The transition from conventional morality (Stages 3-4: approval-seeking and law-following) to postconventional morality (Stages 5-6: universal principles) involves moving from external authority and social conformity to internalized ethical principles. This transition often occurs in adolescence or early adulthood, though not all individuals reach postconventional stages.
You already know Kohlberg's full six-stage framework: from the self-interested reasoning of the preconventional child, through the conformity of conventional morality, to the principled reasoning of the postconventional adult. The transition this topic focuses on — the crossing from Stage 4 to Stage 5 — is arguably the most significant conceptual leap in moral development, because it requires the reasoner to step outside the social system entirely and ask: *is this rule itself just?*
At Stage 4 (Law and Order), moral reasoning is grounded in respect for authority and the integrity of the social system. Rules are followed because they maintain order and because violating them undermines the institutions that make cooperation possible. This is a genuine moral advance over mere approval-seeking (Stage 3), but it has a critical blind spot: it cannot evaluate the legitimacy of the rules themselves. A Stage 4 reasoner asked to hide refugees might refuse, reasoning that the law must be upheld regardless. The social contract is treated as morally terminal — the end of the reasoning chain, not a means to a further end.
Stage 5 (Social Contract) introduces the insight that laws are human constructs designed to serve human welfare, and that unjust laws can — and sometimes must — be challenged. The reasoner now recognizes that rights exist prior to social agreement, and that the purpose of legal systems is to protect those rights. Civil disobedience becomes conceivable because the law is no longer the highest moral authority. The transition is not simply about knowing more — it requires a structural reorganization of how the reasoner relates to authority. This is why it typically emerges through exposure to moral conflict that conventional reasoning cannot resolve: encountering laws that seem arbitrary, engaging with moral philosophy, or living through social upheaval.
Stage 6 (Universal Ethical Principles) represents a further, rarer step: grounding moral judgment in abstract principles — like Kant's categorical imperative or Rawls's veil of ignorance — that apply universally regardless of cultural convention. Kohlberg's own research found Stage 6 reasoning so infrequent in his samples that he eventually removed it from the scoring manual, though he retained it as a theoretical endpoint. The practical implication is that postconventional reasoning is not a single achievement but a continuum, and most adults who reach it operate primarily at Stage 5 in everyday life.
The developmental trajectory matters for understanding moral disagreement. When a Stage 4 reasoner and a Stage 5 reasoner argue about civil disobedience, they are not simply disagreeing about facts — they are reasoning from structurally different moral frameworks. Kohlberg's key claim, supported by longitudinal data, is that development is sequential and irreversible: people can understand reasoning one stage above their own but tend not to spontaneously produce it, and they do not regress to lower stages under normal conditions. This means moral education is most effective not by preaching conclusions, but by presenting dilemmas that expose the limits of the learner's current stage and invite the next one.