The knowledge which Muslims have to acquare and learn is called "Ulûm-i Islâmiyya" ( Islâmic knowledge ). It is fard to learn some of this knowledge. It is sunnat to learn some other branches of it, and it is mubâh to learn even more of it. Islâmic knowledge is mainly divided into two branches. The first one is Ulûm-i naqliyya. This is also called "religious knowledge". This originates from four sources called "Adilla-i Shar'iyya". Religious knowledge is also divided into two: the Zâhirî (external) branches of knowledge and the Bâtinî (internal) branches of knowledge. The first ones are called the Knowledge of Fiqh or Sharî'at; the scond ones are called the Knowledge of Tasawwuf (sufism) or Ma'rifat. The Sharî'at is learned through murshids and through the book of fiqh. Ma'rifat goes into hearts after flowing from murshids's hearts.
The scond branch of Islâmic knowledge is Ulûm-i 'aqliyya (experimental sciences). The branch dealing with living creatures is called Ulûm-i tibiyya (science of medicine), and the branch dealing with non-living creatures is called Ulûm-i hikemiyya. The branch dealing with the sky and stars is called Ulûm-i falakiyya. The knowledge dealing with the earth is called Ulûm-i tabî'iyya. The subdivision of Ulû-i 'aqliyya are mathematics, logic and experimental knowledge. They are aquired by perceiving through the five senses, by obrserving through the mind, experimentation and calculation. This fields of knowledge help us to understand and better carry out religious knowledge. They are necessary for this reason. They change, increase and improve in the course of time. For this reason, it has been said, "Takmîl-i sinâ'ât is fulfilled by talâhuk-i afkâr", which means that "improvement in art, science and technology is realized by adding to one another's ideas and experiments".
The knowledge which acquared trhough tradition, that is, religious knowledge, is very exalted. It is beyond and above the mind, the power of human brains. It can never be changed by any person at any time, and this is the meaning of the statement, "There can be no reform in the religion". Islâm has not prohibited or limited the knowledge which is acquared through the mind; yet it has commanded us to learn it together with religious knowledge and to utilize its result compatibly with the Sharî'at. It has also commanded us to make it useful for people and not to use it as a medium for cruelty, torture and disasters.