There are many ways of not knowing, not seeing, and there are equally many ways of knowing, of coming to know deep in your body, embodying knowledge the way my ancestors embodied culture, the way the earth embodies language and spiritual belief and insult. Or maybe what I want to say is that it takes many ways of knowing to overcome your brain’s many refusals. To admit you know a thing like cancer resides — is seizing control — inside your body.

And each year we kill for food billions of animals we raise as prisoners and whose lives are often more terrible than their deaths. Even if we do continue eating animals, we could do much better by them and raise them more humanely. The way people treat animals affects the way they treat people: if you brutalize animals, you are probably hardhearted toward humans, too.

We think of apocalypse as a moment — a flash of light, then you’re gone — but if we study the earth’s history, we find that it’s not one moment. It’s actually a long process. In fact, it’s hard to see where it begins or ends. Like right now: evidence indicates that we’re experiencing the planet’s sixth mass extinction — a period when the rate of extinction spikes and the diversity and abundance of life decrease. Each such extinction event takes hundreds of thousands of years to play out, and it’s generally 5 to 8 million years before the previous levels of biodiversity return. So are we at the end or the beginning of a cycle? This could just be a temporary spike. The pattern could swerve in a different direction.

During the months when my parents’ dream of owning a farm died, I became a sleepwalker, and Dad became ever more diligent about hygiene. He shaved twice a day: once before the sun rose and again just before sleep. He kept his steel-toed work boots dirt-free, the leather mink-oiled, the laces neatly double knotted.

When I met Randy Livingston in 2000, I was making the long drive from California back to my home state of Minnesota and had stopped in the mountains of Utah to go for a run. On a quiet gravel road three miles from the highway, I found myself face to face with a cowboy on a horse and a couple of dogs trailing behind. He invited me back to his small camper trailer for a cup of coffee.

Largely because of a dog named Fred, who despised hats and joggers and anything that his unknowable mind deemed suspicious, Mateusz and I rented a farmhouse north of Toronto in the summer of 2010.

Our father was blind for five days. He pawed the walls as he felt his way around the house. The television stayed turned up loud, as if the chemicals that had burned his eyes had also scorched his hearing.