Of all the ironies in academia, this one felt particularly unlikely: I was asked to introduce Steven Pinker and moderate the Q&A for his latest book, When Everyone Knows That Everyone Knows... : Common Knowledge and the Mysteries of Money, Power, and Everyday Life.

The problem? Pinker and I inhabit different intellectual universes.

Two Physics, Two Worlds

If you could map cognitive science onto physics, Pinker’s world operates like Newtonian mechanics: clean lines, predictable trajectories, universal laws. Language, in his framework, is an instinct, a distinct module that evolved in our species. It works in clear causal chains and direct relationships. Common knowledge (that recursive structure where I know that you know that I know) is something we can identify, analyze, and deliberately construct to solve coordination problems.

My world looks more like quantum mechanics and relativity. Language, to me, is composed of bits and pieces cobbled together from our evolutionary history. As Elizabeth Bates noted, “It is a new machine built out of old parts,” fragments borrowed from tool use, the lucky accident of our vocal anatomy, the expansion of our brains. These elements converged into something we call language, but it’s fundamentally messy, embodied, and emergent. We are, like so many other animals on this planet, sensing our way through the world, listening, moving, feeling, and from all those sensations, we construct a model of other minds and our own.

Both Pinker and I acknowledge that our models are flawed. But here’s where we diverge: I think the world is far more malleable and far less precise than his framework allows. Even when we establish norms (when something becomes “what everyone knows that everyone knows”), they shift with dizzying speed. This flow of information, what I call the informational singularity, makes knowing what constitutes shared truth unexpectedly treacherous.

The Common Knowledge Question

During the Q&A, someone asked how we should navigate competing narratives on social media, when different communities seem to inhabit entirely different realities. Pinker’s answer was characteristically clear: we can establish common knowledge through rational inquiry (statistics, hypothesis testing, credible sources). If we all agree on the methods, we can build shared understanding.

It’s a compelling answer. It’s also where our points of divergence crystallize.

For Pinker, common knowledge is something we can deliberately construct and maintain. It’s a tool for coordination, built on shared rational standards. For me, what becomes “common” emerges from complex social dynamics we barely understand. It’s not something we build so much as something that happens to us, bubbling up from embodied interactions, status hierarchies, and group dynamics. Common knowledge is an outcome, not a blueprint.

This isn’t just an academic distinction. It shapes how we think about our current predicament.

When Common Knowledge Fractures

Martin Gurri, in The Revolt of the Public, makes a disturbing observation: information has been doubling roughly every year for most of this century. Not just increasing, but doubling. This isn’t Moore’s Law for computers; this is a cognitive deluge. Our world of constant alerts, buzzing phones, video clips, and viral posts pulls us in multiple directions at once. It’s a flood of information that we’re all trying to navigate.

Here’s what makes this dangerous: When information proliferates at that rate, anyone can construct a self-contained ecosystem of common knowledge. Each community develops its own “everyone knows that everyone knows” structure, complete with their own statistics, their own sources, their own standards of evidence. And from the inside, it feels complete, coherent, obvious.

What was once difficult (creating parallel realities of common knowledge) is now almost trivial. You don’t need to control the printing presses anymore. You need a Substack and some motivated followers. Each epistemic bubble generates its own recursive knowledge structure, and people within it can coordinate beautifully with each other. The problem is coordinating across bubbles.

So when Pinker appeals to establishing common knowledge through shared rational standards, he’s assuming a foundation that’s increasingly difficult to maintain. Not impossible, but requiring exhausting, constant work. It’s like trying to use Newtonian mechanics to predict the behavior of particles at the quantum level. The tool isn’t wrong, exactly. It’s just insufficient for the system you’re actually in.

The Value of the Encounter

And yet.

Hosting Pinker was inspiring for reasons I didn’t expect. More than anything, it gave me a glimpse into how measured and systematic his approach to the world truly is. He believes, genuinely and deeply, that we can establish shared understanding through careful thinking. That common knowledge isn’t just something that happens to us, but something we can cultivate and protect.

Even though we diverge in how we understand cognition, there was something refreshing in his conviction. In a world where cynicism and resignation feel easier, where “everyone has their own truth” can become an excuse for intellectual laziness, Pinker holds the line. He insists that we can build bridges across different ways of knowing, that shared understanding is possible if we commit to it.

I don’t share his faith that common knowledge can be deliberately constructed from rational principles. I think it’s more fragile, more contingent, more dependent on social dynamics we can’t reason our way out of. But I found myself grateful for his certainty. Not because he’s necessarily right (I may not be either), but because the world needs people who believe that shared understanding matters, that evidence matters, that we can do better.

First Contact Protocols

Maybe the most important thing I learned from introducing someone with a very different worldview: We need these encounters. We need to sit in rooms with people whose frameworks are alien to ours, not to convert them or to perform debate, but to understand how differently you can see the world and still be committed to understanding it.

Pinker’s Newtonian world has precision I can’t achieve in my quantum one. My world has flexibility his can’t accommodate. Neither of us has it right (though we’d both probably bristle at that formulation for different reasons).

But the conversation between those worlds? That’s where something interesting happens. Not synthesis, exactly. More like the productive friction between tectonic plates, creating something neither of us could have predicted.

I introduced a man whose intellectual vantage point doesn’t fit with my thinking. He spoke with clarity I admire, even when skeptical. The audience watched two cognitive universes orbit each other without colliding.

And somehow, in that careful distance, we all learned something about the limits and possibilities of shared understanding itself.

What frameworks shape how you understand thinking itself? When have you encountered someone whose view of cognition was fundamentally different from yours?