These are different means used in the Qur'an for intellectual thinking and certain proofs, such as:

A - Qur'anic standard

The intellectual criteria and parables set in the Qur'an to reveal the truth, and the ways to know similarity and difference, the Almighty Allah says:

"Shall We then treat the Muslims like the Mujrimoon [criminals, polytheists, disbelievers etc.]? What is the matter with you? How judge you?" [Qur'an, 68:35-36]

B - The standard of the greater reason

This means to confirm a statement or a quality to something on the basis that it is confirmed to its equal, or when there is a greater reason to do that by analogy, as the Qur'an has proved Resurrection in the following verse:

"And he puts forth for Us a parable, and forgets his own creation. He says: "Who will give life to these bones after they are rotten and have become dust?" Say: [O Muhammad] "He will give life to them Who created them for the first time! And He is the All-Knower of every creation!" [Qur'an, 36:78-79]

The Qur'an also used the standard of the greater reason as regards the divine qualities. It confirms for Allah subhanahu wa ta`ala all the perfection that is possible for man and deems Him far above any defect confirmed for man. When the polytheists said that the Almighty Allah has daughters when at the same time they hated having daughters, the Qur'an says:

"Have you then considered Al-Lat and Al-`Uzza [two idols of the pagan Arabs]? And Manat [another idol of the pagan Arabs], the other third? Is it fo you the males and for Him the females?" [Qur'an, 53:19-21]

The Qur'an also uses this method to prove the Oneness of Allah, subhanahu wa ta`ala. Allah says:

"He sets for you a parable from your own selves: Do you have partners among those whom your right hand posses [i.e. your slaves] to share as equals in the wealth We bestowed on you whom you fear as you fear each other....?" [Qur'an, 30:28]

The man among them would not accept to have his slave as equal partner in his wealth, then how can man accept that the created slave be partner to Allah, subhanahu wa ta`ala, in godship and in the right of worship?

C - Exigency

Whoever knows that something is necessary for the realisation of another uses the result to prove the thing that is necessary. This is clear in the following Qur'anic verse:

"Were they created by nothing? Or were they themselves the creators?" [Qur'an 52:35]

No one of a good natural disposition can allege that things can happen without an author or by themselves.