Science and the Muslim Ummah
One of the distinctive features of Islam is its emphasis on knowledge. The Quran and the Islamic tradition (sunnah) invite Muslims to seek and acquire knowledge and wisdom and to hold men of knowledge in high esteem. Some of the Quranic verses and relevant traditions will be mentioned in the course of our discussion.
At the outset we may recall a famous hadith of the Holy Prophet upon whom be Allah's peace and benedictions that has come down through various sources; it says: "Acquisition of knowledge is incumbent on every Muslim."  This tradition brought up the discussion as to what kind of knowledge a Muslim should necessarily acquire an issue around which various opinions were offered in the past.
Abu Hamid Al-Ghazzali (died A.D. 1111), in his famous book Ihya `ulum al-din (The Revival of Religious Sciences), mentions that he had come across twenty different answers to the above question.  The theologians considered that learning of Islamic theology (kaldm) was an obligation, while the jurisprudents (fuqaha') thought that Islamic jurisprudence (fiqh) was implied in the prophetic tradition. Al-Ghazzali himself favoured the view that the knowledge whose acquisition is a religious obligation is limited to what one must know for correct performance of the acts obligatory for a person within the framework of the Islamic Shari'ah. 
For instance,one whose occupation is animal husbandry should acquaint himself with the rules concerning zakat. If one were a merchant doing business in an usurious environment, he ought to be aware of the religious injunction against usury so as to be able to effectively avoid it.
Al-Ghazzali then proceeds to discuss sciences whose knowledge is wajib kifa'i  (something which is obligatory for the whole society as long as the duty for fulfillment of a social need exists, but as soon as the duty is shouldered by enough number of individuals, others are automatically relieved of the obligation). Subsequently, he classifies all knowledge into "religious" and "non-religious" sciences.
By "religious sciences" (â€˜ulum al-shar`) he means the bulk of knowledge imparted through prophetic teachings and the Revelation. The rest constitute the "non-religious" sciences. The non-religious sciences are further classified into "praiseworthy" (mahmud), "permissible" (mubah) and "undesirable" ones (madhmum). He puts history in the category of permissible sciences (mubah) and magic and sorcery in the category of the undesirable fields of "knowledge".
The "praiseworthy" sciences (mahmud), according to him, are those whose knowledge is necessary in the affairs of life and these are wajib kifai; the rest of them bring additional merit to the learned who pursue them. He puts medicine, mathematics and crafts, whose sufficient knowledge is needed by the society, in the category of sciences of which are wajib kifai. Any further research into the detail and depth of problems of medical science or mathematics is put by Al-Ghazzali in the second category which involves merit for the scholar without entailing any manner of obligation.
Al-Ghazzali classifies the religious sciences also into two groups:
praiseworthy (mahmud) and undesirable (madhmum). By "undesirable religious sciences" he means those which are apparently oriented towards the Shari'ah but actually deviate from its teachings. He subdivides the "praiseworthy" religious sciences into four groups: