What is Time?

(I found this as a comment on another blog. It interests me so I stole it.)


On The Nature of Time

To me (subjectively!) time consists of four qualities that can be considered separately:

There is a moment when something happens. Other things happen at the same moment. When it is morning here it is evening there. When the crime was being committed I was elsewhere. I have an alibi. When the ball is flying through the air in front of me my hand will be there at the same time to catch it. At this moment in a distant galaxy something is happening simultaneous to what is happening right in front of me. Despite my inability to ever know what is happening (it is outside of my "light cone") I am certain that there is a simultaneous event. Everywhere in the universe there are events occurring that are just as simultaneous for me as what is going on in the next room. This is the universal moment of simultaneity.

We experience time as continuous. We may divide up our days and lives, but we know that there is no time between one division and the next. Each identifiable moment glides seamlessly into the next. When we anticipate the clock striking or the water boiling we never experience a time between the waiting and the moment of the event. This is the perfect continuity of time.

Time doesn't run backwards. The entire experience of humanity has been a forward flowing experience. Growth and decay, while seeming opposites, are always experienced as the result of time constantly flowing into the future. This fact allows us to define what is past and what is future. Neither is there a sideways movement in time. Time has a permanent direction.

I read somewhere that Einstein, when asked "What is time?", replied "Time is what clocks do." I suspect that he wasn't being entirely facetious and was simply stating the definition that he found sufficient for his purposes. The fourth quality of time can be put simply as "Clocks work". How is it that I can relate the revolutionary period of a remote neutron star with the life span of a dog? Why are the rates and durations of distant, unrelated events seemingly consistent relative to each other? Of course this fact allows us to invent calendars and construct clocks. At first glance many things seem consistent but when we look closer we notice variations. We count more carefully and measure more accurately and discover that a year isn't 360 days. But we do discover that 365 is more consistent, until we realize that's not perfect. Add a quarter day and consistency is regained. Sometimes it is our imperfect counting methods and measuring tools that are the source of inconsistencies. On the other hand many events seem to have random elements that create random variations of period, as in not all dogs living to the exact same age (or the year not being exactly 365.25 days). Looking at the phenomena at a deeper level reveals the consistency. The durations and rates of the biochemical processes that can describe a dog's life are more consistent among different dogs than their separate life spans. Tidal forces and energy loss slow the earth's orbit and almost imperceptibly lengthen the year. These can be accounted for, and consistency regained. Apparently the simpler, or more basic the phenomena the more consistent the periods of duration and rate. It seems that the relative consistency of period between different phenomena is something that applies to all at a fundamental level. The most accurate clock is one that counts the periods of an exceedingly fundamental phenomenon, the energetic vibrations of an atom. The fourth quality of time is that there is a basic consistency of duration and rate for all phenomena relative to each other. (Note that the very concepts of duration and rate are explicitly temporal. The concepts themselves arise from the fact that all phenomena share a consistency that reveals itself when the various phenomena are compared or related to each other- thereby making clocks and calendars, which are designed on the principles of duration and rate, possible.)

Given that the experience of these four qualities of time has always been a commonplace, taken for granted experience, and that the qualities do not present themselves in obviously separate ways, that is, the experience of time is always, more or less, the experience of all qualities together as a piece, then it is reasonable to view time as though it were a separate force of nature. But that force remains undetected and apparently does not exist.

When some ancient philosophers asked the question- What is Time?- they saw an obvious answer. Time is nothing more than change, for without change, how could there be time? In those days one could give a counter-argument that some things are changeless and therefore timeless, yet still exist within and experience time. We now know better. In fact everything is changing all the "time". If we equate time and change then we can say that at the most basic level change is fundamentally consistent, permanently directional(?), perfectly continuous, and universally simultaneous.

What is change? Change reduced to a fundamental level always involves the flow, transfer, or transformation(?) of energy. The flow of energy across the smallest possible distance will occur at the speed of light. This can be seen as representing the briefest possible moment and the most fundamental element of change. These moments of change must be consistent with each other because they all occur at the speed of light. Further, if the speed of light were to "change" self-consistency would be preserved because there exists no phenomenon whose apparent duration or rate is not the result of the "fundamental element" of change. Consistency exists because it is the result of existence itself being necessarily self-referential. This fundamental flow of energy must appear continuous throughout the universe because if it wasn't then parts of (or things in) the universe would appear and disappear spontaneously. Similar to consistency, if there was a universal discontinuity the entire universe would "wink" out of existence and no part (or person) could be aware of it. (I don't think this could ever happen because of the "arrow of time", material existence would have to start over from scratch.) The appearance of simultaneity is also the result of change (the flow of energy) being fundamental to existence. We (or any measuring instrument) can never be aware of an event (at its most fundamental level) except that it is simultaneous to our awareness. When we witness or measure a distant event we say it occurred in the past because of the limiting speed of light. The witnessing or measuring of the event itself though is simultaneous to the effect (change) of the event reaching us or the instrument.

The qualities of consistency, continuity, and simultaneity are therefore all the result of the flow of energy being fundamental to change and existence itself. Another way of putting this is that if existence is all of a single piece then everything occurs at once and therefore at the same "speed" (another explicitly temporal term), that is, the speed of light. This suggests that reality relative to the concept of time is momentary, past and future do not have an independent existence but are conceptual abstractions created by our senses of memory and anticipation. (Time travel is therefore impossible, except in the trivial sense of travel into the future, which nothing can escape.)

What about the time dilation effect? I am not a physicist so I can be glib and simply say that it doesn't exist. What does happen is that clocks (and every macroscopic phenomenon is a clock) can experience spatial distortion under the effects of gravity or acceleration. It is not time but rather the clock (or space, if you prefer) that is being dilated. The spatial path of energy can be expanded or contracted but the speed of light remains constant.

That leaves the Arrow of Time to be dealt with. I think that perhaps this quality of time is not really a quality of time at all, so to speak. It is obviously tied into the concept of increasing and decreasing entropy. It has to do with the effect of energy on matter. I don't understand how energy "condenses" into matter but I would guess that the arrow of time becomes manifest at that point. To again be glib about it I would say that this quality of directionality is an "emergent form".

Overall time is a psychological experience. It is the result of all change being brought about by the universal flow of energy that is necessarily self-consistent and therefore these changes more or less manifest the qualities of simultaneity, continuity and consistency. We humans perceive these qualities in all the phenomena around us (and within us) more or less imperfectly, and in combination with the Arrow of Time, this psychologically forms our concept, or experience, of time. In the end it all rests on the idea that the speed of light is the single, fundamental constant of existence.

Time and quantum weirdness? I've thought about it, but those thoughts might just smack too much of "science fiction". It could be that because existence is less differentiated at the quantum level time as we conceive of it simply doesn't exist. With less differentiation there is less change. With no differentiation there is no change, with no change there is no time. Maybe.

I imagine that our traditional 3-dimensional view of space is like an optical illusion and that illusion betrays a basic fallacy. You are familiar with "Flatland"? It is created by subtracting one dimension from our intuitively based concept of three dimensions, yielding a weird and strangely "incomplete" world. What if 2-dimensional space contained the third dimension in a collapsed, or potential state? If that was so Flatland would look quite different, there would be no "missing" parts or incomplete perspective. Instead of seeing less we would see more, but that "more" would be simpler or less differentiated, which implies that 3-dimensional space is an emergent form.