The establishment of law with the sadd al-dhari'ah-style caused controversy because it was considered subjective, even accused of stepping over the shari'a. However, the existence of sadd al-dhari'ah can't be denied so that clear criteria are needed to avoid subjectivity. But the criteria can't be formulated if the ontologically is unclear. The classical controversy about sadd al-dhari'ah as a source or method continues until this century. Therefore, this study is focused on answering three important issues; 1) What is the essence (mahiyyah) sadd al-dhari'ah?; 2) What is the criteria of sadd...