Rule simplification is pivotal to many administrations today: Can the industry and business be regulated in a simpler and more efficient way? Since the 1980’s this question has spawned many attempts to reduce the administrative burdens in business. Many have failed though, and even the most successful attempts have proved quite ineffective. They have all failed to overcome the seemingly insurmountable barriers to simplification involved/inherent in the modern welfare state. The aim of this article is to contribute to an explanation hereof: What are in fact these barriers? This is done through the testing of four presumptions, which have their background in the classification of regulatory reforms and in that part of the regulation theory which emphasises the private interest as the main cause of regulation.