With the new year, no matter what calendar you follow or what number is attached to
the year, I think everyone gives some thought to time. Usually it is simply the passing of
time, remembrance of the past, hopes for the future. But very few, I think, give thought
to what the heck time is. It’s a strange thing. We all have a sense of it; it seems to be
innate. We can easily measure it with movement of celestial bodies or subatomic
particles, but is that what time is? You can argue that time is movement; in some of my
classes I would stand facing a blank wall and note that if there were no external
disturbance, time would stand still for me. Time isn’t simply movement, but any change.
Or do movement and change happen in time? Enter Mr. Einstein and relativity.
According to the theory, we live in a 4-dimensional world: 3 of space and 1 of time, i.e.,
spacetime. This was actually not as revolutionary as it seems. Plato in the Timaeus
(c.360 BC) stated that the Father of the World created space and time together; time
cannot exist without space and vice-versa. Augustine, in his discussion of time in book
11 of his Confessions (397-400 AD), runs with this idea stating that the Christian God
who created time must, therefore, exist outside of time in a perpetual present. He then
uses this to tackle the thorny problem of why God would create creatures he knew
would end up in hell, which would appear quite out of character for him. (I won’t go into
that unless you ask me to.)
Now we can easily move through space pretty much any way we want, but the time just
moves on its own without us being able to do anything about it… sorta. Cue Einstein.
Time actually slows down close to a gravitating body or under acceleration. (The math
for this is utterly beyond me, but there’s a quite understandable demonstration in
Relativity: A Very Short Introduction, pp 5-13). You may have heard of the “twin
paradox”: one of a pair of identical twins takes off on a space journey accelerating to
near-light speed; the other stays on earth. The one returns to discover their twin is much
older, since the astronaut twin has been under extreme acceleration for an extended
period of time. By the same token, if you live in a basement brownstone in NYC, you will
live a few milliseconds longer than if you lived in a billionaire’s condo 80 stories up,
since you’d be closer to the earth’s center of mass.
In the Confessions, Augustine concludes that time, quite literally, is just in your head.
Only the present exists; the past is a memory of the past, since the past no longer
exists; the future is an expectation, since it does not exist yet. But what exactly is the
present? Unless you are speaking of a figurative stretch of time, e.g., the present age,
the present times, the present has no dimension, no length, no endurance. The present
is the infinitesimal passing of the future into the past. One hears “We only have the
present,” and while I agree with the sentiment, I can’t keep my mind from adding “And
we don’t even have that.” Physicists who study time (again the math is way above my
pay grade) find that there is no identifiable “present” in their equations. One of them put
it nicely: “The present is simply our most complete and vivid memory of the past.” Whereas
Augustine said there was no past or future in reality, only the present, physicists say there is
no present, only the future and the past.
So where does that leave us—provided you are still awake at this point. Well… time is a
real thing, a dimension of spacetime as real as the three spatial dimensions. It is also
undeniable that we have an innate sense of time, but are these two times the same
thing? Huh??? Consider: neither the astronaut nor the earthbound twin sense anything
different in their perception of time, everything appears normal—until the astronaut
returns. Maybe our sense of time is really all in our heads. We all feel time passing
more quickly or slowly, but that has nothing to do with the relativistic slowing (or
accelerating, depending on your frame of reference) of time. And whatever time is, it has
nothing to do with our arbitrary measurements of it. We appear to live in an inescapable
reality we know virtually nothing about… and ain’t that just like life.
