The Extended Mind: State of the Question

It has been twenty years since Clark and Chalmers published "The Extended Mind." In the present article I review the development of the extended mind hypothesis across what some proponents have defined as three theoretical "waves." From first-wave extended mind theory, based on the parity principle, to second-wave complementarity, to the third wave, characterized as an uneasy integration of predictive processing and enactivist dynamics, extended mind theorists have faced and solved a number of problems along the way. The fact that the hypothesis continues to spark debate and to generate both new insights and new objections suggests that it continues to play a productive role in contemporary philosophy of mind.