The attempt to fuse religion and philosophy is difficult because there are no clear preconditions. Philosophers typically hold that one must accept the possibility of truth from any source and follow the argument wherever it leads. On the other hand, classical religious believers have a set of religious principles that they hold to be unchallengeable fact. Given these divergent goals and views, some hold that one cannot simultaneously be a philosopher and a true adherent of Islam, which is believed to be a revealed religion by its adherents. In this view, all attempts at synthesis ultimately fail.