Physicists who are supposed to understand the workings of the universe are frankly perplexed by time. They are in the odd position of having learned to quantify with great precision something whose nature continues to elude them. Isaac Newton’s concept of absolute time pervading the universe like wall-to-wall carpeting turned out to be absolutely wrong. Einstein ripped out the carpeting with his special theory of relativity, which had time speeding up or slowing down, depending on the velocity of an object relative to an observer’s frame of reference. Mind-bending stuff, that. But as for what time is exactly, Einstein couldn’t say. “Time is what a clock measures,” he concluded, a bit lamely.
Looking to a fourth-century theologian to resolve the mystery of time might not seem to be the most fruitful line of inquiry. As might be expected, St. Augustine was generally more concerned with eternity than with time, although you can’t really address the one without reference to the other. At least he didn’t leave it to a clock to tell what time is, since mechanical clocks hadn’t been invented yet. The essential problem remains the same, however you read the time: At any given moment, the past has disappeared, and the future has not yet come into existence, leaving only the present moment, which by definition has no duration. So what exactly is being measured? Augustine parted ways with the Greek philosophers who held that time was synonymous with the movement of heavenly bodies, since presumably time continued whether objects moved or not. Like Newton, Augustine believed that time flowed without reference to anything external, but he went Newton one better by concluding that time itself wasn’t external. Past events no longer exist, but they leave an impression in the mind that is perceived in the present as the passage of time.
We experience time the way an amputee experiences a missing limb, as an uncanny sensation of something that no longer has any tangible existence. Does this mean time is an illusion? Certainly the sensation of time passing is real. But our time travel always seems to bring us back to our starting point, which is the present moment. Sure, we can set our alarm clocks for tomorrow morning. Yet somehow we always wake up to the present moment, whenever that happens to be. I can make a doctor’s appointment for next week or a dental appointment in six months, but when I’m actually sitting in the waiting room, it’s no longer next week or six months from now. It’s now. I have never actually left the present moment. What we think of as the past or the future exists only in relation to what is happening right now, because right now is truly all there is.
What does time have to tell us about eternity, which was the starting point of Augustine’s inquiry? He begins by posing a common question: “What was God doing before he made heaven and earth?” However, he argues this is the wrong question, since it assumes creation takes place in time, which really only exists as an impression that stalks us like footsteps echoing in the corridors of the mind. Normally, our thoughts are so embedded in time that we can’t think of eternity as anything other than unending time. But just because we can’t stop the ticking in our head doesn’t mean that time is embedded in the universe outside our head . If we could only step outside our thoughts, we might discover an entirely new realm -- always new, in fact -- but otherwise identical to the world we left when we left our thoughts behind. We are confronted by the world as it truly is, unfolding ceaselessly, timelessly. It is ever-present reality, another name for eternity.
St. Augustine, Confessions