Among the noblest functions of the intellect is its ability to discern likeness and difference. When it perceives two things that are alike, it knows that this is the same as that and therefore gives them one and the same ruling—just as it does when it beholds water and water, earth and earth, or air and air, and then issues a universal judgment on the common feature shared between them. Should it pronounce a ruling on one concrete instance, draw a parallel with its counterpart, and cite the shared attribute, the exposition becomes clearer still. This is the analogy of correspondence (qiyās al-ṭard).

Conversely, when the intellect encounters two unlike things—water and earth, for example—it distinguishes between them; this is the analogy of contrariety (qiyās al-ʿaks).

The reflective consideration (iʿtibār) that God enjoins in His Book embraces both kinds of analogy. When He destroyed those who belied the messengers because of their denial, the lesson is that anyone who behaves as they did will be struck by what struck them; one therefore avoids rejecting the messengers for fear of punishment. That is analogy by correspondence. At the same time, one realizes that whoever does not belie the messengers but rather follows them will not suffer what befell the others; this is analogy by contrariety. This is precisely the purpose of reflecting on the fate of those who were punished: in the derivative case the ruling is the opposite of that which applied to the root case, not its twin. Reflection thus operates through both methods, as the Exalted says:

“There is certainly, in their stories, a lesson for those endowed with insight.” (12:111)

and:

“There has already been a sign for you in the two hosts that met: one host fighting in the path of God and the other unbelieving; they saw them to be twice their own number before their very eyes. God supports with His help whom He wills. In that is a lesson for those who perceive.” (3:13)

The Balance (mīzān) that God has sent down is sound analogy itself. The Most High says:

“God is the One who sent down the Book with truth, and the Balance.” (42:17)

and:

“We sent Our messengers with clear proofs, and We sent down with them the Book and the Balance so that mankind might uphold justice.” (57:25)

The early scholars explained “the Balance” as justice, while others took it to mean the instrument by which things are weighed; the two meanings are inseparable. God has told us that He sent it down along with His messengers, just as He sent down the Book, so that people might establish equity.

Accordingly, whatever enables us to recognize, in qualities and quantities, the likeness of things that resemble one another is part of the Balance, and so too is whatever enables us to perceive the difference of things that differ—such as recognizing that these dirhams, or any other heavy objects