Historically, one can say that there are two basic motivations for the emergence of kalām, the first was internal; different opinions expressed by Muslim theologians in respect to the fate of the sinner initiated an argument that proceeded to develop into a whole tradition of thought. For example some theologians suggested that a Muslim sinner is a non-believer and should be considered kāfer (one who negates Islamic belief). Other theologians suggested that he should be considered only ‘corrupt’ (fāsiq), a technical middle position which lay between the status of kāfer and believer. The second reason for kalām's emergence the reaction of Muslims to new ideas and thoughts they faced when they came into contact with new nations and civilizations, particularly the classical Mediterranean and Indic. This contact, at a time when Muslims were the dominating power in the world, created a ‘dialogue between civilizations’ rather than a ‘clash of civilizations’. It is quite unfortunate and disappointing that humanity now thirteen centuries after that great experience comes to the state of no choice other than a ‘clash of civilizations’ as articulated by the American strategist Samuel Huntington.
The two main schools of Kalām
The mutakallimūn (the doctors of Kalām) formed two main schools, the Muʽtazilis who was the first to be formed, and the Ash’aris. Yet a third school which was borne in Samarqand and Khurāsan (present day Afghanistan) at the time when the Ashari school was forming in Iraq, that school called the Maturidi shared much views of the Asharis but did not gain much publicity as the Asharis did. Prominent leaders of the Muʽtazilis were Wāṣil Ibn ʽAtta’ (d. 748), Amr Ibn ʽUbaed (d. 762), Abu al- Huthayl al-Allāf (d. 840), Ibrīāhim al-Naẓẓām (d. 835), and al-Jāḥiẓ (d. 868 A.D). Most of the original contributions of the leaders of kalām have been lost, but some of their main ideas and arguments were preserved through the writings of their students or opponents. Valuable monographs and critiques have, however, been preserved from some prominent leaders of Muʽtazilisim who worked in a later period. Most prominent among these was Abu al-Hussein al-Khayyāt (d.~ 912) and Abu al-Kāsim al-Balkhi (sometimes called al-Kabi) (d. 931), Abu Ali al-Jeba’īe (d.915) and his Son Abu Hāshim al-Jubba’īe (d.933). Some of the original works of these prominent Muʽtazilis were preserved through the monographs written by their students and followers like Abū Rashīd al-Naysāburi (d. 1048) and Abdul-Jabbār al-Hamadāni (d.1024) who wrote an extensive monograph about Muʽtazilis that preserved much of their original thoughts and his student Ahmed Ibn Mattaweyh (d. 1059) who wrote a book preserving a good deal of the opinions of early Muʽtazilis on the subjects of Daqīq al- Kalām.
The Ashʽaris school was formed by Abū al-Ḥasan al-Ashʽarī (d. 935) who broke away from the Muʽtazilis and formed a new school of thought within the parameters of kalām. Beside al-Ashʽarī the most prominent contributors to the school which bore his name were Abū Bakr al-Bāqillānī (d.1012), and later Abu’l-Maʽālī al-Juwaynī (d. 1085) who wrote some excellent monographs on both daqīq al-kalām and jalīl al-kalām. However one can say that the most efficient utilization of the kalām was made by al-Ghazālī (d. 1111), whose contributions represented the most mature writings produced among the Ashʽaris. In later times the Ashʽaris kalām was reformulated by ʽAḍud al-Dīn al-Ījī (d. 1355), who is considered the last classical mutakallim.
Daqīq al-kalām investigated some of the basic concepts that are the subjects of contemporary physics, such as space, time, matter, force, speed, heat, color, smells, and the like. So it is quite legitimate to revisit this discipline seeking a common understanding, not necessarily with physics as such but perhaps with the scientific philosophy which surrounds the concepts. This policy is supported by the fact that the resources of kalām are quite different from those of classical natural philosophy, including the philosophy of the Greeks. Mutakallimūn considered the Qur'ān to be the prime source for their knowledge about the world, and accordingly they intended to found their discipline in such a way as to understand the world according to the stipulations of the Qur’ān. This is the main reason why we find that some concepts of kalām are different in their meanings and implications from their apparent counterparts in either Greek or Indian philosophy. For example: the Qur'an stipulates that the world was created by God at some finite time in the past; accordingly the mutakallimūn projected this demand into a whole theory of creation of the world and generated their own understanding of substances (jawāhir: single jawhar) and accidents (aʽrāḍ: single ʽaraḍ) as part of a general principle of discreteness in order to serve the notion of creation. On the other hand, for God to be free in designing the world according to His own unpredictable will, and in order that He exert full control over the world, the world had to be thought of as being composed of a series of unstable and ever-changing events. This requirement generated the concept of ever-changing accidents which was expressed by the principle of continued re-creation. Accordingly, this led theologians to consider the results of the action of the laws of nature (fire burning cotton, for instance) as being undetermined, so that the mutakallimūn were able to develop a new concept of causality.