# What is Unreal Blog?

Tell us a little about why you started your blog, and what keeps you motivated about it.

As my writings started appearing in different magazines and newspapers as regular columns, I wanted to collect them in one place — as an anthology of the internet kind, as it were. That’s how my blog was born. The motivation to continue blogging comes from the memory of how my first book, The Unreal Universe, took shape out of the random notes I started writing on scrap books. I believe the ideas that cross anybody’s mind often get forgotten and lost unless they are written down. A blog is a convenient platform to put them down. And, since the blog is rather public, you take some care and effort to express yourself well.

I will keep blogging, roughly at the rate of one post a week or so. I don’t have any big plans for the blog per se, but I do have some other Internet ideas that may spring from my blog.

Philosophy is usually seen as a very high concept, intellectual subject. Do you think that it can have a greater impact in the world at large?

This is a question that troubled me for a while. And I wrote a post on it, which may answer it to the best of my ability. To repeat myself a bit, philosophy is merely a description of whatever intellectual pursuits that we indulge in. It is just that we don’t often see it that way. For instance, if you are doing physics, you think that you are quite far removed from philosophy. The philosophical spins that you put on a theory in physics is mostly an afterthought, it is believed. But there are instances where you can actually apply philosophy to solve problems in physics, and come up with new theories. This indeed is the theme of my book, The Unreal Universe. It asks the question, if some object flew by faster than the speed of light, what would it look like? With the recent discovery that solid matter does travel faster than light, I feel vindicated and look forward to further developments in physics.

Do you think many college students are attracted to philosophy? What would make them choose to major in it?

In today’s world, I am afraid philosophy is supremely irrelevant. So it may be difficult to get our youngsters interested in philosophy. I feel that one can hope to improve its relevance by pointing out the interconnections between whatever it is that we do and the intellectual aspects behind it. Would that make them choose to major in it? In a world driven by excesses, it may not be enough. Then again, it is world where articulation is often mistaken for accomplishments. Perhaps philosophy can help you articulate better, sound really cool and impress that girl you have been after — to put it crudely.

More seriously, though, what I said about the irrelevance of philosophy can be said about, say, physics as well, despite the fact that it gives you computers and iPads. For instance, when Copernicus came up with the notion that the earth is revolving around the sun rather than the other way round, profound though this revelation was, in what way did it change our daily life? Do you really have to know this piece of information to live your life? This irrelevance of such profound facts and theories bothered scientists like Richard Feynman.

What kind of advice or recommendations would you give to someone who is interested in philosophy, and who would like to start learning more about it?

I started my path toward philosophy via physics. I think philosophy by itself is too detached from anything else that you cannot really start with it. You have to find your way toward it from whatever your work entails, and then expand from there. At least, that’s how I did it, and that way made it very real. When you ask yourself a question like what is space (so that you can understand what it means to say that space contracts, for instance), the answers you get are very relevant. They are not some philosophical gibberish. I think similar paths to relevance exist in all fields. See for example how Pirsig brought out the notion of quality in his work, not as an abstract definition, but as an all-consuming (and eventually dangerous) obsession.

In my view, philosophy is a wrapper around multiple silos of human endeavor. It helps you see the links among seemingly unrelated fields, such as cognitive neuroscience and special relativity. Of what practical use is this knowledge, I cannot tell you. Then again, of what practical use is life itself?

# Only a Matter of Time

Although we speak of space and time in the same breath, they are quite different in many ways. Space is something we perceive all around us. We see it (rather, objects in it), we can move our hand through it, and we know that if our knee tries to occupy the same space as, say, the coffee table, it is going to hurt. In other words, we have sensory correlates to our notion of space, starting from our most precious sense of sight.

Time, on the other hand, has no direct sensory backing. And for this reason, it becomes quite difficult to get a grip over it. What is time? We sense it indirectly through change and motion. But it would be silly to define time using the concepts of change and motion, because they already include the notion of time. The definition would be cyclic.

Assuming, for now, that no definition is necessary, let’s try another perhaps more tractable issue. Where does this strong sense of time come from? I once postulated that it comes from our knowledge of our demise — that questionable gift that we all possess. All the time durations that we are aware of are measured against the yardstick of our lifespan, perhaps not always consciously. I now wonder if this postulate is firm enough, and further ruminations on this issue have convinced me that I am quite ignorant of these things and need more knowledge. Ah.. only if I had more time.

In any case, even this more restricted question of the origin of time doesn’t seem to be that tractable, after all. Physics has another deep problem with time. It has to do with the directionality. It cannot easily explain why time has a direction — an arrow, as it were. This arrow does not present itself in the fundamental laws governing physical interactions. All the laws in physics are time reversible. The laws of gravity, electromagnetism or quantum mechanics are all invariant with respect to a time reversal. That is to say, they look the same with time going forward or backward. So they give no clue as to why we experience the arrow of time.

Yet, we know that time, as we experience it, is directional. We can remember the past, but not the future. What we do now can affect the future, but not the past. If we play a video tape backwards, the sequence of events (like broken pieces of glass coming together to for a vase) will look funny to us. However, if we taped the motion of the planets in a solar system, or the electron cloud in an atom, and played it backward to a physicist, he would not find anything funny in the sequences because the physical laws are reversible.

Physics considers the arrow of time an emergent property of statistical collections. To illustrate this thermodynamic explanation of time, let’s consider an empty container where we place some dry ice. After some time, we expect to see a uniform distribution of carbon dioxide gas in the container. Once spread out, we do not expect the gas in the container to coagulate into solid dry ice, no matter how long we wait. The video of CO2 spreading uniformly in the container is a natural one. Played backward, the sequence of the CO2 gas in the container congealing to solid dry ice in a corner would not look natural to us because it violates our sense of the arrow of time.

