Friday, October 15, 2010

IV. The Speed of Time

We apprehend a three dimensional world in time, and in time it has been since its beginning. From the moment at which the infinitely massive, infinitely dense, concentrated singularity explosively began its expansion outwards, creating space as we know it, the universe had a direction. This asymmetry, this basic directionality in the universe, is called Time
Time is change and change in time is irreversible. Time itself is irreversible, unrepeatable, and whether or not it exists outside of consciousness ,(footnote here regarding theories that time does not exist outside of the subjective consciousness)this principle of irreversibility is what time is. It has one fundamental property: direction. It is even misleading to say that time has a direction, in fact time is direction, and everything that inhabits it, the totality of the three dimensional world, can be described in term s of it.
The measurement of time, and its utilization in human communities throughout the world, in other words, the utilitarian concept of time in common practice, is both different and similar to the existence of time in the sense discussed above, as a universe principle. In the prior sense, time is a dimension, and its effect, that of directionality in terms of itself, is detectable throughout the universe. In our human experience, directionality in time is a fundamental irreversible constant present in every aspect of our experience, and this informs time’s utilitarian applications and our measurement practices regarding it. Commonplace linguistic and practical usage of time referents belie a deeper truth: expandable and compressible spacial dimensions – when describing an object like a planet or a peanut – exist in the medium of time. In the English language, in fact, objects are described as being “in” time, and the use of this preposition, and the inherent inside/outside dualism that it implies places objects within time as as if spacial entities, their developments, and space itself, exist in suspension, floating in a moving river of time, to borrow a common traditional metaphor. In any case, spacial entities, their developments, and space is commonly referred to in terms of time, and it seems as if it must be, as if time with its property of irreversibility, provides a ground on which the figures of spacial articulation, that is three-dimensional objects, interact. Yet a paradox lurks within this idea, for it is the expansion of space itself, outward from its beginning with a big bang, that creates the directionality, the endless change, that gives a future and a past to the universe, and thus creates time, which is this property of movement itself.
So then, looking past the immediate perception of time and thus sidestepping the entire question of whether the perception of time is an artifact of our conscious mind itself, a function of the memories we store as biochemicals in our brains, it is clear that if one adopts a cosmological model of universal expansion – at least for the present development of the universe- than one also accepts that the universe has a shape and a direction. Put another way, it is possible to assume a certain consistency between cosmological scales and human scales of time perception In common practice, given a consistent linearity between time as perceived in our own life experiences, and time as perceived in the earth’s fossil record, for example. In short, the action of time seems consistent across many (foot note ref QED Fenneyman) if not all frames of reference. Such an idea relates our sensation of time not inconsistently to the directionality of the universe as a whole, as implied by spacial expansion in one direction since the big bang.
At least one currently popular cosmological model seems to agree with this (citation). The universe, it seems, and space itself, is expanding, and always has been, since the beginning. Before the big bang time did not exist, and neither did anything else. Judging by recent estimates (citation and footnote) of how much mass exists in the universe, some theories indicate that it should, in fact, continue to expand forever. In such a model reversibility, or repeatability, could not exist on any scale. Such a universe of three, four, or more dimensions exists as a great puddle of change spilling forth from an initial point and such universal, infinite expansion of everything in an outward vector implies direction, at least, from an earlier more inward point. On the other hand, as such an expansion is not an expansion into anything, how can it be said to exist? If reality expands into, as it were, itself, than how can we trace its progress , and would the expansion itself be consistent or variable?
The answer comes along with that energy which itself makes it possible for us to know that such expansion exists. That energy is light. Light emitted by stars represents a broadband, high energy radiation. When it is shifted into the red from the perspective of an observer, this means that the object is travelling away from the observer. Fundamentally, this is very close to the audio phenomena of Doppler Shift, in which, for example, an ambulance approaching an observer at high speed, passing the observer and then continuing to speed away into the distance is heard to emit a siren which, from the standpoint of a stationary observer first rises in frequency (perceived as pitch) and then falls as the ambulance approaches and then passes the observer, respectively. This effect occurs from the standpoint of an observer because the sound waves emitted by a moving object are first compressed in the direction of motion with respect to the listener and then elongated as the sound producing source recedes into the distance. Since higher frequencies are perceived as higher pitches, the spacial compression of the wavelength emitted by the sound producing object (the siren in the example above) results in a higher frequency as perceived by the stationary observing listener, though the sound emitted by the siren itself (or any sound producing body in motion) remains consistent.
In terms of light higher frequencies correspond to the blue end of the visible spectrum and lower to the perceived red end, therefore objects in recession with respect to an observer appear to be redish in color, while those in motion towards an observer would appear blueish. Since, according to recent astronomical observations, all other galaxies appear to be redshifted with respect to our vantage point in the Milky Way, one can deduce that in fact these redshifted structures are moving away from us. All apparent large scale structures moving apart from one another seems a credible argument for universal expansion, for spacial expaqnsion. This becomes more complicated, however, if one considers the question of what the universe, what space itself, is expanding into.
