There are many arguments within the non-dual traditions that either explain the existence of the conditional worlds, or which deny their reality. In David Godman's wonderful three volume biography of Poonja Swami (Papaji), Nothing Ever Happened, he goes into some detail about Papaji's own fascination with the question of why the conditional worlds continue to appear to arise even in full enlightenment. The general answer within the Vedantic tradition is that the conditional worlds do not arise at all, that the illusion that they arise is all that appears, but that no conditional worlds actually arise, and thus there are no conditional egos to whom these worlds arise. Papaji agreed with this view, and even said that the best verbal summary of enlightenment he could speak in words was "nothing ever happened". Likewise, Ramana Maharshi frequented said that his own experience was that no world ever arose or had been created, and no egos ever existed. He explained that he only made statements about the conditional worlds for the sake of devotees for who such views would be incomprehensible and useless, so instead he would refer to the existence of the world as a "creation of the mind" or something similar.
Poonja Swami continued to wonder why even the appearance of illusion continued in the midst of unconditional realization. He stated clearly that he knew that nothing was actually happening, that the illusion of the world was simply that - an illusion - but he could not answer the question of why that illusion itself should appear. The traditional viewpoint is that the conditional worlds are like a rope lying on a dark road, that a passerby mistakes for a snake. He becomes afraid, and runs to the village for help. The villagers return with torches and spears to kill the snake, but as they get close enough to see better they see that it wasn't a snake at all, but a rope. This analogy explains how it is that in enlightenment the realizer understands that the conditional worlds never appeared at all. Just as the snake never existed, but was only a rope, the conditional worlds have never existed either, but are in reality only the unconditional Reality. Enlightenment, then, is a form of recognition, in which we see that what we have interpreted as a conditional universe of danger and threat and incompleteness, is actually nothing like that at all, but is perfectly unconditional and infinite in all its qualities. This was Poonja Swami's experience, and yet the world-appearance itself continued on, and this seemed a bit baffling, even if he could recognize it as the unconditional Brahman.
Absurd as it might seem that I might offer even the slightest bit of understanding to the teachings of these fellows, I have to report an unusual vision I had years ago, in which some aspects of this issue were addressed in a strange fashion that seems worth mentioning at the very least. In my bloggings from a few years ago, I reported two early cosmic visions, and promised to describe this one as well, completing and odd triumvirate of views about the cosmos and the conditional worlds. In those visions, however, I was led through a series of "disillusionments", in which I progressively moved through various forms of conditional reality to a point where the mind utterly dissolved, and I entered into a kind of formless mindless ecstasy in which no experience was possible, and no memories remained past that point. In some sense the visions "ended" at that point, in the sense that I couldn't remember anything which occurred past those penultimate moments, which was a bit frustrating, but also seemed quite natural, in that the mind simply cannot comprehend the unconditional, and the very structure of our experience cannot hold a vision of it in place.
Or at least that's what I assumed. This third cosmic vision, however, began from an entirely different point of view that's nearly impossible to explain. Rather than ramping up through the conditional worlds and finally going beyond them into a mindless condition beyond all experience, this vision began in the unconditional reality - at least that was the seemingly obvious initial state. It's hard to describe in any rational way without "translating" this vision into ordinary subject-object terms and the structure of three dimensional space and time. Suffice it to say that somehow, "vision" remained not only possible, but unconditional, such that "I" could "see" the Divine Person in all His Glory. It's virtually impossible to communicate this vision in its own terms, since our words are inadequate, but the image that comes to mind now is one of an infinitely gigantic "Amoeba", a formless living Being, utterly whole and complete, and yet having an unconditional "form" of a kind, if one can imagine a form whose dimensions are not only infinite, but in which the number of dimensions is infinite as well. This living Being was also single, without any attributes or forms that could be defined, and yet that never even seemed a contradiction, in that there was not a hint of even the possibility of conditional forms, limits, dimensions, or characteristics.
