In his excellent new book "Did Muhammad Exist? An Inquiry into Islam's Obscure Origins," Robert Spencer has questioned the very existence of Prophet Muhammad.   Robert bases his thesis of the non-existence of Muhammad on the following key reasons.

Quoting from Spencer:

“No record of Muhammad’s reported death in 632 appears until more than a century after that date.

The early accounts written by the people the Arabs conquered never mention Islam, Muhammad, or the Qur’an. They call the conquerors “Ishmaelites,” “Saracens,”“Muha- jirun,” and “Hagarians,” but never “Muslims.”

The Arab conquerors, in their coins and inscriptions, don’t mention Islam or the Qur’an for the first six decades of their conquests. Mentions of “Muhammad” are non-specific and on at least two occasions are accompanied by a cross. The word can be used not only as a proper name but also as an honorific.

The Qur’an, even by the canonical Muslim account, was not distributed in its present form until the 650s. Contradicting that standard account is the fact that neither the Arabians nor the Christians and Jews in the region mention the Qur’an until the early eighth century.

During the reign of the caliph Muawiya (661–680), the Arabs constructed at least one public building whose inscription was headed by a cross – a symbol abhorrent to Islam.

The lack of confirming detail in the historical record, the late development of biographical material about the Islamic prophet, the atmosphere of political and religious factionalism in which that material developed, and much more suggest that the Muhammad of Islamic tradition did not exist, or if he did, he was substantially different from how that tradition portrays him.”

END QUOTE

One of the questions that must be addressed is why there is a “personality change” between the initial peaceful Mecca Surahs and the later violent Surahs.  If the entire Quran was cooked up after the fact, there wouldn’t be that difference – as it would all come from the same “pot.”   

I accept only the possibility of Spencer's premise of the creation of the myth of a warrior prophet. (Read Ali Sina's comments at end of this article,)  (It is possible that there was this warrior prophet – Muhammad much as described that these early Arab conquerors were so jealous of his stature and viewed his legacy and his followers as a threat and therefore did not proclaim Muhammad’s existence until these later 7^th century rulers mentioned by Spencer embraced and possibility embellished his legacy.)  But whatever happened - there is no way Muhammad could have been created from scratch as described by Spencer. I do not believe that these ruthless conquerors had the genius or foresight to create the initial Mecca peaceful teachings and then the violence, sex slave, conquest, violent teachings etc. Without these initial Mecca peaceful teachings granting religious credibility cloaking the murderous evil teachings, Islam would cease to exist. Again, there is no way these rulers could have thought this out. In Spencer’s scenario, it seems more plausible that there was a failed preacher Muhammad who actually created a religion called Islam, God - Allah, book - Quran and then went to historical oblivion like so many thousands of other failed preachers. These 7th century Islamic rulers discovered this man with his already made religion Islam and build their warrior prophet hero mythology - what Spencer termed "legendary hero" to unify their empire.

Following is another explanation

Throughout history, there have been many men who have pertained to be prophets of God possessing a special relationship with God including communicating with God or an intermediary. The fact that there would have been a man called Muhammad proclaiming to be a prophet around 610 AD claiming to be receiving divine teachings thru Angel Gabriel would not have been unusual. 

We know that Islam is divided into 2 phases; the initial Mecca phase where Muhammad preaches peace and tolerance and the Medina phase in which the Quran becomes a violent, military manual of death and destruction bent on conquering the world for Allah, subjugating its peoples and destroying all other religions. 

Again - it is important to understand that Islam without the initial Meccan peaceful teachings would have gone to oblivion. Without the cover provided by these early teachings, Islam would have lacked any religious creditability masking the Medina call to conquest.

Prophet Muhammad was born around 570 AD in Mecca. He belonged to the Quraysh tribe of Mecca.  Muhammad became a trader who married an older, rich woman.  One day in 610, he claims to have met the angel Gabriel in a cave on Mount Hira. Gabriel transmits teachings from God to Muhammad. For the next 13 years, Muhammad labors as a preacher trying to convince the Jews, Christians that his God – Allah is the same God as worshipped by them and convince them and the pagan Arabs to join his new religion Islam and become Muslims.  After 13 years, with his wife dead and no success in Mecca, Muhammad departs Mecca for Medina with a small band of believers where he dies.  After his death, his followers collected the revelations Muhammad claimed to have received from Gabriel into the Quran.  Muhammad, Islam, Allah and the Quran go to historical oblivion. 

Muhammad would have disappeared from history if it had not been for the leaders of the Arab empire who near the end of the 7^th century needed a religious ideology to unify the empire.

Quoting Spencer:

“Historical records make clear that toward the end of the seventh century and the beginning of the eighth, the Umayyad leaders of the Arab domains began to speak much more specifically than anyone had before about Islam, its prophet, and eventually its book. Muhammad, if he did not exist, or if his actual deeds were not known, would certainly have been politically useful to the new Arab Empire as a legendary hero. The empire was growing quickly, soon rivaling the Byzantine and Persian Empires in size and power. It needed a common religion—a political theology that would provide the foundation for the empire’s unity and would secure allegiance to the state.”

These leaders discovered that hundreds of years before there had been a preacher born in Mecca who had preached a new religion called Islam, followers were called Muslims of a God called Allah and had a book recording this new religion’s teachings.  In short, they had a pre-packaged religion and their necessary “legendary hero” upon which to build the mythology of their warrior prophet. 

