Critical human interests are affected on a daily basis by appeal to past decisions deemed to be 'legally valid'. They include statutes, deportation orders, judgments, mortgage contracts, patents and wills. Through the technique of validity, lawyerly reasoning settles morally pressing matters in a way that largely bypasses moral argument. Legal philosophy has paid considerable attention to validity criteria, but it has neglected to explore validity's point: whether, and if so how, the pervasive technique of validity can contribute to a legal system's ability to realise justice and human rights.