Many cosmologists suggest (citation) that the cosmos is not, in fact, expanding into anything, but that space itself is expanding. Stretching, as it were, out into all dimensions. However, since space is more or less nothing, how do we map it in order to understand its direction of expansion. Further, how can we know the shape of the universe?
Space is mapped by the energy that it contains, whether this energy is contained in three- dimensional objects or whether it exists as fields of radiation. Light, or electromagnetic radiation in general, can function as an indicator to map out the shape and development of the cosmos. Radiation, including light, interacts with objects, including our telescopes and other instruments, and offers us a way to theorize about the age, size, direction of motion, or behavior in general;, of cosmological bodies. We look to the galaxies furthest from us, receding, from our perspective on earth, at a rate close to the speed of light, as an indicator of the furthest cusp of spacetime, and the edge of the expanding universe.
Here light emerges again, but this time its function is as a limit. As is well known in popular and professional publications (citation) the speed of light sets certain limitations on the realm of human experience. According to the theory of Special Relativity (citation) frames of reference in motion relative to one another account for the difference in the energies and information perceived by an observing system at rest relative to its own coordinate system and those emitted by a system moving relative to the observers coordinate system (whether or not that system is moving or at rest relative to their own coordinate frame. Further, as a moving system increases in velocity relative to an observer at rest relative to its own coordinate system, the moving system would be seen to elongate in space and become more massive. In addition, it would be observed that a clock present in such a moving system approaching the speed of light in relation to one at rest within a coordinate system would tick slower and slower as the velocity approaches the speed of light. From the standpoint of an observer within the moving system, however, all would progress as usual (or so goes the theory), such an observer would not perceive a change in size, mass, and the clock would tock as before, even Stephen, and the moving system could continue to try to accelerate towards the speed of light.
The problem is that this seems to suggest that in fact the speed of light cannot be exceeded. If, upon approach to it objects mass, and size increase towards infinity and time moves infinitely slower, than the situation becomes similar to trying to cross the threshold of a door by taking a step one half the distance of each previous step. Forgiving for a moment the limit of one’s foot size, which would impose itself on the situation rather quickly, one can see how the situation quickly explodes into an infinity of fractions and the doorway would remain forever unreachable. To try to port this metaphor into our experience of objects moving relative to one another and relative to the speed of light is fairly logical since we have information about objects at a distance do to the radiation, the light that they emit. A system moving faster than itself is not possible, and one moving faster than all energy emitted by it would certainly be invisible, not to say bizarre. Movement exists in relation to a coordinate system perceived to be at rest, or a system at rest relative to its own coordinate system, however if the universe itself is expanding as indicated by the directionality of the time dimension, it is difficult to say that stasis exists objectively anywhere.
Further, if the systems of perception, that is, the systems for receiving information are limited by lightspeed for their reception of radiation-energy than it would be logical that to exceed that would be impossible while inside of such a frame of reference. It also seems impossible to adopt another frame of reference, in practice. Any attempts to break out of this one by crossing the lightspeed limit result in the distortions discussed above, or so goes the theory. Thus, it seems that the speed of light sets a limit on the nature of reality in general. It is interesting to consider, however, if this is true across several orders of magnitude.
This introduces a number of problematic situations. First of all, the galaxies furthest from us, those mentioned above whose light we might hope to use to indicate the furthest visible cusp of the expanding universe, in fact seem to be moving away from us at a rate faster than the speed of light! Further, going the other direction along orders of magnitude, very small particles are sometimes annihilated within atomic reactions in which a particle is said to interact with an anti-particle of the same type (citation). In such reactions it has been argued that in fact what happens is that time is moving backwards as these energies are in motion close to light speed.
With regard to the first situation, that of the galactic recession at super light speed, it is possible to consider that the rate of expansion of space itself is in fact faster than the speed the light from the galaxies is traveling towards us. Thus the velocity of spacial expansion is faster than the velocity of light in space. If the spacial expansion can be utilized to explain the directionality of time, than it could be said that the velocity of time is greater than the velocity of light, and that does not, on the surface seem to make sense.
One partial solution to the problem, however, is to consider the coordinate system from which we are viewing these galaxies from. We too, are in motion, and seeing as the light reaching us from these furthest receding galaxies (as seen by the Hubble Deep Field telescope, citation etc) takes a considerable amount of time to reach us, along with the distortions enacted up on by the gravitational fields of massive objects around which light bends along with space itself, which, according to further relativistic theory, is the cause of gravitation (citation). This introduces still more fascinating problems such as how it is possible that the galaxies furthest from us appear to us to recede from us at a value greater than than of the speed of light. Is this due to some change in the value for the speed of light at the edges of the universe? Or could such a phenomena be caused by our observational position with regard to the universe as a whole?
Space and time, though often conceptually separated in commonplace experience, are tightly united physically and cosmically. Is space itself moving, expanding, faster than the speed of light? Since the Hubble constant is a spacial constant but not a temporal one, could it be said that galaxies expanding along with universe itself could exceed the speed of light? Does this mean that the speed of light might itself be slower than the “speed of time”, which in this case the rate of universal expansion itself?

