Normative theories can be useful in developing descriptive theories, as when normative subjective expected utility theory is used to develop descriptive rational choice theory and behavioral game theory. “Ought” questions are also the essence of theories of moral reasoning, a domain of higher mental processing that could not survive without normative considerations.

A critique of inferences from 'is' to 'ought' plays a central role in Elqayam and Evans' defense of descriptivism. However, the reflective equilibrium strategy described by Goodman and embraced by Rawls, Cohen and many others poses an important challenge to that critique. Dual system theories may help respond to that challenge.