The apparent uniformity of CO2 in the container is due to the statistically significant quantity of dry ice we placed there. If we manage to put a small quantity, say five molecules of CO2, we can fully expect to see the congregation of the molecules in one location once in a while. Thus, the arrow of time manifests itself as a statistical or thermodynamic property. Although the directionality of time seems to emerge from reversible physical laws, its absence in the fundamental laws does look less than satisfactory philosophically.

# Half a Bucket of Water

We all see and feel space, but what is it really? Space is one of those fundamental things that a philosopher may consider an “intuition.” When philosophers look at anything, they get a bit technical. Is space relational, as in, defined in terms of relations between objects? A relational entity is like your family — you have your parents, siblings, spouse, kids etc. forming what you consider your family. But your family itself is not a physical entity, but only a collection of relationships. Is space also something like that? Or is it more like a physical container where objects reside and do their thing?

You may consider the distinction between the two just another one of those philosophical hairsplittings, but it really is not. What space is, and even what kind of entity space is, has enormous implications in physics. For instance, if it is relational in nature, then in the absence of matter, there is no space. Much like in the absence of any family members, you have no family. On the other hand, if it is a container-like entity, the space exists even if you take away all matter, waiting for some matter to appear.

So what, you ask? Well, let’s take half a bucket of water and spin it around. Once the water within catches on, its surface will form a parabolic shape — you know, centrifugal force, gravity, surface tension and all that. Now, stop the bucket, and spin the whole universe around it instead. I know, it is more difficult. But imagine you are doing it. Will the water surface be parabolic? I think it will be, because there is not much difference between the bucket turning or the whole universe spinning around it.

Now, let’s imagine that we empty the universe. There is nothing but this half-full bucket. Now it spins around. What happens to the water surface? If space is relational, in the absence of the universe, there is no space outside the bucket and there is no way to know that it is spinning. Water surface should be flat. (In fact, it should be spherical, but ignore that for a second.) And if space is container-like, the spinning bucket should result in a parabolic surface.

Of course, we have no way of knowing which way it is going to be because we have no way of emptying the universe and spinning a bucket. But that doesn’t prevent us from guessing the nature of space and building theories based on it. Newton’s space is container-like, while at their heart, Einstein’s theories have a relational notion of space.

So, you see, philosophy does matter.

# Why the Speed of Light?

What is so special about light that its speed should figure in the basic structure of space and time and our reality? This is the question that has nagged many scientists ever since Albert Einstein published On the Electrodynamics of Moving Bodies about 100 years ago.

In order to understand the specialness of light in our space and time, we need to study how we perceive the world around us and how reality is created in our brains. We perceive our world using our senses. The sensory signals that our senses collect are then relayed to our brains. The brain creates a cognitive model, a representation of the sensory inputs, and presents it to our conscious awareness as reality. Our visual reality consists of space much like our auditory world is made up of sounds.

Just as sounds are a perceptual experience rather than a fundamental property of the physical reality, space also is an experience, or a cognitive representation of the visual inputs, not a fundamental aspect of “the world” our senses are trying to sense.

Space and time together form what physics considers the basis of reality. The only way we can understand the limitations in our reality is by studying the limitations in our senses themselves.

At a fundamental level, how do our senses work? Our sense of sight operates using light, and the fundamental interaction involved in sight falls in the electromagnetic (EM) category because light (or photon) is the intermediary of EM interactions. The exclusivity of EM interaction is not limited to our the long range sense of sight; all the short range senses (touch, taste, smell and hearing) are also EM in nature. To understand the limitations of our perception of space, we need not highlight the EM nature of all our senses. Space is, by and large, the result of our sight sense. But it is worthwhile to keep in mind that we would have no sensing, and indeed no reality, in the absence of EM interactions.

Like our senses, all our technological extensions to our senses (such as radio telescopes, electron microscopes, redshift measurements and even gravitational lensing) use EM interactions exclusively to measure our universe. Thus, we cannot escape the basic constraints of our perception even when we use modern instruments. The Hubble telescope may see a billion light years farther than our naked eyes, but what it sees is still a billion years older than what our eyes see. Our perceived reality, whether built upon direct sensory inputs or technologically enhanced, is a subset of electromagnetic particles and interactions only. It is a projection of EM particles and interactions into our sensory and cognitive space, a possibly imperfect projection.

This statement about the exclusivity of EM interactions in our perceived reality is often met with a bit of skepticism, mainly due to a misconception that we can sense gravity directly. This confusion arises because our bodies are subject to gravity. There is a fine distinction between “being subject to” and “being able to sense” gravitational force.

This difference is illustrated by a simple thought experiment: Imagine a human subject placed in front of an object made entirely of cosmological dark matter. There is no other visible matter anywhere the subject can see it. Given that the dark matter exerts gravitational force on the subject, will he be able to sense its presence? He will be pulled toward it, but how will he know that he is being pulled or that he is moving? He can possibly design some mechanical contraption to detect the gravity of the dark matter object. But then he will be sensing the effect of gravity on some matter using EM interactions. For instance, he may be able to see his unexplained acceleration (effect of gravity on his body, which is EM matter) with respect to reference objects such as stars. But the sensing part here (seeing the stars) involves EM interactions.

It is impossible to design any mechanical contraption to detect gravity that is devoid of EM matter. The gravity sensing in our ears again measures the effect of gravity on EM matter. In the absence of EM interaction, it is impossible to sense gravity, or anything else for that matter.