Monday, October 4, 2010

in case anyone is actually reading this

please bear with me, citations are coming and so are some revisions, especially for sloppy number 4.

III. Movement Towards Later

All movement exists in relation to the idea of stillness. Bodies in motion move in relation to bodies at rest with respect to their local coordinate systems (citation). This is how we know they are moving. It could even be imagined that this imaginary quality called stillness is the medium within which movement happens. Still, stillness, like movement, is only relative to a particular situation (a coordinate system, ibid.) being considered. An elevator can be be said to be at rest on the 3rd floor of a building, and yet the planet on which the building itself resides is itself speeding through space, in rotation around both the sun, and about its own axis. Our galaxy, further, is in rotation about its center as well, and in fact, according to Edwin Hubble's slowly (from our coordinate system) stretching "constant" the entire universe is moving, expanding, as evidenced by the the fact that galaxies both distant and local to our own appear red-shifted with respect to us. Everything appears to be in motion, spreading apart, away from us, as the fabric of space itself expands.

Despite the fact that everything else is red-shifted, this does not imply that we are in the center, and are motionless, instead such red-shifted galaxies would be seen from any point in our isometric universe, and thus our own galaxy would appear red-shifted if seen from another, or so goes the theory.
Thus, nothing can really be said to be at rest. Even molecules super-cooled to absolute zero would retain the inertial mass of the coordinate system they exist in, the planet they are on. Yet typically human beings measure time as though we ourselves are at rest, and who can blame us? Our common sense idea of time, and thus of rest, as applied to our utilitarian exploitation of time works just fine.

