"Today, Friday, at exactly 12:15 p.m., I will be exactly 20 years old. But what does that mean? It means that if I look at the sky at exactly that moment, I will see the sun in the same place it was when I took my first breath. The Earth has completed its reliable trudge around the sun 20 times since then, and the Earth has finished a complete spin of its own axis 7,305 times. This is how time works, and it is an unrelenting, constraining force on all of our lives. If life expectancy statistics are to be believed then each of us has an average of 80 revolutions around the sun, 29,220 spins on the Earth’s axis before we shuffle off this mortal coil.
"While this chronological force of time is beautiful in all of its symmetry and chronology, it is not quite the way we experience it. No, time is a very odd thing to think about because it does not occur with uniform evenness; one second is often perceived as shorter than another. One hour drags while another flies. Even more maddening is that the one may seem like an eternity to me, but breeze swiftly by for another.
"But, why is this fourth dimension so elusive and slippery? There are myriad methods of measuring time: Physicists measure time in strict seconds, while economists measure time in money. Journalists measure time in words, but lawyers find fees a much better meter stick of the passing of time. Still, these methods are not adequate. The ideal meter of time would account for both the rigidity of the uniform chronology and the flexibility of human perceptive experience.
"Someone once told me that time is personally perceived exponentially, and that, as we age, time speeds up and passes more quickly. More worrisome, is that she pin-pointed the age of 20 as life’s perceptual midpoint, meaning all the time after the age of 20 passes with the same speed as all the time beforehand. If she is correct, then today will literally feel like the middle of my life. This may seem to be a far-fetched assertion, but think about it for yourself. Didn’t an hour at age six feel like an eternity? And doesn’t a day at your current age, with its plethora of challenges and stressors, feel much shorter? When I talk to people, I like to ask them this question as a matter of course. Almost everyone of older generations tell me this is the case: that 20 is the middle-point of life as we experience it.
"This kind of velocity of passing time violates all of our mental preconceptions about time works. This is the direct result of our extremely flawed conceptions of time. Because it is the ultimate intangible, amorphous idea there is no way to visualize or firmly grasp within the brain what time is or looks like. To overcome this hurdle of perception we visualize time as space. This is because we can see space and are familiar with its laws and workings. So for us, space is the one thing comparable to time, thus we analogize them and treat them similarly.
"This metaphor holds up across all cultures and languages: scientists have found that every culture deals with time as if it were space. In the west, we say that the future is ahead of us—perhaps somewhere off in the extreme right, where we might just be able to run fast enough to catch it. Accordingly, we conceive the past as behind us or to the left. This is how we orient ourselves in time, because it is the only way we can hold even a loose grip on the most fundamental of conceptual greased pigs. We do it as if it operated in a grid.
"Researchers have found that most cultures situate the past in the opposite of the direction we read. Some Chinese used to use a writing system where one read from top-to-bottom instead of left-to-right or right-to-left. For these people the past was above, while the future lies below.
"What is the problem with all of this? The fact that time is not space; it doesn’t always follow the same rules or perform the same functions. We pay a price when we over-exert on the analogy, for instance, what about silly inaccuracies embodied by Superman, who is able to reverse time by flying vey rapidly to the left.
"The point is that we live in an eternal experience of the present, even if this moment later becomes part of the past, there is no actual place for the past—we cannot visit it later. The metaphorical timeline points in the wrong direction no matter what direction we face because time is not a vector quantity. That is the modern mystery. The biggest constraint on all of human experience is that we only have so much time with which to enjoy it. But for something so important we have a terribly flawed and inefficient manner of conceiving it. We all dance to the music of time; the tune sometimes quickens and sometimes slows, but we can never read the sheet music.