Moreover...

Moreover, he says, "now that the heretics attempt to induce doubts (in the minds of un­sophisticated believers), adequate knowledge of theology is necessary to confront them." Regarding philosophy, Al-Ghazzali thinks that it is distinguishable into four parts: [^6] Mathematics and geometry, which are legitimate and permissible. 2.Logic, which is a part of theology. Divinities, which discusses Divine essence and qualities and is also a part of theology.

Physics, which may be divided into two sections: One part which involves discussions opposed to the Shari'ah and accordingly cannot even be considered a "science"; the other part discusses the qualities of bodies. The second part is similar to the science of medicine, although medicine is preferable to it. This section of physics too is useless while medicine is needful.

Mulla Muhsin Fayd al-Kashani, in his book Muhajjat al-bayda', says: It is a personal obligation (wajib `ayni) of every Muslim to learn Islamic juris­prudence to the extent of his needs. Further, learning of fiqh to fulfil the need of others is wajib kifa'i for him. Regarding philosophy, Kashani says: The components of philosophy are not the only ones distinguished by Abu Hamid (Al-Ghazzali) upon whom be God's mercy.

Philosophy covers many other fields of religious and mundane matters (for example astronomy, medicine and rhetoric etc.)... Whatever of these sciences that is about the Hereafter exists to the point of perfection in the Shari'ah, and that which is not useful for the Hereafter is not needed; moreover, it may even hinder the pursuit of the path of Allah.

In the case of those portions which are effective for the knowledge of the Divine and are encouraged by the Shari'ah (like astronomy), it is sufficient to be satisfied with the simple unelaborated discussions of the Shari`ah about such matters. [^8] In brief, in Kashani's opinion anyone who wishes to learn these sciences should first acquaint himself with the religious sciences.

Sadr al-Din Shirazi (Mulls Sadra) in his commentary on Usul al-Kafi regards Al-Ghazzali's opinion about the limitation of obligatory knowledge for a Muslim to the matters of ritual practice and legitimate deal­ings as unacceptable. [^9] In his opinion, learning of religious sciences (such as tawhid, Divine qualities and acts) and human sciences (such as dis­positions of the soul, its delights and afflictions) are also obligatory for the majority of human beings.