Spiritualisation

Spiritualisation means the descent of the higher peace, force, light, knowledge, purity, Ananda, etc., which belong to any of the higher planes from Higher Mind to overmind, for in any of these the Self can be realised. It brings about a subjective transformation; the instrumental Nature is only so far transformed that it becomes an instrument for the Cosmic Divine to get some work done, but the self within remains calm and free and united with the Divine. But this is an incomplete individual transformation—the full transformation of the instrumental Nature can only come when the supramental change takes place. Till then the nature remains full of many imperfections, but the Self in the higher planes does not mind them, as it is itself free and unaffected. The inner being down to the inner physical can also become free and unaffected. The overmind is subject to limitations in the working of the effective Knowledge, limitations in the working of the Power, subject to a partial and limited Truth, etc. It is only in the supermind that the full Truth-Consciousness comes into being.

Ref : Letters on Yoga Vol. I