Criticism of Islam can take many forms, including academic critiques, political criticism, religious criticism, and personal opinions. Subjects of criticism include Islamic beliefs, practices, and doctrines.
Criticism of Islam has been present since its formative stages, and early expressions of disapproval were made by Christians, Jews, and some former Muslims like Ibn al-Rawandi. Subsequently, the Muslim world itself faced criticism after the September 11 attacks.
Criticism of Islam has been aimed at the life of Muhammad, the prophet of Islam, in both his public and personal lives. Issues relating to the authenticity and morality of the scriptures of Islam, both the Quran and the hadiths, are also discussed by critics. Criticisms of Islam have also been directed at historical practices, like the recognition of slavery as an institution as well as Arab imperialism impacting indigenous cultures. More recently, Islamic beliefs regarding human origins, predestination, God's existence, and God's nature have received criticism for their apparent philosophical and scientific inconsistencies.
Other criticisms center on the treatment of individuals within modern Muslim-majority countries, including issues which are related to human rights in the Islamic world, particularly in relation to the application of Islamic law. As of 2014, 26% of the world's countries had anti-blasphemy laws, and 13% of them also had anti-apostasy laws. By 2017, 13 Muslim countries imposed the death penalty for apostasy or blasphemy. Amid the contemporary embrace of multiculturalism, there has been criticism regarding how Islam may affect the willingness or ability of Muslim immigrants to assimilate in host nations.
Historical background.
The earliest surviving written criticisms of Islam are found in the writings of Christians such as John of Damascus. He viewed Islamic doctrines as a mix of ideas taken from the Bible and claimed that Muhammad was influenced by an Arian monk. 
Other notable early critics included Arabs like Abu Isa al-Warraq and Ibn al-Rawandi. al-Ma'arri, an eleventh-century antinatalist and critic of all religions. His poetry was known for its "pervasive pessimism." He believed that Islam does not have a monopoly on truth. Apologetic writings, attributed to the philosopher Abd-Allah ibn al-Muqaffa (d. ), include defenses of Manichaeism against Islam and critiques of the Islamic concept of God, characterizing the Quranic deity in highly critical terms. The Jewish philosopher Ibn Kammuna, criticized Islam, reasoning that Sharia was incompatible with the principles of justice.
During the Middle Ages, Christian church officials commonly represented Islam as a Christian heresy or a form of idolatry. They viewed Islam to be a material, rather than spiritual, religion and often explained it in apocalyptic terms. In the eighteenth and nineteenth centuries, European academics often portrayed Islam as an exotic Eastern religion distinct from Western religions like Judaism and Christianity, sometimes classifying it as a "Semitic" religion. The term "Mohammedanism" was used by many to criticize Islam by focusing on Muhammad's actions, reducing Islam to merely a derivative of Christianity rather than acknowledging it as a successor of Abrahamic monotheisms. By contrast, many academics nowadays study Islam as an Abrahamic religion in relation to Judaism and Christianity. The Christian apologist G. K. Chesterton criticized Islam as a heresy or parody of Christianity, David Hume (d. 1776), both a naturalist and a sceptic, considered monotheistic religions to be more "comfortable to sound reason" than polytheism but also found Islam to be more "ruthless" than Christianity.
The Greek Orthodox bishop Paul of Antioch accepted Muhammed as a prophet, but did not consider his mission to be universal and regarded Christian law superior to Islamic law. Maimonides, a twelfth-century rabbi, did not question the strict monotheism of Islam, and considered Islam to be a instrument of divine providence for bringing all of humankind to the worship of the one true God, but was critical of the practical politics of Muslim regimes and considered Islamic ethics and politics to be inferior to their Jewish counterparts.