So then, people characterize time in terms of direction. Tomorrow is in the future. Yet, the systems in place for quantifying and measuring time operates with reference to the three spacial dimensions, in terms of volumes of time, durations. We play out actions in three-dimensional space in terms of these time volumes, and without the implied but not quantified sense of directionality, which is caused by the movement of the expansion of the universe, the movement of space through itself, there would be no before or after. Everything would happen at a point, at once.

So what is time? Time, and the perceived quality of non-repeatability in our universe are analogous and inseparable. What we call time is a perceived vector quality. Time is a direction and a movement within our environment. The strange part is that really, the entire three-dimensional environment is moving, it moves, itself, though time. Everything exists, as it where, in time.

One curious side effect is that although the spacial quantities are reversible, at least to the zero point, time is irreversible. This is curious, because simply put, this is what time is, a principle of irreversibility. We can break time into units, and measure it out quantitatively (this is done despite the lack of any absolute zero state of rest to refer to), but unlike the spacial dimensions, in which reversibility is possible, at least down to zero and further in some cases), in time this simply isn't possible. It goes in one direction, and that maybe is its only attribute. You can lose weight but you can't go back in time.

In fact, when one tries to prove time's existence, the mind finds an irreducible barrier within the concept of non-repeatability. Time has direction, it is direction, in which space and everything in it, everything in our experience and seemingly outside of it, moves. The whole universe is doing it, and that is it, and really all we know about it. Time simply goes. As a certain natural scientist put it "evolution is just one damn thing after another" (citation), and maybe that could be said for time itself, if it wasn't for the fact that the things themselves seem to exist in the medium of time rather than the other way around.

Another curious experience is apparent fluidity of the movement of time. We have all experienced, certainly, at one time or another, the feeling of that time is "flowing" at different rates. This can at times be quite extreme. Waking, for example, from what one thought to be a short rest only to realize that one has slept for hours (if not years in the case of Rip Van Winkle mythologies). To compare such experiences with our imposed regular quantitative divisions of time, that is, clock time, are a source of wonder and amazement, but still all we can say about time is that it moves. It is MOVING. It IS moving. IT is moving. But where is it going? It is going towards Later.

We know this based on one thing: that we cannot go back. Repetition, in a very strict sense, is impossible. Every repetition, in a strict sense, is a new event against the axis of time. It is, at most, a similar shape, in the geometrical sense, if we where to imagine a four dimensional coordinate system with the three spacial axes and time as a fourth axis. The same three dimensional form at two points on the fourth dimensional axis creates a similar form but not the same one.

Perhaps, as present in science fiction and in certain Fenneyman (citation) -esque branches of particle physics (about which, this author admittedly knows almost nothing) retrograde temporal movement is possible. When one finds theories regarding this, they usually are framed in orders of magnitude much smaller or much greater than ours. Some theories about anti-matter particles imply a retrograde temporal movement to account for the existence of these particles but this is on an order of magnitude so much smaller than our own everyday world that very little in fact behaves in similar ways, even though we are made of that world. It seems impossible to experience such a transformation here and, with your pardon, now. No anti-author will appear to annihilate this author. Traveling the other direction, upwards to agreater orders of magnitude of spacetime, should the universe end in a big crunch in which time reverses backwards into an inverse big bang, the experience of this is still quite beyond the scope of our present discussion.

Time has every appearance, and in fact, we find our utility of it in the firm directionality of its development in relation to spacial forms. This directionality is time itself. Although some mathematical models, referred to earlier, describe time and space on a four dimensional coordinate system, and as such, more or less mathematically equivalent to one another, it seems that in some ways they are not equivalent. Spacial events happen in time. Time is, in this sense, the media in which spacial events happen. This idea is very commonly encountered in everyday speech. One doesn't say that time exists inside of an object. Yet an object, like a block of wood, clearly exists in time. The usage illustrates important aspects of how we use time itself, and these are formed by and indeed form our conceptions of what time is itself.

