It is permissible to substitute each of them for the word, and the condition for this indication is that it refers to one of the meanings and specifies it. An example of this is the word "ayn" (eye), which refers to many meanings, including the eye of the beholder, the eye of the spring, and the eye of the sun. The word "ayn" is not understood except by specification, so it is said "the eye of the sun."

Specification: This is when the word refers to a limited meaning, and it conveys what the specification entails, such as our saying "fifty," "one hundred," and "one thousand." The number of fifty is known, as is the number of one hundred and one thousand.

Third: The indication of encompassment. This is when the word refers to multiple meanings by encompassing them all and including everything that falls under it. For example, our saying "animal" is a word that encompasses all living beings of different animal species.

These indications cannot be reversed, as each of them does not extend beyond its subject matter, nor do they overlap, nor does the reality of one return to the reality of another. Whoever reduces the reality of substitution to specification, or the reality of specification to encompassment, has invalidated the indications of language and transmission. For in their overlap and their deviation from their subject matter lies the invalidity of meanings and their deviation. And in the invalidity of meanings and their deviation lies the invalidity of Sharia and its deviation, and this is impossible, and what leads to the impossible is impossible.

Al-Mahdi has provided examples of errors occurring in Sharia due to confusion between these indications, such as the view of some that generality has no specific formula for it, and that it applies to what is mentioned and what comes after it. (See details of this indication in: Ibn Tumart, "A'azz ma yutlab," p. 166).

The majority of Usuliyyun (jurists) hold that generality has a specific formula designated for it, such as relative pronouns, definite plurals, and the definite genus. And the indefinite noun in a negative context. Al-Shawkani mentioned that two scholars from the Hanafi school, Ibn Shuja' al-Balkhi and al-Hakam bin Shuja' al-Balkhi, held that there is no specific formula for generality, and that what is mentioned as formulas are for specificity. He also mentioned that Al-Ash'ari and a group of Murji'ah said that none of the formulas imply generality by themselves or with context, but rather generality occurs when the speaker intends it. Al-Mahdi refuted this by saying that obligation is by command, not by will. Ibn Hazm was one of the enthusiastic proponents of establishing a formula for generality, and his saying in this regard is: "It is obligatory to carry every word to its generality and everything that its name implies, without hesitation or consideration." (See on this issue: Ibn Hazm, "Al-Ahkam," vol. 3, p. 552; Al-Ghazali, "Al-Mustasfa," p. 98 and onwards; Al-Shawkani, "Irshad al-Fuhul," p. 2310 and onwards).