Electromagnetic interactions are responsible for our sensory inputs. Sensory perception leads to our brain’s representation that we call reality. Any limitation in this chain leads to a corresponding limitation in our sense of reality. One limitation in the chain from senses to reality is the finite speed of photon, which is the gauge boson of our senses. The finite speed of the sense modality influences and distorts our perception of motion, space and time. Because these distortions are perceived as a part of our reality itself, the root cause of the distortion becomes a fundamental property of our reality. This is how the speed of light becomes such an important constant in our space time. The sanctity of light is respected only in our perceived reality.

If we trust the imperfect perception and try to describe what we sense at cosmological scales, we end up with views of the world such as the big bang theory in modern cosmology and the general and special theories of relativity. These theories are not wrong, and the purpose of this book is not to prove them wrong, just to point out that they are descriptions of a perceived reality. They do not describe the physical causes behind the sensory inputs. The physical causes belong to an absolute reality beyond our senses.

The distinction between the absolute reality and our perception of it can be further developed and applied to certain specific astrophysical and cosmological phenomena. When it comes to the physics that happens well beyond our sensory ranges, we really have to take into account the role that our perception and cognition play in seeing them. The universe as we see it is only a cognitive model created out of the photons falling on our retina or on the photo sensors of the Hubble telescope. Because of the finite speed of the information carrier (namely photons), our perception is distorted in such a way as to give us the impression that space and time obey special relativity. They do, but space and time are not the absolute reality. They are only a part of the unreal universe that is our perception of an unknowable reality.

[This again is an edited excerpt from my book, The Unreal Universe.]

# What is Space?

This sounds like a strange question. We all know what space is, it is all around us. When we open our eyes, we see it. If seeing is believing, then the question “What is space?” indeed is a strange one.

To be fair, we don’t actually see space. We see only objects which we assume are in space. Rather, we define space as whatever it is that holds or contains the objects. It is the arena where objects do their thing, the backdrop of our experience. In other words, experience presupposes space and time, and provides the basis for the worldview behind the currently popular interpretations of scientific theories.

Although not obvious, this definition (or assumption or understanding) of space comes with a philosophical baggage — that of realism. The realist’s view is predominant in the current understanding of Einstien’s theories as well. But Einstein himself may not have embraced realism blindly. Why else would he say:

In order to break away from the grip of realism, we have to approach the question tangentially. One way to do it is by studying the neuroscience and cognitive basis of sight, which after all provides the strongest evidence to the realness of space. Space, by and large, is the experience associated with sight. Another way is to examine experiential correlates of other senses: What is sound?

When we hear something, what we hear is, naturally, sound. We experience a tone, an intensity and a time variation that tell us a lot about who is talking, what is breaking and so on. But even after stripping off all the extra richness added to the experience by our brain, the most basic experience is still a “sound.” We all know what it is, but we cannot explain it in terms more basic than that.

Now let’s look at the sensory signal responsible for hearing. As we know, these are pressure waves in the air that are created by a vibrating body making compressions and depressions in the air around it. Much like the ripples in a pond, these pressure waves propagate in almost all directions. They are picked up by our ears. By a clever mechanism, the ears perform a spectral analysis and send electric signals, which roughly correspond to the frequency spectrum of the waves, to our brain. Note that, so far, we have a vibrating body, bunching and spreading of air molecules, and an electric signal that contains information about the pattern of the air molecules. We do not have sound yet.

The experience of sound is the magic our brain performs. It translates the electrical signal encoding the air pressure wave patterns to a representation of tonality and richness of sound. Sound is not the intrinsic property of a vibrating body or a falling tree, it is the way our brain chooses to represent the vibrations or, more precisely, the electrical signal encoding the spectrum of the pressure waves.

Doesn’t it make sense to call sound an internal cognitive representation of our auditory sensory inputs? If you agree, then reality itself is our internal representation of our sensory inputs. This notion is actually much more profound that it first appears. If sound is representation, so is smell. So is space.

 Figure: Illustration of the process of brain’s representation of sensory inputs. Odors are a representation of the chemical compositions and concentration levels our nose senses. Sounds are a mapping of the air pressure waves produced by a vibrating object. In sight, our representation is space, and possibly time. However, we do not know what it is the representation of.

We can examine it and fully understand sound because of one remarkable fact — we have a more powerful sense, namely our sight. Sight enables us to understand the sensory signals of hearing and compare them to our sensory experience. In effect, sight enables us to make a model describing what sound is.

Why is it that we do not know the physical cause behind space? After all, we know of the causes behind the experiences of smell, sound, etc. The reason for our inability to see beyond the visual reality is in the hierarchy of senses, best illustrated using an example. Let’s consider a small explosion, like a firecracker going off. When we experience this explosion, we will see the flash, hear the report, smell the burning chemicals and feel the heat, if we are close enough.

The qualia of these experiences are attributed to the same physical event — the explosion, the physics of which is well understood. Now, let’s see if we can fool the senses into having the same experiences, in the absence of a real explosion. The heat and the smell are fairly easy to reproduce. The experience of the sound can also be created using, for instance, a high-end home theater system. How do we recreate the experience of the sight of the explosion? A home theater experience is a poor reproduction of the real thing.

In principle at least, we can think of futuristic scenarios such as the holideck in Star Trek, where the experience of the sight can be recreated. But at the point where sight is also recreated, is there a difference between the real experience of the explosion and the holideck simulation? The blurring of the sense of reality when the sight experience is simulated indicates that sight is our most powerful sense, and we have no access to causes beyond our visual reality.

Visual perception is the basis of our sense of reality. All other senses provide corroborating or complementing perceptions to the visual reality.

