This article addresses the ongoing debate over which criteria should determine what teachers ought to teach as controversial. I argue that this debate rests on false assumptions. It is a mistake to assume that (1) there should be a context-transcending criterion, (2) such a criterion can be prescribed "a priori" and "universally", and (3) this criterion can be utilised by teachers by means of "deductivism". Instead, I argue in favor of a situationist stance in which the means and ends are both worked out from within the situation. This implies that a theory must begin from a practical starting point. In practice, the situation should be the foremost guide rather than a definite criterion.