Tennessee Williams once wrote that “Time is the longest distance between two places,” meaning, I think, that time — because it is finite — is the only real measurement that matters between two points. Humans have yet to find a distance or a depth that is unreachable — at least in the course of a life (which might be thought of as the time allotted us).
But what, exactly, is time? That Facebook just invented a new unit of time (the flick) should say all that needs to be said about time’s human construct. Because for all the as astronomical preciseness, time is still just an imprecise calculation designed to position us at a point in the universe, in history, and in our own existence.
Time, as we understand it, developed over several thousand years, starting around 3,000 BCE, when evidence first appears that the Chinese had measured a 366-day year based on the movements of the sun. A thousand years later they had a 12-month calendar — which included an occasional 13th month. Two thousand years after that and they had recognized what we know today as precession and came to understand that every 300 years, the 12-month calendar would no longer match with the seasons.
In the west, precession was recognized and accounted for in the name of religion. After Constantine established the Easter holiday on the spring equinox, the date of the holiday continued to change (it is, after all, an astronomical event), so in 1582 Pope Gregory XIII implemented the Georgian calendar. The calendar, the one most of us use today, keeps the spring equinox around March 20-21 through the use of the leap year.
As for the more precise measures of time, those which can’t simply be observed by us layfolk through the rising and setting of the sun, their origin is not entirely known. Theories posit that the 24-hour day was devised to match the 12-constellation zodiac cycle. Others speculate that 12 fit nicely into 60 — which fit nicely into the 360-day year.
For being the thing upon which our lives mostly depend — from how long we work each week to how long we sleep each night to how long we live — time is awfully imprecise. Of course, we’ve modified our calendars and walk around with cellular-network-enabled watches in our pocket. But we still live and die by a measure based on our position in the universe, by our relative relation to the sun and the stars. When we are is based on where we are — though in our daily lives that seems to have mostly reversed.
Huw Price, a Cambridge University professor of philosophy, says that the absolute direction of time — the sense that we are constantly hurtling toward the future — exists only in our minds, the result of a “subjective ingredient,” a “temporal perspective” that we project onto the environment around us. Similarly, the passage of time and the existence of moments, he says, are mental constructs. Rather, based on Einstein’s theory of relativity, the block universe that we live in is tenseless: the past, present and future are all equally real.
Massachusetts Institute of Technology physicist Max Tegmark describes this block universe theory of time like a DVD. You watch the movie on the DVD and the movie itself plays and there is a drama and things are happening and changing, but nothing about the DVD changes. Thought of through this lens, the only measure of change — as a product of the passage of time — is memory. (Memory and its relationship with time might be worthy of its own Breaking Eggs entry.)
On the other hand, theoretical cosmologist Andreas Albrecht makes the argument that time exists in relativity. “When you try to discuss time in the context of the universe, you need the simple idea that you isolate part of the universe and call it your clock, and time evolution is only about the relationship between some parts of the universe and that thing you called your clock,” he says.
All of which leads me to believe that change may be the best way to consider time. If time itself is merely a construct, it is at least the reflection of change, whether its the change in sunlight as the day progresses, or the flow of traffic or the accumulation of wrinkles and the loss of hair — time is merely the brain’s way of making sense of change, giving order to the chaos through some linear construct.
Some, of course, have continued to argue for the existence of time as an instrumental piece of our universe. But it seems farfetched. Still, as I sit here mulling it over, it’s hard to imagine a world without time, or a facet of existence that is not built upon time.
To bring back Tennessee Williams, the full passage is, “I didn’t go to the moon, I went much further — for time is the longest distance between two places.” Time, real or not, is imperative to our personhood, to our development and growth, to our progress and our stability — time and our memory of change, is how we measure our maturity and, ultimately, at any given moment, how we know who we are.
To get a much better and more clear picture of time and complex arguments behind its existence, read Robert Lawrence Kuhn’s great “The illusion of time: What’s real?” which is where I gathered a great deal for this piece.