I believe that Muhammad did in fact exist- just most likely not in the context provided by the Qu'ran.

Muhammad is attributed with unifying many different groups in Arabia under Islam; the relatively quick shift from disparate groups and tribes into a more homogenous culture is supported through anthropology, and is unlikely to have arised spontaneously or through warfare, given the sizes of the groups involved.

Muhammad, as stated, is credited with this unification. I don't believe that a name and an individual were fabricated for this, though I also doubt it was a solo effort. I expect that it was a sizeable group, with Muhammad as one of the most prominent or charismatic members, that was responsible for the unification.

Compare, say, the United States. The 'Founding Fathers' are credited with much of our history, but they didn't act alone- they were simply the most prominent members of a much larger movement. If we didn't have recorded records, multiple writings and signatures from these men, etc, but rather passed the stories on via word of mouth, I expect we'd probably be crediting a single person with the founding of the US.

How much of the unification was actually directly attributable to Muhammad alone, and whether or not he was actually a prophet are both questions that can be disputed heavily- but the fact that there was a man named Muhammad who contributed to the unification of the Arab world is not something that I feel can be reasonably disputed.

I am a muslim by birth and an atheist by choice. I have shared the sensibility of the religion for most of my life until recently. And I would say I do believe they existed; Christ or Prophet Muhammed as reformists.

This is a pretty silly debate. There are countless records of his exploits. He was a real man who interacted with many other real people. I am saying this as an atheist who despises his brutal teachings and the barbaric methods the Quran enforces to gain total control over the people he conquered.

History books record the existence of Muhammad, therefore, he did exist.

yes

he is the last prophet and I am Muslim and believe in him !