This is why, when in need of quantitative reference for time, we place a grid over it. This grid consists of assigned, regular units marked off according to a reference point, as we do with spacial coordinates. Throughout history, humanity has relied on myriad reference points such as the behavior or the sun and moon, tides, decaying isotopes, and so forth for such reference points, but what are we trying to do with our grid once established? We are trying to see the progression of three-dimensional events. For example, a baby book, in which parents collect photos of their child at regular intervals displays the three dimensional development (two dimensionally, of course, using photos) with reference to a time grid, here a calender. We make such grids to see change more clearly.

To put the problem another way, imagine an object in an environment. The object's environment (set A) is simply the collection of all other objects not object A (our initial object) inside set A. The development of object A (the changes which this object goes through while remaining, for the purposes of a perceiver, object A)in relation to the other objects in set A represents object A's path through time, if not the path of set A itself. All of this can then be set against time grid T, which is based on a regular division of time (which as stated before is simply this quality of irreversible movement in our universe). The relationships between object A within set A (the development discussed earlier), in reference to grid T, and set A's relationship to grid T can be described as a "rate of change", and units from time grid T can be used to describe it. This quantification thus describes both time and space, and both space and time coordinates are necessary to catch a particular bus or arrange a meeting with a person in the center of a crowded city.

Interestingly, this relationship of interdependence between time and space shows up in the tools of calculus, where rate of change is measured and often expressed graphically. Curves have attributes of being analyzable graphs of functions, and in this way share a behavior with other curves, such as those found in nature or in nature as designed by humans - architecture. Curves turn out to be curves whether they represent data about spacetime, or whether they are stone monuments. Still, this conceptual flattening of spacial and linear curves is something of a game. The effect of negating the function of such curves is unfortunately similar to the flattening effect of treating the three spacial values and the time dimension as mere numerical values or variables in a coordinate system when in fact their behavior seems to be very different.

Consider this final point: if time is taken to be a medium of sorts, in which spacial events happen, and irreversible a paradox emerges. Time described as the concept of movement cannot be quantified. When one tries, the best that emerges is the idea of a field. That is not problematic as certainly spacial events can develop against, or better, in, such a field, but that field itself exists in relation to something, since it itself describes a development. What then, is the field of time in development in, what is its medium, given that nothing could exist without or before it? After all, we have never known stillness.

II. One Hand Clapping

A falling tree in a forest would be heard if someone was there to hear it in the same sense that it would be seen if someone where there to see it. Now there are no trees, no sounds, no observers of them, real or imaginary. We are leaving all that behind to talk about sound in terms of our utilitarian definition of it, as a system of interactions, or rather as an interaction of systems that define both our use and our experience of sound as a phenomena.

What makes a sound?

Every sound, heard or not, is produced, or rather, represents (as "a wavelike disturbance in an elastic media" citation) an interaction between two or more systems. For it to be heard, as we shall see later, still more complexity is required. Firstly, however, here on earth a sound moves outward, wavelike, propagating from an event in all directions, unless obstructed. What was the event? It was a basic interaction between two physical systems like two snapping fingers, or a hammer and a piece of board (and again, a medium, as we shall see momentarily). A sound could be said to be the effect of this interaction, it is not always the desired effect either, as I unfortunately can attest to each morning when the construction begins outside my bedroom window. After all, those machines for sawing wood and shooting nails direct their energies towards the wood and nails used, and the sound produced is actually "radioactive waste" in a sense, or at least wasted radiation, similar to the way that heat produced by machinery and released into the atmosphere can represent lost energy in a physical system. Nevertheless, the cause of the sound is the same, be it a saw or a violin (and often there is little difference), two systems interact, energy propagates outward, and if we hear it we call it sound. In fact, when we organize it for amusement or communicative purposes it is called music or poetry, or some other things, but we must leave that for an entirely different discussion. The point is this: hammer and wood interact, air pressure is displaced between the two, a sound wave (which is a pressure wave in air and water) vibrates outward in all directions at a constant rate. This is sound production on earth, that is, inside of our atmosphere.