Even so, this Infinite Divine Amoeba was full of light, with an utterly beautific display of brilliant Self-illumined patterns on its "skin". It was obvious that this light was simply the very nature of the Divine Person, it was non-separate, and simply an irreducible aspect of the infinite consciousness of this formless Divine Being. These patterns of light were like an oil slick on the ocean of the Divine Being, an infinitely thin layer of lights upon an infinitely deep ocean of consciousness. Keep in mind that this analogy is in some sense literally how I saw it, but also not limited by the description to any conditional reference frame. The infinitely thin conditional lights were simply inseparable from the infinite depth of consciousness upon which they rested, and there was a perfect harmony between them, and no sense of contradiction whatsoever. The effect was one of utter Beauty, beyond any comprehension, except that in the context of the vision, it was all utterly comprehensible as itself, since I was not using any conditional mind to either see it or interpret it. What I was, is hard to describe, except that I was not a conditional being, and I was not at all separate from what I was "seeing".
Even so, the vision progressed as a kind of inspection of this infinitely thin "oil slick" of lights, ever-shifting and never the same, but always perfect and beautiful and an expression of perfect harmony. And yet, it was also clear that the entire infinite universe of lights was always sacrificed to its own Self-Nature, the Infinite Consciousness in which it arose, perpetually and constantly, such that these patterns could be said to be utterly empty of any independent existence, in that sense that such a possibility never even arose, because it was simply not in their nature. I could see that every single pattern within these realms of light was infinitely conscious, and also infinitely founded in the same consciousness of the whole Being.
And yet, it was also clearly possible for these conscious beings to assume a perspective from within the infinitely thin oil slick and its realm of lights. When this perspective was assumed, the infinite consciousness the oil slick was founded on could no longer be seen. It was as if the Divine Person "withdrew" from the oil slick, and yet this was not actually the case. Instead, the Divine Person remained only as a universal "Goddess Force" within the now seemingly conditional and limited worlds, the primordial energy of the worlds, but not contained within any of the forms themselves. Consciousness, rather than being the infinite foundation for all forms, became modified by its own identification with these forms, to the point where a fundamental fear arose.
This fundamental fear was based upon the sacrificial nature of all the forms that arise within the Divine Person. As mentioned before, all these patterns were eternally sacrificed. What this meant, within the context of the conditional vision, was that all these patterns of light were flashing in and out of existence trillions upon trillions of times every second. Every single pattern, every form of light, was utterly sacrificed, and died, trillions upon trillions of times, going out of existence, and then flashing back into form. Each time these patterns flashed back into form, they were altered, never appearing exactly the same. They could have changed utterly, and randomly, since all patterns had literally died, and there was no sense of attachment to them. But another aspect of the Divine, what one could call "The Preserver", kept a harmonious continuity between flashes, such that all changes flowed from one to the next without many great disruptions.
And yet, from the perspective of the conditional worlds, this Divine Continuity could not be observed. Instead, the conscious beings who lived in these worlds were aware only of that their own forms were subject to constant death and sacrifice. They could feel this process of death and resurrection going on, but they could not see beyond it. So they could only feel fear and anxiety in relation to their own forms' perpetual death. Their response to this death process was to "hold onto" their forms, which were constantly disappearing trillions of times every second and a new version reappearing just as fast. They would literal grab onto these forms, and prevent them from disappearing or dying. Somehow, they could actually do this, because they had an innate power within them derived from their own Divine Consciousness.
