“Certainty is so essential, that law cannot even be just without it”, Francis Bacon once observed in the good old times. In the context of the general 20th century's trend from formal to substantive justice, however, policy objectives such as distributive justice, democratic political governance, or effective transnational regulation increasingly came to the focus of private law legislation. The rise of “consumerism” in contract law is the paradigmatic example of this development, which – at least from a German perspective – was triggered mainly by European measures on the harmonisation of private laws. While all intellectual capacities were absorbed by “regulating contracts” in the light of the new principle of “contractual solidarity”, the basic need of a legal system for overall consistency as a prerequisite for the administration of justice (“treating like cases alike”) obviously got out of sight. The critique with regard to pointillism and eclecticism in the European approach to private law harmonisation (“piecemeal legislation”), which lead to the patchwork character of the acquis communautaire, is a common place today, even within the European Commission. However, the conclusion, that has to be drawn, is not formulated straight forward: As consistency goes, arbitrariness comes, an inconsistent law is a contradictio in adjecto.