Jean Piaget, a Swiss psychologist, proposed a theory of moral development that suggests that children go through two stages of moral reasoning. Piaget's theory focuses on how children develop their own sense of morality and make moral judgments. The two stages of moral development in Piaget's theory are:

1. Heteronomous morality: In this stage, which occurs from ages 4 to 7, children believe that rules are fixed and unchangeable. Children at this stage see rules as coming from authority figures such as parents, teachers, and God. They believe that breaking a rule will inevitably result in punishment, regardless of the intentions behind the action.
2. Autonomous morality: In this stage, which occurs from ages 10 to 12, children develop a more sophisticated understanding of rules and their underlying principles. Children at this stage begin to recognize that rules can be changed through negotiation and agreement among individuals. They begin to understand that rules are not absolute and that there may be valid reasons for breaking a rule in certain situations.

According to Piaget, children progress through these stages of moral development as they grow and develop cognitively. As children become more capable of abstract thinking and logical reasoning, they are better able to understand the principles behind rules and to make moral judgments based on these principles. Piaget's theory of moral development has been influential in understanding how children develop their own sense of morality and in guiding the development of moral education programs. However, it has also been criticized for being too focused on individual reasoning and not taking into account the influence of cultural and societal factors on moral development.