Allah Most High says:

“We have certainly created for Hell many of the jinn and mankind. They have hearts with which they do not understand, eyes with which they do not see, and ears with which they do not hear. They are like livestock; rather, they are further astray. It is they who are heedless.”

Allah Most High also says:

“Or do you think that most of them hear or understand? They are only like livestock; rather, they are further astray from the way.”

Allah Most High also says:

“He sends thunderbolts, striking with them whomever He wills, while they dispute about Allah; and He is mighty in power.”

Allah Most High also says:

“Or He destroys them for what they have earned, yet pardons much. * And those who dispute concerning Our signs will know that they have no escape.”

There are many similar passages.

Just as thinkers have differed over knowledge—whether it is immediate, acquired through reasoning, or attainable in either way—holding three positions, so too have they held three positions concerning the obligation to undertake reasoning that leads to knowledge of Allah Most High.

One group says that it is obligatory for everyone. Another says that it is obligatory for no one. The majority say that it is obligatory for some people but not others.

Thus, whoever attains knowledge—or faith, according to those who say that faith can be attained without knowledge—without reasoning is not obliged to undertake it. Whoever cannot attain either knowledge or faith except through reasoning is obliged to undertake it.