[This post has borrowed quite a bit from my book.]

# Light Travel Time Effects and Cosmological Features

This unpublished article is a sequel to my earlier paper (also posted here as “Are Radio Sources and Gamma Ray Bursts Luminal Booms?“). This blog version contains the abstract, introduction and conclusions. The full version of the article is available as a PDF file.

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Abstract

Light travel time effects (LTT) are an optical manifestation of the finite speed of light. They can also be considered perceptual constraints to the cognitive picture of space and time. Based on this interpretation of LTT effects, we recently presented a new hypothetical model for the temporal and spatial variation of the spectrum of Gamma Ray Bursts (GRB) and radio sources. In this article, we take the analysis further and show that LTT effects can provide a good framework to describe such cosmological features as the redshift observation of an expanding universe, and the cosmic microwave background radiation. The unification of these seemingly distinct phenomena at vastly different length and time scales, along with its conceptual simplicity, can be regarded as indicators of the curious usefulness of this framework, if not its validity.

#### Introduction

The finite speed of light plays an important part in how we perceive distance and speed. This fact should hardly come as a surprise because we do know that things are not as we see them. The sun that we see, for instance, is already eight minutes old by the time we see it. This delay is trivial; if we want to know what is going on at the sun now, all we have to do is to wait for eight minutes. We, nonetheless, have to “correct” for this distortion in our perception due to the finite speed of light before we can trust what we see.

What is surprising (and seldom highlighted) is that when it comes to sensing motion, we cannot back-calculate the same way we take out the delay in seeing the sun. If we see a celestial body moving at an improbably high speed, we cannot figure out how fast and in what direction it is “really” moving without making further assumptions. One way of handling this difficulty is to ascribe the distortions in our perception of motion to the fundamental properties of the arena of physics — space and time. Another course of action is to accept the disconnection between our perception and the underlying “reality” and deal with it in some way.

Exploring the second option, we assume an underlying reality that gives rise to our perceived picture. We further model this underlying reality as obeying classical mechanics, and work out our perceived picture through the apparatus of perception. In other words, we do not attribute the manifestations of the finite speed of light to the properties of the underlying reality. Instead, we work out our perceived picture that this model predicts and verify whether the properties we do observe can originate from this perceptual constraint.

Space, the objects in it, and their motion are, by and large, the product of optical perception. One tends to take it for granted that perception arises from reality as one perceives it. In this article, we take the position that what we perceive is an incomplete or distorted picture of an underlying reality. Further, we are trying out classical mechanics for the the underlying reality (for which we use terms like absolute, noumenal or physical reality) that does cause our perception to see if it fits with our perceived picture (which we may refer to as sensed or phenomenal reality).

Note that we are not implying that the manifestations of perception are mere delusions. They are not; they are indeed part of our sensed reality because reality is an end result of perception. This insight may be behind Goethe’s famous statement, “Optical illusion is optical truth.”

We applied this line of thinking to a physics problem recently. We looked at the spectral evolution of a GRB and found it to be remarkably similar to that in a sonic boom. Using this fact, we presented a model for GRB as our perception of a “luminal” boom, with the understanding that it is our perceived picture of reality that obeys Lorentz invariance and our model for the underlying reality (causing the perceived picture) may violate relativistic physics. The striking agreement between the model and the observed features, however, extended beyond GRBs to symmetric radio sources, which can also be regarded as perceptual effects of hypothetical luminal booms.

In this article, we look at other implications of the model. We start with the similarities between the light travel time (LTT) effects and the coordinate transformation in Special Relativity (SR). These similarities are hardly surprising because SR is derived partly based on LTT effects. We then propose an interpretation of SR as a formalization of LTT effects and study a few observed cosmological phenomena in the light of this interpretation.

#### Similarities between Light Travel Time Effects and SR

Special relativity seeks a linear coordinate transformation between coordinate systems in motion with respect to each other. We can trace the origin of linearity to a hidden assumption on the nature of space and time built into SR, as stated by Einstein: “In the first place it is clear that the equations must be linear on account of the properties of homogeneity which we attribute to space and time.” Because of this assumption of linearity, the original derivation of the transformation equations ignores the asymmetry between approaching and receding objects. Both approaching and receding objects can be described by two coordinate systems that are always receding from each other. For instance, if a system $K$ is moving with respect to another system $k$ along the positive X axis of $k$, then an object at rest in $K$ at a positive $x$ is receding while another object at a negative $x$ is approaching an observer at the origin of $k$.

The coordinate transformation in Einstein’s original paper is derived, in part, a manifestation of the light travel time (LTT) effects and the consequence of imposing the constancy of light speed in all inertial frames. This is most obvious in the first thought experiment, where observers moving with a rod find their clocks not synchronized due to the difference in light travel times along the length of the rod. However, in the current interpretation of SR, the coordinate transformation is considered a basic property of space and time.

One difficulty that arises from this interpretation of SR is that the definition of the relative velocity between the two inertial frames becomes ambiguous. If it is the velocity of the moving frame as measured by the observer, then the observed superluminal motion in radio jets starting from the core region becomes a violation of SR. If it is a velocity that we have to deduce by considering LT effects, then we have to employ the extra ad-hoc assumption that superluminality is forbidden. These difficulties suggest that it may be better to disentangle the light travel time effects from the rest of SR.

In this section, we will consider space and time as a part of the cognitive model created by the brain, and argue that special relativity applies to the cognitive model. The absolute reality (of which the SR-like space-time is our perception) does not have to obey the restrictions of SR. In particular, objects are not restricted to subluminal speeds, but they may appear to us as though they are restricted to subluminal speeds in our perception of space and time. If we disentangle LTT effects from the rest of SR, we can understand a wide array of phenomena, as we shall see in this article.

