The mirror is a frequently represented, used and cited symbol in the Traditional Roman Sprituality, as well as in all the expressions of the Ancient Traditional Spirituality.
When observing the antique mirrors, one can see that they show often peculiar features making them hardly comparable to modern mirrors.
In the past the mirror was never a "profane" tool: it always involves complex implications.
The act of looking him/herself in a mirror hence is never a "neutral" gesture, but it rather involves complex meanings.
Today we have lost the memory about all this: not only we are unable to understand the deep meaning of "the mirror and looking at the mirror", but we assimilate in a totally profane way, also the antique mirrors into an exclusively modern vision completely deprived of any symbolic meaning.
Being a so extremely complex symbol, I can just mention few approximate considerations here.
The mirror is always linked to Dionysus: it is therefore always involved, even as an allusion, in the mystery cults. The mirror is an esoteric symbol of "knowledge" but, at the same time, it is a symbol of illusion, because what one see in the mirror does not exist in reality, since it is only a reflection. The mirror in fact generates "spectres" (speculum-spectrum)
As already mentioned, the mirror is a symbol of knowledge (reflex-reflection) because looking through the mirror a person knows and re-knows. Knowledge thus means bringing the world "inside the mirror", reducing it to a reflex that can be observed. When one looks into the mirror, he/she looks at himself/herself therefore at the world.
Deception and knowledge are hence closely linked (reflex-reflection) in the symbol of the mirror and in the act of mirroring. Moreover through these reflections we also may however know the divine within the world; through the symbol of the mirror, we may know Gods and Goddesses in their appearance. Knowing, even the Divine dimension, means mirroring, observing, revealing. We look at ourselves, we look at the world, we see the Gods and Goddesses: all this means "knowledge." Looking at the image of our physical and material being in the mirror involves observing a reflected imagine of the Divine. This is the deepest meaning of the concept: "men and women are made in the image and likeness of Gods and Goddesses" (a concept also considered in monotheism, but in completely confused, clumsy, misunderstood and profane terms).
The world we know is therefore a product symbolically reflected by a mirror: it is surely illusion and deception, but it is a form of knowledge, in particular, rational knowledge. What may defined it as "Scientific Knowledge."
In this image generated by the mirror, deception and reality, appearance and divinity, are linked together. Reflection illuminates; in the same time it deceives. Ourselves and the world we observe, and we believe to know, anything is an illusion. Reality is beyond the conventional and profane idea of knowledge whose understanding is linked to the the choice of the "correct Via": on the one hand there is the "Via of the Initiates", on the other hand there is the "Via of the vulgar mankind".