Gambaro is certainly right, but the reason why these rules are looked at as most adapted to the locality", has in my view more to do with the investments that have already been made in the path of property law and from which it is to too costly to deviate, than with the nature"of property rights. To change the national law in the areas mentioned by Gambaro, would mean that third parties' interests have to be reconsidered on a very large scale. The reliance of the parties involved on the existence of absolute" rights that have effect erga omnes would be violated if the applicable rules on, for example, the establishment of limited real rights and the registration of these rights would be eliminated or even changed. The taking into account of so many different interests has led to delicate static systems of property law with- most of the time-a numerus clausus of limited real rights. Moreover, to get to know the ins and outs of property law in a specific system is far more difficult than to get to know a country's law of contract: the information costs of the former are much higher. In this sense, property law is indeed"stuck in a local equilibrium". In the most part of property law, this does not pose a true problem: any need to have uniform law is virtually absent. It is a problem, however, where there is a need, namely in the field of security interests: here, the desire to create uniform law and the present practice as it has evolved in the past(adapted as it is to a national system of law) are the most divergent This is all different in case of the law of contract The parties to a contract would not be truly hampered by a change of the law because of their ability to set the rules for their relationship themselves. The law of contract's dynamic character guarantees the elimination and survival of rules that are respectively the least and the most suited for their new environment. Benson quotes Rubin as he says If conditions change () and two individuals decide that, for their purposes behaviour that was attractive in the past has ceased to be useful, they can voluntarily devise a new contract stipulating any behaviour that they wish. That is, old custom can be quickly replaced by a new rule of obligation toward certain other individuals without prior consent of or simultaneous recognition by everyone in the group(or of some legal authority) This evolutionary idea is backed up by evidence from both the economic analysis of law and compa Economic analysis of law shows the need for a distinction between default and mandatory rules. This type of analysis makes clear that rules should be mandatory when any other rule that the parties would adopt would be violating third parties interests. Mattei and Cafaggi rightly point out that the amount of mandatory rules should decrease in a system where alternative means of protection of third parties are available. They mention for example the lesser amount of mandatory rules in contract law if the tort system protects third parties. It is obvious that property law is much more related to these mandatory rules than contract law. The economic reason for property 72 C SMITS, Supra note 5, at 249 is C. Meinrad Dreher, Wettbewerb oder Vereinheitlichung der Rechtsordnungen in JURISTENZEITUNG 105, 109(1999):"Da Wissen und Kosten eng miteinander verbunder stellt Unwissenheit zumindest vor Informationskosten und begrenzt so auch die Faktormobilitat ganz entscheidend” 74 Bruce L. Benson, Evolution of Commercial Law, in THE NEW PALGRAVE DICTIONARY OF ECONOMICS AND THE LAW, VOL 1, 90(1998) Mattei& Cafaggi, supra note 60, at 34812 Gambaro is certainly right, but the reason why these rules are looked at as most adapted to the “locality”, has in my view more to do with the investments that have already been made in the path of property law and from which it is to too costly to deviate, than with “the nature” of property rights. To change the national law in the areas mentioned by Gambaro, would mean that third parties’ interests have to be reconsidered on a very large scale. The reliance of the parties involved on the existence of “absolute” rights that have effect erga omnes would be violated if the applicable rules on, for example, the establishment of limited real rights and the registration of these rights would be eliminated or even changed. The taking into account of so many different interests has led to delicate static systems of property law with – most of the time – a numerus clausus of limited real rights.72 Moreover, to get to know the ins and outs of property law in a specific system is far more difficult than to get to know a country’s law of contract: the information costs of the former are much higher.73 In this sense, property law is indeed “stuck in a local equilibrium”. In the most part of property law, this does not pose a true problem: any need to have uniform law is virtually absent. It is a problem, however, where there is a need, namely in the field of security interests: here, the desire to create uniform law and the present practice as it has evolved in the past (adapted as it is to a national system of law) are the most divergent. This is all different in case of the law of contract. The parties to a contract would not be truly hampered by a change of the law because of their ability to set the rules for their relationship themselves. The law of contract’s dynamic character guarantees the elimination and survival of rules that are respectively the least and the most suited for their new environment. Benson quotes Rubin as he says: If conditions change (…) and two individuals decide that, for their purposes, behaviour that was attractive in the past has ceased to be useful, they can voluntarily devise a new contract stipulating any behaviour that they wish. That is, old custom can be quickly replaced by a new rule of obligation toward certain other individuals without prior consent of or simultaneous recognition by everyone in the group (or of some legal authority).74 This evolutionary idea is backed up by evidence from both the economic analysis of law and comparative law. Economic analysis of law shows the need for a distinction between default and mandatory rules. This type of analysis makes clear that rules should be mandatory when any other rule that the parties would adopt would be violating third parties interests. Mattei and Cafaggi rightly point out that the amount of mandatory rules should decrease in a system where alternative means of protection of third parties are available. They mention for example the lesser amount of mandatory rules in contract law if the tort system protects third parties.75 It is obvious that property law is much more related to these mandatory rules than contract law. The economic reason for property 72 Cf. SMITS, supra note 5, at 249. 73 Cf. Meinrad Dreher, Wettbewerb oder Vereinheitlichung der Rechtsordnungen in Europa?, 54 JURISTENZEITUNG 105, 109 (1999): “Da Wissen und Kosten eng miteinander verbunden sind, stellt Unwissenheit zumindest vor Informationskosten und begrenzt so auch die Faktormobilität ganz entscheidend”. 74 Bruce L. Benson, Evolution of Commercial Law, in THE NEW PALGRAVE DICTIONARY OF ECONOMICS AND THE LAW, VOL. I, 90 (1998). 75 Mattei & Cafaggi, supra note 60, at 348