Among the Islamic schools of thought, intellect as a source for deriving jurisprudential rulings is usually mentioned by Shia Islam, the others like the Sunni school of thought suggest Comparison, Discretion, and other speculative arguments.
Definition
'Aql literally is used in wisdom, maturity, knowledge, contemplation in opposition to asininity and idiotism. Technically, it is used for a faculty discovering good and evil and instigating good and avoiding evil. Man's sayings, behaviors, and judgments of things are through this reasoning that helps analyze the data received and choose the best one. Thus, the intellectual proof here is any certain intellectual ruling that leads to a Sharia ruling. Intellect can be classified according to its object into:
First: theoretical intellect that is used when intellect cognizes what is subject to knowledge and is non-relevant to practice like the impossibility of the conjunction of the opposites or two plus two is four.
Second is the practical intellect; that is when intellect cognizes what is relevant to practice like an evil being of injustice or goodness of hospitality. What we mean here, as the intellectual proof is the practical one.
Literature review
The first Usūlīs have not declared intellect as a source of Sharia; for example, Sheikh Mufīd (413 A.H) considers the Quran and Sunnah as Sharia sources and regarded the intellect as one of the ways to reach to the Quran and Sunnah. Sheikh Tūsī (460 A.H) only mentions that intellect finds out the obligation of appreciating the kindness of others and that justice is good, and injustice is evil, without counting intellect as a separate source of Sharia. Maybe Sayed Sharif Murtadhā (436 A.H) was the first one to name intellect as an independent source for Sharia rulings. According to him, when there is not a ruling for an issue in the three other sources (the book, Sunnah, and consensus), the jurist has to refer to intellect, and then, the ruling of intellect will be the ruling of Allah. Ibn Idrīs Hillī (598. A.H) declares this issue later without explaining it more. Later, Muhaqqiq Hillī (676 A.H) and Shahid Awwal (786 A.H)came to explain intellect as a source. Then, recent scholars like Mīrzāye Qummī and Sahib Al-Fusūl delivered more accurate and detailed discussions concerning intellect. On the contrary, Akhbārīs do not consider intellect as a source of Sharia.
Types of intellectual rulings/proofs
Intellect as an independent source for deducing Sharia rulings may be of two types:
1)Independent intellectual proofs
It is when intellect deduces a Sharia ruling without appealing to any Sharia premise. In logic, any Syllogism is made of two premises (minor and major premises) and a conclusion. If both premises are intellectual then it is an independent intellectual proof. For example:
- Justice is rationally good.
- Whatever is good rationally is obligatory according to Sharia
*Therefore, Justice is obligatory according to Sharia
Another example:
- Injustice is rationally evil.
- Whatever is evil rationally is prohibited according to Sharia.
*Therefore, Injustice is prohibited according to Sharia.
Studying the views of Usūlīs here shows that the only Independent intellectual ruling is the issue of essential intellectual good and evil. In these arguments, the minor premise deals with the goodness or evil being of things and the major premise is the co-implication between the ruling of Sharia and that of intellect. Thus, there are two points to be explained:
a)Meaning of good and evil
Being good and evil might be interpreted in different ways:
A. what is counted as perfection and positive characteristic for man can be called good and contrary to it what is regarded imperfection is considered evil. For example, knowledge, bravery, kindness is good and ignorance, forgery, betrayal is evil. All scholars agree that intellect can specify this kind of good and evil.
B. what causes pleasure or is to the interest of man is considered by intellect to be good and what is unpleasing or is disadvantageous is taken to be evil. For example, exercising is good and drinking is evil. The scholars agree that intellect can specify this kind of good and evil as well.
C. those deeds that are befitting and admired by the intellect are considered to be good and their doers deserve rewards for doing them, like justice. On the contrary, the disagreeable, unappealing, inappropriate conducts are considered evil that their doers are to be blamed and punished such as injustice. Good and evil by this meaning are the subjects of debate here.