Metaphor of light

How pervasive is the metaphor of light for the activity of cognition? In Śaiva texts, not only is the metaphore absolutely common, but the authors even elaborate on it, using several different synonyms, at first sight with no different denotations.

The following is a stanza of Utpaladeva's Stanzas on the Recognition of the Lord (Īśvarapratyabhijñākārikā).

Nor is the appearance of a remembered thing possible, if there is a separation [of the past experience] from memory, |
Therefore this knower is the unity of cognitions pertaining to different times || 1.4.3 ||

(na ca yuktaṃ smṛter bhede smaryamāṇasya bhāsanam | tenaikyaṃ bhinnakālānāṃ saṃvidāṃ veditaiṣa saḥ ||)

Next comes his Vṛtti (short commentary) thereon:

And the object which has been experienced before [and] which appears now together with that experience in the light of the memory regarding that time, must be unseparated from memory, because something separated from the light cannot shine. In this way, the unity of the cognitions such as experience and memory is the Self, the knower.

(pūrvānubhūtaś cārtho 'nubhavena saha tatkālikasmṛtiprakāśe 'vabhāsamānaḥ smṛtyabhinna eva prakāśād bhinnasya prakāśamānatānupapatteḥ. evam anubhavasmṛtyādisaṃvidām aikyaṃ sa eva cātmā vedakas.)
(Text edited by R. Torella, 2007; my translations)

The general idea is that something insentient cannot acquire the quality of being intelligible, because the process of cognition is not seen as involving an active side (the knower) and a purely passive side (the object known), but as an 'event', during which the object known becomes 'luminous'. Something intrinsically non-luminous would never be able to become luminous. Hence, even in matter there must be some latent trace of light. Hence, all is pervaded by the Self's light. This makes the Recognition with the Lord possible.

Do readers see any different connotations among these words?

On the topic of the argument from memory in Śaiva texts, see here.