The numerus clausus of property rights is one of the fundamental principles of property law (Van Erp 2006a; Akkermans 2008). It refers to the idea that both the number and content of property rights is limited and is traditionally placed in contrast to party autonomy that reigns in contract law. Property rights are special rights because they have effect against third parties, usually against everybody else. The holder of such a right is therefore in a more powerful position than the holder of a personal right, which is a right that is only valid between two, or at least a limited category of persons.
Strongly connected to the effect of property rights is the role of property law itself. Property law in many perspectives is transactional law and deals with the way in which property rights can be created, transferred and destroyed (Van Erp and Akkermans 2012). These rules are mandatory rules and can therefore not be deviated from by the parties creating, transferring or terminating property rights.
However, there is an inherent tension in these mandatory rules, both regarding property rights themselves as well as the transactional rules that govern them. This tension exists in the way in which property law operates. In almost all cases, to start applying property law an initiating legal act in another field of law is needed. Most of the time this is contract law, where contracts of sale provide the seller with an obligation to transfer his or her property right, or with a contract between parties seeking to establish a property right. Alternatively, the initiating act lies in the law of marriage or succession, where either property rights become jointly held, or pass to heirs or legatees. All of these areas, contract, marital property law and succession law are characterised by the possibility for parties to give content to their legal relationship. Party autonomy therefore enables contracting parties to provide conditions and make special arrangements in terms of the functioning of property law, spouses can make a marriage contract governing the property relations between them and through a last will anyone can determine, within the limits of the applicable succession law, what happens to his or her property after he or she passes away.
For centuries, therefore, parties have sought to introduce flexibility in property law to mirror the flexibility they enjoy in contract, marital property law and succession law. However, the rules of property law, especially due to the principle of numerus clausus that prescribes the available property rights and their content, prevent such flexibility. The reasons provided for this spring directly from the nature of the closed system of property rights and are therefore worth considering. Moreover, approaching numerus clausus from this perspective also sheds light on the limitations of property law and explains the rise of contract law to a considerable degree.
This contribution will focus on the origins of numerus clausus (section 2) and its scope (section 3), before turning attention to different academic perspectives on numerus clausus, such as legal doctrinal and law and economics (section 4). At the end of this section the focus will be on the future of property law and the role numerus clausus can play in this respect.
Akkermans, Bram, The Numerus Clausus of Property Rights (November 20, 2015). M Graziadei and L Smith, eds, Comparative Property Law: Global Perspectives, Cheltenham: Edward Elgar, 2016; Maastricht Faculty of Law Working Paper No 2015/10.