Alhazen

"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 suspends 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."

"Whosoever seeks the truth will not proceed by studying the writings of his predecessors and by simply accepting his own good opinion of them. Whosoever studies works of science must, if he wants to find the truth, transform himself into a critic of everything he reads. He must examine tests and explanations with the greatest precision and question them from all angles and aspects."

"He was one of the most distinguished and prolific mathematicians in the medieval tradition of Arabic Islamic science. He became known in Europe in the thirteenth century as the author of the book on optics—the mathematical theory of vision. In his Kitâb al-Manâ zir (De aspectibus), if the eleventh-century he offered a new solution to the problem of vision, combining experimental investigations of the behavior of light with inventive geometrical proofs and constant forays into the psychology of visual perception — all systematically tied together to form a coherent alternative to the Euclidean and Ptolemaic theories of "visual rays" issuing from the eye."

"He lived in a period of competitive patronage of the sciences, especially mathematics and astronomy, in the Middle East and Central Asia. He is said to have been a high administrative official in a small principality made up of Basra, in what is now Iraq, and the adjacent region of Ahwâz."

"He moved to Egypt and supported himself by teaching and by copying Arabic translations of Greek mathematical classics such as Euclid’s Elements and Ptolemy’s Almagest."