We are interested in using computational methods to gain knowledge of mental phenomena. It is said that Plato’s Academy had the sign at the entrance, “Let nobody enter who is ignorant of geometry.” Mathematics has proven to be an uncannily suitable language for phenomena ranging from heavenly bodies (by Newton) to neurons (by Hodgkin-Huxley). Math makes an important contribution to questions such as whether mental disorders are discrete or continuous, what symptoms constitute various disorders, and how mental conditions can be “measured” with the use of tests. The chain of reasoning required by the scientific method and the inference about the cause behind the observations, would be impossible without math. Our group is called computational psychiatry because (thankfully) computers and software can perform the calculations that we would otherwise carry out by hand.