The market does price discovery if it's not program traded. What markets are doing is recording and publishing the results of auctions for the particular good

The market does price discovery if it's not program traded. What markets are doing is recording and publishing the results of auctions for the particular good as a time series of data. Indexes hide some of that but there's something far worse: HFT. The problem is that program trading and HFT has far more in common with the old Scientific American COREWAR game than it does with the fundamentals of price discovery. The buy/sell decisions are about gaming other players rather than discovering price. There are also nonlinear feedback loops with very short loop time constants created that are "nonconservative" in a physics sense and create instablity. The fact that hard limits are required to deal with flash crashes is a warning, not a solution!!