The delusory power inherent in the structure of creation, by which the One appears as many. Maya is the principle of relativity, inversion, contrast, duality, oppositional states; the "Satan" (lit., in Hebrew, "the adversary") of the Old Testament prophets; and the "devil" whom Christ described picturesquely as a "murderer" and a "liar," because "there is no truth in him" (John 8:44).
Paramahansa Yogananda wrote: "The Sanskrit word maya means 'the measurer'; it is the magical power in creation by which limitations and divisions are apparently present in the Immeasurable and Inseparable. Maya is Nature herself—the phenomenal worlds, ever in transitional flux as antithesis to Divine Immutability.
"In God's plan and play (lila), the sole function of Satan or maya is to attempt to divert man from Spirit to matter, from Reality to unreality. 'The devil sinneth from the beginning. For this purpose the Son of God was manifested, that he might destroy the works of the devil' (I John 3:8). That is, the manifestation of Christ Consciousness, within man's own being, effortlessly destroys the illusions or 'works of the devil."
"Maya is the veil of transitoriness in Nature, the ceaseless becoming of creation; the veil that each man must lift in order to see behind it the Creator, the changeless Immutable, eternal Reality."
The consciousness of the unenlightened person is blinded by four successive veils of maya, delusion, which prevent him from perceiving Truth or God:
1. Atomic form the world of gross material manifestation wherein the One Substance appears as innumerable objects;
2. Space whereby the idea of division is produced in the Ever-indivisible;
3. Time whereby the mind conceives of change in the Ever-unchangeable;
4. Vibration the universal creative force that obscures our realization of the Ever-uncreated.
Man is so drunk with delusion, it obliterates his true perception so that the darkness of his ignorance cannot apprehend the light of God vibrating everywhere. Both cosmic delusion (maya) and individual illusion or ignorance (avidya) work together to thus obscure and confound the soul's inherent intuitive sense of God's omnipresence. (SC p.21)
Maya is the mass hypnosis of God by which He makes every human being believe in the same illusory "reality" of creation as perceived by the senses; avidya gives individuality of form, experience, and expression (it supports the ego or I-consciousness). (SC p.19)
Swami Shankara: "You never identify your self with the shadow cast by your body, or with its reflection, or with the body you see in a dream or in your imagination. Therefore you should not identify yourself with this living body, either." (SC p.249)