The mind can justify a world of illusion that has its outlet in an escape to unity with an undifferentiated, unmoving Absolute; and it can equally justify a world of reality that is the manifestation of the Being who creates, sustains, informs, contains and constitutes that world. The various concepts each provide a basis for a spiritual seeking and realisation. One of these paths leads away from the world of existence. The other unifies the transcendent, the universal and the individual in the One Reality, the “one without a second” while describing that “all this is the Brahman.”
To the extent that there is an illusionary existence, it is the artificial fragmentation of the world of forms and actions upon which our minds fixate and treat as the sole reality. It is not the reality of the world that is the illusion, but the artificial distinction between the world and the spiritual truth of existence. This distinction comes about through the methodology of the manifestation of consciousness, which evolves through Time. The earlier stages do not grasp the entirety of the sole Reality and thus, are limited within the frame of their capacity. As consciousness continues to evolve, and the prior limits are thereby removed, the evolutionary beings become more capable of the spiritual understanding and the integration that proceeds from it.
Sri Aurobindo notes: “There is possible a realistic as well as an illusionist Adwaita. The philosophy of The Life Divine is such a realistic Adwaita. The world is a manifestation of the Real and therefore is itself real. The reality is the infinite and eternal Divine, infinite and eternal Being, Consciousness-Force and Bliss. This Divine by his power has created the world or rather manifested it in his own infinite Being. But here in the material world or at its basis he has hidden himself in what seem to be his opposites, Non-Being, Inconscience and Insentience. This is what we nowadays call the Inconscient which seems to have created the material universe by its inconscient Energy, but this is only an appearance, for we find in the end that all the dispositions of the world can only have been arranged by the working of a supreme secret Intelligence. The Being which is hidden in what seems to be an inconscient void emerges in the world first in Matter, then in Life, then in Mind and finally as the Spirit. The apparently inconscient Energy which creates is in fact the Consciousness-Force of the Divine and its aspect of consciousness, secret in Matter, begins to emerge in Life, finds something more of itself in Mind and finds its true self in a spiritual consciousness and finally a supramental Consciousness through which we become aware of the Reality, enter into it and unite ourselves with it. This is what we call evolution which is an evolution of Consciousness and an evolution of the Spirit in things and only outwardly an evolution of species. Thus also, the delight of existence emerges from the original insentience, first in the contrary forms of pleasure and pain, and then has to find itself in the bliss of the Spirit or, as it is called in the Upanishads, the bliss of the Brahman. That is the central idea in the explanation of the universe put forward in The Life Divine.
Sri Aurobindo, Integral Yoga: Sri Aurobindo’s Teaching and Method of Practice, The Integral Yoga and Other Systems of Yoga and Philosophy, pp. 26-28