Optionality

This Chapter focuses on a distinctive characteristic of an important portion of contemporary rules of contract law that sets them apart not only from public law but also from other branches of private law (e.g. property and family law), i.e. that these rules can be set aside freely by the contracting parties. Contrary to national civil codes, however, positive EU contract law does not include many instances of non-mandatory rules. This raises the question of what exactly justifies the existence of such optional rules: should public institutions be providing elaborate sets of contract law rules if private parties can set them aside as they please, and, if so, what kind of considerations should determine the content of such rules? Similar questions can be asked with respect to other instances of optional contract law, such as choice of law in cross-border contracts.