Time: A Brief Consideration

“Time keeps flowing like a river,” (song lyric, The Alan Parsons Project)

This is probably how most people think about time. It’s real; it’s been flowing for billions of years; we move through time from birth to death; time flies; it waits for no one; sometimes it flows faster than at other times. Hold on a minute - if time flows, how fast does it flow? One minute per minute? One hour per hour? This is the kind of nonsensical question that alerted me years ago to the fact that time is not what people commonly think it is.

The ‘river of time’ is a metaphor for a feeling we have that something is carrying us through life. We assume it’s something we have or don’t have in certain quantities (“She has too much time on her hands.”) The sands of time are running out. We can waste it; we can use it productively. We can measure it with pendulum clocks, stopwatches, and atomic clocks. In short, people think time is a metaphysical reality. It began to flow with the Big Bang and just kept rollin’ along like “That Old Man River’ for almost 14 billion years to the present day, and it will keep on rollin’ along until the Great Heat Death of the universe some unknown billions of years in the future.

Some people think we exist “in time” just as we exist in space.  St. Augustine, for example, used this idea to contrast with the existence of God, who is eternal and therefore not in time.  This is to imagine time as a kind of ever-moving container or medium in which we live and move like fish in water.  The 'river of time.'  This kind of thinking is obsolete.

Thanks to Immanuel Kant, logical positivism, and postmodern philosophy, we can’t think about time that way anymore. Our perceiving and thinking are limited to experience and whatever time is, we have to discover its nature within experience.  One obvious experience to begin with is our perception of change and motion.  Weather changes; the moon and planets move around, as do animals and people in their environments.  From earliest days, humans found it necessary  to invent systems of measuring the flow of events for ordering their memories and planning for the future.  Solar, lunar, and seasonal cycles were used by ancient peoples as natural clocks ("It is 12 moons since our last hunt.")   

Later, sundials were succeeded by pendulums, analogue and digital watches, stop watches, and atomic clocks that are clearly measuring devices.  What do they measure?   "Time, of course." But when pressed to show where in the world time is, people resort to metaphysics.  "Well, it's hard to say exactly, but it's out there somewhere.  Hardly satisfactory.  Happily, there is no need to postulate some mysterious metaphysical ‘river of time’ for the answer.  We don’t use clocks to measure time.  We use them to measure change or motion or the duration of events that we observe in the physical world.  Just as we use rulers to measure the lengths of objects and thermometers to measure heat, we use clocks to measure the changes or movements of physical objects or processes in our experience. What was the winning time in the 3d race at Belmont?  From the starting gun to the finish, the stopwatch shows 3m 9s.  Sometimes we need smaller units like microseconds.  Sometimes larger -  years and centuries to measure really big changes like the rise and fall of the Roman Empire, the Thirty Years War, or the universe from the Big Bang to now.  

And that’s all time is, a system we invented to help us manage our lives in an ever-changing world. And there is more than one system, each constructed to serve a specific purpose in a specific context.  Our familiar 24-hour watch is splendid for getting us to meetings 'on time' but not for understanding the structure of the cosmos.  For that we need Einsteinian space-time.  What is the real time?  Depends on what you want to do.

Time, then, is an artifact, a social construction, a system of ordering and measuring change and for making predictions. This fact has some startling implications.  Since only humans create artifacts, it follows that time came into existence, not with the Big Bang, but only when our ancestors evolved into linguistic societies where farming and business required it, perhaps around 6000 years ago.  The Big Bang itself, being a social construct, a theory, did not exist before scientists thought of it, and those 13.7 billion years didn’t happen until cosmologists used math to calculate the number.

So, is time real? You bet – real in the same way all artifacts are real, as objects or systems devised by humans for their various purposes.  If you still think there is some other, metaphysical kind of time flowing along ’out there’ in the ’real world,’ then tell me what observation or experiment I should carry out in order to discover it.