This article discusses how hearing aid engineers have applied the Bayesian probability theory approach to the problem of hearing aid fitting. Currently more an art than a science, it is likely that probability theory will play a large role in future generations of fitting software used by dispensing professionals. We will show that probability theory is consistent with common-sense reasoning, a feature that is not shared by alternative mathematical frameworks for intelligent reasoning.
While probability theory gets to the same answers as a consistently reasoning human expert, it can deal with larger problems than a typical human is capable of handling. Since human expertise cannot be replaced by a mathematical system, we expect that mathematical reasoning systems, like the one described here, will serve as an assistant to the dispenser in difficult fitting tasks