The law must be stable, but it must not stand still.

Roscoe Pound (1870–1964), a leading figure in American “sociological jurisprudence” and later dean of Harvard Law School, used this line while arguing that legal systems must balance continuity with responsiveness to social change. In the early 20th century, Pound criticized rigid formalism—treating law as a closed set of logical rules detached from real life—and urged judges and lawmakers to consider law’s social purposes and effects. The remark is commonly cited in discussions of legal reform and judicial method, capturing Pound’s view that legitimacy depends on stability and predictability, yet law must evolve as economic conditions, technology, and social values shift.

The aphorism frames a central tension in the rule of law. “Stable” signals that law must be reliable: citizens and institutions need predictable rules to plan their affairs, and abrupt, politicized change undermines fairness. “Must not stand still” insists that the same stability cannot become stagnation; when society changes, unchanged rules can produce injustice or inefficiency. Pound’s point is not that law should chase every trend, but that it should adapt through principled development—legislation, interpretation, and institutional reform—so that legal doctrine continues to serve its social ends rather than merely preserve inherited forms.