The Slide Rule for Time

Can you think in deep time and still be an asshole?

As the plane landed in Arctic Svalbard, Marcia Bjornerud scanned the landscape from altitude. All was white, a flat sheet of snow, ice, and permafrost stretching in all directions, broken only by knife-steep ridges in the distance. There was only one feature down there, something brown and small. She stared at it, trying to resolve it; a tiny brown cube in the snow. As they got a little closer she recognized it as an ancient, beat-up wooden fruit crate. It must have been there for ages, abandoned by unknown travelers or explorers, and left to rot, but the process would take decades in this cold wilderness.

As the plane got lower the object came into focus, and resolved itself. It was the hut where she and her team would be living.

This story, from 1984, opens Marcia Bjornerud's book Timefulness and serves as a central metaphor for the book as a whole. Timefulness is a book about seeing the hut as a hut. It is about placing a human lifetime within the vastness of the Earth's deep history.

Bjornerud states her goal for the book:

I’ve written this book in the belief (possibly naïve) that if more people understood our shared history and destiny as Earthdwellers, we might treat each other, and the planet, better.

I love the central lesson of this book. Timefulness is a powerful tool. But I do not think it is enough. Timefulness is not wisdom; it can be used by fools, saints, engineers, cultists, billionaires, and assholes alike. It expands the time horizon, but not the moral one.

This is a review of Timefulness. It is also an argument about how thinking like a geologist is not enough to save the world. Geology can teach us how small we are in time. To treat the planet better, we need more help, because we are assholes. I propose Treefulness, a tree of life perspective taken from biology, to show us how small and entangled we are in the tree of life.

What it Means to be Timeful

Early on in Timefulness, Bjornerud outlines a mental health condition called chronophobia, the fear and denial of the passage of time. Her book seeks to break that condition.

Our problems with time are only getting worse. We are all on a coal-hungry freight train, shoveling a heavy dusty fuel into a ceaselessly hungry, burning maw. Everyone is rushing, and no one has enough time to do the massive work that needs to be done. And yet no one is happy with where the train is going. Still, we shovel.

Many of us suffer from chronophobia, and because of this our species is likely to leave an especially dark and long-lasting stain on the planet. Bjornerud argues that Timefulness, mindfulness in time, is a critical insight for a flailing species. If we can zoom out and gain a sense of scale, we may act differently.

Bjornerud believes that a geological point of view can cure chronophobia. I agree: drunk on speed and blinded to both the past and future, we should be more timeful. But will this make us better Earthdwellers? In the eight years since the book came out, a lot has happened to make me doubt.

A Slide Rule for Time

Reading Timefulness reminded me of my first experience with Google Maps. I went to find my apartment at the time, in the middle of a large US city. I then zoomed out from my apartment, zooming to the city, to the state, to the continent; soon I could see the whole blue-and-green planet floating in inky space.

I don't think I am the only one who did this.

The magic of Google Maps is not satellite imagery. It is scaling. The feeling of vertigo-adjacent happiness that we all got zooming from house to planet relies on a trick, multiplicative scaling. Logarithms make multiplicative changes feel like even steps. Without them, Google Maps would suck:

You go to your house. You start to zoom out, and each move of your fingers zooms you out 1 km. After 10 swipes, you have the city core; double that for the whole St. Louis metro area. But 50 more swipes and you are still in Missouri, barely advancing into other states.

Google zoom works by multiplying, not adding the scale. Each swipe increases your view by a certain percentage. Swipe once, double the distance; two swipes is a quadrupling; three swipes is times eight; and so on.

A slide rule is the ultimate tool for logs. To make a simple slide rule, you need two sticks. Put even marks on one to represent a linear scale; the other has marks representing a log scale. For example, on a log-base-10 scale, you can have evenly spaced marks representing 1, 10, 100, 1000, and so on. Aligning the marks then transforms numbers (on the uneven scale) to their logs (on the even scale).

You can use a slide rule to multiply very large numbers quickly. Using the marks, you move each number onto a log scale. Then add them. Transform the sum back, this time using the slide rule in reverse. Now you have the multiplication product of the two numbers. If, instead of adding, you subtract, the result is division. It's like magic, really.

Slide rules were invented in the early 17th century. These first analog computers were a huge boon for some. Turning multiplication (hard) into addition (easy) is really useful when you need to multiply fast - like, you are calculating the positions of the stars and planets.

