The technique of the separation of Purusha and Prakriti is the key to the achievement of the detachment of the mind from the body. The first step is to look upon the activities of the body and the body itself as an expression of Prakriti through the operation of the three Gunas or qualities of Nature. The seeker takes the poise of being the silent witness consciousness, observing but not participating in the action of the body. Sri Aurobindo observes: “We shall find, if we try, that the mind has this power of detachment and can stand back from the body not only in idea, but in act and as it were physically or rather vitally. This detachment of the mind must be strengthened by a certain attitude of indifference to the things of the body; we must not care essentially about its sleep or its waking, its movement or its rest, its pain or its pleasure, its health or ill-health, its vigour or its fatigue, its comfort or its discomfort, or what it eats or drinks.”
Due to the propensities of the mental consciousness to treat everything as separated into opposites, we find that many will use this conceptual tool with an extreme bias and either treat this as a requirement for strict asceticism or even as a basis for torturing the body. Sri Aurobindo reminds us that this is not the intention: “This does not mean that we shall not keep the body in right order so far as we can; we have not to fall into violent asceticisms or a positive neglect of the physical frame.” The object here is simply to not have the witness get itself involved in whatever happens to the body and attach itself to the status or the response, so that the Purusha can gain the leverage of detachment as the basis for achievement of the higher status of consciousness that is the object.
All of the habitual beliefs the seeker holds in his mind regarding the relationship of the body and the mind are to be put aside, as once the Purusha gains its freedom, it has the possibility of modifying the nature and basis of the relationship between mind and body.
Sri Aurobindo, The Synthesis of Yoga, Part Two: The Yoga of Integral Knowledge, Chapter 7, The Release From Subjection to the Body, pp. 328-329