The views of Ibn Taymiyya made him a polarizing figure in his own times and centuries that followed.Tim Winter The Cambridge Companion to Classical Islamic Theology Cambridge University Press, May 22, 2008 p. 84 He is notable for his fierce polemics against various schools of Kalam, primarily Ash'arism and Maturidism, while defending the doctrines of Atharism. This made him a contentious figure with many scholars and rulers of the time, and was imprisoned several times as a result.
Today, Ibn Taymiyya's numerous treatises advocating for al-salafiyya al-iʿtiqādiyya (creedal Salafism), based on his scholarly interpretations of the Quran and prophetic way, constitute the most popular classical reference for contemporary Salafi movements.
Epistemology Sources of Sharīʿa Of the four fundamental sources of the sharia accepted by thirteenth century Sunni jurists, 1. Qur'an, 2. Sunnah, 3. Consensus of jurists (ijma), 4. Qiyas (analogical reasoning), Ibn Taymiyya opposed the use of consensus of jurists, replacing it with the consensus of the "companions" (sahaba).
Like all Islamic jurists Ibn Taymiyya believed in a hierarchy sources for the Sharia. Most important was the Quran, and the Sunnah or any other source could not abrogate a verse of the Qur'an. (For him, an abrogation of a verse, known in Arabic as Naskh, was only possible through another verse in the Qur'an.) Next was Sunnah which other sources (besides the Qur'an) must not contradict.
Consensus (ijmaʾ) Concerning consensus (ijma), he believed that consensus of any Muslims other than that of the companions of Muhammad could not be "realistically verifiable" and so was speculative, and thus not a legitimate source of Islamic law (except in certain circumstances). The consensus (ijma) used must be that of the companions found in their reported sayings or actions. According one supporter, Serajul Haque, his rejection of the consensus of other scholars was justified, on the basis of the instructions given to the jurist Shuraih ibn al-Hârith from the Caliph Umar, one of the companions of Muhammad; to make decisions by first referring to the Qur'an, and if that is not possible, then to the sayings of Muhammad and finally to refer to the agreement of the companions like himself.
An example of Ibn Taymiyya use of his interpretation was in defense of the (temporary) closing of all Christian churches in 1299 in the Mamluk Sultanate during hostility against crusader states. The closing was in violation of a 600-year-old covenant with Christian dhimmis known as the Pact of Umar. But as Ibn Taymiyya pointed out, while venerable, the pact was written 60 years or so after the time of the companions and so had no legal effect.
Analogy (qiyās) Ibn Taymiyya considered the use of analogy (qiyas) based on literal meaning of scripture as a valid source for deriving legal rulings. Analogy is the primary instrument of legal rationalism in Islam. He acknowledged its use as one of the four fundamental principles of Islamic jurisprudence. Ibn Taymiyya argued against the certainty of syllogistic arguments and in favour of analogy. He argues that concepts founded on induction are themselves not certain but only probable, and thus a syllogism based on such concepts is no more certain than an argument based on analogy. He further claimed that induction itself depends on a process of analogy. His model of analogical reasoning was based on that of juridical arguments., pp. 16–36 Works by American computer scientists like John F. Sowa have, for example, have used Ibn Taymiyya's model of analogy. He attached caveats however to the use of analogy because he considered the use of reason to be secondary to the use of revelation. Ibn Taymiyya's view was that analogy should be used under the framework of revelation, as a supporting source.
There were some jurists who thought rulings derived through analogy could contradict a ruling derived from the Qur'an and the authentic hadith. However, Ibn Taymiyya disagreed because he thought a contradiction between the definitive canonical texts of Islam, and definitive reason was impossible and that this was also the understanding of the Salaf. Racha el-Omari says that on an epistemological level, Ibn Taymiyya considered the Salaf to be better than any other later scholars in understanding the agreement between revelation and reason. One example for this is the use of analogy in the Islamic legal principle of maslaha (public good) about which Ibn Taymiyya believed, if there were to be any contradiction to revelation then it is due to a misunderstanding or misapplication of the concept of utility. He said that to assess the utility of something, the criteria for benefit and harm should come from the Qur'an and sunnah, a criterion which he also applied to the establishment of a correct analogy.
An example of Ibn Taymiyya's use of analogy was in a fatwa forbidding the use of hashish on the grounds that it was analogous to wine, and users should be given 80 lashes in punishment. "Anyone who disagreed was an apostate, he added, whose corpse ought not to be washed or given a decent burial."
Reason (ʿAql)
Issues surrounding the use of reason ('Aql) and rational came about in relation to the attributes of God for which he faced much resistance. At the time, Ashari and Maturidi theologians thought the literal attributes of God as stated in the Qur'an were contradictory to reason so sought to interpret them metaphorically. Ibn Taymiyya believed that reason itself validated the entire Qur'an as being reliable and in light of that he argued, if some part of the scripture was to be rejected then this would render the use of reason as an unacceptable avenue through which to seek knowledge. He thought that the most perfect rational method and use of reason was contained within the Qur'an and sunnah and that the theologians of his time had used rational and reason in a flawed manner.
