palindrome (as per your wish, I am dropping all the other 'fixes' I have used to address you),
Your question is excellent, as this goes directly to the model constructed by Guru Shankara's thesis.
The axiom of Advaitha, as supported by several Vedas and Upanishads is that there is a Brahman, who is Nirguna, who is the most ancient, who is not sublatable and therefore the ultimate reality. This entity, always exists, is beyond time and space. However, for some odd reason (leela?), this entity spins itself and creates the physical world out of itself and is the cause and foundation of this world, including the appearance of time and space at it's inception.
The above can not be proved or disproved (modern physics tend to agree with this postulate on the creation part with the big bang theory), but can only trace it's validity through the statements in the Srutis. If one does not accept these axioms, then Advaitha philosophy is not for them.
But, if one accepts, then, we will go to the next step.
The other reality is the world in which the sentient beings see the world through their senses and experience distinctive perceptions that validates the 'real' existence of 'I' and 'others'. But from the axiom above, we know that there is only one ultimate reality - Brahman, who created this physical world out of himself and by inference the world is that entity. So, this means that the physical world is sublatable to this entity and therefore is empirical, relative and not absolute.
Because to defend the hypothesis according to the rules of Nyaya, Guru Shankara accepts this reality of the existence of this empirical world as 'real'. But 'real' relative to what? It can only be real to our perceptions, but since everything in the physical world is made of the entity, it can not be absolute real.
So there is 'relative real' with respect to the functioning of the empirical world we experience daily, and there is the 'absolute real' with respect to Brahman. So then what explains these differences in reality - why don't we experience the Brahman?
Here is where Maya/Avidya (interchangeable) comes in. While the 'I' thinks that it is the subject and perceives objects as external, the real 'I', which is the stuff of Brahman is the real subject and there can not be any object as everything else is this stuff and therefore, everything is subject only. Once one 'understands' this (through 'knowledge' - not the academic kind), Maya/Avidya disappears with its two qualities: ability to conceal and ability to project.
I would not bore you with the examples of rope and snake, mirage of water or dream state to explain these two qualities of Maya/Avidya, except to say that none of the three examples often cited, by themselves can explain the concept of Maya/Avidya, but together, they come close.
This is why the Maya/Avidya concept is central to Guru Shankara's thesis, because that explains the relationship between the relative real to the absolute real. I personally don't like the word 'illusion' to describe Maya, because while it's meaning is true in terms of the absolute reality, it is wrongly perceived as Guru Shankara saying that it applies to the relative reality or the empirical world's experiences.
To the epistemological questions of when does Maya rise, where it is located and what are it's origins etc., it is stated that Maya arises simultaneously in the creation process as part of the process, like the empirical world it is rooted in Brahman, but yet is not part of the Brahman in the empirical sense, and as we do not know why the creation takes place, we do not know it's origins.
Because the main two Advaitha schools after the Guru believed in different answers to these questions about Maya, and since Guru Ramanuja raised the well known questions about them, it is perceived that there are 'holes' in the model. IMHO, if you read closely, these differences in opinions can be answered, or outright dismissed. Most of these questions arise, because of the misunderstanding that Guru Shankara states that the physical world and the 'jivas' are illusory, and the misconception about the nature of Maya.
I tried my best to explain this. But, a philosophical construct perspective, Advaitha philosophy is accepted as a valid one, not only from the Vedic perspective, but also from the western canons of the construct of a philosophical system. The main difference is, from the Eastern perspective, it is not just a philosophical theory, but also a guide path for exercising one's spirituality.
In addition to reading Professor John Grime's book that I and Sri Sangom Ji have cited, you may want to read : 'Advaita Vedanta - a philosophical reconstruction' by Professor Eliot Deutsch', published by University of Hawaii Press, Honolulu, Hawaii, to understand this philosophy from the principles of the western philosophical construct discipline.
Regards,
KRS
Thankyou sir. In that case, would the "I" ego be an illusion or maya? The question deeply remains, why would brahman produce an illusion as part of it?
Many traditions and many unknown or not so popular gurus explain(ed) maya and karma. I too am of opinion nothing can be diminished for everything adds to the path of knowledge.