With the addition of the atmosphere we must increase our model by an order of complexity. Instead of two systems of interaction we now must include a third: the atmosphere. This environment, the medium through which our sound travels, is certainly of itself complex, but then upon consideration one realizes that so is our hammer, forged from complex mineral crystals melted at high heat and recast in an iron alloy, and the wood itself, which it strikes. Unfortunately those fundamental layers of complexity, those systems and their own fascinating molecular interactions will not be considered here. We must return instead to our earth-based common practice human definition of sound as audible radiation which depends on at least two interactive three-dimensional systems and a closed system of atmospheric pressure. This pressurized atmospheric room surrounding the earth provides "ground" necessary for the "figurative" changes in the pressure which allow it to become audible, and thus to fall within our definition of sound itself as an "audible" energy. Our definition, it turns out, is already recursive on one order, and also a bit self-centered: The pressurized atmosphere renders sound waves audible to us because it is the medium through which the waves that we can hear propagate.

Such circular thinking produces a crises of third order, for now it is clear than it is not enough to have two interacting systems interacting within an atmospheric system which forms the medium for their interaction but further that to hear any of this further complexity is required! So, then, our common practice definition of sound implies the presence of a listener. Earlier, it was determined neither to precede with an investigation of the medium (our atmosphere, in the example given) nor of the two interactive systems (the hammer and the piece of wood it strikes) in terms of their internal complexity. Still, a listener, a human listener, as implied by the common practice definition of sound as audible energy, is worth looking into. What systems are required for a listener to hear, and further, to make meaningful, the pressure data retrieved from the environmental medium as sound?

Depending on the organism in question these systems can be integrated or separate from one another. Most animal life, including humans, feature highly complex inter-connected systems of perception and interpretation (further reading reference here). Computers, to the extent one chooses to consider them to be organisms, often feature perception and interpretation systems discretely housed if not totally separated from one another, often dependent on user interface for systemic integration. The main idea, however, is that these systems, whether animal or computer, are frightfully complex, and find their greatest interdependence in that mysterious complex known as consciousness. Since we are discussing particularly human listeners, it is germane to explore how the human sense of awareness functions in the listening process.

Consciousness, as entity or idea, remains fascinating and strange. Despite the research into it being conducted in multifaceted ways, it's structure and function remain largely unknown. Thus, it will be approached in materialistic terms. Despite volumes of research into sound perception, it is clear that we do not yet understand how the perception of sound happens in the human brain in a clear way. I do not understand my own, and I certainly do not understand yours.

So then, what can be said about sound as a perceived phenomena?

For one thing, it is clearly not a static, momentary, individual, occurrence, but rather something in time. It is dependent on the three spacial dimensions but by it's nature also implies a continuity in another dimension. Sound exists in relation to time and has a shape in time, a history. This history, the perception of which could be said to be based on the memory of the perceiver of the sound, relates to the cause and the chain of integral effects within the sound, producing it's line of development in time. This is what musicians call the form of a piece or what electronic musicians refer to in terms of individual sounds as an envelope, the two dimensional line which describes the life of the sound from it's birth (attack), life (sustain), old age (decay), and finally death (release). It describes the perceived effects of the process of a sounds creation, existence, transformation, and conclusion, for any sound no matter what duration. Yet from this one sees that a "sound" is actually itself a complex, an aggregate of parts, of systems of interaction that through a person's choice have been made into one meta-system, that makes a whole that can be described by such an envelope.

What is required for such a choice to be made? What is required to take a selection of pulsations within an environmental medium and group them together as a concrete line of development and to claim that these together, through their interactions, produce one thing, this sound? The answer is memory. Yet the experience of this envelope, this line of sonic development as perceived by the listener says something more about the listener than simply that memory is required and the listener has one. To be able to interpret, much less acknowledge the existence of this time dimension, or to have a memory at all a special sense is required, a sense different in kind from the normal five of seeing, hearing, touching, smelling, and tasting. To experience the development of a sound, or of anything, one must ask what the sound is developing against, what the medium for this development is.

