  Is there a mathematical theory underlying intelligence? Control theory
addresses the output side, motor control, but the work of the last 30 years has
made clear that perception is a matter of Bayesian statistical inference, based
on stochastic models of the signals delivered by our senses and the structures
in the world producing them. We will start by sketching the simplest such
model, the hidden Markov model for speech, and then go on illustrate the
complications, mathematical issues and challenges that this has led to.
