The Hindus have analyzed the process of mental approach to Reality, and the part the mind should play, more clearly, perhaps, than any other group of thinkers. Shankaracharya tells us that:

"The Yogi, whose intellect is perfect, contemplates all things as dwelling within himself (in his own 'Self,' without [189] out any distinction of outer and inner), and thus, by the eye of Knowledge (Jnana-chaksus, an expression which might be rendered fairly accurately as 'intellectual intuition'), he perceives (or rather conceives, not rationally or discursively, but by a direct awareness and an immediate 'assent') that everything is Atma."
- Quoted by Guénon, René, in Man and His Becoming, page 254

The Yogi, or the one who has achieved union (for Yoga is the science of union) knows himself as he is in reality. He finds, when ignorance gives place to transcendental awareness, that he is identified with Brahma, the Eternal Cause, the One and the Alone. He knows himself to be, past all controversy, God - God immanent and God transcendent. The seer goes on to tell us that

"He is 'the Supreme Brahma, which is eternal, pure, free, alone (in Its absolute perfection), incessantly filled with Beatitude, without duality, (unconditioned) Principle of all existence, knowing (without this Knowledge implying any distinction of subject and object, which would be contrary to 'non-duality'), and without end' ".

"He is Brahma, by which all things are illumined (partaking of Its essence according to their degrees of reality), the Light of which causes the sun to shine and all luminous bodies, but which is not made manifest by their light."

"The 'Self' being enlightened by meditation...,then burning with the fire of Knowledge (realizing its essential identity with the Supreme Light), is delivered from all accidents, ...and shines in its own splendor like gold which is purified in fire."

"When the Sun of spiritual Knowledge arises in the heart's heaven (that is to say at the center of the being...), it dispels the darkness (of ignorance veiling the [190] single absolute Reality), it pervades all, envelops all, and illumines all."
- Guénon, René, Man and His Becoming, pages 956, 258, 259, 260.

Father Maréchal tells us that the

"...psychological experience lived by the contemplative passes through the two phases of mental concentration and unconsciousness described by M. Oltramare, according to the Sarva-darsana-sangraha: 'It is in two successive phases that the Yogi saps by anticipation the basis of further existences and effaces the impressions that determine the present existence. In the first it is conscious...; thought, then, is exclusively attentive to its proper object, and all the modifications of the thinking principle are suspended in the degree that they depend on exterior things; the fruits it gains under this form are either visible - the cessation of suffering - or invisible - immediate perception of Being which is the object of the meditation...The second period of Yoga is that in which it is unconscious...the thinking organ is resolved into its cause...the feeling of personality is lost; the subject who is meditating, the object on which his thought dwells, the act of meditation itself, make but one thing..."
- Maréchal, Joseph, S. J., Studies in the Psychology of the Mystics, pages 312-313.

Patanjali, the greatest teacher of the science of Yoga in the world, has summed up the final stages in his fourth Book in the following words: