Out of the Cave, Into the Darkness
Kathleen Hamilton, Howard Community College ’17, University of Maryland College Park
Mentored by: Helen Mitchell, Ph.D. and Alex M. Barr, Ph.D.
Abstract
Over the past century, our understanding of the universe has evolved. Exciting new theories have emerged, enlightening us as to how things truly are and yet confounding our sense of reality. As science continues to progress in multiple fields, human experience is driven further from mundane daily routines governed by Newtonian mechanics. These laws still hold – but only under certain circumstances. In light of this, questions in metaphysics take center stage. As the world is revealed to be vastly different from how we perceive it, how can we know what is truly real? Ancient philosophies may aid us in understanding and mentally accepting these new discoveries.
Paper
From the smallest particles to the largest regions of space, our previous ideas have been refined if not completely re-defined. Revolutions at the sub-atomic level have transformed our understanding of matter and energy, showing them to be two sides of the same coin. Quantum mechanics reveals a world constantly in motion, based on probabilities, to rival our fairly static, routine, and deterministic experiences. On the other end of the spectrum, relativity presents time dilation on a universal scale, questioning how far removed we are from the past. Dark energy pervades the universe along with the equally-mysterious dark matter. We are aware of their presence even though we can neither directly observe them nor identify their composition. The search for knowledge extends to the boundaries of what we know, leading theorists to postulate concepts such as supersymmetry and M-theory, potentially altering how we perceive the universe – including ourselves – by envisioning the smallest building blocks of everything as vibrating, one-dimensional strings.
Such exotic theories are currently studied as cosmology, formerly the province of philosophers but now the domain of scientists. Nonetheless, the philosophical implications of modern science can easily be seen. Metaphysics asks what is real, and how can we know? Our growing understanding of our world seems to bring more confusion. Considering this, Western philosophy may benefit from integrating ideas found in other traditional forms that visualize a truly interconnected cosmos.
One of the pedestals of Western philosophy is Plato’s Allegory of the Cave [1]. As part of his Republic, Plato describes prisoners who have been chained in a cave for as long as they can remember, watching shadows cast on the cave wall by a fire behind them, their only source of light. Reasonably, they think that these shadows represent reality. When one prisoner is finally freed and emerges into the light, disorientation and temporary blindness caused by the sunlight naturally follow. It takes time to realize that the objects casting the shadows are real and that the shadows are merely echoes of the true forms. At last, the prisoner sees the world as it truly is [1]. This ascent from a life of shadows into the world of light and being is Plato’s vision of philosophical comprehension. His concept of metaphysics involves a separate world, in a higher plane of existence, consisting of true forms. No matter how pure something seems in this world, it is merely a reflection of its true form elsewhere [1]. Those who study philosophy are led out of the cave, into the light.
While our basic ideas are sound, we seem to be in a system of caves within caves as far as our current understanding of modern science goes. At the beginning of last century, the distinction between matter and energy was clear: matter has mass and takes up space, while energy appears massless, being absorbed and emitted by matter. Einstein’s famous equation, E=mc2, showed that energy and matter are interchangeable with a relationship involving the constant speed of light. Around the same time that Einstein published this result, the famous double-slit experiment was changing the way we looked at energy and matter at the sub-atomic level.
Although first devised and performed in the early 1800s, the full ramifications of the double-slit experiment would not be realized for another century and a half. The setup is fairly straightforward: light in a controlled beam is aimed through an obstruction containing two slits. Once through the obstruction via the slits, the beam forms a pattern on the backdrop. When light shines through both slits, it creates an interference pattern on the backdrop. The experiment elucidated a physical argument of the day, demonstrating the wave nature of light. Were light to travel as classical particles, there would only be two bright spots, corresponding to the particles that travelled through one slit or the other. Instead, light waves pass through both slits simultaneously. The wave crests and troughs passing through each slit interact in distinctive ways to form an interference pattern containing many bright spots.
