Ibn al-Haytham, Kamāl al-Dīn al-Fārsī and Wave Motion of Light

Apart expressing the cause of the reflection of light from the surface of polished objects, Ibn al-Haytham in his al-Manāẓir claims that the acceptance or rejection of light by these objects is only due to their polished surfaces and have nothing to do with their solidity, because the reflection of light from the surface of soft polished objects such as water is also possible. Kamāl al-Dīn al-Fārsī in the Tanqīḥ al-Manāzir criticizes this theory. He denies Ibn al-Haytham’s idea about simultaneous reflection and refraction from soft polished objects. In other words Fārsī thinks that Ibn al-Haytham’s explanation for reflection from solid surfaces cannot be used in the case of soft surfaces. He also believes that the propagation of light is similar to the propagation of sound and not to the motion of material objects. In 16th and 17th centuries Europe there is a similar discussion between those who believes in the particle theory and those who believing in the wave theory. This article proposes to study this challenge.