Scholar Roslan Abdul-Rahim defends the concept of naskh pointed out the numerous Islamic scholars who have studied and written on the subject and how "very elaborate, sophisticated and ... complex" scholarly discussion of naskh became. "Over seventy" scholars — both classical and contemporary — have written "solely on naskh". Critics have noted the lack of consensus on what verses or Quran and hadith are abrogated, but Abdul-Rahim replies that while "the Muslim scholars of antiquity" may have disagreed about what revelations of the Qur'an were abrogated, at "the conceptual level of definition" they agreed. He asks rhetorically "How could a long tradition established by a community bounded by faith and integrity, and supported by continuity and sustainability be so wrong? ... Could they have not understood or simply misunderstood something that is naturally ingrained in the language of their own culture?" While it is true that scholars have not been able to agree on the instances, number, details or classification of naskh, this is no reason to conclude that naskh "as a theory and a phenomenon is false" and he quotes philosopher of science Thomas Kuhn: "failure to achieve a solution discredits only the scientist and not the theory". Some orthodox scholars, such as Ibn Hilal al-Nahwi found the theory so crucial to Islamic belief that they declared takfir against those who opposed it. Eleventh century scholar Ibn Hilal al-Nahwi (mentioned above) declared that "whoever says" that there is no abrogation in Islam "is not a believer, but rather a kafir," and "must renounce his position or be killed". More recently, Abd al-Aziz ibn Baz (Wahhabi scholar and Grand Mufti of the Kingdom of Saudi Arabia at the time), responded to an article which included some ideas against the concept of abrogation, by stating that the author was guilty of "an act of clear disbelief, a repudiation of Islam, and denial of Allah the Glorious and His Prophet on whom be peace ... It is obligatory upon the governing authority to have that man brought to the courts and ask that he retract his statements, and to rule upon him according to that which the pure Shari'ah summons". (Ibn Baz having called for the execution of Muslims guilty of what he considered acts of unbelief on other occasions.) Alternative Theories Among those who deny the orthodox theory of Naskh out of concerns over how God would change his eternal will,