I have a hard time explaining logs to undergraduate students. But it turns out that we probably have some intuition about this. Human senses work on a log scale. We notice proportional, rather than absolute, changes in sound, light, and touch. You can easily tell the difference between 1 and 2 candles, but never between 100 and 101.

So, the slide rule is fabulous, logs are everywhere, we know them even when we say we don't. We can use these principles to approach timefulness.

Our normal view of time is impossibly short. We live in minutes, planning in hours or days. Our long range plans may reach out into weeks or months. Tomorrow, and tomorrow, and tomorrow, and so on, and this petty pace is where our thinking most naturally lies. We are shaped by our past, obviously, since birth. I would trace my story a bit deeper, to my grandmother on my mother's side born just over one hundred years ago. Like most people this is about as far back as my mind wants to go.

One strength of Timefulness, perhaps its main strength, is using geology to provide a slide rule for time. Start with a long human life, 100 years. Multiply by 100, one swipe, and you have the ice ages. Glaciers advance and recede, shaping landscapes in ways that you can easily see if you know where to look. Another factor of 100, and you have a million years, the typical lifespan of a vertebrate species. Another, and you are at 100 million years, the life expectancy of a mountain range. One more, and we are at 10 billion, the life expectancy of our solar system (see Appendix II of Timefulness).

The time-slide-rule of geology is both images and language that help place our own lifetime in the full context of planetary history. It can be very moving. In that way, Timefulness is a quietly radical book.

The Mantras of Timefulness

Bjornerud's book has three main mantras.

First, the present is thin. As humans, we see one frame, one still image, of the film of Earth's history. We can pretend that this is the whole story, but we are deluding ourselves. The human timescale is incredibly short.

Bjornerud is a geologist. As such, she views time through a rock lens. Layers in a split hillside, rock types, even fossils; all tell a tale of time deeper than the human experience. Much deeper. Time that we can barely even extrapolate. And I've tried. But I don't know any way of describing a million years to you, quickly, that will clearly differentiate it from a billion years, even though that is 1000 times longer.

The book helps break free of that. In a lengthy section on radioactive dating, Bjornerud shows us how time has expanded based on clever geological techniques.

Second, long does not mean gentle or slow. Considering the interplay of processes at different time scales, Bjornerud, quoting Richard Alley, describes "playing with a yoyo while bungee jumping off of a roller coaster." Cycles within cycles, the slow and gradual added to the rare and dramatic. The past is anything but uniform.

For example, landscape features change in an intricate rhythm. The ocean floor spreads and continents drift. Collisions raise mountains, which then gradually melt or collapse. Even the wobble of the Earth on its rotation and orbit drives geological changes. The yoyo-bungee-rollercoaster, the interplay of processes that vary in both strength and timing, is why it is almost certainly a blast to go hiking with Bjornerud.

And third, humans are now a geological force. This, I think, is the real agenda of the book. Bjornerud frequently compares geological events over long time scales to contemporary human activities. For example, recent coal mining in West Virginia via "mountaintop removal" moves as much of the Earth as erosion by the Ganges and Brahmaputra rivers in India over a decade. The combined argument is as such: by observing slow change, we see that the Earth is old; but even on the old Earth, change can sometimes be rapid and catastrophic; and what we are doing is even more extreme than that. The book is a plea for a combination of timefulness and imagination.

At all of the great ancient monuments of the world, people have carved dumb shit: hearts, initials, names, curses of various sorts. As a species we are the equivalent, scarring on a much deeper scale. Knife poised mid-line, we are being challenged here by Bjornerud: how long do you think this mark will last?

In a chapter about the atmosphere, Bjornerud combines microbial chemistry with geology to paint a picture of the Earth's atmosphere over five billion years. In this deep history of the air, the planet is geoengineered by microbial life. Cyanobacteria invent a way to get energy from the sun, and that invention generates oxygen as a byproduct, poisoning most of the biosphere. I think this might be the best example of the Law of Unintended Consequences in the history of the universe. Bjornerud takes a lesson from the cyanobacteria:

Tinkering with atmospheric chemistry is a dangerous business; ungovernable forces can come out of thin air.

In a way, this book is written like an old German fairy tale. You might start to feel like a child who is suddenly alone in the forest, and the sun is setting. Your picnic basket is empty. And the ominous howls from the unseen darkness are getting pretty loud.

