The mental consciousness starts from a standpoint of ignorance, what one may call darkness, and attempts to cast about, gather impressions, organize them and shed some light on them. Because it starts from a position of darkness, its action is always something like attempting to explore a darkened room with a candle or flashlight. The individual sees partial and shadowed forms and attempts to draw conclusions about the facts and the truth of what is being observed.
The supramental consciousness starts from a standpoint of knowledge, what one may call light, and is able to see and understand both the individual details being observed and their relation to one another and the whole of which they make up the components or parts.
The intuitive mind, standing between the two, has its advantage based on its ability to receive and reflect the light of the supramental consciousness, thus, getting flashes of light, while it still has its roots in the mind and thus, is still subject to the darkness and the fragmentation that is the basic characteristic of the mental consciousness.
Sri Aurobindo observes: “The intuitive mind appears at first a lightening up of the mind’s half-lights, its probabilities and possibilities, its aspects, its uncertain certitudes, its representations, and a revealing of the truth concealed or half concealed and half manifested by these things, and in its higher action it is a first bringing of the supramental truth by a nearer directness of seeing, a luminous indication or memory of the spirit’s knowledge, an intuition or looking in through the gates of the being’s secret universal self-vision and knowledge. It is a first imperfect organisation of that greater light and power, imperfect because done in the mind, not based on its own native substance of consciousness, a constant communication, but not a quite immediate and constant presence. The perfect perfection lies beyond on the supramental levels and must be based on a more decisive and complete transformation of the mentality and of our whole nature.”
Sri Aurobindo, The Synthesis of Yoga, Part Four: The Yoga of Self-Perfection, Chapter 20, The Intuitive Mind, pp. 779-780