The first section demonstrates the non-desirability of the unity principle of time and space in schooling from the perspective of the five most widely discussed aims of the educational system—the three explicit aims: the enhancement of learning, sociability and autonomy, and the two ‘tacit’ aims: socialisation of students into the labour force and the provision of baby-sitting services to parents. In the second section the non-desirability of the principle is demonstrated from the perspective of a less widely discussed function of the educational system: the propagation of socially sacred norms and categories of thought. Three groups of such norms or categories that could be used to justify the domination of the unity principle are discussed. Since the impact of these on post-modern Western society is declining, they are no longer functional. In the third section, a further defence of the unity principle is examined on the basis of a fourth group of sacred norms and categories (referred to as the concept of ‘identity’). I shall argue that although this group is still viable and important for Western society, nowadays it cannot justify the exclusive domination of the unity principle. The fourth section outlines the practical implications for the education system of the future.