 20th-century developmental psychology drew deeply on the Kantian legacy. Piaget (1932/1948) treated moral development as principally involving increasing cognitive sophistication. More particularly, Piaget saw that sophistication as a matter of taking more and more general or universal views of moral issues, and endorsed the Kantian and rationalist idea that morality rests on and can be justified in terms of considerations of justice. Piaget saw a “law of evolution” in moral development, from an understanding of rules (including moral rules) as being “heteronomous” impositions of authority, to which one is objectively responsible, to a grounding in mutual respect, accompanied by subjective responsibility to others (Piaget 1932/1948, p. 225). This transition is fostered through social interaction, and attention to norms of equality and reciprocity replace those of mere obedience.