These results fit nicely with the standard definitions of matter being particles and energy – of which light is a form – consisting of waves. When the double-slit experiment is performed with electrons, however, the patterns created change with observation. When the electrons’ paths are observed, they behave as classical particles, passing through only one slit or the other and creating a pattern with two bright spots. When only the end result is observed, electrons appear to have travelled through both slits simultaneously, creating an interference pattern as waves do [1]. Electrons therefore exist in both states simultaneously and can behave as waves! Such a contradiction is hard to imagine in an everyday scenario – hence the popular quantum mechanics thought experiment of Schrödinger’s Cat. Trapped in a box with radioactive atoms that could decay and force the release of a poison, the cat is both alive and dead simultaneously. All possibilities exist simultaneously, and only upon opening the box is one outcome selected and presented by nature [2]. Of course, this doesn’t make sense in our large-scale existence, but in the quantum world, outcomes exist as probabilities with the act of observation determining the result. To further blur the distinctions between particle and wave, light has a particle nature under certain conditions. Aspects of the photoelectric effect, whereby electrons are emitted from a material when light shines on it, can only be explained by light traveling in discrete chunks of energy, known as photons. Thus, the components of matter and energy are more properly thought of as hybrid “wavicles.” With even the basic structure of objects constantly fluctuating due to specific situations, metaphysics becomes more complicated.
When Einstein postulated his theories of relativity in the early 1900s, he joined two other concepts that were thought to be separate entities – space and time. One of the surprising consequences was time dilation – far from being immutable, time could be impacted by actions in space. Understanding frame of reference is necessary for grasping these effects. Much like perspective, everyone’s frame of reference is slightly different. High velocities and gravitational forces make the differences more pronounced, closer to culture shock. When two observers are moving relative to each other, such as in spaceships repeatedly passing each other, the other’s time will appear to be moving more slowly. Similarly, clocks will run more slowly when in a stronger gravitational field. These effects are not significant enough to be felt in our everyday lives, but they may become a feature in the future with increased, faster space travel. Currently, the best we can do is to confirm the phenomenon on the International Space Station. Atomic clocks on Earth do not synchronize with those in orbit: to us, time is running very slightly slower onboard because, in our frame of reference, the space station is moving. Its increased distance from Earth’s center of gravity reduces this effect, but it is still measurable.
The fluidity of time usually comes as a jolt to Western civilizations, but not everyone sees time as inalterable. Many cultures more in tune with the natural world feel that time simply exists, a limitless resource [1]. West Africans do not try to manage time or control it: events happen whenever they do, without stress [1]. Natives of both America and Australia share the view of timelessness, contrasting with typical Western views of time rushing by [1]. These perceptions of time do not envision it speeding up or slowing down due to relative velocities and/or gravitational wells, but they provide a framework within which this is not necessarily a surprising development. As far as the progression of time, Buddhists appear to be ahead of the curve, eschewing the concepts of past and future in favor of the enlightened realization that all time is now [1]. While science may not quite be ready for that, past and future can be subjective. The relativity of simultaneity comes into play at high velocities, where observers in different reference frames will not necessarily agree on whether events occurred at the same time.
Even in our own solar system, we on Earth never observe the Sun as it is right now, because sunlight takes eight minutes to reach our eyes [1]. Communication between far-flung planets complicates the matter even further. Suppose a being four billion light-years away looked in our direction. Instead of a technologically-developed Earth, surrounded by one natural satellite and several artificial ones, the view would consist of a molten, roughly spherical world under constant bombardment from other solar system fragments. Similarly, if we could somehow look at where that being is, we wouldn’t see them – rather, we would observe the area as it was four billion years ago [3]. Which of those two is “now”?
Having explored time, a philosopher would naturally ponder the effects of relativity on space itself. This theory depends on the speed of light being constant throughout the universe. Ironically, this leads into a dark area, as the rate of expansion of space is accelerating, causing distant objects to seem as if they are moving away from us faster than the speed of light. The main culprit is dark energy, a mysterious force that seems to be the opposite of gravity: it exerts a repulsive force, encouraging everything to move away from everything else. The ramifications of this are staggering: there is a theoretical limit to how much of the universe we can perceive. Called the observable universe, this is the spherical region centered on Earth containing all the galaxies we might ever hope to see. Due to the accelerating expansion of the universe, there are some galaxies that we’ll never be able to see because light simply can’t travel fast enough to overcome the increasing distance between there and here.
