Lawrence Kohlberg’s Stages of Moral Development has its roots primarily in Jean Piaget’s two-phase theory of moral judgment in children and secondarily in John Dewey’s three-stage theory of moral development. Piaget’s first phase is that of young children who see rules as fixed and absolute and handed down from an authority; and who also base moral judgments more on consequences than intention. By contrast, older children in Piaget’s second phase see rules as more relative and changeable, somewhat like a malleable social construct; and base moral judgments more on intention than consequences. John Dewey’s three-stage theory consisting of impulsive, group-conforming, and reflective stages is what led Kohlberg to the three levels of pre-conventional, conventional, and post-conventional.
Kohlberg’s Research Method
Kohlberg, over at least 20 years, interviewed or had other qualified researchers interview several dozens of people ranging from childhood to adulthood and across cultures. The questions were based on a series of moral dilemmas, with follow up questions for various types of responses. Kohlberg was interested in the reasoning behind the moral judgment, not the conclusion itself. To check the reliability of the scoring of responses, Kohlberg would have multiple researchers score the same responses. Kohlberg found the consistency of the score determination to be high among the researchers.
The Six Stages
Level I: Pre-Conventional Morality
Stage 1: Punishment and Obedience
Stage 1 is the morality of young children. An act is wrong because you’ll get punished. Punishment is what makes it wrong. Rules are handed down from an all-powerful authority and are to be unquestionably obeyed. At this stage, there is no realistic concept of morality.
Stage 2: Self-Interest and Fair Deals
Stage 2 is the morality of older children and unfortunately, many adults, especially in highly competitive occupations (certain corporate executives, most career politicians, and certain professionals) at least while they’re engaging in their occupations (they may move up to Stage 3 in family matters). At this stage, morality is relative to the self-interest of the deal maker and punishment is just a risk we want to avoid. We may exchange or return favors, but only if the continued relationship is worth carrying on from a self-interested point of view. There is no sense of community or even any substantial sense of morality, just self-interest and deal making.
Level II: Conventional Morality
Stage 3: Good Relationships
At Stage 3, people become genuinely concerned about good intentions and the well-being of their family and friends. The circle of concern, however, does not go much beyond kin selection. The moral community is small at this stage and is made up of those we know and trust. This stage is common in small, isolated villages and among tribal people. This stage is also common in many nonhuman animals, such as chimpanzees and dogs.
Stage 4: Social Order
Stage 4 is about law and order, respecting authority, and maintaining the coherence of society as a whole. A typical Stage 4 comment is, “If everyone acted in self-interest and broke the law, we’d have chaos.” At this stage, what is moral is what society (including most religious groups, e.g. the Bible or the law) says is moral. As we shall see more clearly after covering stages 5 and 6, this is the level at which many adults in our current industrial societies eventually arrive and stay, especially if they are not in the more aggressive careers mentioned in Stage 2.
“Stage 4.5”: Moral Skepticism
Kohlberg noted in his longitudinal subjects (people he was testing more than once at various ages to look for stage progression) that some of them stated “principled-sounding” (i.e. stage 5 or 6) reasons in high school, but seemed to regress back to moral relativity (Stage 2) in college. Upon further questioning, these subjects seemed to be exploring meta-ethics and challenging the ultimate basis of morality, asking questions such as “Why be moral?” This moral skepticism often led them to adopt moral relativity as a solution to the problem.
What they hadn’t yet arrived at was the fact that moral relativity is inherently unstable through self-contradiction and an inherent moral degeneration into might-makes-right. Moral relativity is self-contradictory in the sense that if one person or society’s morals are as good as another, then moral absolutism is as good as moral relativity: an obvious contradiction. Also, if morals are relative, then we shouldn’t judge others’ morals; but then the morals which do judge other morals shouldn’t be judged either: another contradiction. Moral relativity degenerates into might-makes-right because it allows arbitrary judgments. If plainly arbitrary judgments are permitted at all, on what basis can we draw lines on how much arbitrariness is permitted? Certainly not consistent reason. Stage 2 might-makes-right (i.e. moral nihilism or universal amorality) is the logical conclusion.
The reasoning process of “Stage 4.5” is a prerequisite to advance to the “post-skeptical rationalism” of Stages 5 and 6. Otherwise, the “principled-sounding” reasons are likely little more than Stage 4 “received opinion” from Stage 5 or 6 mentors (e.g. parents or teachers) in high school. We need not spend any significant time at “Stage 4.5”, but we must genuinely think through “4.5” and reject it on rational grounds to prevent severe moral retardation at Stage 2.
Level III: Post-Conventional Morality
Post-conventional morality, particularly Stage 6, is the engine of all moral progress in civilization. By definition, post-conventional morality evaluates and challenges conventional morality from a higher and more impartial point of view. This level is the reason that the Church lost its “authority” to burn people alive for heresy, that we stopped burning “witches” alive, that liberal democracies formed, that chattel slavery was abolished, that women gained the right to vote, that federal civil rights laws were passed, and hopefully someday, that our society will eventually become vegan and give nonhuman animals the right to life and to be left alone. To most people, a vegan society sounds unrealistic now, but many of today’s realities sounded just as unrealistic 50 to 350 years ago.
Stage 5: Social and Individual Improvement and Individual Rights
Stage 5 is where people start to ask what makes for right action, a good individual, and a good society, without referring to their own society as a standard. People at Stage 5 think in terms of rights for individuals and democratic procedures in government for the improvement of laws.