At this point, they turned the Quran and Islam into a military ideology with their God – Allah rewarding his followers with a virgin delight Paradise for those who killed kafirs or were slain in the attempt, as many sex slaves as they could conquer, women as their property and 80% of the booty from the conquered territories.  To finance the conquests, a special tax was imposed on the Jews and Christians and later the Hindus. 

These new teachings were incorporated into the original peaceful Quran and the original peace teachings were cleverly utilized to give Islam its religious cloak to deceive the kafirs while the Muslim armies planned their military demise.  Of course, the new Quran’s teachings abrogated Muhammad’s original Quran.

If this is so, then Prophet Muhammad was a good man who never killed, raped, terrorized, tortured anyone but tried to make a difference to his community.  Prophet Muhammad after his death would have joined Gabriel in heaven. 

The Muslim men followers of this new Islam created by these evil leaders upon their death would not ascend to any paradise filled with virgins but descended into hell to join not only these evil Islamic conquerors but all the other killers of history: Hitler, Stalin, Mao, etc who sold their souls for power.

A WAY OUT

The bastardization of the original Quran and the creation of a monster from Prophet Muhammad life by these men of evil gives Muslim men a way out of the Islamic nightmare that now perils mankind. Muslim men could rise up and renounce these pretenders, denounce their warrior prophet fabrication and embrace Prophet Muhammad and his teachings. Unfortunately this is not going to happen.

Muslim men will never give up the benefits granted to them by these later teachings made up by these Islamic conquerors. Their women and children are their property, unlimited sex with sex slaves, child brides, unlimited booty, unlimited political power and unlimited eternal sex. 

So tonight, Prophet Muhammad is in heaven to be joined by all Muslim women who having been brain washed and mentally and physically abused from their birth deserve external solace while all their sons, brothers, fathers, husbands having been born with free will have chosen to follow evil condemning their souls for all eternity.   

In conclusion, whatever be the truth about Muhammad’s existence, whether he never existed as proposed by Spencer, or was an obscure preacher as I described embraced by these later Islamic conquerors who created the mythology of the warrior prophet, or a warrior killer much as described in Hadeth, Sira giving us the historical record as mentioned by Ali Sina (read below) namely “the Tabaqat, and has seen the log list of Muslims of Mecca, of Medina, the women in Islam, the names of the mohadethin, and all those detailed stories about each one of them” but never achieved a stature that would have made him a hero to these early Islamic conquerors until these later rulers embellished his legacy, or he is exactly as Ali Sina states in his commentary - Muhammad, as presented in his actions outlined in the Quran, Hadiths, and Sira, was one of the most diabolically evil persons in history. Such an evil incarnate can never be a representative of the supreme creator of the Universe. Even if one claims that Muhammad was thoroughly bastardised by these later Islamic rulers, it is impossible that a true prophet of the omnipotent God could be so badly bastardised by earthly man to the point of making him the most evil ever. So, Muhammad was never a prophet of God, period! 

Whether Muhammad existed or not, is not of so much importance today. Muhammad matters because of the religion of Islam, whether founded by Muhammad, or created in his name. Islam is there, believed to be the truest and the final religion for all mankind, by the world's fast expanding 1.5 billion people. And Islam – a violent and fascist ideology – threatens the future of civilized humanity. And we have to fight Islam, accepting for what it is. Doubting Muhammad's existence – which is impossible to establish – would help little in the battle against Islam. Some say, it might even act as counter productive in the battle against Islam.

So, we have to fight the threats of Islam in the very term what it is, which is real. An imaginary speculation, such as whether Muhammad existed, would bear no fruit in defeating what is real. We have to focus our attention to the ideology and doctrines of Islam.

What is of most critical importance and we must stay focused on in our struggle against Islam is that Allah of the Quran is a fraudulent creation. If Allah was created by a real Muhammad, He represented nothing but the mind of Muhammad himself, and a most vile one. Muhammad never received God’s message via Gabriel. The Quran is a fraudulent book – a product of a psychotic human mind, whether of a real Muhammad or of the ones, who created it in Muhammad’s name. ISLAM IS “EVIL IN THE NAME OF GOD™”

Read the second article that was posted  at http://www.islamreform.net/new-page-154.htm
titled “Whether Muhammad Existed or Not, Allah is certainly a Fraudulent Creation. ALLAH IS NOT GOD. ALLAH (of the Quran) NEVER EXISTED. ALLAH AKA MUHAMMAD”

PS

Following is a commentary by Ali Sina editor www. faithfreedom.org

Of course Muhammad existed and he is just as the Sira depicts him. I am really surprised that this question is even discussed. I read half of the book of Robert. Most of the questions he raises can be answered. They are misunderstandings. The ones that cannot be answered is because we just don't have enough data. For example the coin. On the coin there is Muhammad, a cross and Ankh, the Egyptian symbol of life. We don't know who made this coin and whether it was a coin for exchange or simply a decorative object. We can't take this coin which is utterly ambiguous and throw away thousands of solid evidences pointing to Muhammad.

Anyone who has read the Tabaqat, and has seen the log list of Muslims of Mecca, of Medina, the women in Islam, the names of the mohadethin, and all those detailed stories about each one of them will not entertain the question about the existence of Muhammad not even for a second.