Even thought they were able to prevent their forms from disappearing, they could not prevent the next form from appearing. And so the next form would materialize in the same place as the old one, and then the next would appear on top of that, and then the next, ad infinitum, with each form piling on top of the last, "thickening" these forms of light, until they began to achieve a certain kind of fixed solidity. This is how the entire conditional universe began to collapse out of the infinite conscious light of the Divine Person. Each pattern of light became solidified by fear, and each form began to see itself more and more as an independent pattern reified in its appearance as an actual "thing". But each thing became motivated at every level to survive the inherent threat to its existence that was replayed in every moment. From there, every feature of the conditional worlds naturally appeared, and every pursuit became a quest for survival and permanence in the face of an inherently impermanent structure of existence. The only way beyond this was the Guru, the Goddess Power, which pervaded the entire conditional universe as a transcendental Presence, but which could not be seen or understood by conditional methods, nor could it be "made solid"
At that point, the vision came to an end, or really, I moved out of the unconditional perspective, and moved down through the conditional worlds, one step at a time, seeing my own perspective change at each level, until I was merely another being concerned about my own survival, and my vision was reduced into a "memory", that no longer contained the full force of its infinite nature. Like anything else, it became a form in the mind, and not only was any description of it inadequate, but even the images that remained in my mind were merely a pale shadow of the original experience. It could not be any other way, of course, so long as I held onto my own form.
And that is the most pressing lesson of that vision: that we have to let go of this grip we have on our own forms, and stop trying to keep ourselves from dying. We have to trust the process of the Divine Person's own Light, to harmoniously manifest whatever pattern it wishes, confident that we are not threatened, because we are not any of these patterns, but are the Divine Ocean of consciousness upon which they arise.
Another lesson, however, is an answer to the question of where does the appearance itself come from: it arises because Radiance and Light are the eternal and infinite nature of the Divine Being, and there is nothing inherently illusory about their patterns in any way whatsoever. Their impermance is not a limitation, in reality, but a reflection of their eternal nature as sacrifice. The Light itself is not an illusion, only the perspective from which they are viewed.
In this sense, the classic rope/snake analogy falls a bit short. The problem is not merely "ignorance", to be solved by bringing light to the situation. The real problem is the lack of proper perspective. If one views the conditional worlds from any perspective within the conditional worlds, one will fall prey to these illusions. One must "step out" of the conditional worlds instead, and see them from the perspective of the Divine Being. Then, they are no illusions about their nature or origin, because one has been restored to the right perspective. Otherwise, there is no possibility of "seeing the light", because one is wrongly positioned. This is why all conditional views fail to enlighten us, and leave us bewildered. We try to figure out or in some way see or experience the Divine Being from a perspective within the conditional worlds, and this simply isn't possible. This is why the Guru is necessary, because the Guru Power comes from beyond this world, from the unconditional perspective, and that Power lifts us beyond the vision of conditionality that we are fixated in. Of course, what is necessary to see things from the Guru's perspective is a total letting go of our own forms, of every kind of impulse to survive and hold onto our forms, and instead to let ourselves be sacrificed by the Divine Principle, and reformed and resurrected according to the Divine's own harmonious power. This requires a supreme trust, both in the Guru and the Divine Nature of our own being.
It also requires an fundamental understanding that the Guru is not identical to any form or appearance, even when it appears that way to us. And any human Guru who tells us that his own appearance is the Divine Person, we should recognize as a false teacher who is holding onto their own form in some way or other, and using us to reinforce those illusions. From the perspective of the Divine Person, the Guru has no form, and from the perspective of the conditional worlds, the forms the Guru takes all die and none of them contains her power, which always lies beyond the perspective of this universe. The Guru cannot be held onto, therefore, and their form cannot become a final object of devotion, only a means by which to go beyond form itself, including the forms the Guru might take from time to time.
The process of genuine enlightenment, therefore, is one of letting go not merely of our forms, or the forms of the Guru, but of letting go of all conditional perspectives. Forms themselves are nothing but the reflection of a particular perspective we have held onto, a false perspective. If that perspective is released, so to is the illusion of conditional existence and all the threats to our survival that go along with it. We cannot let go of those forms so long as we see them from the perspective of the conditional self. This is why self-enquiry is so crucial. It is only by releasing ourselves from the illusory perspective of the conditional self that we can grasp who we really are and where we really are, which is an unconditional being who lives beyond the conditional world, gross and subtle. The vision of the Divine Person can be restored to us by the Guru, if we will recognize the Guru as beyond all form and appearance. This requires a supreme gesture of letting go of both our own forms and the form of the Guru. That is the opening which allows us to stand outside all the worlds, and see them arising as the singular light of an infinite God.