In this paper I examine where Bion's theory of freedom fits within the traditional philosophical debate. I claim that the notion of freedom is the organizing centre of Bion's thought and that the traditional debate has focused with too great a concentration upon the will. I propose that underlying the workings of the will there is a fundamental substratum. This is governed either by the reaction model or by the response model. Freedom is coextensive with the latter mode of functioning but not with the former. The traditional debate needs to take this layer of personality functioning into account.