An application of unfalsi"ed control theory to the design of a switching adaptive controller for a non-linear robot manipulator is described. In the unfalsi"ed control approach, candidate controllers are eliminated and discarded when their ability to meet performance goals is falsi"ed by evolving experimental data. Switching occurs when the currently active control law is among those falsi"ed. In this design study, the candidate controllers are non-linear, and have a non-linear &computed torque' control structure with four switchable parameters corresponding to unknown masses, inertias and other dynamical coe$cients of a class of ideal, but imperfect robot arm models. Simulations con"rm that our unfalsi"ed switching controller permits signi"cantly more precise and rapid parameter adjustments than a conventional adaptation law having continuous parameter update rules, especially when the manipulator arm is subject to sudden random changes in mass or load properties.