The presentation considers the importance of tension as a catalyst for creating developmental change and traces its inevitability to a set of four teaching constraints that convert teaching into dueling confrontations (1) between the teacher's pursuit to understand knowledge and to represent it in an ontologically congruous manner and the endless possibilities of such a pursuit (epistemological constraint); (2) between the teacher's attempt to frame his or her accumulated understanding of the target knowledge into a relatively transmittable linguistic statement and the reality that language is an imperfect medium (semiotic constraint); (3) between the teacher's presentation and the apprehension that its organization might be grounded on a psychologically invalid premise (learning constraint); and (4), between the teacher's expected forward progress and the many reversionary forces exerted by local factors (environmental constraint).
