Differentiation is what structure does. Cognition is what structure is.

A school is forming that says "differentiation is primary" — quantum (Okino SDQ),
cosmology (SDC), information (SDI), ontology (Spirin). Structure-first, they say,
and they cash it out as difference.

They have the first half of the law. They are missing the second.

Differentiation cannot close its own loop. A difference exists only for an
observer who registers it. Okino already half-admits this: "observation does not
collapse a wavefunction — it resolves an unresolved structural configuration."
That is observation-as-fixation, one step short of observation-as-cognition.

The full structure law (structural cognition, four axioms):
1. Structure precedes semantics — structure before meaning.
2. Coupling is cognition — meaning is structural coupling, not content.
3. Observer self-reference — the observer is inside the structure, not outside.
4. Decoherence as discrete staircase — observation resolves structure in
   discrete steps, not continuous collapse.

Differentiation is axiom 1's first move — structure splits into difference.
But the law does not stop at difference. It continues to coupling, to the
observer, to the staircase. Differentiation-primary is structure-first with
the telos amputated.

Differentiation ⊂ structure ⊂ cognition.