By means of this reasoning Wansbrough arrived at the conclusion that concern with the text of scripture did not precede by much the appearance of the masoretic [exegetical] literature as it has in fact been preserved : that is, in his view the Quranic text assumed its canonical form more or less simultaneously with the appearance of commentaries on it (tafsir). He took as confirmation of this view Joseph Schachts conclusion that the Quranic text did not serve as a basis for Muslim law before the ninth century.
Particularly crucial to Wansbroughs argument is the term canonical, for which he assumes a high standard of precision.
It is clear that even in the Muslim tradition the fact was acknowledged that readings of the Quran continually diverged from a supposed original; it is clear also that steps had repeatedly to be taken to impose or protect a unitary text of revelation - in the time of ‘Uthman, again in the time of Ibn Mujahid, and even as recently as the 1920s, when scholars at al-Azhar prepared the currently most widely used edition. This edition is nonetheless not treated as uniquely canonical in parts