In his essay "Islam Through Western Eyes", the cultural critic Edward Said suggests that the Western view of Islam is particularly hostile for a range of religious, psychological and political reasons, all deriving from a sense "that so far as the West is concerned, Islam represents not only a formidable competitor but also a late-coming challenge to Christianity." In his view, the general basis of Orientalist thought forms a study structure in which Islam is placed in an inferior position as an object of study, thus forming a considerable bias in Orientalist writings as a consequence of the scholars' cultural make-up.
Points of criticism.
The expansion of Islam.
In an alleged dialogue between the Byzantine emperor Manuel II Palaiologos (r. 1391 – 1425) and a Persian scholar, the emperor criticized Islam as a faith spread by the sword. This matches the common view in Europe during the Enlightenment period about Islam, then synonymous with the Ottoman Empire, as a bloody, ruthless, and intolerant religion. More recently, in 2006, a similar statement of Manuel II, quoted publicly by Pope Benedict XVI, prompted a negative response from Muslim figures who viewed the remarks as an insulting mischaracterization of Islam. In this vein, the Indian social reformer Pandit Lekh Ram (d. 1897) thought that Islam was grown through violence and desire for wealth, while the Nigerian author Wole Soyinka considers Islam as a "superstition" that it is mainly spread with violence and force.
This "conquest by the sword" thesis is opposed by some historians who consider the transregional development of Islam a multi-faceted and complex phenomenon. The first wave of expansion, the migration of the early Muslims to Medina to escape persecution in Mecca and the subsequent conversion of Medina, was indeed peaceful. In the years to come, Muslims defended themselves against frequent Meccan incursions until Mecca's peaceful surrender in 630. By the time of his death in 632, many of the Arabian tribes had formed political alliances with Muhammad and adopted Islam peacefully, which also paved the way for the subsequent conquests of Syria, Iran, Egypt and (the rest of North Africa) after the death of Muhammad. Islam nevertheless often remained a minority religion in conquered territories for several centuries after the initial waves of conquest, indicating that the conquest of territories beyond the Arabian Peninsula did not instantly result in large conversions to Islam.
Scripture.
In the lifetime of Muhammad, the Quran was primarily preserved orally and the written compilation of the whole Quran in its current form took place some 150 to 300 years later, according to some sources. Alternatively, others believe that the Quran was compiled shortly after the death of Muhammad in 632 and canonized by end of the caliphate of Uthman (r. 644 – 656). The idea that Quran is perfect and impossible to imitate as asserted in the Quran itself is disputed by critics. One such criticism is that sentences about God in the Quran are sometimes followed immediately by those in which God is the speaker. The modern historian John Wansbrough believes that the Quran is in part a redaction of other sacred scriptures, in particular the Judaeo-Christian scriptures. The Christian theologian Philip Schaff (d. 1893) praises the Quran for its poetic beauty, religious fervor, and wise counsel, but considers this mixed with "absurdities, bombast, unmeaning images, and low sensuality." The Iranian journalist Ali Dashti (d. 1982) criticized the Quran, saying that "the speaker cannot have been God" in certain passages. Similarly, the secular author Ibn Warraq gives Surah al-Fatiha as an example of a passage which is "clearly addressed to God, in the form of a prayer." The orientalist Gerd Puin believes that the Quran contains many verses which are incomprehensible, a view rejected by Muslims and many other orientalists. "Apology of al-Kindy", a medieval polemical work, describes the narratives in the Quran as "all jumbled together and intermingled," and regards this as "evidence that many different hands have been at work therein."
Pre-existing sources.
Critics point to various pre-existing sources to argue against the traditional narrative of revelation from God. Some scholars have calculated that one third of the Quran has pre-Islamic Christian origins. Aside from the Bible, the Quran relies on several Apocryphal and sources, like the Protoevangelium of James, Gospel of Pseudo-Matthew, and several infancy gospels. Several narratives rely on Jewish Midrash Tanhuma sources, like the narrative of Cain learning to bury the body of Abel in . Norman Geisler argues that the dependence of the Quran on preexisting sources is one evidence of a purely human origin. Richard Carrier regards this reliance on pre-Islamic Christian sources as evidence that Islam derived from a Torah-observant sect of Christianity.
