Moral dilemmas engender conflicts between two traditions:
consequentialism, which evaluates actions based on their outcomes, and
deontology, which evaluates actions themselves.
These strikingly resemble two distinct decision-making architectures: a model-based system that selects actions based on inferences about their consequences; and a model-free system that selects actions based on their reinforcement history. Here, I consider how these systems, along with a Pavlovian system that responds reflexively to rewards and punishments, can illuminate puzzles in moral psychology.