Legal certainty is a principle in national and international law which holds that the law must provide those subject to it with the ability to regulate their conduct. The legal system needs to permit those subject to the law to regulate their conduct with certainty and to protect those subject to the law from arbitrary use of state power. Legal certainty represents a requirement that decisions be made according to legal rules, i.e. be lawful. The concept of legal certainty may be strongly linked to that of individual autonomy in national jurisprudence. The degree to which the concept of legal certainty is incorporated into law varies depending on national jurisprudence. However, legal certainty frequently serves as the central principle for the development of legal methods by which law is made, interpreted and applied. Legal certainty is an established legal concept both in the civil law legal systems and common law legal systems. In the civil law tradition, legal certainty is defined in terms of maximum predictability of officials' behaviour. In the common law tradition, legal certainty is often explained in terms of citizens' ability to organise their affairs in such a way that does not break the law. In both legal traditions, legal certainty is regarded as grounding value for the legality of legislative and administrative measures taken by public authorities. The legal philosopher Gustav Radbruch regarded legal certainty, justice and purposiveness as the three fundamental pillars of law. Today legal certainty is internationally recognised as a central requirement for the rule of law. According to the Organisation for Economic Co-operation and Development (OECD) the concept of the rule of law "first and foremost seeks to emphasize the necessity of establishing a rule-based society in the interest of legal certainty and predictability." At the G8 Foreign Ministers' Meeting in Potsdam in 2007, the G8 committed to the rule of law as a core principle entailing adherence to the principle of legal certainty.