Which theorist focused on how perception and the nature of knowing evolve in adulthood?

C
Perry identified positions, or stages of knowing, that he described as linear, or occurring in a specific order, with each succeeding position dependent upon the previous one. The first position is dualism, in which the knower sees him- or herself as passive and authorities as all-knowing. The next position is multiplicity, in which the knower recognizes that authorities may not always have the right answer and that the knower can have a personal opinion. The third position is relativism, in which the individual comes to understand that any apparent truth is valid primarily in a particular situation.