"From now on everyone has a watch and no one has the time. Let us exchange one for the other. Give away your watch and take your time." - Michel Serre

How long have humans lived by the clock, using a highly quantified system to chunk up our days? Actually, it's a fairly recent development.

A few hundred years ago with the Industrial Revolution, our modern sense of time began when factory shift changes were marked by a whistle calling workers to their jobs. That's when 'natural' time fell by the wayside.

Today, as members of a complex society with rules and regulations, we've agreed upon a measure of time that is specific and global. We sometimes forget that time hasn't always been so minutely defined.

Time was basic in our days as hunter-gatherers, and even into the early days of agriculture. There were days, nights, and seasons.

Religion and settled communities made things more complicated because humans needed to keep track of holidays and other agreed upon events, so the calendar was born: weeks and months and years. At that point, we had become rigorous about measuring and quantifying time.

Fast forward to today, when time's measure is agreed upon world-wide, a necessary condition for the Internet, GPS, and most of today's communication technologies to work. What made it possible to synchronize everywhere and with anyone on the planet was the invention of the atomic clock in 1945.

Atomic clocks use the oscillating frequency of the element Cesium 133 to keep track of passing time. Cesium atomic clocks are accurate to within one second per million years, and so they are more accurate at measuring the passage of time than even the rotation of Earth. Atomic clocks keep our modern world ticking.

While our global technologies require total temporal accuracy to function, I usually don't need to know the time to an exact degree. In fact, I rarely wear a watch. I only have a couple of clocks in my house: the alarm clock and one in the great room. But I can read the time on my cell phone and it's before me on the dashboard when I'm in the car.

Even if I've managed somehow to go several hours without seeing a clock, I can usually tell you within half an hour what time it is at any given point in the day. Overcast or sunshine, the habit of chunking up the day occurs internally, whether it's necessary to track the time or not.

What is time, anyhow? Paraphrasing St. Augustine, "I know the meaning of time