Basically, if one chooses to believe a basic tenet (in this case, the assumption that a causal force is the driving meaning and reason for all percieved existance) one must still clarify what flows from that basic tenet. If someone comes up to me and says 'I am God, the one whom has called all of this', I may disprove that through logic. Similarly, if a Christian comes up to me and say that they believe in the Father and the Son and the Holy Ghost as that force, I will reply that any absolute power by its very nature must be indivisible, similarly I will ask how it is that Christ can be God, that God can 'suffer' for us, when 'He' is all-powerful.
That is not to start on the problems within the bible, the contradictions and innaccuracies etc.
This means that such an idea is internally flawed, so, even if the basic tenet is true, their explanation of it must not be. The Sheikh did not have any contradictory explanations, no flaws in logic or quirks of understanding. The Qu'ran is without flaw or contradiction, similarly the message of Islam is holistic and perfect. Faced with a window into that, a crushing logical force, based on that first choice 'to believe', I submitted. Sagacity leads to Allah.