Finally at the end of the book we see the wolf of climate change. Bjornerud frames human-caused climate change within the repeated cycles of warming-and-cooling over the past few hundred thousand years, the ice ages.

This framing is critical. If you were to find someone passed out and surrounded by beer cans after a night out, you might laugh it off. But if you knew that they were an alcoholic, and that there were more cans than ever, you would not laugh. Bjornerud sees climate change as a dangerous acceleration of an existing pattern. She writes a compact summary of a complicated and ever-changing world.

But then she starts to discuss solutions and my enthusiasm starts to wane. Her list seems to come out of nowhere, and includes paying teachers more and reordering science curricula to put geology last after physics, chemistry and biology. These may be good ideas, but do not address the core problem. She does include a lengthy discussion of cross-cultural inspirations and has some specific, and promising, policy goals. But the ending feels sparse compared to the detailed and grounded preceding chapters.

I am in full agreement with Bjornerud with this vision of the slide rule as a tool. But I am less certain about what happens when we use it.

A Hidden Moral Assumption

The hidden assumption of Timefulness is that expanding the time horizon expands the moral horizon. Teach someone to see a million years, and they will be humble and selfless; show them geology, and they will be better Earthdwellers. In other words, temporal enlargement leads to moral enlightenment.

I wish this were true. But I am not so sure. Sometimes scale intoxicates, and there are many ways to be a timeful asshole.

Think of the imperial timeful, justifying suffering as part of the destiny of their empire. Bloodlines, colonization, and monuments are all aimed at the distant future.

Or the apocalyptic timeful, eyes cast on eternity. At the cusp of their end-times, the Earth is a disposable waiting room.

The techno-narcissist timeful speak eloquently about human extinction, Mars, AI, and the survival of consciousness. The deep future is on other planets, presumably full of statues of their genius, and the people around them mostly obstacles, NPCs, or raw materials.

And some of the timeful build bunkers, stocking up for a future that is too precious to share.

All of these people do see themselves as part of a deeper story in time. Some are even more-or-less consistent with scientific geology. But they are also assholes.

The Problem with the Secretary of the Future

At the end of Timefulness, Bjornerud makes some recommendations for a timeful version of human civilization. All are philosophically aligned, but only some of them are directly related to the preceding material in the book. Others recommend, for example, that teachers be paid more and geology classes follow, rather than proceed, other scientific courses. But one Bjornerud recommendation is especially interesting when viewed from her near future of 2026. Quoting Kurt Vonnegut, she recommends that the president's cabinet include a Secretary of the Future.

Humor me for a moment and consider Elon Musk as the first Secretary of the Future. I think that Musk has Timefulness, in the Bjornerud sense. He speaks frequently of long time horizons: he has the slide rule in his hand. But his timefulness, unbraided with humility, is not the future that Bjornerud envisions.

Can we become Timeful by thinking and knowing about geology? I think so. I found this book a good entry point into deeper time scales. As I think you might have detected, I have a deep love for this book. I am trying my best to be Timeful, even though it makes people think I am weird. Marcia Bjornerud is right, but her point is incomplete.

A Morally Neutral Tool

I am fully with Marcia Bjornerud: we need the slide rule of time. But slide rules are morally neutral, able to predict the melt of a glacier as well as they can aim a nuclear weapon.

Timefulness is not enough. It cures chronophobia, but not narcissism, here a taxonomic narcissism of a species that believes itself to be the only leaf that matters.

To heal the planet we need humility and wisdom. We need to see ourselves as a part of this old planet, linked to the living and nonliving alike.

I would suggest that one complementary perspective comes from biology. As humans, we are one leaf on the tree of life. We are connected by genealogy to all other species on the planet. We all share a common ancestor. More than that, we can all trace back, through our mothers and grandmothers and so on, to common ancestors with every other living thing that we know of. We share obvious traits with our closest relatives, but at the cellular level life on Earth is highly similar.

In the spirit of Bjornerud, call this treefulness: mindfulness of ourselves as a leaf among other leaves, all connected in the massive branching tree of life.

We do not need the proclamations of asshole leaves, fallen from the tree and wilting on the ground. We do not need powerful saviors of deep time.

We need people both timeful and treeful, people who can imagine the deep future without becoming its hero.