Unlike SR, considerations based on LTT effects result in intrinsically different set of transformation laws for objects approaching an observer and those receding from him. More generally, the transformation depends on the angle between the velocity of the object and the observer’s line of sight. Since the transformation equations based on LTT effects treat approaching and receding objects asymmetrically, they provide a natural solution to the twin paradox, for instance.

#### Conclusions

Because space and time are a part of a reality created out of light inputs to our eyes, some of their properties are manifestations of LTT effects, especially on our perception of motion. The absolute, physical reality presumably generating the light inputs does not have to obey the properties we ascribe to our perceived space and time.

We showed that LTT effects are qualitatively identical to those of SR, noting that SR only considers frames of reference receding from each other. This similarity is not surprising because the coordinate transformation in SR is derived based partly on LTT effects, and partly on the assumption that light travels at the same speed with respect to all inertial frames. In treating it as a manifestation of LTT, we did not address the primary motivation of SR, which is a covariant formulation of Maxwell’s equations. It may be possible to disentangle the covariance of electrodynamics from the coordinate transformation, although it is not attempted in this article.

Unlike SR, LTT effects are asymmetric. This asymmetry provides a resolution to the twin paradox and an interpretation of the assumed causality violations associated with superluminality. Furthermore, the perception of superluminality is modulated by LTT effects, and explains $gamma$ ray bursts and symmetric jets. As we showed in the article, perception of superluminal motion also holds an explanation for cosmological phenomena like the expansion of the universe and cosmic microwave background radiation. LTT effects should be considered as a fundamental constraint in our perception, and consequently in physics, rather than as a convenient explanation for isolated phenomena.

Given that our perception is filtered through LTT effects, we have to deconvolute them from our perceived reality in order to understand the nature of the absolute, physical reality. This deconvolution, however, results in multiple solutions. Thus, the absolute, physical reality is beyond our grasp, and any assumed properties of the absolute reality can only be validated through how well the resultant perceived reality agrees with our observations. In this article, we assumed that the underlying reality obeys our intuitively obvious classical mechanics and asked the question how such a reality would be perceived when filtered through light travel time effects. We demonstrated that this particular treatment could explain certain astrophysical and cosmological phenomena that we observe.

The coordinate transformation in SR can be viewed as a redefinition of space and time (or, more generally, reality) in order to accommodate the distortions in our perception of motion due to light travel time effects. One may be tempted to argue that SR applies to the “real” space and time, not our perception. This line of argument begs the question, what is real? Reality is only a cognitive model created in our brain starting from our sensory inputs, visual inputs being the most significant. Space itself is a part of this cognitive model. The properties of space are a mapping of the constraints of our perception.

The choice of accepting our perception as a true image of reality and redefining space and time as described in special relativity indeed amounts to a philosophical choice. The alternative presented in the article is inspired by the view in modern neuroscience that reality is a cognitive model in the brain based on our sensory inputs. Adopting this alternative reduces us to guessing the nature of the absolute reality and comparing its predicted projection to our real perception. It may simplify and elucidate some theories in physics and explain some puzzling phenomena in our universe. However, this option is yet another philosophical stance against the unknowable absolute reality.

# The Philosophy of Special Relativity — A Comparison between Indian and Western Interpretations

Abstract: The Western philosophical phenomenalism could be treated as a kind of philosophical basis of the special theory of relativity. The perceptual limitations of our senses hold the key to the understanding of relativistic postulates. The specialness of the speed of light in our phenomenal space and time is more a matter of our perceptual apparatus, than an input postulate to the special theory of relativity. The author believes that the parallels among the phenomenological, Western spiritual and the Eastern Advaita interpretations of special relativity point to an exciting possibility of unifying the Eastern and Western schools of thought to some extent.

– Editor

Key Words: Relativity, Speed of Light, Phenomenalism, Advaita.

#### Introduction

The philosophical basis of the special theory of relativity can be interpreted in terms of Western phenomenalism, which views space and time are considered perceptual and cognitive constructs created out our sensory inputs. From this perspective, the special status of light and its speed can be understood through a phenomenological study of our senses and the perceptual limitations to our phenomenal notions of space and time. A similar view is echoed in the Brahman-Maya distinction in Advaita. If we think of space and time as part of Maya, we can partly understand the importance that the speed of light in our reality, as enshrined in special relativity. The central role of light in our reality is highlighted in the Bible as well. These remarkable parallels among the phenomenological, Western spiritual and the Advaita interpretations of special relativity point to an exciting possibility of unifying the Eastern and Western schools of thought to a certain degree.

#### Special Relativity

Einstein unveiled his special theory of relativity2 a little over a century ago. In his theory, he showed that space and time were not absolute entities. They are entities relative to an observer. An observer’s space and time are related to those of another through the speed of light. For instance, nothing can travel faster than the speed of light. In a moving system, time flows slower and space contracts in accordance with equations involving the speed of light. Light, therefore, enjoys a special status in our space and time. This specialness of light in our reality is indelibly enshrined in the special theory of relativity.

Where does this specialness come from? What is so special about light that its speed should figure in the basic structure of space and time and our reality? This question has remained unanswered for over 100 years. It also brings in the metaphysical aspects of space and time, which form the basis of what we perceive as reality.

#### Noumenal-Phenomenal and Brahman-Maya Distinctions

In the Advaita3 view of reality, what we perceive is merely an illusion-Maya. Advaita explicitly renounces the notion that the perceived reality is external or indeed real. It teaches us that the phenomenal universe, our conscious awareness of it, and our bodily being are all an illusion or Maya. They are not the true, absolute reality. The absolute reality existing in itself, independent of us and our experiences, is Brahman.