Similar to the momentary pressure displacement in the air required to produce the sound wave discussed in the first section, the medium against which the movement of the subsequent sound wave is gauged is that of time itself, as apprehended by an observer, with their own relative clock. If we had no memory, we would know no time, or possibly if there was no time there would be no memory, or stranger perhaps if there was no memory there would be no time (citation), and eggs before chickens before eggs into eternity.

Sound, in the widest physical sense requires no observer. A wavelike disturbance can and will continue to disturb it's elastic media in the absence of awareness of it by anyone. Otherwise, the universe would not exist, after all more than likely no one was around to observe that. Yet nevertheless sound still requires an interaction of at least two separate systems and a medium to exist. It is often difficult in practice to isolate these three systems, but nevertheless, they exist. Finally, a time dimension is implied, and perhaps the ubiquitous use of the word "wave" in definitions of sound implies this, as a wave itself is a periodicity, even if it is a modified periodicity. Sound requires two interactive systems, an elastic environment, and time. So to solve an old problem totally out of context: One hand cannot clap, especially if taken out of time and therefore produces no sound.

I. Ghost of a Fallen Tree

Children find fascination, or alternately horror, in imagining what goes on in their rooms when they leave home, or what goes on under their beds when the lights go out. In the imagination, toys become animate and monsters form out of the syrupy ether of darkness, as soon as one turns one's back on an environment. Adults too share in this obsession. People set up cameras to see if anything happens in their rooms when they leave. They ask themselves questions a to whether unobserved trees falling in an unobserved forest produce a sound.

Normally, upon investigating these questions it turned out that there where no monsters beneath the bed, that one's toys very likely remained in place and inanimate for the duration of one's absence from an undisturbed room. That, in the absence of intruders, the only action caught on the video camera left to record one's empty flat while one visited the grocery store was the changing light, the accumulation of dust, perhaps the movement from floor to couch and back of a dog or cat, or, given the presence of a time-lapse system and a longer duration, the normally imperceptible growth of one's houseplants, rendered visible. Still, the unobserved tree falling in the forest does in fact make a sound. The splintering crash of the this tree, though unheard, resonates down to the root of our perceptual and cognitive processes and this essay will be about why and how, and beyond this, will open a discussion of what sound is, what it is made of, and later what time is itself, and what it is made of.

Let's begin with the tree. Only the most dedicated solipsist would suggest that an unperceived event does not exist. Some take the situation still further to the point at which any event not perceived or experienced directly by themselves as observers cannot be said to exist. Such persons would do well to consider their own birth, or better, their conception. Luckily, none of us where around to witness that! Still, the affect of the action of our own conception in the womb is visible in terms of our existence. So unless the universe is far stranger than can even begin to be discussed here, extrapolating from what we know about other people and their bedroom behaviors, we can assume that something similar happened between our parents, and that this brought us into existence. Most of us would agree that this was not an action we witnessed (no doubt fortunately) and yet, here we are.

Thus, events do not need to be perceived directly to be said to exist. In fact, even their effects need not be perceived as we constantly assume or become convinced of the reality of objects and situations by the mere plausibility of them. Consider, for example, a news broadcast. We hear about an environmental crisis in Madagascar. YWould a reasonable person question the existence of weather in Madagascar, or the island itself? Of course not. If a friend brings you a report of a new restaurant in the neighborhood, you likewise accept the existence of such a restaurant. Why? Firstly, because the event is simply possible, and more than that, it is likely, it is ordinary. Secondly, analyzing the motivations of the speaker, we find that there is no reason we should doubt our friend's enthusiastic report, and we may even alter our plans for the afternoon and choose to visit this restaurant with our friend, similar to the way we may alter our commute based on the traffic report on the morning radio. In such a way we accept the existence of things we cannot see, and even modify our behaviors based on the mere plausibility of the existence of some situation, and the absence of a reasonable reason to doubt it.

