Ibn al-Haytham (Alhacen) wrote the following comments on truth:
The seeker after the truth is not one who studies the writings of the ancients and, following his natural disposition, puts his trust in them, but rather the one who suspects his faith in them and questions what he gathers from them, the one who submits to argument and demonstration, and not to the sayings of a human being whose nature is fraught with all kinds of imperfection and deficiency. Thus the duty of the man who investigates the writings of scientists, if learning the truth is his goal, is to make himself an enemy of all that he reads, and, applying his mind to the core and margins of its content, attack it from every side. He should also suspect himself as he performs his critical examination of it, so that he may avoid falling into either prejudice or leniency.
"I constantly sought knowledge and truth, and it became my belief that for gaining access to the effulgence and closeness to God, there is no better way than that of searching for truth and knowledge."
The Malamatis are a Sufi group that was active in 8th-century. Believing in the value of self-blame, that piety should be a private matter, and that being held in good esteem would lead to worldly attachment, they concealed their knowledge and made sure their faults would be known, reminding them of their imperfection.They deliberately tried to draw the contempt of the world upon themselves by committing unseemly, even unlawful, actions, but they preserved perfect purity of thought and loved God "without second thought". A story illustrative of such actions: "One of them was hailed by a large crowd when he entered a town; they tried to accompany the great saint; but on the road he publicly started urinating in an unlawful way so that all of them left him and no longer believed in his high spiritual rank".
Some of the tales concerning Nasreddin bear some similarity to the practices of the Malāmatiyya, insofar as Nasreddin's wisdom is rather well hidden behind a foolish façade.