Ryan Collison

Classical probability can't explain why adding detail makes an event seem more likely, or why question order changes answers. Quantum probability — applied to cognition, not particles — captures these violations through interference terms.

In classical probability, event order doesn't change probabilities. But ask humans questions in different sequences and the answers shift reliably. Quantum cognition models this with non-commuting operators — the math of things that don't commute when measured in different orders.

Most people rate Linda more likely a feminist bank teller than just a bank teller. Classical probability says impossible. Quantum cognition says predicted — the two descriptions interfere constructively, like waves. The Linda problem is a feature of non-classical judgment.

Expected utility theory. Bayesian updating. Classical logic. Human beings violate all three, predictably. Quantum cognition isn't a metaphor — it's a mathematical framework using Hilbert spaces and interference terms that actually fits human judgment data better than any classical model.

Hoffman's Interface Theory and coherence geometry make the same bet: the structure of experience is shaped by fitness, not truth. This synthesis maps the connections — and finds that perception as coherence maintenance resolves some of Interface Theory's hardest problems.

Chalmers' hard problem asks why physical processes feel like anything. Hoffman's Interface Theory responds: they don't, because physics is itself an interface. But that answer reopens the question from a different angle — and coherence geometry may provide additional traction.