Western philosophy is just a little too hung up on Greek philosophy. Lets recall that even Plato said this and reminded his readers that philosophy has antecendents and in his case he pointed to the Egyptians. Moreover, tradition says that Pythagoras was influenced by Zoroastrian philosophy.
Here are two examples that show the originality of Islamic philosophy. Recall two famous innovations in Western philosophy:
Hume's scepticism of causality which prompted Kant to awake from his "dogmatic slumber". Einstein said it eas Hume's criticism of causality that helped him to criticise the Newtonian concept of absolute time. He wrote in 1949, "the type of critical thinking required for this central point [the denial of absolute time] was decisively furthered, in my case, especially by reading Hume and Mach's philosophical writings."
Descartes infamous "I think therefore I am". This began a turn towards epistemology in the Western tradition.
Now, the first observation was anticipated by al-Ghazali over six hundred years earlier than Hume when he criticised the Greek influenced Islamic philosophers of his day in his The Incoherence of Philosophers (Tahafut al-Falsasifa) by stating:
The connection between what is habitually believed to be a cause and what is habitually believed to be an effect is not necessary
For
Each of the two things has its own individuality and is not the other, and is neither the affirmation nor the negation, neither the existence nor the non-existence of one is implied in the affirmation, negation, existence and non-existence of the other.
Al-Ghazali re-established causality by developing the Asharite doctrine of occasionalism. The SEP notes that it is sometimes stated that the notion of "occasional cause" is first attributed to Louis de la Forge in the early 17th C, they affirm that the first philosophers to expound this doctrine were Islamic and did no belong to the falasifa, the Greek influenced Islamic philosophy. This is a case of genuine philosophical innovation un-influenced by the Greek tradition.
Furthermore, the second observation listed above by Descartes was anticipated by Ibn Sina (Avicenna) in his The Book of Healing (Kitab al-Shifa) in his 'floating man argument':
One of us must suppose he was created at a stroke, fully developed and perfectly formed but with his vision shrouded from percieving all external objects - created floating in the air or in space, not buffeted by any perceptible current of the air that supports him, hisclimbs separated and kept out of contact with each other, so that they don't feel each other.
Then let the subject consider whether he would affirm the existence of his self. There is no doubt that he would affirm his existence although not affirming the reality of any of his limbs or inner organs, his bowels, or his heart or brain, or any external thing. Indeed he would affirm the existence of this self
of his while not affirming that it had any length, breadth or depth. And if it were possible for him in such a state to imagine a hand or any other organ, he would not imagine it a part of himself or a condition of his existence.
Ibn Sinna used this thought experiment to argue for the immateriality and existence of the soul. He wrote this argument also around six hundred years before Descartes attempted his "cogito ergo sum". Whilst Avicenna was very definitely in the Aristotelian tradition (he called Aristotle The First Teacher (al-mu'allim al-awwal), this argument owed nothing to Aristotle and was his own original contribution.
Now, whilst in the above I say that both Hume and Descartes were anticipated by al-Ghazali and Ibn Sina respectively. I think given the stature and fame of both Islamic philosophers - Dante depicted Ibn Sina in his Divine Comedy and the Soviet Union in 1980 celebrated his thousandth birthday by releasing a set of commemorative stamps. In the Islamic world he was called The Pre-eminent Master (al-Shaykh al-Rais). It was largely due to Avicenna that Aristotelian philosophy was revived in the West after the tradition died in the sixth century. His influence was so great, that a movement developed in the 12th C called Avicennism, particularly in Paris and Oxford influencing philosophers such as Aquinas, Duns Scotus and Roger Bacon. Whilst al-Ghazali influenced Aquinas amongst many other medieval philosophers.
Given all this, I think its safe to say its unlikely that Hume and Descartes independently discovered these ideas and that it is more likely they discovered them through directly reading them in al-Ghazali and Ibn Sina - or at least a hint or a summary of them - in their wide reading, they were both well read in the philosophical literature.
So one can say that Einstein had Ibn Sina to thank, never mind Hume. Still, Einstein claimed science really began with Galileo shrugging off the already well-acknowledged beginning of Western science in Aristotle thus underlining what Plato said about Western intellectual parochialism.
