Legal positivism positions the law in the formal validity. However, the law theory also focuses on other aspects of empirical to understand the legal phenomenon, we seek such elements in the works of Herbert Hart and Alf Ross. To Hart the rule of recognition's content, that we can use to meet the validity of the right, should be measured empirically in each legal system and may also (but not necessarily) incorporate moral elements. Differently, the realistic Ross theory is independent of the validity criterion and he argues that the effectiveness is verifiable by the effective application of the law by legal authorities.
Validity; Effectiveness; Vigência; Herbert L. A. Hart; Alf Ross