitz [1646-1716], German philosopher and mathematician.) All natural processes have constraints imposed by geometry and by the presence of other things nearby. What happens, and what is possible, is only what is allowed by these constraints.
 Many who have used balance scales assume that they are making a static measurement with everything in the system at rest. How would we know we had achieved the balance if we had not achieved that rest position by carefully adjusting the mechanism to remove the initial unablance? This requires motion of some part of the instrument. The resting condition of the scale might even have been due to a "sticking" malfunction.
 Classical physics was permeated with implicit, unexamined and untested assumptions that treated the real world as something "out there", independent of our sense impressions of it. If every person perceived events differently, it's hard to imagine how we could do physics. So the only part of our sense experiences that we trust are those that are precisely repeatable, no matter who does the experiment. But, we have learned that naive assumptions about the "real world" need to be put to the test of experiment.
Intelligent Design Creationism: Fraudulent Science.
Intelligent Design: The Glass is Empty.
Order from Disorder. Creation in Everyday Life.
Random thoughts on randomness.
Uses and Misuses of Logic.
The Scientific Method.
Proofs of Unknowables. The Proof is Pudding.
Theory or Process?
Is Intelligent Design an Interesting Philosophical Idea?
Why not Angels?
What's bugging the creationists?
Summary and Conclusions.