When critical thinking is mentioned, some people assume that it means doubting everything; this is not right. Critical thinking means distinguishing between claims supported by evidence and those that aren’t, then between valid inferences and false ones.
Critical thinking in this sense has been supported and encouraged by the Sharia (Islamic law) in many verses, such as the saying of Allah Almighty: “Say, produce your proof, if you should be truthful” [02:111], and “O you who believe, if there comes to you a disobedient one with information, verify it” [49:6], among others.
This support and encouragement by the Sharia law for critical thinking signifies its importance. A person who does not verify what he hears or receives, will for sure, be imbued with delusions and falsehoods.
Information that others want us to believe are of three types; they either contradict our ascertained information we reached through sound reasoning, or contradict our suppositive information, or do not contradict any of our information.
In the first case, we reject the information presented to us because they contradict established facts, even without referring to the steps I’ll mention shortly. For the other two cases, however, we have to follow the following steps before rushing to accept or reject information.
The first step is searching for evidence in the claimant’s speech. Is there any evidence that supports his claim?, if not, his claim is then rejected. If a person says to you: “Zaid is a killer,” without presenting evidence, his claim should be rejected, not because you know that Zaid didn’t kill anyone, but because this claim is missing supportive.
The second step is when the claimant presents evidence for his claim. You should then analyze his statements as they contain what he wants you to believe supported with an evidence to justify that belief. For example, someone may say: “life is absurd; because I don’t know its purpose.”
Here we have two claims. The first one is “life is absurd”, which is the conclusion that he wants you to believe. The second claim is “I don’t know its purpose”, which is the evidence for that conclusion. But there is an implied claim which he made to link the evidence with the conclusion. The implication is that ignorance of something means it doesn’t exist.
Once the statements are analyzed, we move to the third step, i.e., to verify the validity of the evidence. Evidence in this context means what the claimant depends on to prove his claim. An example of that is when someone says: “Islam is pagan religion because Muslims worship the Ka’ba”. He wants you to believe the claim that attributes paganism to Islam and presented this false evidence to support it. The evidence is invalid because Muslims do not worship the Ka’ba. Indeed, worshiping the Ka’ba renders a person as non-Muslim. How come then he claims Muslims worship it?!
The fourth step: Once the validity of the evidence validity is verified, move on to examining the relationship between the evidence and the conclusion. In other words, does the validity of evidence necessitate the validity of the conclusion? Sometimes, the evidence is valid by itself but it doesn’t lead necessarily to the claimed conclusion. An example of this is what we mentioned in the second step: the person who claimed the absurdity of life used his ignorance of the purpose of as evidence of its claimed absurdity. But does ignorance of the purpose of life necessitate the non-existence of a purpose for life? Of course not, as absence of evidence doesn’t mean an evidence of absence! Once the correlation between ignorance of something and its non-existence is revoked, his inference is then rejected.