Islamic Jurisprudence
Whenever Muslims are faced with an issue that is not directly addressed in either the Qur'an or the Sunnah, they may rely on laws derived by jurists, who base their opinions on the primary Islamic sources and a methodology of reasoning and analysis. This method is called fiqh, or the deep understanding of something based on study and reasoning.
A legal opinion is only that — an opinion — and is not automatically binding on all Muslims. Only persons who are qualified to interpret Islamic law may issue a valid fatwa, and it is not uncommon for scholars to come to different conclusions about the same issue. Each individual Muslim evaluates the evidence and makes a decision to accept a fatwa or not.
Sources of Fiqh
Sources of Islamic jurisprudence include ijmah, the joint agreement of the companions of the Prophet for issues that came up shortly after Muhammad's death, and qiyass, the opinion of later scholars who research a topic and come to a conclusion based on these other main sources. These secondary sources must spring from and depend on the Qur'an and the Sunnah; they may not in any way contradict either of these main sources.
Legal Opinions
A qualified scholar may issue a formal legal opinion on a topic. Such a legal opinion, which must be based on sound reasoning and with evidence from primary Islamic sources, is called a fatwa. Examples include the prohibition on smoking and the legality of some methods of alternative reproduction.
