I get asked this a lot. “Why not apply your methods and skills to the question of whether Muhammad actually existed or not?” My answer is always the same: I will not likely ever be able to do that, because it would require getting a whole second Ph.D. in Medieval Arabic Studies & Languages (and those languages include not just Medieval Arabic, but also Syriac at the very least). And I must emphasize, I would need not just a good command of the languages (as I do the Greek and Latin required for studying the origins of Christianity), but also “a strong grasp of the historical, cultural, political, social, economic, and religious context” of the origins of Islam (Proving History, p. 18), and that happens to include numerous relevant yet distinct cultural contexts (not just of the Middle East and North Africa, but Byzantine as well).
And I’m not going to do that. Because that period bores the shit out of me. If I ever get a second Ph.D., it will be in contemporary philosophy, to improve myself even further in that area, or a modern science. But Medieval Arabic Studies? Sorry. No. I have all these skills with respect to the origins of Christianity, so I am well qualified to produce peer reviewed studies of the historicity of Jesus (hence my book On the Historicity of Jesus, published by the University of Sheffield). But not so for Islam. We need someone to do that who has parallel skills in that field. I can competently communicate the findings of experts in the field. But on this topic, those findings are confusing and disputed at present.
Okay. So. Lacking my ability to test the question myself, or fully vet anyone else’s case as an expert, can I at least answer whether there is any plausibility to the claim that there was no Muhammad, that he was invented by early Arabic military leaders to give a name to a text they cobbled together to inspire their soldiers and build a new civilization on? In other words, that he was invented in exactly the same way and for exactly the same reasons as the militaristic Jews invented Moses?