Over 120 Muslim leaders and scholars, including UC Berkeley's Hatem Bazian, Hamza Yusuf of Zaytuna College, and Brandeis University's Joseph E.B. Lumbard, have signed an open letter to the Islamic State (ISIS) disputing the theological basis for ISIS's heinous actions. Yet Ayman S. Ibrahim, a PhD candidate in Islamic studies at Fuller Theological Seminary, points out at First Things that "the statement is ambiguous in crucial areas, which not only weaken its argument, but also question whether it is truly a rigorous and valid refutation of ISIS's deeds and claims."