Yes, and let us remember one of the more entertaining philosophical debates in history:
"The Incoherence of the Philosophers" (al-Ghazali)
answered by........
"The Incoherence of the Incoherence" (Ibn Rushd, aka Averroes)
http://en.wikipedia.org/wiki/The_Incoherence_of_the_Philosophers
Islam conquered superior cultures; adopted their already existing philosophy and science and, today, claim them as muslim.
In every instance, as the muslim grip tightened, the excellence of the previous culture stagnated and ultimately died.
By the way, why not quote us some great philosophy, mathematics, medicine and science out of islam --- say in the last 500 years, after they ran out of cultures to destroy?