Stage 6: Universal Principles
At Stage 6, universal principles of justice are the moral standard by which actions, individuals, and societies are judged. The philosophers Immanuel Kant  and John Rawls provide the theoretical framework of impartial, universal justice of Stage 6. Great moral leaders such as Gandhi and Martin Luther King provide the spirit of Stage 6.
An example of the impartiality of Stage 6 is described by John Rawls in A Theory of Justice. An even better example and more impartial and universal description of Stage 6, since it avoids Rawls’s speciesism , is provided in Animals Like Us (an easy read written for the general reader) and Animal Rights: A Philosophical Defence (written for the philosopher), both by Mark Rowlands. Briefly, the description goes like this: we are asked to take an impartial perspective by assuming a “veil of ignorance” of what role we will have in the society or situation which we are evaluating. We are then asked to prescribe the policies or acts which would be most fair to all roles involved, knowing we could end up in any of those roles (including birth as a chicken, pig, etc). If the prescriptive policies or acts given are irrational under the veil of ignorance, then they are immoral in the real world.
Two principles are salient in Stage 6: the principle of equal consideration and the principle of desert. The principle of equal consideration requires us to give equal moral consideration to others to the extent that others have interests which are crucial or important to them, regardless of whether those interests are important to anyone else. The principle of desert, inherent in the idea of justice as fairness, is that we (including nonhuman animals) should get what we deserve. In considering what we deserve, we must consider what we are responsible for, or what is within our control, versus what we are not responsible for, or what is beyond our control. Circumstances of birth, such as mental capacity, capacity for moral agency, place of birth, race, sex, and species are clearly beyond our control; therefore we don’t have responsibility for those circumstances; therefore we don’t deserve to have our important interests (e.g. life, liberty, bodily integrity) ignored because of those circumstances; therefore we have basic moral rights protecting those important interests.
The Six Stages and Speciesism
Speciesism can exist and even thrive at Stages 1 – 4, thriving best at the lowest stages and starting to be slightly threatened at Stage 4. At Stage 5, speciesism is significantly more threatened because of the willingness to question society, but there is nothing at Stage 5 which is inherently antithetical to speciesism because universal principles of justice are not yet considered important or even necessary. Speciesism is inherently antithetical to Stage 6 moral reasoning due to Stage 6’s impartiality and universality in the application of justice. If we engage in genuine and careful Stage 6 reasoning, we cannot avoid landing in the middle of a strong animal rights paradigm.
The most significant reason that animal rights is currently “on the fringe” of current society is that a vast majority of people, perhaps around 99% of the population, are dwelling in Stages 2 through 5, at least in behavior, if not also in reasoning. Even when animal rights advocates reason with non-vegans at Stage 6, there are other factors, such as cultural and psychological influences (primarily habits), which cause non-vegans’ behavior to remain largely unchanged. Still, Stage 6 is the primary moral reasoning under which all previous social justice movements succeeded. Stage 6 thought also entails animal rights, and at this point, the best animal rights advocates can do is to continue to repeat Stage 6 principles to non-vegans until these principles penetrate the social barrier of conventional-level morality as they have in the past for freedom of speech, freedom of religion, freedom from witch trials, freedom from chattel slavery, women’s suffrage, and civil rights.
 For an excellent analysis on why Kant’s universality entails moral consideration of animals while Kant failed to live up to his own idea of universality in this regard and other ways, see Tom Regan’s classic 1983 work, The Case for Animal Rights, pages 174 to 185. For 18th century cultural prejudices and ignorance Kant was likely a victim of, see the September 2007 essay in this blog entitled, “Present Realities and the Moral Status of Animals.” Kant’s universality is a Stage 6 concept, but Kant was not a Stage 6 thinker in the application of his universality.
 We might reasonably ask, if John Rawls’s A Theory of Justice provides a Stage 6 framework for impartiality, and Stage 6 entails animal rights, then why didn’t John Rawls argue for animal rights? Tom Regan examines this contradiction in Rawls’s thought in The Case for Animal Rights in significant detail.
Rawls is considerably ambiguous and equivocal not only on the issue of what duties, if any, we owe to nonhuman animals, but even on the issue of what duties, if any, we owe to moral patients (i.e. those incapable of moral reasoning, but capable of benefiting from the moral behavior of moral agents). In an essay written prior to A Theory of Justice, Rawls claims, in so many words, that moral agency (e.g. the ability to have a sense of justice) is required to qualify as an object of direct duties of justice. In other words, we have no direct duties of justice to moral patients (e.g. very young children, the mentally ill or disabled, the senile or nonhuman animals). Rawls backs off of this position in A Theory of Justice, but is still ambiguous and equivocal about direct duties to sentient nonhumans. Regan, from pages 163 to 174 in The Case for Animal Rights, analyzes Rawls’s position quite carefully and charitably, and in the process, shows how Rawls grossly misapplies and contradicts his own theory when it comes to nonhuman animals. Essentially, Regan shows in detail how setting up Rawls’s “original position” so as to exclude nonhuman animals is no different (i.e. no less arbitrary) than setting up the original position so as to exclude certain racial or ethnic groups or to exclude everyone except white, propertied males. Rawls’s theory of justice is a Stage 6 framework, but Rawls was not a Stage 6 thinker in the application of his theory.