"Perspective-Taking and Object Construction" by Edith Ackermann, also addresses the issue of relationships with knowledge. Ackermann brings together Piagetian and situated-cognition approaches, illustrating how the alternation between assimilative and accommodative attitudes punctuates an individual's interactions with the world. Drawing on results from the study of perspective-taking, Ackermann argues that the ability to decenter from one's own standpoint and to take another person's point of view requires the construction of cognitive invariants: a recasting of the world's stabilities that transcends any given viewpoint. According to Ackermann, this separation is a necessary step toward the construction of a deeper understanding; adopting a god's eye view is by no means contrary to situating one's own stance in the world. Ackermann notes that the process of learning includes opposites: forging relationships and creating separations at the same time. One cannot relate without, at times, separating.