Condemning formal logic as "laughable and boring", Ibn Taymiyya writes: "The validity of the form of the syllogism is irrefutable, but it does not lead to knowledge of things in the external world... Even if the syllogism yields certitude, it cannot alone lead to certainty about things existing in the external world... It must be maintained that the numerous figures they have elaborated and the conditions they have stipulated for their validity are useless, tedious, and prolix. These resemble the flesh of a camel found of the summit of a mountain, the mountain is not easy to climb, nor the flesh plump enough to make it worth the hauling"
Ikhtilaf
Even though jurists may err in their fatwas, Ibn Taymiyya asserted that they should never be deterred from pursuing ijtihād. A stagnated juristic system propelled him to advance legal pluralism, defending the freedom of multiple juristic interpretations. According to Ibn Taymiyya, on legal issues that are subject to Ikhtilaf (scholarly disagreement), every Muslim is allowed to formulate and express his own opinion:
Theology God's attributes
Ibn Taymiyya said that God should be described as he has described himself in the Qur'an and the way Muhammad has described God in the Hadith. He rejected the Ta'tili's who denied these attributes, those who compare God with the creation (Tashbih) and those who engage in esoteric interpretations (ta'wil) of the Qur'an or use symbolic exegesis. Ibn Taymiyya said that those attributes which we know about from the two above mentioned sources, should be ascribed to God. Anything regarding God's attributes which people have no knowledge of, should be approached in a manner, according to Ibn Taymiyya, where the mystery of the unknown is left to God (called tafwid) and the Muslims submit themselves to the word of God and the prophet (called taslim). Henri Laoust says that through this framework, this doctrine, "provides authority for the widest possible scope in personal internationalization of religion."
In 1299, Ibn Taymiyya wrote the book Al-Aqida al-hamawiyya al-kubra, which dealt with, among other topics, theology and creed. When he was accused of anthropomorphism, a private meeting was held between scholars in the house of Al-Din `Umar al-Kazwini who was a Shafii judge. After careful study of this book, he was cleared of those charges. Ibn Taymiyya also wrote another book dealing with the attributes of God called, Al-Aqidah Al-Waasitiyyah. He faced considerable hostility towards these views from the Ash'ari's of whom the most notable were, Taqi al-Din al-Subki and his son Taj al-Din al-Subki who were influential Islamic jurists and also chief judge of Damascus in their respective times.
Ibn Taymiyya's highly intellectual discourse at explaining "The Wise Purpose of God, Human Agency, and the Problems of Evil & Justice" using God's Attributes as a means has been illustrated by Dr. Jon Hoover in his work Ibn Taymiyya's Theodicy of Perpetual Optimism. Ibn Taymiyya regarded Tawhid al-Asma wa Sifat ('monotheism of God's Names and Attributes') as the third aspect of Tawhid and as part of Tawhid al-Uluhiyya (monotheism of Worship). According to Ibn Taymiyya, God must be worshipped by His Own Names and Attributes – by which He described himself in the Qur’ān and Hadith – and to do otherwise would be to commit shirk (polytheism) by associating God with improper ideas.
Duration of Hellfire Ibn Taymiyya held the belief that Hell was not eternal even for unbelievers. According to Ibn Taymiyya, Hell is therapeutic and reformative, and God's wise purpose in chastising unbelievers is to make them fit to leave the Fire. This view contradicted the mainstream Sunni doctrine of eternal hell-fire for unbelievers. Ibn Taymiyya was criticised for holding this view by the chief Shafi'i scholar Taqi al-Din al-Subki who presented a large body of Qur'anic evidence to argue that unbelievers will abide in hell-fire eternally. Ibn Taymiyya was partially supported in his view by the Zaydi Shi'ite Ibn al-Wazir.
Opposition to Bidʿah
Even though Ibn Taymiyya has been called a theologian, he claimed to reject ʿIlm al-Kalam, known as Islamic theology, as well as some aspects of Sufism and Peripatetic philosophy, as an innovation (Bid'ah). Despite this, Ibn Taymiyya's works contained numerous arguments that openly refer to rational arguments (kalam) for their validity and therefore he is included by some scholars as amongst the Mutakallimin.
On the other hand, Ibn Taymiyya has also been regarded by various scholars as "a literalist and reactionary" and as the "thirteenth-century scourge of reason", who saw it as his mission to purify Islam of all inauthentic outgrowths and return to the purity of Muhammad's time. Islam, in the eyes of Ibn Taymiyya, was to adhere strictly to the Qur’an, Hadith, and the practices and interpretations of the salaf – a view Ibn Taymiyya called madhhab al-salaf or ‘the doctrine of the predecessors’. Any idea not found in these fundamental sources was bid‘a, reprehensible innovations to pristine Islam. He engaged in fierce debates against Ash'arite scholars and denounced the rationalist Qur'anic commentary of Ash'arite theologian Fakhr al-Din al-Razi, as a heresy that altered the meaning of Scriptures. According to Ibn Taymiyya, philosophically minded Ash‘ari theologians like Al-Razi were "innovators who prefer the pseudo-philosophical approach of recent ages", rather than the approach of the Salaf.