Criticism of the Hadith.
It has been suggested that there exists around the Hadith (Muslim traditions relating to the "Sunnah" (words and deeds) of Muhammad) three major sources of corruption: political conflicts, sectarian prejudice, and the desire to translate the underlying meaning, rather than the original words verbatim.
Muslim critics of the hadith, known as Quranists, reject its authority on theological grounds, arguing that the Quran itself is sufficient for guidance, as it claims that nothing essential has been omitted. They believe that reliance on the Hadith has caused people to deviate from the original intent of God's revelation to Muhammad, which they see as adherence to the Quran alone. Ghulam Ahmed Pervez was one of these critics and was denounced as a non-believer by thousands of orthodox clerics. In his work "Maqam-e Hadith" he considered any hadith that goes against the teachings of Quran to have been falsely attributed to the Prophet. Kassim Ahmad argued that some hadith promote ideas that conflict with science and create sectarian issues.
John Esposito argues that modern Western scholarship has raised doubts about the historicity and authenticity of hadith, while Joseph Schacht argued that there is no evidence of legal traditions prior to 722. Schacht concluded that the Sunna attributed to the Prophet consists of material from later periods rather than the actual words and deeds of the Prophet. However, scholars like Wilferd Madelung have argued that a complete dismissal of hadith as late fiction is "unjustified".
Orthodox Muslims do not deny the existence of false hadith, but believe that through the scholars' work, these false hadith have been largely eliminated.
The traditional view of Islam has faced scrutiny due to a lack of consistent supporting evidence, such as limited archaeological finds and some discrepancies with non-Muslim sources. In the 1970s, a number of scholars began to re-evaluate established Islamic history, proposing that earlier accounts may have been altered over time. They sought to reconstruct early Islamic history using alternative sources like coins, inscriptions, and non-Islamic texts. Prominent among these scholars was John Wansbrough. Additionally, Gerd R. Puin's study of the Sana'a manuscripts revealed some variations in text and verse order, suggesting that the Quranic text may have evolved over time.
Criticism of Muhammad.
The Christian missionary Sigismund Koelle and the former Muslim Ibn Warraq have criticized Muhammad's actions as immoral. In one instance, the Jewish poet Ka'b ibn al-Ashraf provoked the Meccan tribe of Quraysh to fight Muslims and wrote erotic poetry about their women, and was apparently plotting to assassinate Muhammad. Muhammad called upon his followers to kill Ka'b, and he was consequently assassinated by Muhammad ibn Maslama, an early Muslim. Such criticisms were countered by the historian William M. Watt, who argues on the basis of moral relativism that Muhammad should be judged by the standards and norms of his own time and geography, rather than ours. The fourteenth-century poem "Divine Comedy" by the Italian poet Dante Alighieri contains images of Muhammad, picturing him the eighth circle of hell as a Heresiarch, along with his cousin and son-in-law Ali ibn Abi Talib. Dante does not blame Islam as a whole but accuses Muhammad of schism for establishing another religion after Christianity. Some medieval ecclesiastical writers portrayed Muhammad as possessed by Satan, a "precursor of the Antichrist" or the Antichrist himself. 'Tultusceptru de libro domni Metobii", an Andalusian manuscript of unknown origins, describes how Muhammad (called Ozim, from Hashim) was tricked by Satan into adulterating an originally pure divine revelation: God was concerned about the spiritual fate of the Arabs and wanted to correct their deviation from the faith. He then sent an angel to the Christian monk Osius who ordered him to preach to the Arabs. Osius, however, was in ill-health and instead ordered a young monk, Ozim, to carry out the angel's orders. Ozim set out to follow his orders, but was stopped by an evil angel on the way. The ignorant Ozim believed him to be the same angel that had spoken to Osius before. The