Sri Aurobindo
Letters of Sri Aurobindo
5. Planes and Parts of the Being
It [the true vital] is capable of receiving the movements of the higher consciousness, and afterwards it can be capable of receiving 
the still greater supramental power and Ananda. If it is not, then the descent of the higher consciousness would be impossible and supramentalisation would be impossible. It is not meant that it possesses these things itself in its own right and that as soon as one is aware of the true vital, one gets all these things as inherent in the true vital.