“Till Nature is ready, the supramental Force has to act indirectly; it puts the intermediary powers of Overmind or Intuition in front, or it works through a modification of itself to which the already half-transformed being can be wholly or partially responsive.” The Supramental Force, according to Sri Aurobindo, cannot begin to directly transform the nature until a lot of preparation has been done to permit of its action in a more or less pure and forceful way. Sri Aurobindo describes the process required to prepare the nature for this action:
The first step, which he has termed the psychic change, is essentially moving the consciousness inward, breaking down the normal barrier or walls between the surface consciousness and the inner consciousness. The second step is the spiritual change, a moving of the consciousness upward into higher reaches where there is a universalisation of the consciousness, so that the individual has “recast his individual mind in the boundlessness of a cosmic mentality, enlarged and vivified his individual life into the immediate sense and direct experience of the dynamic motion of the universal life, opened up the communicatino of his body with the forces of universal Nature, before he can be capable of a change which transcends the present cosmic formulation and lifts him beyond the lower hemisphere of universality into a consciousness belonging to its spiritual upper hemisphere.” He must also become aware of the higher ranges of consciousness and begun to experience their descent, their presence reshaping his mental outlook, vital reactions and physical responsiveness.
These preliminary steps can occur more or less “side by side”, and develop into their fullness. Eventually however, for the supramental change to occur, “it can only commence when the supramental Force begins to act directly, and this it does not do if the nature is not ready. For there is too great a disparity between the power of the supreme Force and the capacity of the ordinary nature; the inferior nature would either be unable to bear or, bearing, unable to respond and receive or, receiving, unable to assimilate.”
Sri Aurobindo, The Life Divine, Book 2, Part 2, Chapter 26, “The Ascent Towards Supermind”