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.