Aside from pushing the universe apart and functioning as a foil to gravity, we don’t know much about dark energy. This is somewhat alarming from a metaphysical stand-point: it’s real, because we can see the effects, but we can’t know it’s real because we don’t know anything else about it and can’t directly observe it. Current estimates place dark energy first in the total matter-energy budget of the universe, with an enormous lead of 74%. All of the matter and energy we are familiar with constitutes a meager 4%. The other 22% is a mysterious substance we call dark matter [4]. As with dark energy, humans are still trying to discern exactly what dark matter is. In the decades since their discovery, despite many strong efforts, we still lack a cohesive theory for either.
Direct observations of dark matter have proven difficult, since it only seems to interact with ordinary matter gravitationally [4]. Significantly, this means dark matter doesn’t interact with electromagnetic radiation of any kind. When studying a substance that doesn’t absorb or emit light, our only inference of dark matter’s existence is from its effects on what we actually can see. Observing the rotation curves of galaxies provides a powerful piece of evidence. Stars orbiting far from the centers of their galaxies have velocities comparable to those orbiting much closer to their centers. For comparison with our solar system, this would be like Neptune orbiting around the Sun as quickly as Mercury does. If that were the case, Neptune’s high velocity would allow it to overcome the Sun’s gravity and escape our solar system. Yet in many galaxies, stars orbiting rapidly and far from the center remain gravitationally bound within the galaxy. Scientists speculate that there could be some form of missing matter accounting for the high rotational velocities at the edges of galaxies, where visible matter is minimal.
Ordinary matter is baryonic, composed of protons and neutrons. Along with electrons, these subatomic particles make up the atom. Placing these particles in different ratios (according to the laws of chemistry) creates the variety of chemical elements we’re familiar with, from which compounds and more complex substances form. Dark matter, however, appears to be non-baryonic, making it truly unlike anything we currently know. A current contender for its composition is the neutralino, which is a hypothesized particle in SUSY [4]. The abbreviation for supersymmetry, SUSY was developed as one of many grand unification theories. Like early philosophical cosmologists, modern scientific cosmologists long to unite the cosmos in one glorious, cohesive theory of everything. SUSY expands the standard model of particles to include supersymmetric partners for every known particle [5]. Neutralinos are truly electrically neutral particles, which would explain dark matter’s lack of interaction, other than gravitationally, with baryonic matter. One of the primary goals of experiments performed with the Large Hadron Collider is to detect and produce supersymmetric particles. If neutralinos can be proven to exist, we have a chance to study them and perhaps come closer to understanding dark matter. At the very least, discovering what constitutes dark matter would move it from a shadow on our cave wall into the light, where we can probe a little deeper into our world.
Scientific acceptance necessitates evidence, but many concepts on the edge of what’s known gain popularity while trying to be proven. Such is the case with SUSY, which does not yet have any experimental support. Researchers continue to look for evidence because of supersymmetry’s necessity for the most promising grand unification theories. Initially known as string theory, M-theory combines multiple superstring theories, all relying on supersymmetry. Despite the name changes, the underlying idea remains the same: instead of point particles, the smallest building blocks of the universe are vibrating, one-dimensional strings. Behaving similarly to three-dimensional strings in our everyday lives, such as those in musical instruments, string theory’s main components have natural vibrating frequencies that correspond to the particles we observe [5]. A major point in favor of M-theory is its mathematical beauty akin to philosophical elegance.
An intrinsic human characteristic is the desire to make sense of everything. M-theory provides a world where we can achieve this, but it relies on as yet unproven models and notions to do it. Many current scientific theories depend on evidence that we can’t straightforwardly see for ourselves. When our understanding of the bulk of what makes up the universe comes from indirect observations, and our knowledge of the building blocks of matter changes with observation, the gap between reality and perceptions widens. From a metaphysical standpoint, which of these is real has long been debated. Plato believed in ideas as the “really real,” while Aristotle held that the union between form and matter constitutes the real [1]. Their debate has formed the foundation of Western philosophy, shaping the way many cultures view the world. Other viewpoints espouse less tangible metaphysical ideas. Buddhism champions enlightenment with the realization that what is real is beyond what we currently see [1]. Taoism also follows this train of thought with a greater emphasis on the natural world and going with the flow [1]. Both Eastern philosophies seem better equipped to handle our perceptions being vastly different from, and even contradictory to, experimental results.
