(ḥurr; ḥurra-yi bāsita; kiyān; kiyān-i ḥurra; nayyirān; nūru'l-ḥayāt; nūru'l-ʿaql; nūru'l-yaqīn)
Nūr (light) indicates ishāra (allusion) to manifestation (ẓuhūr). Manifestation, however, is a relative matter. Something is certainly a nūr-zulmat (light-darkness) for one and is manifest to one, while it is hidden from another. Thus, relatively (in relation to that thing), it becomes either manifest (ẓāhir) or hidden (bāṭin). There is no doubt regarding the relativity of that thing to perceptions. For the common people, the strongest and highest of perceptions are the senses. The sense of sight is among these.
Objects, in relation to the sense of sight, are of three kinds: things that are not seen themselves, like dark bodies; things that are seen themselves but by which nothing else is seen—such as stars and the flames of fire when not burning, like luminous bodies; and things like the sun, the moon, burning fire, and a lamp, which are both seen themselves and by which other things are seen. Nūr is the name of this third category.
Sometimes, the term nūr is also used for what is spread from luminous bodies onto the surfaces of opaque bodies. It is said, "The earth was illuminated," meaning the light of the sun was reflected onto the earth. The reflection of the lamp's light on the wall and clothing is also of this kind.
Sometimes, the term nūr is used for the luminous bodies themselves, because they are illuminating by their very essence. In summary, nūr is that which, like the sun, is seen itself and by which other things are also seen. (Mishkāt, 43)
The secret and essence of nūr is its manifestation to perception. Perception depends on the existence of nūr and the seeing eye. For nūr is a manifesting (revealing) ẓāhir. For the blind, nūrs have neither a manifest nor a manifesting quality. The seeing rūḥ (spirit) and manifest nūr are equally necessary elements for perception. Moreover, the seeing rūḥ is preferred because it is the perceiver and perception is realized through it. Nūr itself does not perceive, nor is perception possible through it alone. It is only a means for perception. To call the seeing nūr by the name nūr is more appropriate than to call the seen nūr by this name. (Mishkāt, 44)
Because deficiencies are removed by its means, calling the intellect nūr is more appropriate than calling the external eye by this name. (Mishkāt, 46)
Even if by borrowing from one another, there are celestial nūrs from which terrestrial nūrs are borrowed. It is most appropriate to call the one closest to the first source nūr, for that is the highest rank. (Mishkāt, 55)
The use of the term nūr for anything other than the first nūr is entirely metaphorical. For everything other than the first nūr is only worthy of the name nūr in relation to His Essence. In themselves, they possess no nūr. Rather, their nūriyya (luminosity)...