I believe that the interesting question is not so much about Islam as such but rather about what we might call "Militant Messianic Monotheism" (3M), of which Islam is only one possible form.
Let me explain. After starting off as a local form of monolatry, rather than full monotheism, Judaism had split, by the time of 0 AD, into 3 currents :
- The Sadducees, which were the conservative faction and represented the tradition of local Jewish sacrificial Temple-based monolatry.
- The Pharisees, with their emphasis on legalistic rules of purity.
- The Zealots, which were the first example of what I have called 3M above.
The Zealots were wating for a Messiah which they pictured as a great military conqueror in the mould of Alexander the Great. Since, as Messiah, he would be backed by God, this conquering hero was going to subjugate the whole world in the name of YHWH and the Zealots were preparing to be the core of his army. In other words, the worlview of the Zealots, and of every 3M movement since then, is very close to that of Daesh in our own time.
The zealots inspired 2 major Jewish revolts in the Ist and IInd centuries (in 66-70 and in 135 respectively). Both were savagely suppressed by the Romans and turned out to be huge disasters for the Jewish people. There were massive casualties and the Jews were almost completely evicted from Palestine. As a result, Judaism was now split in two:
- The Mishnaic Rabbis, heirs of the Pharisees, who adapted Judaism to a life in exile by solidifying its legalistic practices. While Pharisees had had some sympathy for the Zealot movement, the Rabbis now understandably disowned them completely in view of the disaster they had caused and therefore surrounded the idea of a Jewish Messianic savior with so much theological precautions and rules that it would be almost impossible for any claimant to meet them all.
- The early Christians, who had a more radical approach. Indeed, Jesus, according to earlier Jewish criteria, is not a Messiah at all but an anti-Messiah because he is a failed Messiah (in this world). As a result, Chrsitianity is the most anti-messianic movement of the whole history of Monotheism.
In short, early Monolatric Judaism had given birth to the first Messianic movement which, through the Zealot-inspired revolts, had nearly destroyed itself completely. As a result, the two main movements that survived identified 3M as a great threat, albeit a great temptation, and devised safeguards against it. Among these, the most radical and the most effective proved to be the Christian solution: proclaim that on the one hand the
real Messiah was Jesus, a failed Messiah in this world, and on the other, that all other potential Messiah claimants (exemplified by Barabbas) are figures of the
Antichrist.
Christianity proved to be hugely sucessful, for this reason and for others. When Islam appeared IOTL, it had been the official religion of the Roman Empire for 3 centuries and continued to spread at a rapid rate. The situation at this time is therefore one in which the religious landscape is dominated by a strongly
anti-messianic movement.
Now it is crucial to realize that Islam is much less anti-Messianic than Christianity. Jesus is still officially the Messiah but his crucifixion is denied. As a result, he is less of a failure but also much less central. In Christianity, all hopes (temptations) of
being the Messiah or of finding a Messiah to
follow are sacrificed at the feet of the crucified Jesus. In Islam, such is no longer the case. Furthermore, the character of Muhammad is that of a quasi-Messiah: he is victorious in war and described in all respects as a successful role-model. As a result, it is not surprising that the developping Islamic theology was quick to re-generate a fully Messianic character: the Mahdi. Here we have come full circle as the Mahdi is, like the old Jewish Messiah, a conquering Hero who will subjugate the whole world in the name of Allah.
In view of all this, it is not surprising that Islam has been plagued by a large number of 3M movements, the latest of which is Daesh. Like the Rabbis, the Muslim ulema have tried to mitigate this threat through a multitude of rules and theological restrictions. These measures have been partially sucessful but not completely as we can see in our own day with Daesh.
If we follow this line of reasoning, I believe that the question is not whether or not Islam was inevitable but whether or not the resurgence of some form of 3M-friendly, or at least 3M-permissive, monotheism was inevitable.
My personal opinion is that such a resurgence was highly probable and it is such a scenario, distinct from Islam, that I am exploring in the thread below, on which I am currently working.
