THE FORM OF OUR ARGUMENTS hasn’t changed over the 49 years of our awareness of each other, just the nature of our mutual miscomprehensions. When we were six, we’d piled up couch cushions in the living room, and argued for the rest of the day about whether we’d built a fortress or a fort. (He was a knight, I an Apache.)

That is, we decided too late what game we were playing.

And I still wasn’t sure, despite his first volley, what the game was for today, whether the metaphors and analogies of his attack stood only for themselves or represented something else, some different logical implication of his Initial Position.

But the day was young. The sun had just shown itself against the high blue sky at the rising end of the high-walled canyon, infusing light into the layer of mist hanging low over the river and inflicting a shattering brightness, a blinding, time-stopping flash, on our wind-teared eyes. But our drift boat, bound to the current with its broad upswept bottom, floated along as smooth as a forgotten argument, as I wish ours already was.

“It wasn’t my question I was answering,” Walker said. “It was yours. Mine was different.”

“No, actually, it’s just a rephrasing of the one you’ve been asking since your first visit home from college.”

He smiled and winked. “Kind of like a broken record?”

I hated that wink. I hate all winks. Their soundless performance. Their unanswerable claim to insight, to certainty. Their thing-in-itself brutality.

A half-smile was all I could force onto my face. “But only kind of.”

THE RIVER OPENED INTO what we called Papa’s Pool. When we were 10, our father had fallen in here while netting a deep-bellied Pacific salmon he was so anxious to capture that he reached himself right out of the boat.

A couple of hundred years ago, the Yurok Indians named the area Ah Pah, meaning the beginning of the stairway, because from here the river begins its ascent into the mountains (though I’m sure some Indians fell in here, too).

Walker’s game on a previous trip was to argue that, for people like me, the question had to arise whether it was the same pool at all. It didn’t for him, because, “There’s only one world, so it doesn’t make any difference what you call it. It is what it is.”

It is what it is. The verbal form of his wink.

That was the trip he began saying, “You’re being obtuse.”

Only much later did I realize he was using the word not in the normal sense of dull or boorish but in a geometric sense, meaning that I had failed either to meet his argument at a straight angle or to attack it from 90 degrees. Frankly, I still don’t quite understand what he means. But I understand why he thinks he can mean whatever he means.

As a child, Walker read Through the Looking Glass and declared Humpty Dumpty his hero—probably because he was the snarkiest character in the book. As a late teenager, Humpty Dumpty, now known to Walker as Humpty D, became his hero because he was the master of his words: words meant what he wanted them to mean even though others might never be sure what he meant in using them. He later Humpty D’d his entire company by insisting that all policy and procedure manuals begin with a glossary of terms he titled The Ontology, by which he meant the basic categories of things and actions in the world of BioMed Devices, LLC: team members, not employees; clients, not customers; staff conferences, not staff meetings.

During our Papa’s Pool/Ah Pah argument, I pointed out that his ontologies read like the definitions sections of contracts, where words have force. And, contrary to his often-made claim, a contract, like a promise, does indeed oblige people to take actions in the future that they might no longer desire to take. After all, why create these ontologies if not to set standards and govern how people engage with each other and with the world?

But instead of acknowledging the truth of all this, he accused me of being obtuse.

THE LOW FOG WAS CLEARING and the rising sun shone through the clear water and exposed boulders that had fallen off the cliff and scattered on the sandy river bottom. I spotted a winter-run chinook, sometimes known as a king salmon or a tyee or, as Walker liked to remind me, an Oncorhynchus tshawytscha, hook-jawed and spawning red, resting in the dead water behind a ragged chunk of granite. After our shadow moved over it, it cut into the current, swam upstream, and disappeared into the rapids we’d just passed.

Just thinking the almost unpronounceable Oncorhynchus tshawytscha made me recall that when we were in the fifth grade our teacher invited my parents for a conference in which she announced that Walker suffered from Asperger’s. Her evidence, which she apparently learned to recognize from a 60 Minutes episode, was that he had taken to speaking and writing about dogs as canines and cats as felines. She believed this was a sign of his inability to engage with other children—ignoring that he used the words when he was, in fact, engaged with other children. The teacher took Walker’s distancing himself from the language of our classmates as a symptom of a mental disorder, while my overeducated parents took that distancing to be, at worst, irony.