“Experimental jurisprudence” draws on empirical data to inform questions typically associated with jurisprudence or legal theory. Scholars in this flourishing movement conduct empirical studies about a variety of legal language and concepts. Despite the movement’s growth, its justification is still opaque. Jurisprudence is the study of deep and longstanding theoretical questions about law’s nature, but “experimental jurisprudence,” it might seem, simply surveys laypeople. This Article elaborates and defends experimental jurisprudence. Experimental jurisprudence, appropriately understood, is not only consistent with traditional jurisprudence; it is an essential branch of it.