FWP:
SETS
MIRROR: {8,3}
SUN: {10,5}
ZARRAH: {15,12}
ABOUT THE HEART AS MIRROR: One of the fundamental metaphors in Persian and Urdu ghazal is that the heart is a mirror (another is that it is, or contains, a knot, as in {8,2}). For a specific example, see {12,4x}. Sometimes the heart is a glass mirror (which can then be most effectively 'broken'); these verses tend to be later, because of the slow development of good glass-silvering technology, but by Mir's day the image was certainly available. Much more commonly, however, the heart is a metal mirror. In this case it needs to be polished frequently (especially in monsoony South Asia), in order to scrub off the accumulated 'dust' or (metaphorically) vexation (see for example {27,9x} and {335x,9}) and verdigris [zangaar], and bring out a sufficiently high shine for reflectivity. This process leaves 'polish-lines' [jauhar] that can be considered 'eyelashes', so the mirror can also become an eye. Through enduring the pain of polishing, the heart-mirror, most crucially, becomes able to reflect or mystically 'see' the light of Divine glory. Sometimes it fails: in {349x,2}, the mirror is implicity reproached for being able to show only a mere 'reflection'. There's also the petrified phrase describing disturbance or anxiety, ;Gubaar-e ;xaa:tir , literally 'dust of the mind/heart'; on this see {431x,7}.
Ghalib uses mirror imagery all the time; the mirror is probably his number one favorite image. I have hyperlinked every 'mirror' verse in the divan on this website in {8,3}. (I have linked only explicit uses; there are other implicit ones as well, of the kind noted above by Faruqi (see for example {228,9}); and there are a great many in the unpublished verses as well, most of which I have not linked.) If one goes through the 'mirror' verses, it's striking what an array of extravagant things the verses identify as mirrors, and how few verses specifically invoke (as does the present verse) the heart as a mirror. My theory is that this is because Ghalib always wanted to avoid the beaten track (as Hali reminds us in {230,5}); so when everybody expected the heart to be the mirror, the verse could well be made to ricochet off, with energy redoubled by the hearers' surprise, in some entirely new direction.
This verse feels to me like one of mood. It feels like {105,2}. The mystery, the seductiveness, is especially in the first line. The first line has a flowingness of its own, with a sensuously strong amalgamation of dil-o-dil (increased by the meter, which causes it to be read 'di-lo-dil'). The clear semantic separation into two independent clauses as in (1a), on which the commentators agree, is logically irreproachable of course. Still, it doesn't accord with how the verse either sounds or feels.
The reading I love for the first line is 'from sun to sand-grain, heart upon heart is a mirror' (2b). Heart after heart? Heart and heart? Depths of heart? Something more compelling, anyway, than simply a full stop and a fresh sentence that just happens to begin with the same word that the last one ended with. Also, I like to imagine only one mystically extended heart-mirror, reaching from the sun to the sand-grain, rather than a zillion little tiny ones; and here the grammar is with me (though it's not against the usual interpretation, either).
But perhaps my reading wouldn't even make much difference, since either way the first line is almost uninterpretably abstract, and whatever specificity the verse has is contained in the second line. Here, Faruqi's explanation works excellently, although the verse seems to apply the mirror-training process not only to poets, but to everyone-- or at least, everyone with a 'heart'. I can't add a thing to it, except to emphasize the verse's sensuous texture, which is (to me at least) even more compelling than its striking parrot-speech metaphor.
For other parrot-and-mirror verses, see {29,2}. For other such evocations of the 'six directions', see {41,4}.
Nazm:
That is, in the world face and face, and heart and heart, are mirrors to each other-- that is, one sees his aspect in the other, and the other in the one. The gist is that the whole world is unified in its being, and is one, and they are not alienated from each other. One sees himself in another, as when someone would look in a mirror. When this is the situation, then whichever direction a parrot would look, a mirror is present before him. And the parrot is only a metaphor; the point is that individual who would see the unity, and in a state of mystic absorption would raise the song ana al-;haqq . (138)
== Nazm page 138