A similar view of reality is echoed in phenomenalism,4 which holds that space and time are not objective realities. They are merely the medium of our perception. In this view, all the phenomena that happen in space and time are merely bundles of our perception. Space and time are also cognitive constructs arising from perception. Thus, the reasons behind all the physical properties that we ascribe to space and time have to be sought in the sensory processes that create our perception, whether we approach the issue from the Advaita or phenomenalism perspective.

This analysis of the importance of light in our reality naturally brings in the metaphysical aspects of space and time. In Kant’s view,5 space and time are pure forms of intuition. They do not arise from our experience because our experiences presuppose the existence of space and time. Thus, we can represent space and time in the absence of objects, but we cannot represent objects in the absence of space and time.

Kant’s middle-ground has the advantage of reconciling the views of Newton and Leibniz. It can agree with Newton’s view6 that space is absolute and real for phenomenal objects open to scientific investigation. It can also sit well with Leibniz’s view7 that space is not absolute and has an existence only in relation to objects, by highlighting their relational nature, not among objects in themselves (noumenal objects), but between observers and objects.

We can roughly equate the noumenal objects to forms in Brahman and our perception of them to Maya. In this article, we will use the terms “noumenal reality,” “absolute reality,” or “physical reality” interchangeably to describe the collection of noumenal objects, their properties and interactions, which are thought to be the underlying causes of our perception. Similarly, we will “phenomenal reality,” “perceived or sensed reality,” and “perceptual reality” to signify our reality as we perceive it.

As with Brahman causing Maya, we assume that the phenomenal notions of space and time arise from noumenal causes8 through our sensory and cognitive processes. Note that this causality assumption is ad-hoc; there is no a priori reason for phenomenal reality to have a cause, nor is causation a necessary feature of the noumenal reality. Despite this difficulty, we proceed from a naive model for the noumenal reality and show that, through the process of perception, we can “derive” a phenomenal reality that obeys the special theory of relativity.

This attempt to go from the phenomena (space and time) to the essence of what we experience (a model for noumenal reality) is roughly in line with Husserl’s transcendental phenomenology.9 The deviation is that we are more interested in the manifestations of the model in the phenomenal reality itself rather than the validity of the model for the essence. Through this study, we show that the specialness of the speed of light in our phenomenal space and time is a consequence of our perceptual apparatus. It doesn’t have to be an input postulate to the special theory of relativity.

#### Perception and Phenomenal Reality

The properties we ascribe to space and time (such as the specialness of the speed of light) can only be a part of our perceived reality or Maya, in Advaita, not of the underlying absolute reality, Brahman. If we think of space and time as aspects of our perceived reality arising from an unknowable Brahman through our sensory and cognitive processes, we can find an explanation for the special distinction of the speed of light in the process and mechanism of our sensing. Our thesis is that the reason for the specialness of light in our phenomenal notions of space and time is hidden in the process of our perception.

We, therefore, study how the noumenal objects around us generate our sensory signals, and how we construct our phenomenal reality out of these signals in our brains. The first part is already troublesome because noumenal objects, by definition, have no properties or interactions that we can study or understand.

These features of the noumenal reality are identical to the notion of Brahman in Advaita, which highlights that the ultimate truth is Brahman, the one beyond time, space and causation. Brahman is the material cause of the universe, but it transcends the cosmos. It transcends time; it exists in the past, present and future. It transcends space; it has no beginning, middle and end. It even transcends causality. For that reason, Brahman is incomprehensible to the human mind. The way it manifests to us is through our sensory and cognitive processes. This manifestation is Maya, the illusion, which, in the phenomenalistic parlance, corresponds to the phenomenal reality.

For our purpose in this article, we describe our sensory and cognitive process and the creation of the phenomenal reality or Maya10 as follows. It starts with the noumenal objects (or forms in Brahman), which generate the inputs to our senses. Our senses then process the signals and relay the processed electric data corresponding to them to our brain. The brain creates a cognitive model, a representation of the sensory inputs, and presents it to our conscious awareness as reality, which is our phenomenal world or Maya.

This description of how the phenomenal reality created ushers in a tricky philosophical question. Who or what creates the phenomenal reality and where? It is not created by our senses, brain and mind because these are all objects or forms in the phenomenal reality. The phenomenal reality cannot create itself. It cannot be that the noumenal reality creates the phenomenal reality because, in that case, it would be inaccurate to assert the cognitive inaccessibility to the noumenal world.

This philosophical trouble is identical in Advaita as well. Our senses, brain and mind cannot create Maya, because they are all part of Maya. If Brahman created Maya, it would have to be just as real. This philosophical quandary can be circumvented in the following way. We assume that all events and objects in Maya have a cause or form in Brahman or in the noumenal world. Thus, we postulate that our senses, mind and body all have some (unknown) forms in Brahman (or in the noumenal world), and these forms create Maya in our conscious awareness, ignoring the fact that our consciousness itself is an illusory manifestation in the phenomenal world. This inconsistency is not material to our exploration into the nature of space and time because we are seeking the reason for the specialness of light in the sensory process rather than at the level of consciousness.

Space and time together form what physics considers the basis of reality. Space makes up our visual reality precisely as sounds make up our auditory world. Just as sounds are a perceptual experience rather than a fundamental property of physical reality, space also is an experience, or a cognitive representation of the visual inputs, not a fundamental aspect of Brahman or the noumenal reality. The phenomenal reality thus created is Maya. The Maya events are an imperfect or distorted representation of the corresponding Brahman events. Since Brahman is a superset of Maya (or, equivalently, our senses are potentially incapable of sensing all aspects of the noumenal reality), not all objects and events in Brahman create a projection in Maya. Our perception (or Maya) is thus limited because of the sense modality and its speed, which form the focus of our investigation in this article.

