"I Don't Know" Is Half of Knowledge
At a time when some people feel embarrassed to say "I don't know" when asked about certain matters — regarding this as a sign of ignorance or a blow to their standing — Islamic Sharī‘ah actually requires the Muslim to speak only about what he genuinely knows. Allah, the Exalted, says {what means}: "And do not pursue that of which you have no knowledge. Indeed, the hearing, the sight, and the heart — about all those [one] will be questioned" [al-Isrā'/36]. Ibn ‘Abbās (raḍiyallāhu ‘anhumā) said, explaining this verse: "Do not say 'I saw' when you did not see, 'I heard' when you did not hear, or 'I knew' when you did not know." [Tafsīr al-Qurṭubī, Vol.5/P.123]
Saying "I don't know" about matters one genuinely has no knowledge of is, in fact, a sign of self-respect and integrity. It reflects an avoidance of deceiving or misleading others, who might otherwise suffer harm or embarrassment as a result. It also guards against invalid conclusions across the full range of issues connected to matters of creed ('aqīdah), sharī‘ah rulings, and the social, educational, psychological, medical, and professional sciences — all fields in which verification, accuracy, and the avoidance of error are essential.
To establish the soundness and positive nature of saying "I don't know," the Noble Qur'an points out that the prophets, peace be upon them, themselves used to say this very phrase regarding matters on which Allah, the Exalted, had not revealed knowledge to them. This is reflected in Allah's words {which mean}: "But if they turn away, then say, 'I have announced to [all of] you equally. And I know not whether near or far is that which you are promised'" [al-Anbiyā'/109]. As explained in Tafsīr al-Baghawī: "'And I know not' — meaning, I do not know — 'whether near or far is that which you are promised' — referring to the Day of Resurrection." Similarly, Allah says {what means}: "And I know not; perhaps it is a trial for you and enjoyment for a time" [al-Anbiyā'/111] — meaning, "I do not know." And Allah says {what means}: "Say, [O Muḥammad], 'I am not something original among the messengers, nor do I know what will be done with me or with you. I only follow that which is revealed to me, and I am not but a clear warner'" [al-Aḥqāf/9] — meaning, "I do not know."
The Messenger of Allah ﷺ, when asked about certain matters, would himself say: "I do not know, until I ask Jibrīl [Gabriel]." Among such instances: a man once asked the Prophet ﷺ which places on earth are best, and which are worst. He ﷺ said: "I do not know, until I ask Jibrīl, peace be upon him." So he asked Jibrīl, who said: "I do not know, until I ask Mīkā'īl [Michael]." Mīkā'īl then came and said: "The best of places are the mosques, and the worst of places are the marketplaces." [Related by Ibn Ḥibbān, 1599]
Among such instances as well is what he ﷺ said to Umm al-‘Alā' (raḍiyallāhu ‘anhā), when she said: "‘Uthmān ibn Maẓ‘ūn came to us by lot for lodging, when the Anṣār drew lots for the lodging of the Muhājirūn (Emigrants). He then fell ill, and we nursed him until he passed away. We then wrapped him in his garments, and the Messenger of Allah ﷺ came to visit us. I said: 'May Allah's mercy be upon you, Abū as-Sā'ib — I bear witness that Allah has surely honored you.' The Prophet ﷺ said: 'And how do you know that?' I said: 'I do not know, by Allah.' He ﷺ said: 'As for him, certainty [i.e., death] has come to him. I do indeed hope good for him from Allah — yet by Allah, even though I am the Messenger of Allah, I do not know what will be done with me, nor with you.'" Umm al-‘Alā' said: "By Allah, after that, I never again declared anyone [definitively] pure [of sin]." [Ṣaḥīḥ al-Bukhārī, 7018]
‘Alī ibn Abī Ṭālib (raḍiyallāhu ‘anh) said: "Part of a man's knowledge is that he says, regarding what he does not know, 'Allah knows best' — for Allah, the Mighty and Majestic, said to His Messenger ﷺ: 'Say, I do not ask you for it any payment, and I am not of the pretentious'" [referring to Sūrat Ṣād/86]. He also said: "Among the most soothing things for the heart is that a man, when asked about something he does not know, says: 'Allah knows best.'"
Ibn ‘Abbās (raḍiyallāhu ‘anhumā) said: "When the scholar abandons saying 'I don't know,' his most vital point [i.e., his intellectual integrity] has been struck." On the authority of Ibn ‘Umar (raḍiyallāhu ‘anhumā), he said: "Knowledge is of three kinds: a speaking Book [the Qur'an], an established Sunnah, and 'I don't know.'" Mālik [ibn Anas] said: "It used to be said: when the scholar neglects to say 'I don't know,' his most vital point has been struck."
The Messenger of Allah ﷺ — the leader of the Muslims and master of all the worlds — would sometimes be asked about a matter and would not answer until revelation came to him from the heavens. Ash-Sha‘bī said: "'I don't know' is half of knowledge." [al-Ādāb ash-Shar‘iyyah wal-Minaḥ al-Mar‘iyyah, by Ibn Muflih, Vol.2/P.58]
Neglecting to say "I don't know" when one genuinely lacks knowledge negatively affects a person's life and conduct across various domains — whether religious, humanitarian, medical, or professional — leading people into sin, embarrassment, and harm. It also exposes anyone who speaks on such matters [without knowledge] to sharī‘ah accountability, legal liability, and financial responsibility for any damage resulting from their hesitant, unfounded speech. This is based on the words of the Messenger of Allah ﷺ: "Whoever issues a fatwā without sound basis, its sin falls upon the one who issued it." [Related by Abū Dāwūd (3657), Aḥmad (8266), and Ibn Mājah (53)]
Likewise, the Messenger of Allah ﷺ said: "Whoever practices medicine without being known to possess medical knowledge is liable [for any resulting harm]." [Related by Abū Dāwūd (4586), an-Nasā'ī (4830), and Ibn Mājah (3466)]
The scholar Ibn Farḥūn al-Mālikī (raḥimahullāh) said: "As for when the physician is ignorant, or acts beyond what he was authorized to do due to error, or exceeds the permitted limits of his authorization, or falls short of the required standard — he is liable for whatever damage results from that." [Tabṣirat al-Ḥukkām, Vol.2/P.340]
Imam al-Khaṭṭābī (raḥimahullāh) said: "I know of no disagreement [among scholars] that if a treating physician oversteps [his bounds] and the patient is harmed as a result, he is held liable." [Ma‘ālim as-Sunan, Vol.4/P.39]
From all of the above, it becomes clear that a person's saying "I don't know," regarding matters he genuinely has no knowledge of, does not diminish his scholarly standing — rather, it strengthens his credibility and drives him to seek further knowledge, in keeping with what Allah, the Exalted, instructed His noble Messenger ﷺ to say: "And say, 'My Lord, increase me in knowledge'" [Ṭāhā/114]. This is because knowledge varies from one person to another, as Allah, the Exalted, says {what means}: "And above every possessor of knowledge is one [more] knowing" [Yūsuf, /76]. Qatādah said, in explaining this verse: "[This continues] until knowledge ultimately reaches Allah — from Him it began, and from Him the scholars learned, and to Him it shall return." [Tafsīr al-Qurṭubī, Vol.4/P.213]
A Muslim, then, should never hesitate to say "I don't know" when he genuinely lacks knowledge, understanding, or familiarity with a matter he is asked about.
