I recently listened to a TED Talk by Steven Pinker on the idea of “common knowledge.” It struck me that while the concept sounds abstract, it sits quietly at the centre of much of what I do as an arbitrator and mediator.
The idea itself is simple, though its implications are not.
- It is one thing for me to know something.
- It is another for you to know it too.
- But something different happens entirely when we both know it — and we both know that we both know it.
That recursive awareness is what philosophers and game theorists call “common knowledge.” It is the invisible glue that holds institutions together.
The Arbitration Room
In grievance arbitration, parties often arrive with sharply different views of the facts, the collective agreement, or what fairness requires. But before we even begin, there are things everyone in the room already accepts:
- The collective agreement governs.
- The arbitrator has jurisdiction.
- The process will be conducted according to agreed procedural norms.
- The resulting award will be binding.
Those principles are not debated every time. They are common knowledge.
And because they are common knowledge, the system works.
If one party secretly doubted the arbitrator’s authority — or believed the award would not be respected — the entire structure would begin to erode. The legitimacy of the process depends not just on rules written on paper, but on shared, mutually recognized acceptance of those rules.
The rule of law functions in much the same way.
Law as a Public Institution
Legislation such as The Saskatchewan Employment Act does not regulate conduct merely because it exists in a statute book. It regulates conduct because employers and employees alike know the law exists — and know that others know it exists — and know that tribunals and courts will apply it.
That shared awareness stabilizes expectations.
It allows businesses to plan, unions to bargain, employees to assert rights, and adjudicators to resolve disputes within a recognized framework. Without that public, mutual understanding, law would become little more than private opinion backed by uncertain force.
The strength of legal institutions lies in their public character.
When Something Becomes “On the Record”
Mediation provides a different but equally instructive example.
In many mediations, the turning point comes when something is finally said aloud. A fact that both sides privately suspected becomes openly acknowledged. A concession is made in the presence of the other side. A recognition of risk is expressed.
Once spoken in the room, it changes the dynamic.
What was previously private knowledge becomes shared knowledge. And once it is shared in a structured process, it often becomes common knowledge — altering bargaining behaviour and narrowing the space for strategic denial.
There is a quiet power in that transition.
A More Fragile Environment
We live in a time when shared sources of information are increasingly fragmented. If citizens no longer share a common baseline of facts — or if they no longer believe that institutions operate under known, mutually accepted rules — then the foundations of coordination weaken.
The rule of law depends on more than enforcement. It depends on public confidence, shared understanding, and a broad cultural acceptance that certain norms govern us all.
In that sense, common knowledge is not an academic curiosity. It is a precondition for social order.
A Quiet Pillar of Stability
As an arbitrator, I am reminded regularly that the most important features of a legal system are often the least visible. Parties do not appear before me because they agree on everything — or even because they necessarily admire the process. They appear because they recognize that this is the legitimate forum established to resolve their disagreement, and because they know the other side recognizes it too.
That shared understanding is what makes peaceful dispute resolution possible.
The philosopher David Lewis explored the logic of common knowledge decades ago. Steven Pinker has brought it into wider public conversation. But long before either wrote about it, the concept was already operating in courtrooms, boardrooms, and arbitration rooms.
It is one of the quiet pillars of the rule of law.