The field of judgment and decision making has seen an explosion of research and analyses since the 1990s, notably in five closely related fields: Rational choice and its variants, the concept of intuition, “dual process” theories, the “heuristics and biases” literature, and the concept of “naturalistic” decision making. Yet none of these theories captures—by design or because of the limits of the approach—the actual mechanism by which emergent judgment occurs on complex decisions. Such decisions are non-optimizable and guided by multiple and often conflicting objectives and values; their outcomes will flow from the nonlinear interaction of many variables whose causal relationships are poorly understood. As a result, critical assumptions of many classical decision making models cannot be met in such situations, and the default approach relies not so much on calculative decision making as on instinctive judgment. This term implies a mechanism that is less calculative and consequentialist that it is imaginative, creative, and unconscious. Emergent, largely intuitive judgment is the only mechanism appropriate to such complex, nonlinear situations in which both an objective maximization of utilities and an accurate assessment of likely consequences are impossible. The concept of judgment broadly defined, as a form of unconscious, emergent, and imaginative interpretation of facts and events, offers the best model for how decision makers approach non-optimizable situations.