Sri Aurobindo
Letters of Sri Aurobindo
Volume I - Part 3
He is using the word supermind too easily. What he describes as supermind is a higher illumined consciousness; a modified supramental light may touch it, but not the full power of the supermind; and, in any case, it is not the supermind. He speaks of a supramental part which is unreceptive,– that is impossible, the supramental cannot be unreceptive. The supermind is the 
Truth-consciousness itself; it already possesses the Truth and does not even need to receive it. The word vijñāna is sometimes used for the higher illumined Intelligence in communication with the Truth, and this must be the part in himself which he felt – but this is not the supermind. One can enter into supermind only at the very end of the sadhana, when all difficulties have disappeared and there is no obstacle any longer in the way of the realisation.