Reasoning with Signs in the Qur’an

The Almighty’s use of signs as proofs is frequent in the Qur’an. The difference between a sign (āyah) and formal analogy (qiyās) is that a sign is a distinctive mark—a proof that entails the very reality to which it points. Its referent is not some general, shared universal; rather, the mere knowledge of the sign itself produces knowledge of the specific object signified. The sun, for example, is a sign of daytime. The Most High says:

“We have made the night and the day two signs; then We effaced the sign of the night and made the sign of the day radiant.” (Q 17:12)

Thus, the moment one knows that the sun has risen, one necessarily knows that day exists. The same holds for the signs of Muḥammad’s prophethood—may God bless him and grant him peace: simply knowing those signs yields certainty about his very prophethood; they do not establish a universal concept shared with anyone else. Likewise, the signs that point to the Lord—exalted is He—give direct knowledge of His sanctified Self; they are not pointers to some generic, shared idea.

Knowing that one thing entails another is what makes it a proof. Every proof must, of necessity, entail its object. Moreover, recognizing that a particular thing entails the particular conclusion sought is closer to the innate human disposition than grasping that every particular falling under a universal premise entails the conclusion. Such is the nature of universal propositions: unless their particulars are known independently of exemplification, they can be known only through exemplification. Hence one must perceive the necessary link between the proof and what it proves—the middle term.

Accordingly, one must be aware that every individual instance encompassed by the desired universal judgment follows from every individual instance of the proof. Consider the classic syllogism: “Every A is B, and every B is C; therefore every C is A.” One must understand that each particular C entails each particular B, and that each particular B entails each particular A. It is evident that perceiving the entailment of this specific C for this specific B, and of this specific B for this specific A, is more immediately grasped by innate human nature than the abstract universal formulation.

This is precisely what we noted earlier in the examples of their so-called demonstrative syllogisms, such as their statement, “The whole is greater than the part.”