The Depth and the Shallowness of Time

The passage of time is inevitable. There are physicists out there who claim time doesn’t even exist at all, but they can’t really prove it. As far as everyday experience is concerned time is constantly moving forward, both for us as individuals and for everything around us. Time moves for the universe just as it moves for ourselves.

There are at least two distinct types of time. There is personal or shallow time, which is the experience we have in our day to day, second to second lives. And there is deep time, which can span thousands, millions, and even billions of years.


It can seem like even longer if you’re waiting for something.

Personal time is easy for us to understand. It is one of those things that is so common, and seems so universal, that it is sort of difficult to explain. Like trying to explain being alive to someone who is living, or to explain the concept of thinking to someone who is already embroiled in thought. As conscious beings that exist, we cannot help but have intimate experience with our own personal time. From that, we can infer how others experience the passage of time.

A hypothetical person who is a thousand years old would have the same day-to-day experience as a person with a regular lifespan. A hypothetical time traveler would still have an experience of personal time. They might be in ancient Egypt one day, and in the future the next day, but would still know those days as today, tomorrow, and the day after that.

Deep time is easier to explain but more difficult to understand. As a person caught in my own personal time stream, I’m not sure I can ever really get deep time. But I believe it is important to try. Things that happen in deep time can effect out personal time, and maybe vice versa, for better or worse.

Deep time happens on geologic and cosmic time scales. The Earth, the Solar System, and the Galaxy all experience deep time, but they can’t tell us about it. At least, not in any sort of language we can understand.

pulsar communication

This pulsar just made a joke about your mom.

Deep time is anything that happens that cannot be contained within a single, personal experience. This means most of what exists is probably on the deep time scale. How can we understand things that are beyond the scope of our own experience? How can we bridge the gap between deep time and personal time?

Science offers one possible way to connect personal time and deep time. Geology can show us how the Earth we inhabit came to be the way it is over billions of years. When you see the exposed layers of rock that have been laid down over eons, a monstrous stalactite in a cave that was build one drip at a time, or find the fossil of a sea creature on top of a mountain, then you are face-to-face with deep time. Still, it might be difficult to make any kind of connection between your personal experience and the experience of the ages.

History may provide another way to understand deep time. While history itself is not nearly as old as the Earth, humans have been making history for a considerably long time. To come across an ancient petroglyph, a medieval manuscript, or even a civil war journal puts you in contact with a person who lived and died long before you ever existed. Unlike a rock that just sits around for billions of years, these people had memories and feelings.


Mostly just felt angst and nostalgia.

A rock that existed in the deep past more than likely still exists in the present, and will go on into the future. People who existed in the deep past are gone forever, and yet we can still find traces of them. In the far future we will all be gone, but maybe there will still be traces of our own fleeting lives and meager accomplishments. Meanwhile the rocks will just keep plodding along without a care in the universe.

Science can help us understand what deep time is, and history can help us empathize with what deep time means, but is there any way for a mortal person to actually experience deep time itself? Probably not, but I think there may be an approximation.

Since I was a kid I have enjoyed playing grand strategy games on the computer. Games like Civilization where you, as an immortal omnipotent leader, guide a nation through centuries or even millennia of development. An hour of game time for the player may be many years for the little world inside the game. You can watch as the brand new city you had built grows, ages, and eventually falls into ruin.

Civilization 3 rods

Watch as the beautiful landscape is covered in useless roads!

Playing a grand strategy game can directly show you how small things that happen early on may have great impacts later. Playing games like this demonstrate how it would be amazing to actually experience deep time, but also a little bit sad. A conscious thing that experiences deep time would get to see everything that happens, but might not be able to go down and look at those events on a more personal scale. They wouldn’t be able to live in the little cities, or get to know the little people. When you have seen countless stars ignited and then extinguished in the void, would it still be possible to appreciate a single sunrise? Do you watch the lives of the little mortals with genuine care, or is it more like morbid curiosity?

Here I have been wondering what it would be like to experience deep time. Now I wonder, if there are immortal beings who exist on the eternal scale, do they ever wonder what it would be like to experience shallow time? Or are they happy with their grand perspective, and merely start a new game whenever they get bored?

“OK, time to start over, but lets watch an island planet this time.”