In summary, it can be argued that the noumenal-phenomenal distinction in phenomenalism is an exact parallel to the Brahman-Maya distinction in Advaita if we think of our perceived reality (or Maya) as arising from sensory and cognitive processes.

#### Sensing Space and Time, and the Role of Light

The phenomenal notions of space and time together form what physics considers the basis of reality. Since we take the position that space and time are the end results of our sensory perception, we can understand some of the limitations in our Maya by studying the limitations in our senses themselves.

At a fundamental level, how do our senses work? Our sense of sight operates using light, and the fundamental interaction involved in sight falls in the electromagnetic (EM) category because light (or photon) is the intermediary of EM interactions.11

The exclusivity of EM interaction is not limited to our long-range sense of sight; all the short-range senses (touch, taste, smell and hearing) are also EM in nature. In physics, the fundamental interactions are modeled as fields with gauge bosons.12 In quantum electrodynamics13 (the quantum field theory of EM interactions), photon (or light) is the gauge boson mediating EM interactions. Electromagnetic interactions are responsible for all our sensory inputs. To understand the limitations of our perception of space, we need not highlight the EM nature of all our senses. Space is, by and large, the result of our sight sense. But it is worthwhile to keep in mind that we would have no sensing, and indeed no reality, in the absence of EM interactions.

Like our senses, all our technological extensions to our senses (such as radio telescopes, electron microscopes, red shift measurements and even gravitational lensing) use EM interactions exclusively to measure our universe. Thus, we cannot escape the basic constraints of our perception even when we use modern instruments. The Hubble telescope may see a billion light years farther than our naked eyes, but what it sees is still a billion years older than what our eyes see. Our phenomenal reality, whether built upon direct sensory inputs or technologically enhanced, is made up of a subset of EM particles and interactions only. What we perceive as reality is a subset of forms and events in the noumenal world corresponding to EM interactions, filtered through our sensory and cognitive processes. In the Advaita parlance, Maya can be thought of as a projection of Brahman through EM interactions into our sensory and cognitive space, quite probably an imperfect projection.

The exclusivity of EM interactions in our perceived reality is not always appreciated, mainly because of a misconception that we can sense gravity directly. This confusion arises because our bodies are subject to gravity. There is a fine distinction between “being subject to” and “being able to sense” gravitational force. The gravity sensing in our ears measures the effect of gravity on EM matter. In the absence of EM interaction, it is impossible to sense gravity, or anything else for that matter.

This assertion that there is no sensing in the absence of EM interactions brings us to the next philosophical hurdle. One can always argue that, in the absence of EM interaction, there is no matter to sense. This argument is tantamount to insisting that the noumenal world consists of only those forms and events that give rise to EM interaction in our phenomenal perception. In other words, it is the same as insisting that Brahman is made up of only EM interactions. What is lacking in the absence of EM interaction is only our phenomenal reality. In the Advaita notion, in the absence of sensing, Maya does not exist. The absolute reality or Brahman, however, is independent of our sensing it. Again, we see that the Eastern and Western views on reality we explored in this article are remarkably similar.

#### The Speed of Light

Knowing that our space-time is a representation of the light waves our eyes receive, we can immediately see that light is indeed special in our reality. In our view, sensory perception leads to our brain’s representation that we call reality, or Maya. Any limitation in this chain of sensing leads to a corresponding limitation in our phenomenal reality.

One limitation in the chain from senses to perception is the finite speed of photon, which is the gauge boson of our senses. The finite speed of the sense modality influences and distorts our perception of motion, space and time. Because these distortions are perceived as a part of our reality itself, the root cause of the distortion becomes a fundamental property of our reality. This is how the speed of light becomes such an important constant in our space-time.

The importance of the speed of light, however, is respected only in our phenomenal Maya. Other modes of perception have other speeds the figure as the fundamental constant in their space-like perception. The reality sensed through echolocation, for instance, has the speed of sound as a fundamental property. In fact, it is fairly simple to establish14 that echolocation results in a perception of motion that obeys something very similar to special relativity with the speed of light replaced with that of sound.

#### Theories beyond Sensory Limits

The basis of physics is the world view called scientific realism, which is not only at the core of sciences but is our natural way of looking at the world as well. Scientific realism, and hence physics, assume an independently existing external world, whose structures are knowable through scientific investigations. To the extent observations are based on perception, the philosophical stance of scientific realism, as it is practiced today, can be thought of as a trust in our perceived reality, and as an assumption that it is this reality that needs to be explored in science.

Physics extends its reach beyond perception or Maya through the rational element of pure theory. Most of physics works in this “extended” intellectual reality, with concepts such as fields, forces, light rays, atoms, particles, etc., the existence of which is insisted upon through the metaphysical commitment implied in scientific realism. However, it does not claim that the rational extensions are the noumenal causes or Brahman giving raise to our phenomenal perception.

Scientific realism has helped physics tremendously, with all its classical theories. However, scientific realism and the trust in our perception of reality should apply only within the useful ranges of our senses. Within the ranges of our sensory perceptions, we have fairly intuitive physics. An example of an intuitive picture is Newtonian mechanics that describe “normal” objects moving around at “normal” speeds.

