1) Kohlberg's theory proposes that moral reasoning develops through six stages across three levels - pre-conventional, conventional, and post-conventional.
2) The Heinz dilemma describes a situation where a man considers stealing a drug to save his dying wife from cancer.
3) Kohlberg used this dilemma to understand people's moral reasoning and identify which stage they align with based on their evaluation of whether Heinz should steal the drug.