A tree has fallen in the forest. Did it make a sound? Have you ever witnessed a tree fall in the forest that did not make one?

On such grounds an idea can be said to have an existence, at very least in terms of it's effect, similar to that of a physical object immediately perceived. There is something else, however, hiding in the question itself: a tree falls, unobserved, in the forest. Does it make a sound? Well, based on what we have discussed, yes. It makes an unobserved, unheard sound. Yet there is something strange in this, something that reaches both the physical and perceptual roots of what a sound is in itself, and this has to do with questions of utility, that is, with the tone the question is asked in. Thus, two further philosophical questions present themselves.

The first question is "what is a tree to itself?".
Beginning from a basic stance, it is clear that if a tree had any kind of consciousness or awareness at all that it would likely be very different from our own. We have completely different physiologies, for one thing. Thus, the second question: "Does a tree call itself a tree?" Unlikely, especially given that even among humans we don't agree on what a tree is or what it should be called (for example in Czech language a tree is "strom" and in Hindi it is " "). So then, with some sadness, the discussion must be narrowed. If an Englishman observes a tree falling in the forest and then is asked for a report, they will likely reply something to the effect of "a tree has fallen". Still, this event, as experienced by the tree itself, by an insect on the tree, or a squirrel on the ground, would no doubt be characterized quite differently than by our Englishman. So then, returning to our original question with the modifications we have based on the two questions above we rephrase it to read: "If a tree falls in forest, in the absence of an observant Englishman, has a tree fallen?" The action, of course, happens either way. The experience of it, is infinite.

This approach negated a highly important element of the original question. Looking back to the original, it is clear that the question was not, in fact, about the existence of the tree itself, but the sound which a tree might make upon falling. This is even more mysterious when one considers that sound is simply radiative energy. Our Englishman calls it "sound" simply because it is perceived the way most of what we have been taught to call sounds are perceived, that is, by the ears. Of course, if one takes a physicist like Harry F. Olson's definition, as expressed in the second edition of his seminal acoustics text from 1967:

"Sound is an alternation in pressure, particle displacement, or particle velocity which is propogated in an elastic medium, or superposition of such propagated alterations. Sound is also the auditory sensation produced through the ear by the alterations described above."

than one can see that here sound can exist apart from it's sensation. In addition, it is common (citation and example here) to simplify the above definition to "sound is a wavelike disturbance in an elastic medium", and here, as in the first part of the previous definition it is clear that an opening exists, as not only need sound not be heard, but sound need not even be hearable.

Though at first this seems surprising after a moment, it is clear that this is not a new idea. Dog whistles produce a sound. We cannot hear it. Still, we refer to it as a sound. Still it is interesting to consider the fact that sounds need not even be audible. Rather, like the sounds that make up earthquakes, they may simply be the energy, and medium around them, that is, that which resonates, determines how they are characterized.

I can hear the critical chorus rising even now: "But we are not," they sing forth in my imagination, "questioning the existence of radiation. We are asking a question about a tree in a forest." Therefore, let us return to common practice definitions of sound as heard energy, and continue to try and get to the bottom of this. "Tree" "falling" "inside forest" "unobserved". Does it "make" a "sound"?

Ignoring the ambiguities inherent in the quoted words above and forging forth with the common practice definitions of these things we nevertheless find ourselves stuck. How can that portion of the energy that would normally be heard, as produced by a tree falling unobserved in a forest be heard energy if no one, not even a squirrel, snake, bird, or insect, is there to hear it? One must again simply rely on the plausibility argument, extending to what one knows about the system called "forest". We know of no soundless forests, as all known forests are dependent on the pressurized atmosphere of our planet. Therefore, just as it is eminently plausible for a tree to fall unobserved, it is likewise expected that such a tree would produce a sound, though an unobserved, that is to say an unheard, one.

In the next section we will consider this common practice definition of sound, as "audible energy", and in particular what such a definition means in terms of our utility of sound in general.