A price is a compressed argument about the future.
A market is not merely a machine for setting prices. It is a distributed process for turning private beliefs into public signals. Participants arrive with different information, incentives, time horizons, and tolerances for being wrong. The price is where those disagreements temporarily settle.
That makes markets epistemic systems: imperfect machines for knowing.
information needs permission to move
The useful question is not whether markets are efficient in the abstract. It is which information can become price. Capital constraints, mandates, regulation, career risk, and liquidity all decide which beliefs are permitted to express themselves.
A trader can be right and still be unable to act. A fund can recognize a mispricing and still be forced to sell. A public signal can be accurate while arriving too late to matter. Efficiency is always conditional on the pipes carrying the information.
measurement becomes cause
Prices do not only describe reality; they alter it. A high valuation lowers the cost of capital. A falling probability changes behavior. Once a signal becomes important enough, participants optimize around it and the measurement becomes part of the system it measures.
Better models begin at these fractures: where information is blocked, where incentives distort it, and where reflexivity turns belief into reality.