In this paper, I use a debate between Albert Einstein and Henri Bergson about the nature of time as a heuristic tool to understand the nature of teacher subjectivity. This debate outlines notions of time as measurable and time as duration or flow. These two interpretations of reality, one from a physicist and one from a philosopher, are used to examine the bi-Discoursal nature of the teacher identity An ethnographic participatory action research project in a preschool class in England finds that teachers operate as both physicist and philosopher, sometimes simultaneously. At times, the teacher is a physicist, measuring the geometry of child development and comparing it to a fixed point of normative expectations. At other times, the teacher is a philosopher, existing in the moment with children. The simultaneous existence of these two identities is a cause of anguish, forming a conflicted and contested self.