Perhaps the most disquieting apparent contradiction is quantum entanglement. Under certain conditions, particles can interact in such a way that their quantum states are connected with each other [6]. This means that, if one particle is impacted through measurement, the effect is instantaneously observed in the other particle as well. Most impressively, the particles do not need to be in contact – or even remotely close to one another [7]. As an early implication of the weirdness of quantum mechanics, Einstein famously dismissed this as “spooky action at a distance” [6]. It has since been proved, however, with revolutionary applications for communications, including teleportation. Quantum teleportation uses the principles of entanglement for data transmission [7]. Theoretically, this could extend to objects, creating a new set of philosophical conundrums [3]. Rather than the exact transfer of an object, popular in science fiction, modern views of teleportation involve the exact re-creation of the object on a sub-molecular level [1]. If people could teleport in this same fashion, would someone be the same person afterwards?
If we can’t easily perceive the world as it truly is, or even us as we truly are, then our place in the grand scheme of being is called into question. Everything we know – including everyone we’ve ever met or ever will meet – only makes up 4% of the universe, which is naturally a bit unsettling. Western philosophy has long placed humanity at the epitome, but this allegation has been increasingly challenged by cosmological studies. Remarkably, Buddhism’s Net of Indra seems very similar to the current image of the fabric of spacetime. The Net of Indra symbolizes our interconnectedness: at each intersection of the Net, a jewel sits and reflects every other, and any movement within the Net is felt by all [1]. Visualizing this as a representation of one-dimensional strings connecting every manifestation of matter and energy via quantum entanglement provides a picture of contemporary cosmology.
Having thoroughly explored what we can see, humans are now investigating new frontiers. Even with our technological advancements, there are potential limits to what we can actually observe. These include not only measurements changing observations in quantum mechanics, but also the sensitivity of machines and tools themselves to make measurements. Despite our best efforts, there may be a limit to how much can be discovered in the universe.
With the dawn of modern physics, we’ve been finding our way out of the cave. Instead of light, however, we’re being greeted by darkness. This is figurative when considering the wave-particle duality of matter and energy. It’s rather literal in the case of dark matter and energy permeating the universe, leaving only a small fraction for the matter and energy we know and understand.
Past scientific revolutions, such as the Enlightenment, truly brought us out of caves filled with superstitions, showing us the reason behind events. As the period name implies, we saw the light. With the development of relativity theory, this light was revealed to be more complex than we expected. Newton had led us out of a cave with his three laws governing the physical motion of matter. Huygens and Young brought us literally into the light by demonstrating its properties. Joule and Kelvin illuminated the concept of energy and its transfer between objects. The development of quantum mechanics showed us that all three of these caves had actually led us into a bigger one. Our daily observations are only a piece of the action in the world, shadows on this new cave’s walls that we can’t access without fundamentally altering the outcome.
The line between science fact and science fiction seems to be getting blurrier all the time, as theory and our imaginations race to comprehend the mystery our deeper understanding of the universe has presented. Short-range quantum teleportation and minor time travel are already occurring. These events may become more commonplace – and their effects more pronounced – in the future.
Through all the discoveries, philosophy continues to search for metaphysical answers. What’s real, and how do we know? Currently, wavicles, quantum mechanics, relativity, dark matter, and dark energy appear to be real. Their existence is supported by vast amounts of research, although direct observation is problematic in many cases. Supersymmetry, M-theory, and strings themselves are merely theories at the moment, awaiting evidence. We long for proof, but nothing can ever be truly “proven” in science. Generally accepted theories gain their status because they can successfully make predictions that are verifiable by experimentation with a low degree of uncertainty. In keeping with the philosophical concept of paradigm shifts, theories will continue to be challenged as long as there is undisputable contradictory evidence.
When we ventured out of our most recent system of caves, Newton and Maxwell had showed us the world as it appeared to be: logical, reasonable, and able to be explained. Now we seek to understand the universe as it truly is. The cosmological search continues, both scientifically and philosophically. We know there’s more to be known, discovered, and understood. Now we know we’re in a cave. Do we have the tools to finally make it into the light?
Contact: kahamil@umd.edu
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References
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[7] Mann, R. B. (2008). Quantum Entanglement in Noninertial Frames. Physics Essays, 21(1), 26–32.