When we get closer to the edges of our sensory modalities, we have to modify our sciences to describe the reality as we sense it. These modifications lead to different, and possibly incompatible, theories. When we ascribe the natural limitations of our senses and the consequent limitations of our perception (and therefore observations) to the fundamental nature of reality itself, we end up introducing complications in our physical laws. Depending on which limitations we are incorporating into the theory (e.g., small size, large speeds etc.), we may end up with theories that are incompatible with each other.

Our argument is that some of these complications (and, hopefully, incompatibilities) can be avoided if we address the sensory limitations directly. For instance, we can study the consequence of the fact that our senses operate at the speed of light as follows. We can model Brahman (the noumenal reality) as obeying classical mechanics, and work out what kind of Maya (phenomenal reality) we will experience through the chain of sensing.

The modeling of the noumenal world (as obeying classical mechanics), of course, has shaky philosophical foundations. But the phenomenal reality predicted from this model is remarkably close to the reality we do perceive. Starting from this simple model, it can be easily shown our perception of motion at high speeds obeys special relativity.

The effects due to the finite speed of light are well known in physics. We know, for instance, that what we see happening in distant stars and galaxies now actually took place quite awhile ago. A more “advanced” effect due to the light travel time15 is the way we perceive motion at high speeds, which is the basis of special relativity. In fact, many astrophysical phenomena can be understood16 in terms of light travel time effects. Because our sense modality is based on light, our sensed picture of motion has the speed of light appearing naturally in the equations describing it. So the importance of the speed of light in our space-time (as described in special relativity) is due to the fact that our reality is Maya created based on light inputs.

#### Conclusion

Almost all branches of philosophy grapple with this distinction between the phenomenal and the absolute realities to some extent. Advaita Vedanta holds the unrealness of the phenomenal reality as the basis of their world view. In this article, we showed that the views in phenomenalism can be thought of as a restatement of the Advaita postulates.

When such a spiritual or philosophical insight makes its way into science, great advances in our understanding can be expected. This convergence of philosophy (or even spirituality) and science is beginning to take place, most notably in neuroscience, which views reality as a creation of our brain, echoing the notion of Maya.

Science gives a false impression that we can get arbitrarily close to the underlying physical causes through the process of scientific investigation and rational theorization. An example of such theorization can be found in our sensation of hearing. The experience or the sensation of sound is an incredibly distant representation of the physical cause–namely air pressure waves. We are aware of the physical cause because we have a more powerful sight sense. So it would seem that we can indeed go from Maya (sound) to the underlying causes (air pressure waves).

However, it is a fallacy to assume that the physical cause (the air pressure waves) is Brahman. Air pressure waves are still a part of our perception; they are part of the intellectual picture we have come to accept. This intellectual picture is an extension of our visual reality, based on our trust in the visual reality. It is still a part of Maya.

The new extension of reality proposed in this article, again an intellectual extension, is an educated guess. We guess a model for the absolute reality, or Brahman, and predict what the consequent perceived reality should be, working forward through the chain of sensing and creating Maya. If the predicted perception is a good match with the Maya we do experience, then the guesswork for Brahman is taken to be a fairly accurate working model. The consistency between the predicted perception and what we do perceive is the only validation of the model for the nature of the absolute reality. Furthermore, the guess is only one plausible model for the absolute reality; there may be different such “solutions” to the absolute reality all of which end up giving us our perceived reality.

It is a mistake to think of the qualities of our subjective experience of sound as the properties of the underlying physical process. In an exact parallel, it is a fallacy to assume that the subjective experience of space and time is the fundamental property of the world we live in. The space-time continuum, as we see it or feel it, is only a partial and incomplete representation of the unknowable Brahman. If we are willing to model the unknowable Brahman as obeying classical mechanics, we can indeed derive the properties of our perceived reality (such as time dilation, length contraction, light speed ceiling and so on in special relativity). By proposing this model for the noumenal world, we are not suggesting that all the effects of special relativity are mere perceptual artifacts. We are merely reiterating a known fact that space and time themselves cannot be anything but perceptual constructs. Thus their properties are manifestations of the process of perception.

When we consider processes close to or beyond our sensor limits, the manifestations of our perceptual and cognitive constraints become significant. Therefore, when it comes to the physics that describes such processes, we really have to take into account the role that our perception and cognition play in sensing them. The universe as we see it is only a cognitive model created out of the photons falling on our retina or on the photosensors of the Hubble telescope. Because of the finite speed of the information carrier (namely light), our perception is distorted in such a way as to give us the impression that space and time obey special relativity. They do, but space and time are only a part of our perception of an unknowable reality—a perception limited by the speed of light.

The central role of light in creating our reality or universe is at the heart of western spiritual philosophy as well. A universe devoid of light is not simply a world where you have switched off the lights. It is indeed a universe devoid of itself, a universe that doesn’t exist. It is in this context that we have to understand the wisdom behind the notion that “the earth was without form, and void'” until God caused light to be, by saying “Let there be light.” Quran also says, “Allah is the light of the heavens.” The role of light in taking us from the void (the nothingness) to a reality was understood for a long, long time. Is it possible that the ancient saints and prophets knew things that we are only now beginning to uncover with all our advances in knowledge? Whether we use old Eastern Advaita views or their Western counterparts, we can interpret the philosophical stance behind special relativity as hidden in the distinction between our phenomenal reality and its unknowable physical causes.

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1. Dr. Manoj Thulasidas graduated from the Indian Institute of Technology (IIT), Madras, in 1987. He studied fundamental particles and interactions at the CLEO collaboration at Cornell University during 1990-1992. After receiving his PhD in 1993, he moved to Marseilles, France and continued his research with the ALEPH collaboration at CERN, Geneva. During his ten-year career as a research scientist in the field of High energy physics, he co-authored over 200 publications.
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