Discover the meaning of the term Al-ʿks (عكس) in Islamic vocabulary.
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Updated on 11 April 2026 at 1:05 AM
📖 4 min readIn language: returning a thing to its first way (sunna), that is, its original way, like the reflection of a mirror: when it returns your gaze, through its surface, to your face by the light of your eye. Among the jurists' usage: making the opposite of the mentioned judgment conditional upon the opposite of the mentioned cause, by returning to another principle, as in our saying: what is obligatory by vow is obligatory by commencing (ishra'), like hajj; and its converse: what is not obligatory by vow is not obligatory by commencing. Al-'aks is thus, in this, the opposite of entailment (itirad).
It is the inseparability in negation, meaning that whenever the definition (hadd) is not true, the defined (mahdud) is not true either. It has been said: al-'aks is the absence of the judgment due to the absence of the cause.
Returning the thing to its first way, that is its original way, like the reflection of a mirror when it returns your gaze, by its surface, to your face by the light of your eye. It is also turning a thing back to its end; one says 'akasahu 'aksan (he turned it back), on the pattern of daraba, and in'akasa (it turned back), in the sense of reciprocity. Among the usulis: inversion, in the chapter on the ways of the cause ('illa), is that whenever the attribute is absent the judgment is absent, like the absence of the prohibition of wine upon the disappearance of its intoxication, its odor, or one of its other attributes; it is also called al-'aks, and is thus the opposite of regular entailment (itirad). It is: the absence of the judgment for the absence of the cause. Ibn Khalf al-Baji said: al-'aks is the absence of the judgment for the absence of the cause. In the jurists' usage: making the opposite of the mentioned judgment conditional upon the opposite of the mentioned cause, returning to another principle. Shaykh Zakariyya al-Ansari said: al-'aks is the disappearance of the judgment, or of its supposition, upon the disappearance of the cause; and 'aks' is ordering the nonexistence of a thing upon the nonexistence of another. [al-Tawqif p. 522, Ihkam al-fusul p. 53, al-Hudud al-aniqa p. 83, al-Mawsu'a al-fiqhiyya 5/113, 28/341].
That a part in speech be put first, then put last.
Returning the thing to its first way, that is its original way, like the reflection of a mirror when it returns your gaze, by its surface, to your face by the light of your eye.
In the jurists' usage: making the opposite of the mentioned judgment conditional upon the opposite of the mentioned cause, returning to another principle, as their saying: what is obligatory by vow is obligatory by commencing, like hajj; and its converse: what is not obligatory by vow is not obligatory by commencing; al-'aks is thus the opposite of itarad, as al-Sayyid said.